Sign In / Register
A significant slip at one of the largest fill sites on the O Mahurangi Penlink route has delayed construction of the Stillwater and Ara Wēiti section of the road.
The slip occurred at Fill 9, which was to hold around 350,000 cubic metres of excavated earth. As there is no alternative storage site for this material, earthworks along the route cannot proceed at the same pace until a solution is implemented, the project team says.
This means the project will now open as a single corridor in 2028, rather than in stages as originally planned. Despite the setback, the team says the overall timeline for completion remains on track.
Cracking in the ground was first identified last December and work in the area was paused while engineers assessed the site. Testing revealed that a deep underground layer was significantly weaker than expected, leading to continued ground movement.
Emergency works were declared in March to allow early remediation and reduce the risk of damage to nearby infrastructure and private property. Since then, groundwater pressure relief drains have been installed to help stabilise the area. These will support further construction of a buttress and the final design solution.
The project team says more than 20 boreholes have been drilled since December to support ongoing monitoring and geotechnical investigation.
Albany ward councillor John Watson acknowledged the delay will disappoint Stillwater residents.
“From my perspective, the reassuring point is that the completed project as a whole is still on track to open in 2028,” he said. “If you look along the entire 7km route, there is significant progress being made at all the major work stations.
“The instability of the land along the Penlink route has long been signalled as an unknown. With a bit of luck, all the different stages of this challenging project will still come together as planned.
“It’s costing the best part of a billion dollars and includes the first extradosed bridge of its kind in New Zealand. This is a very significant project that will transform the transport network on the Hibiscus Coast – and in the scheme of things, we don’t have too long to wait.”
O Mahurangi-Penlink updates
State Highway 1 and Ara Weiti Road: In July, full closures will be in place on State Highway 1 between Oteha Valley Road and Silverdale to allow works. Full details will be notified closer to the time.
Upcoming river closure: July will also see the last of three months of temporary Wēiti River closures needed to ensure safe and continuous supply of concrete for the Pier 4 pile cap. The final closure is from 5pm Monday, July 7 to 9am Wednesday, July 9. The channel closure does not affect vessels navigating the river downstream of the worksite. When the work is complete, the 18-metre-wide navigable gap for vessels to pass through will reopen.
