The City of Whitehorse has planned a project to reduce the landslide risk along Robert Service Way that is without precedent in the city’s history. Areas of concern left behind after the April 8 landslide that closed the roadway will removed using an excavator’s bucket to knock them down the hill.
During a May 1 update on the conditions of the slide site given by Whitehorse Mayor Laura Cabott and city engineering manager Taylor Eshpeter, reporters were told that work could begin as soon as May 2 and be complete within two weeks if all goes well. Cabott said the city has entered into an agreement with P.S. Sidhu Trucking Ltd. for the project, expected to cost up to $175,000.
Eshpeter described a plan for the excavator to dig benches in the hillside above the section of the escarpment that could soon be the site of a landslide. This will allow the excavator to descend as many as eight metres from the top of the ridge and then access the unstable areas. It is the first time such a mechanically-triggered slide has been tried on the Whitehorse escarpment. Eshpeter said the removal of the material is expected to be more controlled than the unexpected slides.
“So why are we doing this? Again, there’s pressure from the public and from emergency services and what have you to see if we can open Robert Service Way,” Cabott said.
“We’ve done a lot of background work on this and work with our experts and come up with this plan.”
Eshpeter said geotechnical engineers will be constantly monitoring the slope to ensure conditions allow the work to proceed safely. A health and safety plan is in place and Eshpeter called the methodology selected by the contractor “reasonably safe” and a good approach in this situation.
“If there’s any sign of it creating greater instability, or causing more harm than its benefit we’re getting from it, we would be stopping to work immediately,” he said
While landslides will still be possible as spring freshet occurs, Eshpeter said the work with the excavator will eliminate a known risk that could slide down onto the road at any time if it is left as is. The material will be collected at the bottom and removed after it is brought down by the excavator. Eshpeter said the planned work will remove about 500 cubic metres from the escarpment’s face and about 6,000 cubic metres overall will have to be hauled away.
Cabott stressed that the planned work is just a temporary solution and specific to this site, not the whole escarpment.
The city is planning to apply to the federal government’s disaster mitigation fund to pay for a more permanent fix. Cabott said long-term solutions could take the form of reshaping the escarpment or moving the roadway, but noted the challenges posed by the road’s proximity to the Yukon River. She said more details would be available closer to the application deadline for the government funding in July.
When a landslide closed Robert Service Way last summer, the city quickly instituted free transit service as a traffic mitigation measure. Cabott said the city had resolved to send a letter to the territorial government’s department of community services asking it to pay for transit through July 1. She said the city is awaiting the results of further discussion around the letter.
Cabott repeated her earlier instructions that people should stay out of the areas that are closed due to last month’s landslide stressing the danger they put themselves and first responders in by going around the barricades. She said the city would institute enforcement of the area closures if they are not respected.
Contact Jim Elliot at jim.elliot@yukon-news.com