Brynderwyn Hills recovery and enabling works

22 April 2024

Progress at zone E, Monday 22 April

We are now on the home straight with less than a month to go before the road reopens, but there is still plenty of work to be done to ensure a safe and successful reopening.

In light of last week’s heavy rain watch for Northland, we wanted to share how our project responds to such events. Close contact is maintained with local authorities and we receive regular updates from the MetService to stay informed about weather conditions.

Our team checks the readiness of the onsite environmental controls, such as silt control fences and silt ponds. Additionally, machinery and equipment are moved away from potential slip areas and secured to prevent any damage. Depending on the severity of the event, the project emergency response plan will be activated. If conditions deem it unsafe to continue, work will stop until weather improves. The safety of our teams is paramount in these situations.

In the newsletter this week we also talk about the monitoring sensors that are in place to check the stability of the slopes and water content in the soil.

As we approach the reopening date, we are committed to keeping you updated on our progress and what to expect when the road reopens.

Check out this timelapse footage showing the work that’s been done on 2 of our biggest cuts at zone E and zones I and J.

• Timelapse footage of zone E.
• Timelapse footage of zones I and J.

Steel piles being installed at zone F (top photo) and the flatbed truck reversing up the hill, to deliver materials to site (bottom photo)

Stabilising the downslopes using retaining walls

Last week we talked about our focus on stabilising the downslopes, or the undersides of the hill. Here’s how we are progressing so far:

• All retaining walls are on track with 2 critical walls already complete.
• We’ve put in over 50 rock anchors to support the downslopes.
• Our skilled operators manoeuvred a 12m flatbed truck to deliver the necessary materials. Due to the narrow, windy road they needed to reverse 1.5kms up to the site. The delivery had to be carefully timed, using a small window of clear road to not interfere with Moxy runs to the fill site.
• At the completion of the project, there will be a total of 220m of retaining walls.

Specialist equipment for weather monitoring

With the extent of the works on the Brynderwyn Hills and the steep topography, it is vital we understand any conditions that could affect the site. 

To achieve this, we have a complex network of onsite sensors working non-stop to monitor ground movements, how wet the soil is and how much rain has fallen. 

Every day, these sensors send data to a central dashboard where it is reviewed as it comes in; providing essential information for geotechnical engineers to assist in decision making and planning.  

Some sensors are used to inform a special plan known as a Trigger Action Response Plan or TARP for short, which helps figure out how at risk the slopes are.   

If it rains a lot over four hours, or if it it’s been raining consistently, the TARP level goes up automatically and people on the ground are notified of the increase.

Moxys (articulated dump truck) on the site

Beside the excavators, our other key earthwork machines are our Moxys. They are a type of articulated dump truck (ADT) that we use to cart dirt to the fill sites within the closure. On the Brynderwyn Hills project we use either 30 or 40-tonne models. When fully loaded a 30 tonne Moxy can weigh 50 tonnes and the larger Moxys upwards of 60 tonnes. 

During our busiest times we’ve had 27 Moxys on site. So far, these machines have carted over 160, 000 m3 of dirt, equivalent to the volume of more than 60 Olympic sized swimming pools. The Moxy trucks are the ‘work horse’ of our equipment family.  

A few other reasons Moxys make a good choice for this job include their ability to articulate and having a self-levelling cab. A standard dump truck can’t move the cab and chassis separately.  The benefit of an articulated dump truck allows our drivers to turn more easily in narrow spaces. The self-levelling cabs are also helpful, making the machines suited to working on uneven ground.  

Check out our latest video where we talk to some of the Moxy drivers.

Meet Justin Tighe-Umbers

What is your role at National Road Carriers? I’m the latest in a long line of Chief Executives at the helm of National Road Carriers (NRC), which started out in 1936. Looking after owner drivers who make a living out of the road freight industry is in our DNA. These days, we have 1, 500 members, which includes everything from multi-nationals such as Mainfreight at the big end all the way down to a single-truck owner-driver. 

What is your connection to the project? NRC has a great relationship with Waka Kotahi, we work closely together. NRC gives the pulse of the road freight industry, giving insights, advice and feedback as to how an NZTA project is going to affect transport operators. Paula Rogers on our team is world famous in Northland. As Commercial Transport Specialist, she is a transport expert who looks after all our members in Northland. For the Brynderwyn Hills project, that has meant working hard communicating with members about the closure, how it will affect them, and providing insights and feedback to NZTA on the detour routes.

What will this project enable? Keeping the Brynderwyn Hills open. Cyclone Gabrielle and flooding caused so many closures it cost the Northland economy millions in extra freight costs. This project will give another 7 to 10 years life and reliability while work progresses on an alternative Brynderwyns route.

Where is your favourite place in Northland? Without a doubt it is Russell in the beautiful Bay of Islands – we go as a family every year. I am a bit of a history buff, so love the heritage village along with the beaches. Over Christmas we had an amazing sailing adventure out of Opua up to Paradise Bay in Urapukapuka Island, my first time there – absolutely stunning.

Tell us something about yourself My real full-time job is as a Dad, looking after 3 beautiful boys with my wife Shari. An absolute joy and exhausting at the same time, it makes my day job in the trucking industry look like a piece of cake!

Key information at a glance

SH1 Brynderwyn Hills closed: 3 April (12:01 am) - 12 May (11:59 pm)

SH1 Brynderwyn Hills reopens: 13 May (12.01 am)

Three scenic detour routes

• Cove Road route: Turn off at Kaiwaka, use Kaiwaka Mangawhai Road, Garbolino Road, Tara Road, Cove Road, Nova Scotia Drive and connect back to State Highway 1. (Restrictions are in place for trucks with trailers on Cove Road between Mangawhai Heads Road and McLean Road).
• Paparoa Oakleigh Road route: Trucks and trucks with trailers up to 50 tonnes can use this route.
• SH12/SH14 route: HPMV (high productivity motor vehicles) must use this route.

Local routes contact:

Whangarei District Council 0800 932 463

Kaipara District Council 0800 727 059

State Highway route contact:

NZTA 0800 444 449

More information

For more information on the SH1 Brynderwyn Hills project, contact us at northlandproject@nzta.govt.nz

Visit the project website www.nzta.govt.nz/brynderwyn-hills