Water from the Rouge River travels under the bridge on Highway 148 near Grenville-sur-la-Rouge on Thursday.
Tony Caldwell / Postmedia News
The forced evacuation of Grenville-sur-la-Rouge Thursday over fears the Bell Falls dam could rupture brought to mind troubling images of the Saguenay flooding of 1996 that caused eight Quebec dams to breach, and inflicted heavy damage on 19 more. The total cost of houses, businesses, roads and infrastructure destroyed amounted to more than $1.5 billion.“The magnitude of the destruction during these floods sparked a profound reflection on how Quebec’s hydrological resources were being managed, and its dams,” Quebec’s auditor general noted in a 2015 report. Quebec has close to 6,000 dams scattered across its territory to create hydro-electric power, control spring flooding and manage river overflows.Based on the recommendations of a commission led by engineer Roger Nicolet that was created in the wake of the Saguenay disaster to study the issue, the government enacted dam safety laws in 2001 and created the Quebec Centre for Hydrological Expertise, with the goal of ensuring dams were regularly inspected and proven safe.Instead, the auditor general’s 2015 investigation turned up just the opposite.Quebec’s Ministry for the Environment and Fight Against Climate Change had not been able to ensure dam security laws were followed, with only 10 per cent of dam owners (be they private companies, municipalities or the Quebec government) submitting completed safety evaluations on a timely basis, the auditor general found. For 25 per cent of the dams, no safety evaluations had been received for six years. In addition, the Ministry did not know whether owners had carried out necessary repairs within the timelines given. In 2015, the Ministry significantly reduced surveillance of dams, no longer respecting the norms set out. The Ministry carried out only 30 repair procedures annually, when more than 300 had been deemed priority cases in terms of security.Asked whether it had responded to the issues spelled out in the report, officials at the Ministry did not provide an answer by press time Friday.But Nicolet, the engineer responsible for spurring the dam safety laws, told La Presse Friday he didn’t think the recommendations had been carried out, two decades later.“The worst has been plugged up, but I don’t think we are close to a dam strategy management (of dams and flood zones) that will shelter us from the recurring events like those we have been living the last years.”The Bell Falls dam north of Grenville-sur-Rouge was built in 1915 and stands roughly 18 metres tall. It is one of 63 dams Hydro-Québec owns and runs for power generation purposes. Hydro-Québec says its dams are inspected twice a year. No one at the utility could remember ever having to call for an evacuation order for one of its dams.Twenty-eight of Hydro-Québec’s dams are reservoir types, where the energy utility can release water when needed to generate power. The rest, like the Bell Falls dam, are run-of-the-river type dams where the water flows freely through turbines to create power, without a large reservoir created behind. The Bell Falls dam hasn’t generated electricity since 1999 because Hydro-Québec has a surplus of power. When it does, it generates enough electricity to power 5,000 homes.Normally, about 100 cubic metres of water per second run over Bell Falls. On Friday, the rate of flow was at 990 cubic metres a second. Over the weekend, the flow was predicted to increase to 1,100 cubic metres, eleven times what the dam usually handles. In 2017, the year of the last major floods, maximum flow was just under 700 cubic metres a second.If the dam ruptures, water levels below it are predicted to rise by two metres, inundating the 60 residences in its wake.“We still have the conviction that our installation can withstand that pressure, except we are in the unknown at this point, because we’ve reached the maximum level of water” said Hydro spokesman Cendrix Bouchard. “Since we are in the kind of position that happens one in a thousand times, we made the decision, as protocol dictates, to evacuate the houses below the dam.”Hydro-Québec doesn’t know yet whether it will reinforce Bell Falls after this spring. But the energy utility is well aware of the severe weather events that are intensifying, as evidenced by the ice storm that struck Laval in early April and winds that downed power lines in the Magdalen Islands this winter, spokesman Maxence Huard-Lefebvre said.“For us it’s certain that we take it very seriously,” he said. “It’s a preoccupation, and we will address it.”firstname.lastname@example.orgRelated