NZTA DIGGING DEEP FOR A SOLUTION TO SH25A
Written by John Grant on February 10, 2023
With the Coromandel once again bracing for bad weather due to Tropical Cyclone Gabrielle, Waka Kotahi NZ Transport Agency will closely monitor the slip site on State Highway 25A (SH25A) for further damage.
Associate Transport Minister Kiri Allan visited the Coromandel and SH25A today to better understand the size of the job ahead. She was joined by Regional Manager of Infrastructure Delivery, Jo Wilton.
“Waka Kotahi has begun the work needed to get a full picture of the damage to SH25A, but the right solution cannot be established until preliminary work is complete,” Ms Wilton says.
The slip now measures around 110 metres across and is highly unstable, and the coming weather event will potentially bring new challenges. A full geotechnical assessment cannot be undertaken until the site has dried out. However, with the use of technology such as drones, early investigations are underway.
The hole where once there was road, now measures around 110 metres across.
“The geotechnical investigations will help inform the best option to reinstate the highway. We are exploring a range of options for this site – but we won’t know more until the experts can share their findings.
“This is a critical thoroughfare for Coromandel residents and visitors, and what we do know is that any fix will be complex and will take considerable time. It’s imperative it’s restored in a way that ensures resilience and long-term confidence for the peninsula,” Ms Wilton says.
Waka Kotahi continues to monitor the site on a daily basis to look for further movement and any changes in geotechnical conditions.
“The community can be assured that we have the expertise to get this done. From specialist roading and geotechnical engineers, to our local maintenance crew who will establish a safe access to allow contractors and machinery in,” Ms Wilton says.
Geotech work still to be done includes drilling boreholes and excavating test pits to assess the stability of the underlying foundation at the site and surrounding area. This needs to be done from the bottom of the slip and we are exploring remote options for our worker safety.
Waka Kotahi is also working to mitigate the impact the closure of SH25A has on the rest of the Coromandel state highway network. From assessing how traffic and truck volumes are changing around the peninsula to clearing drains and culverts in readiness for the next weather event.
At the SH25A slip site. Associate Transport Minister Kiri Allan receives an update from Waka Kotahi today.
Waka Kotahi expects to be able to share more information about potential solutions with the public and stakeholders in the next fortnight.
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