HALIFAX, NS –
Atlantic Canadians living along highways cut off by torrential rains this week say it’s time for governments to focus on retrofitting roads to ensure they can Surviving floods is expected to become more frequent.
Peter MacGillivray said Wednesday following two sewers on Highway 245 near his home in northern Nova Scotia. was taken out by the latest storm.
The 59-year-old said he was using a four-wheeler and crossing a forest road to get from his home to an undamaged stretch of highway after the drains failed to withstand about 116mm of rain for two days.
In southwestern Newfoundland, which was also affected by the same storm, Joe Murphy said winding country roads along the coast were in poor condition and locals had said they needed to be lifted. level for many years.
“If we’re going to have terrible storms and we have poor infrastructure, it’s obviously going to cause significantly more damage,” the Codroy, NL resident said in an interview today. Thursday.
Nova Scotia reported Wednesday that 25 roads have been washed away in three counties, with northern Cape Breton being the hardest hit. Meanwhile, in southwestern Newfoundland, the storm closed parts of the Trans-Canada Highway and isolated some communities.
While provincial officials say building new roads takes climate change into account, Canadian experts say engineers must do more work to assess risks – and both Ottawa and the provinces need to spend more to avoid repeat problems.
A federal report on climate change published in April 2019 said the consensus among Canadian researchers was that the number of extreme rainfall events, lasting for several days, is expected to increase. up on the East Coast. The report says if current global carbon emissions continue, Atlantic Canada will experience a 12% increase in annual precipitation over the next century and 30% of 10-year hurricanes producing downpours. as big as pouring water.
Slobodan Simonovic, technical research director for the Institute for Disaster Damage Reduction, says a fundamental rethink of how roads are designed to accommodate these projections is needed. “Things are happening in Canada, we are repeating the same mistakes, and it is hard for me to understand that that message is not going to get through,” said Simonovic, professor emeritus of engineering at Western University in London, Ont. with anyone”.
Instead of relying on standards that use historical information to determine culvert size or specify pavement materials, he said civil engineers should perform “performance-based” calculations of how a Certain road sections can survive the storm. “We need to simulate a certain structure under different conditions … and I usually recommend that we choose an option that can maximize the resilience of the structure,” he says.
Blair Feltmate, head of the Principles Center for Climate Adaptation at the University of Waterloo, has noted that there are well-established ways to adapt existing roads to heavy rainfall events.
These include protective embankments, channels to divert storm water from highways, and retention ponds to keep water in safe locations. There could also be methods for placing natural features near roads to draw water in before it spills onto the pavement, he said, and systems could be in place to clear debris in drains and prevent blockages, he said.
“We knew what to do. The problem was that we weren’t taking actions to mitigate the flood risk,” he said in an interview on Wednesday. “We’ve been living an illusion.”
Tim Webster, leader of the applied geoinformatics research group at Nova Scotia Community College, says improved computer modeling is needed to predict the risk of heavy rain to roads. It needs to cover the entire province, he said, not “the fragmentary patchwork that exists today.”
However, Peter Hackett, Undersecretary for Public Works in Nova Scotia, said in an interview Thursday, his engineers are sizing ditches and culverts to withstand the harshest storms of the year. The last 100 to 200 years, and also taking into account the slope of the land. near roads.
“On our new constructions, we try to take these into account with local calculations…how we can get water without destroying the infrastructure,” he said. It is even more difficult to retrofit old roads that run around mountains and along the coast to protect them from drying up, he added.
As for improving the model, Hackett said the department has yet to map the entire network on climate risk, but he supports the concept.
“We’re doing the job we can. I think we’re doing really well and when things happen, we have to get out there and fix them. But we’re trying to get ahead,” he said.
This Canadian Press report was first published on November 26, 2021.