Work is expected to begin early next month to get State Highway 6 (SH6) at Diana Falls re-opened to two-lane and 24/7 traffic by mid-year.
"There have been some delays in getting this work underway as we have worked to finalise what is needed on site, to complete the design, source material and appoint a contractor," says the NZ Transport Agency's Senior Network Manager Mark Pinner.
SH6 at Diana Falls, between Haast township and Makarora, has been reduced to single-lane traffic from 8am to 7pm, and closed at night, for the last five months, after heavy rainfall lashed the region back in September causing a major slip at the site.
Mr Pinner says a contractor will be appointed within the next couple of weeks to undertake the work which includes installation of a catch fence above the road, a debris fence about one-third of the way up the slip face and the blasting and removal of large rocks that are considered at risk of creating instability at the site.
"At this stage it is expected the works will begin within the next two to three weeks and be completed by the end of May. However, weather will be a significant factor in achieving this date.
"It is likely that additional traffic delays will be needed throughout the day to complete this work, to ensure the safety of motorists travelling through the area and our road crews working at the site."
He says the Transport Agency will provide as much warning as possible regarding any delays to ensure travellers and business operators can plan their travel through the area.
The first phase of the work will be the construction of a fence that is draped up against the 30-metre vertical rock face that rises up from the road. This will have a large opening at the top of the rock face to channel and contain any material that moves down the slope against the rock face to prevent it from falling on the highway.
Next, a temporary fence will be erected at the top of the slope to enable the bigger, up to 200-tonne rocks at the head of the slip to be broken into smaller, one-tonne rocks for removal from the site.
The last phase of the work is to erect a fence about one-third of the way up the slip which has the dual role of catching any larger rocks that may move off the slope and to contain the gravel that is expected to continue to wash down the rock face as the slope re-establishes its natural stability level.
Mr Pinner says it is not known at this stage how much the work will cost. "This will not be known until a contractor is appointed and the specific detail of the programme finalised."
For more information, visit the Diana Falls site here(external link).
For more information please contact:
Media Manager - Christchurch
T: 03 964 2885
M: 021 427 442