Graham Valley South Branch Road Under Slip

A result of heavy Rainfall in the region during May 2023 this under slip on the road to the Mount Arthur carpark was put at the top of priority by DOC to ensure safety for trampers accessing the Kahurangi National Path.

Donaldson Civil was engaged by Downer New Zealand who manages the DOC Roads in the region to supply a team to complete the project.

As the Roadway was very narrow Rock had to be brought into a central location before being stockpiled, then re-loaded onto a truck and backed 3km up to the slip site. With an 8m almost vertical drop from the steep section of roadway down to the riverbed this project required a high level of Risk Management and the right machinery to gain access to the river to begin stacking the Rock Wall.

A 23T zero tail swing excavator was used to perform the benching operation, a specialist Rock Grab bucket was then used to stack the rock to the engineers’ requirements. Near the top the excavation was lined with Geofabrics to protect from future Erosion.

By the end of the project approximately 1800T of Rock was stacked into position to form the new wall. Our team worked long hours through some very cold and wet conditions to deliver the project under budget and ahead of schedule.