Location: Queenstown, Arrowtown and Gibbston
Contract Value: $1,155,000 still in progress
Project Completion Date: Still in Progress
Company: Queenstown Lakes District Council
The Twin Rivers, Swiftburn and Kawarau Trails are being constructed during 2011 & 2012. The tracks start at Gibbston Valley and follow the Shotover and Kawarau River’s along into Frankton. The track’s start just above river level and as they follow along the banks of the river over the course of the trail. As part of this trail we constructed an underpass under State Highway 6 which consisted of 160meters of crib walls, 8meters of post and rail retaining walls and 26 tons of stonemasonry. The total of kilometers of trail formed between these projects is 110+ of diverse terrain connects the three main hubs – Central Queenstown, Arrowtown and Gibbston. The trail crosses three major rivers – the Kawarau, Shotover and Arrow and meanders past Lake Wakatipu and Lake Hayes. We constructed over 668meters of retaining walls and 16835m3 amounts of earthworks were undertaken.
A large majority of this trail was covered in dense bush which was cleared by laborers and chainsaws, the track was then constructed using bulk earthwork techniques, a bull dozer pushed a trail through and an excavator followed in behind forming the batters and water tables. In the sections of trail over the flatter land directly beside the river topsoil was stripped and spread along the sides of the trail and then pitrun was imported to lift the trail levels up above the existing ground level as not to create a channel. The track has varying conditions along the stretch of rivers and different construction techniques have been used, such as rock breaking and rock blasting, using our fully qualified explosives handlers, importing pitrun to mix with onsite silts and mixing onsite materials where used to create a subgrade on which a track could be formed. The large presence of rock on the site made the traditional timber retaining walls impractical so we suggested an alternative option of crib walls, These proved a lot more effective in the terrain we were working as they didn’t require posts to be augured or driven into rock. They also provide a more natural look for the trail finish. We also installed gabion baskets to stabilize a slip section of the track as well as multiple culverts to deal with onsite storm water.