Source: New Zealand Transport Agency
Golden Bay residents can expect to see contractors on site on State Highway 60 at Birds Hill next week with resilience work to start on the Birds Hill landslide.
The slip reactivated in 2017 and has continued to gradually move, creating a large hump in what was the left-hand lane of the highway. While the highway is open to two lanes at the slip site, it has been under a long-term 50 km/h temporary speed limit.
SH60 Birds Hill slip site.
Rob Service, System Manager Nelson/Tasman, says work will begin next week (10 February) to repair the site and improve its stability.
“Any future landslide movement poses a real risk to State Highway 60 in an area where there are no alternative detour routes. Maintaining and preserving access to Collingwood and western areas of Golden Bay is critical.”
“To reduce the risk, contractors will carry out substantial drainage work at the slip site above the highway. This includes building horizontally drilled drains into the slip, constructing cut off drains above the hump, and redesigning and resurfacing the road to allow the current 50 km/h speed limit to be removed,” Mr Service says.
However, he warns the work will not remove the current hump at the slip site.
“The hump is at the toe of the slip and geotechnical assessments show it provides stabilisation, reducing ground movement. To remove it would likely increase slope instability and increase the risk of more movement, particularly after wet weather.”
“In this case it is better to work with nature and leave it in place. Site studies have shown the slip’s stability is sensitive to groundwater. So, improving the drainage and removing water from the slope is the best and most cost-effective option,” Mr Service says.
He says the work will affect traffic travelling between Tākaka and Collingwood.
“For a project of this scale, it is unavoidable. The project site will be under stop/go during the day. Drivers will still be able to get through but can expect short delays. Outside of work hours, the highway will be open to two lanes.”
“Weather permitting, we expect the project to be finished by late April. So, please bear with us while our contractors work hard to get this job finished,” Mr Service says.
Works schedule
- Monday, 10 February to Thursday, 24 April (Weather dependent). Monday to Saturday, 7 am – 7 pm
- Stop go traffic management and 30/km/h temporary speed limit
- Road open to two lanes and 50 km/h temporary speed limit outside work hours
- No work will be done during the Easter Holidays
More Information
This project is funded out of the Crown Resilience Programme – a $419 million investment package of resilience improvement activities that will reduce the impact of severe weather events on our national roading networks. More information can be found on our website: