The recent flooding of the Ottawa-Gatineau region made it clear to Canadians the risks and dangers when rivers spill their banks. Locally, it’s a pain familiar to residents living here along the edges of the Grand River. But shifting weather patterns brought about by climate change and population growth are seeing the risks of another kind of flooding rise in Canada, in communities previously thought able to weather such storms.
Urban communities living outside of flood plains are feeling the twin pressures of aging infrastructure and increased urbanization, and it’s deteriorating their ability to cope with weather events large and small. And “as climate change brings more frequent and more extreme precipitation events, the problem is getting worse.”
That’s according to a report by Green Communities Canada, a national association of community groups supporting green initiatives, which is calling for a concerted effort to improve urban flood resiliency in Ontario.
“So riverine (river) flooding is in the news a lot right now, and that’s happening in a lot of places. But there’s a system in place already for managing riverine flooding with the conservation authorities and the Ministry of Natural Resources,” explained Clara Blakelock, manager of water programs at Green Communities, of the motivation behind the report, Ready, Set, Rain!
“But urban flooding also occurs a lot … and that’s happening outside of floodplains. It’s not being mapped at all and it’s actually causing even more damage then what’s going on with the riverine flooding. And there’s no provincial strategy to address it, so that’s what led us to try to tackle this issue.”
While the devastation of riverine flooding is making headlines right now, urban flooding has had an immense, though at times subtler effect. Visually, the problem can seem milder as the damage often manifests in flooded basements and sewer backflow. But the damage of these floods can be measured in the billions of dollars.
“Approximately 40 per cent of all personal property claims result from flooding and water-related damages, making flooding the leading source of Canadian personal disaster claims,” notes a 2017 report by Rain Community Solutions, a joint venture of Green Communities. In the GTA alone, the report notes, insurance claims for extreme events have skyrocketed, topping $1 billion in 2013.
The problem is compounded by the advance of climate change, which is predicted to see rainfall intensity rise in the Waterloo Region. A 2015 report by University of Waterloo climate scientists mapping out possible futures for the Waterloo Region over the next 60 years, found that even in the best case situation, the region would see rainfall increase in amount by a minimum of seven per cent. That figure jumps to 12 per cent in the “business-as-usual” model.
“Rainfall intensities are projected to increase across all scenarios and time periods, with large magnitude rainfall events expected to occur more frequently than in the historical record,” notes the report ominously.
But while climate change is an aggravating factor, removing it from the equation doesn’t address the fundamental problems of urbanization and infrastructure.
Urbanization is reducing our environment’s capacity to absorb excess water, as natural landscapes are paved over with hard, impermeable surfaces. Our stormwater and wastewater systems are likewise being overwhelmed with runoff and water content that they were never designed accommodate.
The Green Communities report suggests a four-pronged approach for governments, conservation authorities, homeowners and business to build up urban flood resiliency.
Prioritize locations at risk of flooding. This means first identifying and mapping urban as well as riverine flood risks.
Prepare properties to limit flood risks. “There’s some really simple things they can do to protect their homes,” said Blakelock of property owners. “Things like just making sure downspouts are directed away from the foundation. If they’re in an area where there’s sewer backup risk, you can install backflow prevention.”
The third approach, called “protect and restore”, looks to protect existing natural environments, limit impervious surfaces added to environments, and manage rainfall where it falls. “Then there are … things they can do sort more on a water shed scale, which is about trying to reverse this trend of paving over everything, and what we call managing rain where it falls.”
The final part is to improve infrastructure that protects communities from storms. That requires investments for infrastructure projects, planning for the adverse effects of climate change, and organizing new developments to have built-in resiliency to floods and other extreme weather events.
“Flooding can happen even nowhere near a body of water. Flooding isn’t just about rivers overflowing their banks,” said Blakelock.
With the country preparing for a federal election in October of this year, climate change, and how we deal with the causes and consequences of the issue, will be one of the crucial questions Canadians will have to decide at the ballot.