Geoquest’s Legacy of Infrastructure Resilience
For more than four decades, Geoquest has helped shape some of New Zealand’s most significant infrastructure—quietly strengthening the landscapes, communities, and critical assets that New Zealanders rely on every day. Our history here stretches back to the early 1980s, delivering engineered solutions that have stood the test of time in some of the country’s most challenging geological environments.
As Geoquest Australia & New Zealand continues to evolve, we are proud to celebrate our long-standing contribution to resilient infrastructure—from iconic hydro projects to major landslide stabilisation works that remain essential to community safety today.
A Landmark Project: Clyde Dam & the Cromwell Gorge
Few projects capture the complexity of New Zealand’s natural landscapes quite like the Clyde Dam and the surrounding Cromwell Gorge. During the dam’s construction, engineers faced significant geological instability, with major active landslides and known fault lines posing risks to the project and surrounding communities.
Geoquest’s Reinforced Earth® mechanically stablised earth (MSE) solutions were used to stabilise key areas around the Clyde Dam. The first structure was a TerraClass® buttress wall built beside the western end of the dam. A second structure — a large TerraTrel® mesh MSE wall solution — was later constructed to stabilise the upper slopes of the gorge as part of the Cairnmuir Landslide project.
The Clyde Dam is the country’s largest concrete gravity dam and was the centerpiece of a massive geotechnical stabilisation project in the Cromwell Gorge. While the dam itself is a 100-meter-high concrete gravity structure, the broader project required extensive landslide stabilisation and reinforced earth techniques to secure the slopes around the new reservoir through the Cromwell Gorge.
TerraClass® Reinforced Earth Wall (Turning 40 This Year!)
Built to support the hillside on the western end of the Clyde Dam, this largescale Geoquest Reinforced Earth® structure provided stability for both the riverbank and the tower supporting an aerial ropeway critical to dam construction operations. Forty years later, it continues to perform as designed—an enduring example of how engineered earth solutions can deliver long-term resilience.
Cairnmuir Landslide: A Landmark in Landslide Stabilisation
The second Geoquest structure deployed for the project — a large TerraTrel® MSE structure — was later constructed to stabilise the upper slopes of the gorge as part of the Cairnmuir Landslide project. Completed in 1993–1994, the Cairnmuir Landslide stabilisation project in the Cromwell Gorge remains one of the most ambitious landslide safety projects in New Zealand.
The Challenge: The Cairnmuir landslide sits high above the Clutha River above the reservoir, its failure surface more than 50 metres above lake level. Long-term monitoring had shown unacceptable movement, prompting urgent intervention to prevent potential catastrophic impact for Clyde and Alexandra. Any intervention needed to be constructed on a moving landslide with a surface slope of 30 degrees.
Geoquest’s Solution
Geoquest designed and supplied Reinforced Earth® TerraTrel® wire mesh MSE retaining walls with rock fill, for an area of 14,000 m², constructed along steep 30–45° slopes.
These stabilisation measures allowed engineers to:
- Control water infiltration—one of the main drivers of landslide movement
- Create safe, stepped platforms along the slope
- Direct rainfall away from the landslide mass via lined gully systems
- Maintain stability during construction on an actively moving slide
Since completion, landslide movement has reduced to just a few millimetres per year, demonstrating the long-term performance of the system.
A Living Legacy: Continuing to Protect Communities
Both the Clyde Dam Reinforced Earth wall and the Cairnmuir Landslide Reinforced Earth® systems remain fully operational, performing as intended four decades later. These structures continue to safeguard communities and infrastructure in Central Otago—an enduring testament to engineering collaboration between owners, consultants, contractors, and our team.
Read our full case study here.
Looking Ahead: Sharing Knowledge at LaRGE 2026
This April, the Landslide Risk & Geo‑Education (LaRGE) 2026 Conference in Queenstown will include an optional technical visit to these sites—an opportunity for geotechnical and engineering professionals to see firsthand how Geoquest’s Reinforced Earth® structures built decades ago remain integral to New Zealand’s infrastructure network. We’ll be joining the site visit and look forward to meeting fellow engineers and discussing our contribution to this landmark project.
40 Years of Geoquest in New Zealand — And We’re Just Getting Started
Today, as Geoquest Australia & New Zealand, we remain committed to delivering modern, sustainable, and resilient solutions for the future—drawing on decades of local experience and global innovation.
While technologies and methods evolve, one principle remains constant. Time builds trust.
Our history in New Zealand is long, proven, and still growing. We look forward to partnering with councils, government agencies, contractors, and communities on the next generation of resilient infrastructure projects across the country.
Contact our New Zealand team for leading geotechnical engineering support and precast concrete solutions.
