As we arrive on the shores of Lake Monique north of La Malbaie, we see two overturned rowboats and a gaping hole in the middle of the forest, where old, moldy tree stumps border mud puddles.
Posted at 5:00 am.
Almost a month ago a dam burst. The water from the lake poured into the breach and carved an impressive furrow several meters deep. Below, a section of the forest road was destroyed.
Since 2021, the retention structure has been under the responsibility of the Ministry of the Environment. Previously abandoned, it was built to convert a former wetland into a body of water to develop the land and catch trout.
“It was probably not an engineer who built it,” jokes Jean Côté, a professor of civil engineering at the University of Laval and a specialist in the life cycle of dams.
On a cold November day, he and a class of students accompanied a team from the Environment Ministry that had come to assess the damage. He stands with both feet on the edge of a huge hole in the ground in which there was an earthen dam about 2 meters high and 20 meters wide.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
Lake Monique was neither very large nor very deep. Today, old, moldy tree stumps lie next to mud puddles.
The lake was neither very large nor very deep. And yet the power of the water took everything away. “It shows the power of erosion. It probably emptied very quickly,” he says.
One of the aspects that Mr. Côté focuses on in his research is the resilience of dams in the context of climate change.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
Jean Côté, professor of civil engineering at the University of Laval
Our century-old floods were the ancient thousand-year floods. Rainfall is extremely intense after droughts. This causes large amounts of water to enter the tanks and can cause them to burst.
Jean Côté, professor of civil engineering at the University of Laval
In the case of Lake Monique, that’s exactly what happened. “The ministry is of the opinion that [la rupture] is due to significant rainfall in this area. Actually the data […] “We report significant rainfall, that is, more than 135 mm of rain in two days in the Charlevoix sector,” notes Josée Guimond, communications advisor at the Ministry of the Environment.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
The type of soil that fills the region weakens the foundations of the dams.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
Since 2021, the retention structure of Lake Monique has been under the responsibility of the Ministry of the Environment.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
The power of the water took everything away. There are hundreds, even thousands, of dams like that of Lake Monique in Quebec.
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The structure was built in 1970. During its 2021 inspection, the ministry found it was covered in “debris” and noted a “general breakdown of the structure.” The condition of the section is “poor” and the reliability of the evacuation facilities is “insufficient”.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
Christophe Dandurand, owner of the Spa Canada Chalets, located between Mont Grand-Fonds and Lake Monique
The dam was probably already weakened. Christophe Dandurand, who met nearby, is the owner of the Spa Canada chalets between Mont Grand-Fonds and Lake Monique. He remembers that “in 2016 or 2017,” “the water was overflowing the dam,” which needed repairs because it also served as a passageway for a regional snowmobile route. That was before the Ministry took possession of it. “It happened in a hurry, as is often the case in Quebec,” lamented Mr. Dandurand.
Another peculiarity: the type of soil that fills the region and weakens the base of the dams. “When it failed, the foundation was over-excavated. “This is a well-known phenomenon in the region, where the soil consists of easily eroded glacial deposits,” notes Michel Dolbec, energy project manager at WSP Canada.
He emphasizes that all dam owners have a duty to keep their works in good condition. In this case, however, the risk was “low”. “The biggest loss is the outfitter who lost their lake,” he said.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
Will Lake Monique ever be reborn? The ministry has not yet decided the issue.
Martin Dufour, owner since late 2020 of the outfitter Domaine Comporté, where Lake Monique was located, was still afraid and questioned the ministry’s standards. “Whether it’s low capacity or high capacity, it’s dangerous. I’m not an engineer, but I have a lesson in life. You don’t have to be a hydrologist: seeing the damage, it’s certain that if I had been out at the wrong time I would have been killed. Still, capacity is expected to be low,” he said.
He points out that his employees use this forest road every day, and he uses it two to three times a day.
There are hundreds, even thousands, of dams like Lake Monique across Quebec. Whether in an urban environment or in the great outdoors. The Ministry of Environment alone owns 930 state-owned dams, including 391 high-capacity dams, 263 low-capacity dams and 276 small-capacity dams.
Even today, the Quebec government “finds” some of them. He inherits works that were built in the past by property developers, vacationers or outfitters. The government has already tightened the law to force owners to better maintain this infrastructure, but the challenge remains very significant.
PHOTO EDOUARD PLANTE-FRÉCHETTE, LA PRESS
Will Lake Monique ever be reborn? The ministry has not yet decided the issue.
This year, a dam broke in Sainte-Émélie-de-l’Énergie and a protective wall failed in Baie-Saint-Paul, causing significant damage. A few years ago, residents of Grenville-sur-la-Rouge were worried about the risk of the Chute Bell dam breaking. It is impossible to say whether the phenomenon is increasing since “the ministry does not keep a list of dams that break or suffer damage.”
Will Lake Monique ever be reborn? The ministry has not yet decided the issue. “A cost-benefit analysis is carried out based on technical feasibility, type of foundations, environmental impact, environmental needs and safety aspects,” notes Ms. Guimond.
As for Martin Dufour, he is preparing for the worst. If the lake is abandoned, he predicts losses of almost more than $1 million. He canceled all reservations for his two cabins, which now overlook a swamp. “It was the third attack of water since the spring. I’m confused,” he says.