While the dam at the North Spur is not yet completed, Dave Raeburn can’t help but feel apprehensive about what could happen to his little community.
Raeburn, a resident of the village of Mud Lake — located about eight kilometres southeast from Happy Valley-Goose Bay by boat or snowmobile — said there has been a lack of movement on what exactly the plan is for Mud Lake in the event of a catastrophic break in the North Spur dam at Muskrat Falls.
“The last time (Nalcor) came to Mud Lake to speak to us about an emergency evacuation plan was about two years ago,” claims Raeburn, who has lived in the village of 60 residents for 12 years.
“We haven’t heard anything since.”
The North Spur is a feature of the landscape that juts out into the Churchill River at the Muskrat Falls site, forming a partial natural barrier, which will be incorporated into the Muskrat Falls hydroelectric dam.
Raeburn said there would be little to no time to get residents out of Mud Lake should the North Spur ever break.
“I’d like to get a conversation going about the logistics,” he said. “We’re not talking about a trickle of water; we’re talking about a 20-feet high wall of water, moving at about 20-50 miles per hour, descending on Mud Lake within an hour.
“It would be next to impossible to get people out.”
Raeburn said no one can guarantee the dam will be 100 per cent fail-proof.
“No one can,” said Raeburn. “Whatever the percentage is, there is still the possibility of it happening.”
Gilbert Bennett, vice president of the Lower Churchill project, said while the design approach and design standards of the North Spur dam make the possibility of a break an “extremely unlikely event,”Nalcor will be sharing information with each community in the Upper Lake Melville area within the next two months.
“As we look at our emergency preparedness plans and our dam safety plans… it’s an important public safety issue, making sure that the residents of the area are aware of the facility and the consequences of a very unlikely event,” he said.
“That being said, the potential for an event does exist, therefore we would communicate that to the communities.”
Bennett said each of the communities would incorporate this event into their emergency preparedness plan.
“The first one starts with our coffer dam we’re building for construction purposes for our main dam. After that we’ll have another series of documents to deal with the facility after it goes in service and we build the reservoir,” he said.
Bennett said no matter the situation — whether it is a forest fire, natural flood, or a break in a dam — every community across the province should have an emergency preparedness plan ready to implement. He added Nalcor has contact information with each community, as well as contact and designated interfaces with emergency responders such as law enforcement, Fire and Emergency Services and other emergency agencies in case of a break in the dam.
“Then, that becomes an event that each of the communities would look at and say, ‘OK, I have an emergency plan. I have a communication plan for dealing with my residents.’ Then they would take it from there and notify their residents,” Bennett said.
Bennett noted simulations were undertaken to estimate the impacts of a breach at Muskrat Falls on downstream water levels during “fair weather” conditions and are on Nalcor Energy’s website for anyone to view at http://muskratfalls.nalcorenergy.com/wp-content/uploads/2015/07/Muskrat-Falls-Dam-Break-Study_for-web.pdf.
Inundation mapping corresponding to a dam break scenario is provided in appendices A and B of the document, noting water levels could begin to rise around 1.7 hours after a breach and could reach peak levels at around 7.3 hours.