A temporary alternative route for the Tapu-Coroglen Rd will be ready for use in June, estimates the Thames Coromandel District Council.
The Tapu-Coroglen Rd was closed to traffic when a section of it slipped into the river below, during the storm events of January and February. Only the slip site, some 10.2 km from Tapu, is closed, and there is currently no access for through traffic. Residences and businesses on either side of the slip are still open to the public.
The temporary route will be for light traffic only and will be single-lane, with limited visibility, tight corners and passing/waiting bays at either end of the bypass site.
The council is intending to undertake the works in May and June as weather allows. Improvements will also be made to drainage systems and the road surface, to ensure the road remains usable over winter.
The temporary route will be monitored daily for ground movement. While every effort will be made to keep the temporary road open, the council has warned that ground movement or necessary work on permanent repairs may force its closure.
A permanent repair is in the works, and the council estimates it will be complete in December.
The repair will consist of a retaining wall from the river below, to the level of the road. Specialist contractors will be required, and work will begin in spring, once the weather allows. The council is aiming to complete the new wall as soon as possible before Christmas.
Geotechnical investigations have determined the cause of the fault was a section of soft material separating two sections of harder material, where a spring line appears to have moved as a result of the cyclone rains. The spring is now discharging through the softer material at the base of the slip, destabilising the slip’s toe. It is likely that the slip will continue to move without notice, requiring the continued closure of the road.
