NZ Transport Agency Waka Kotahi can confirm it is planning to reopen State Highway 1 Brynderwyn Hills at the end of June following a delay caused by an active slip.
NZTA National Manager of Infrastructure Delivery, Mark Kinvig, says since the two significant slips on 26 April and 30 April, NZTA and its contractors have been urgently working on a solution.
“SH1 had been on track to reopen 13 May until these slips occurred. We know how difficult the highway closure is on local businesses and communities.
“Our priority has been to undertake geotechnical and safety assessments to determine the best option for stabilising the hillside and getting State Highway 1 Brynderwyn Hills open as quickly as possible.
“While our plan is to reopen at the end of June, if there is a significant amount of unexpected rain, or further instability is found, that could delay the reopening timing, however we are committed to completing these vital recovery works as quickly as possible to ensure a safe and reliable SH1 Brynderwyn Hills for the short to medium term.”
Excavation has already started, with operators working from a platform at the top of the ridge. Removing soil from the top of the ridgeline reduces the likelihood of further slips, which will then enable safe work to be undertaken from the bottom to remove material.
Up to 55,000 cubic metres of earth will be excavated to stabilise the site where the two slips occurred at Kauri Tree Corner.
“Our team is working 7 days a week, where weather allows, to get the road open,” Mr Kinvig says.
“We are maximising the number of trucks, diggers and workers on site to ensure the soil removal is a continuous operation, utilising daylight hours, to get it clear.”
The remaining planned works, including drainage and pavement works, are on track and continue in parallel; with night works where it is safe to do so.
We have built in contingency for poor weather, however the ground conditions remain unstable and continue to be actively monitored by staff and GPS sensors. There is a risk of further slips until we complete the stabilisation works.
While the closure is in place we continue to have crew proactively monitoring the three official detour routes to ensure these are safe and as high quality as possible and NZTA will be undertaking essential repairs on these routes.
We thank everyone for their patience and remind people to drive safely when using the three detour routes to access Northland - SH12/SH14, Paparoa Oakleigh Road and Cove Road.
NZTA will keep everyone updated through our e-newsletter and social media channels, as we continue to work at pace to complete the work as soon as possible.
Excavators work at the top of the Kauri Tree Corner ridgeline
