Restoring road access on State Highway 23 (SH23) between Whatawhata and Raglan is urgently underway. This crucial link between Raglan and Hamilton was fully closed on Wednesday last week, following a serious slip on the section known as the Raglan Deviation.
Waka Kotahi NZ Transport Agency is now constructing a temporary diversion road around the slip site through private property.
The plan started to take shape on Friday, and after the Waka Kotahi team met with landowners, fence and tree removal began. Earthworks will be carried out over the next few days to create the new temporary road, which if at all possible will be two lanes wide.
“We are very grateful to landowners for their generous co-operation, and to Vodafone NZ for enabling us to work within close proximity of the fibre optic cable that runs through the site of the slump,” says Cara Lauder, Waka Kotahi System Manager for the Waikato.
The new temporary road will be raised to protect the cable, which is not exposed by the current slip. The cable is around 600mm deep. “While we cannot give a firm opening date at this stage, we want to assure the community that every effort is being made to create access as a matter of urgency,” Ms Lauder says.
"The temporary diversion road allows us the time we need to thoroughly investigate and plan the long-term restoration of SH23."
The slump continues to move, and geotechnical testing, including drilling, is ongoing.
Meanwhile, while SH23 remains closed, our contractors are taking the opportunity to bring forward some planned resurfacing work to a steep section of the deviation further west. This work is scheduled to be carried out from Thursday 9 February until Saturday 11 February.
We will provide another update on the expected timeline as soon as we can.
The official detour route remains Ohautira Road, Waingao Road, Herschel Street, Ellery Street, Whatawhata Avenue, Ngāruawāhia Road, Horotiu Road to re-join SH23; please be careful and drive to the conditions, as it has tight, winding sections.
Monday 30 January: SH23 closed to one lane due to cracking
Tuesday 31 January: Crack became 300mm drop
Wednesday 1 February: Drop became slump. Geotechnical assessments underway. Road closed overnight and detour route established.
Thursday 2 February: Road closed to all traffic, while engineers continued to investigate severity of the situation and ongoing risk.
Friday 3 February: Plan actioned to construct a temporary diversion road.