The provincial Crown corporation that's building a massive hydroelectric project on the Churchill River in Labrador has released new data about the stability of a naturally occuring dam, just days after a landslide in the area put some residents on edge.
Nalcor's newly published geotechnical peer review refutes claims by Swedish researchers about the stability of what's known as the North Spur.
"We felt that the proper way to deal with that was to have a peer review done by four highly respected international experts," said Nalcor CEO Stan Marshall.
The North Spur is a landmass that juts out into the Churchill River, acting like a dam. It was fortified as part of the Muskrat Falls construction project, and conventional, concrete dams were built to span the remainder of the river.
Some residents opposed to the project question whether the North Spur can withstand the weight of a reservoir behind it, especially in the event of a landslide or an earthquake.
Their concerns were supported by research conducted by Stig Bernander, a retired professor at Luleå Technical University in Sweden. He and his colleagues contended the soil composition of the North Spur make it susceptible to landslides and unsuitable to act as a dam.
Nalcor's peer review panel, comprised of experts from Memorial University, Université Laval and the Norwegian Geotechnical Institute, disagreed. In their report to the energy company, the researchers said Bernander's work lacked key data.
Some of Bernander's findings "are based on several incorrect assumptions and … the results are therefore not realistic," the report stated.
'The battle never ends'
Marshall, who last week described Muskrat Falls as an "over-governed"project where "nobody saw the big picture," said it was reasonable for the public to question Nalcor's research.
"It's valid for people to raise concerns and we'll try to address those concerns. But there comes a point when some people adopt a position that they believe in something despite the facts."
Marshall said he'd continue to try to convince the public of the dam's safety.
"The battle never ends. That's why I'm here this morning," he said in an interview Monday with CBC Radio's Labrador Morning.
Landslides a natural occurrence
There is a long history of landslides on the Churchill River near the Muskrat Falls project. Marshall said Nalcor has strengthened the North Spur to withstand slides, earthquakes and flood waves caused by such incidents.
"In the natural state, there's no question that many areas of the banks are unstable and have been eroding ever since the last ice age," Marshall said.
"These factors were recognized, and so work has been done for many years," he continued. "So today the North Spur is very stable."
Warning system in the works
Marshall also stressed that Nalcor closely monitors dam functionality and will continue to when the project is complete.
"Dams just don't collapse like some people assume," he said. "The circumstances that give rise to dam collapse usually develop over days, months, years, even."
Should there ever be a concern about the safety of the dam, Marshall said, residents downstream would be warned well in advance.
He said the company is working with the town of Happy Valley-Goose Bay on an alarm system.
In the past, residents have called for a siren or horn of some sort, but Marshall said the two groups have yet to decide on a mechanism.
"It's being sorted out so I'll have to wait until we all agree upon what we think is appropriate."