BC Hydro says the Site C megaproject construction site in northeastern B.C. is safe from a landslide despite calls for an independent safety review from a retired engineer who helped design the area's three dams.

Up to 200 people from the community of Old Fort four kilometres from Site C could be out of their homes for the entire winter while emergency officials wait for a landslide first reported on Sept. 30 to stop moving. The Peace River Regional District has deemed the area south of Fort St. John unsafe to enter,

Andrew Watson, the director of design engineering for Site C, says BC Hydro is aware the area is prone to landslides and has designed the project with those risks in mind.

"We don't have any concerns," said Watson.

It's fairly flat land, and there's a lot of people downriver from there. That's really what I worry about. - Vernon Ruskin, retired engineer

As one example, he said roughly 11 million cubic metres of earth on the left bank of the dam has been excavated to provide more stability. A two-million-cubic-metre concrete buttress has also been installed to protect against slides and earthquakes.

Calls for independent safety review

But a retired engineer with experience in the area said he's worried the landslide-prone region isn't a good location for the dam, and is calling for an independent safety review of the project.

"If the landslide hits the structure of the dam, it will get damaged," said Vernon Ruskin, who was part of the design team for Site C as well as the W.A.C. Bennett and Peace Canyon dams under the old BC Electric company, which later became BC Hydro.

"It's fairly flat land, and there's a lot of people downriver from there. That's really what I worry about."

BC Hydro says it has lowered the angle of the slope around the Site C dam in order to reduce risks from landslides and earthquakes. (Justin McElroy/CBC)

Ruskin said the danger comes from the makeup of the ground in northeastern B.C., namely the high volume of shale in the area.

"It's almost like a sponge," he said. "It expands when it gets wet and it's very, very slippery."

Ruskin said he doesn't want to be the "judge" of whether Site C is safe or not, but simply would like to see an independent body review it for safety.

"Spend a dollar doing that, because they're spending a lot of money and I'm worried about the people in the [Peace River] Valley," he said.

Listen to the full interview with Ruskin

Area prone to slides

BC Hydro noted these same concerns when submitting Site C project to a federal joint review panel for approval, along with its proposed solutions to the risks of slides. In response, the panel wrote "the planned mitigation is adequate" and "the Panel is assured [BC Hydro] would provide warning of any potential landslides that may affect the project."

Watson said a technical advisory board consisting of experts from around the world has advised BC Hydro on the dam project, and that his team is relying on the most up-to-date information as construction moves ahead..

"It's been carefully designed," he said.

Listen to the full interview with Watson

With files from Nicole Oud and Daybreak North