SH10 Bulls Gorge Realignment
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 NZ Transport Agency 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 project was undertaken during the summer months to reduce environmental impact. Some 200,000 tonnes of earth was excavated to form 22 m high cuts and 20m 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 100m long ∅2.6 m stormwater culvert installed has inlet and outlet structures designed to facilitate fish migration. Construction was programmed to avoid work in stream during fish migration season. Significant ecological plating was undertaken, all 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 NZ Transport Agency, NCC, DoC, Transfield and their subcontractors.
LOCATION: SH1 / Whangarei Central
CLIENT: NZ Transport Agency (Waka Kotahi)
CONSULTANT: NCC Consulting Engineers
CONTRACTOR: Transfield Holdings Ltd.
KEY SERVICES:
Team Lead Delivery (ECI)
Planning
Design-Build Contract
Geotechnical Design
Structural Design
Pavement Design
Landscaping
Road & Infrastructure Design
Site Supervision
MSQA
Communications & Engagement