Source: New Zealand Transport Agency
Waka Kotahi NZ Transport Agency advises that while a solution is still being worked on, it will be around nine to 12 months before State Highway 25A is fully re-opened in the Coromandel.
“There are three main options for reinstating this highway. One – we build a bridge replacing the lost section of road; two – we build a deviation which bypasses the slip site; three – we build a retaining wall and effectively rebuild the road from the ground up,” says Regional Manager of Infrastructure Delivery, Jo Wilton.
“We don’t know which option is most feasible yet. The right solution cannot be established until the geotech work is complete. We know the rebuild must be resilient and as timely as possible. We understand how critical this highway is for Coromandel residents, businesses, and visitors,” Ms Wilton says.
Geotechnical engineers are continuing their critical assessments. There has been some further deterioration of the slip site following Cyclone Gabrielle. Some cracks across the road near each edge of the slip have widened, but there has been no further movement at this stage.
“The Hikuai side of the slip is high and possibly unstable. Assessment of the stability of this slope is underway.
“The next step is to construct a temporary track, to allow access for a geotech drilling rig up to the site of a potential deviation above the slip area. We also need to form another access track to the base of the slip where a retaining wall could be founded, but the ground is too wet to do this yet. Until we can get a rig in – we can’t get significant testing done.
“Our current focus is to build the tracks so the geotechnical assessments can be completed. It is anticipated these tracks will be in place in approximately two weeks – subject to the weather,” Ms Wilton says.
SH25A was closed on Friday 27 January to ensure the safety of road users, following the formation of deep cracks in the road after Ex-Cyclone Hale. The cracked section of the road at the summit slipped away during the Auckland Anniversary storm event.
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