Location:
Client:
Consultant:
Contractor:
Key Services:
SH10, Bulls Gorge
New Zealand Transport Agency (NZTA)
NCC Consulting Engineers
$7.5 million
Transfield Services Ltd
Planning
Geotech
Pavement Design
Landscaping
Road Design
Site Supervision
Value:
SH10 Bulls Gorge
Significantly improving road safety
Bulls Gorge on SH10 in Northland is a strategic link between Auckland and the Far North for both the tourism and freight industries. Bulls Gorge has been the site of many accidents over the years. This crash record and a number of fatalities prompted action from the New Zealand Transport Agency (NZTA) and work began in late 2010 to realign the road through the gorge replacing it with easier curves, better gradient and a wider highway with improved shoulders and wire rope edge protection.
Reducing environmental impact
Most of the work on the $7.5 million project was undertaken during the summer months to reduce environmental impact. Some 190,000 tonnes of earth was excavated to form 22 m high cuts and 20 m high fills. The state highway ran alongside the Bulls Gorge Scenic Reserve, which is home to many endangered Kiwi. The new alignment intruded into the scenic reserve and because of the huge volumes of earthworks being carried out beside a scenic reserve, substantial environmental protection and restoration was required.
Before the work started a fish survey was carried out at night using electric fishing. Kiwi were located using specially trained dogs and tracking collars were attached. A 100 m long 2.6 m dia culvert had inlet and outlet structures designed to facilitate fish migration. Construction was programmed to avoid work in stream during fish migration season. 45,000 plants that were produced from seed, collected locally and grown well in advance of construction, were planted around Bulls Gorge as part of the project.
A collaborative approach
The Bulls Gorge makeover is now complete. The straighter route through the gorge is safer for motorists, freight carriers, tourists and cyclists. Achievement of the successful engineering and environmental objectives is testament to the great cooperative spirit between NZTA, NCC, DoC, Transfield and their subcontractors.