As the climate heats up, severe flooding has taken lives and damaged communities in Western Europe, India and China this summer. Canada has been spared extreme flooding but the risk here is just as real: flooding is already the country’s most widespread and costly natural disaster.

Part of the solution lies in updating the country's flood maps — a critical tool to protect homes, communities, and public infrastructure — the majority of which are 20 to 25 years out of date. New federal support could make that a priority, but Canadians are already paying the price of inaction.

How costly is flooding in Canada?

Between 2005 and 2014, federal assistance payouts for natural disasters increased tenfold. Flooding accounted for 75 percent of that increase. And in the past five years, residential insurance premiums have increased 20 to 25 percent on average. About 60 percent of that increase is due to flooding. Furthermore, from Victoria to Halifax, a growing proportion of the housing market is uninsurable for basement flooding.

“We keep talking about flood maps year after year after year, so why aren't they in place? Fundamentally, it's because flood risk maps are a political hot potato,” said Blair Feltmate, Professor and Head of the Intact Centre on Climate Adaptation at the University of Waterloo, in an interview with Research Money. 

More complete and accurate maps, covering floodplains, rivers and coastlines, as well as urban flooding, are urgently needed to identify existing flood hazards and predict future risks. But homeowners, real estate developers and municipalities aren't always keen to learn their valuable land lies in a floodplain.

Figure 1. Costs of Extreme Weather: Catastrophic Insurable Losses ($CAD)

Courtesy of the Intact Centre on Climate Adaptation. Sources: CatIQ, PCS, IBC Facts Book, Statistics Canada, IMF WEO Database​.

For municipalities, it also doesn't pay to have updated flood maps in place. In interviews with city officials, researchers at the Intact Centre learned that municipalities without flood maps often find it easier to access federal recovery funding after catastrophic flooding than those with comprehensive maps in place. 

“We don't know where the water's going to go when the big storms hit,” said Feltmate. “Not only do we need to produce up-to-date flood risk maps for the weather that's on the ground today, but we need to anticipate the increasing flood risk and delineate where water is going to go in the future, 25 to 50 years down the road.”

Recent federal investments in flood mapping could change that picture dramatically. 

Budget 2021 proposed $63.8 million over three years to Natural Resources Canada, Environment and Climate Change Canada, and Public Safety Canada “to work with provinces and territories to complete flood maps for higher-risk areas.” (The expenditure is still awaiting Treasury Board approval.) It also committed $11.7 million over five years through Infrastructure Canada to renew a program that is establishing guidance, codes, and standards that take the impacts of climate change into account, including flood mapping standards. 

The federal investments in flood mapping signal a broader policy shift toward climate adaptation, said Feltmate.

“There is greater enthusiasm to produce the flood risk maps, because we're realizing that not doing so and paying attention to them is very costly," he said. "There's no way around it."

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