Can Canada build homes away from flood zones?

With the threat of increased flooding on the horizon, new homeowners may be the ones paying the price. 

Construction of an estimated 5.8 million new homes is needed by 2030 to restore affordability, according to the Canada Mortgage and Housing Corporation. Meanwhile, Statistics Canada suggests rising sea levels and heavier precipitation due to climate change mean more areas in Canada are now at risk of flooding. 

But a Canadian Climate Institute report says existing policies for new homes built in flood-hazard areas could cost owners and insurance companies millions — or even billions — of dollars. With the push to build more homes amidst the threat of climate change, municipalities may not be equipped to build homes out of harm’s way. 

“If you have to rebuild a house over and over again, building it no longer contributes to solving our housing affordability crisis,” said Ryan Ness, co-author of the report. “It’s not that the places we have to build in Canada are largely flood-prone, but if we rush to build, especially in areas near water, we run the risk of building risky homes.” 

BUILDING SOLUTIONS

The report estimates that Canada could build more than 150,000 homes in high flood-hazard zones by 2030. These numbers were calculated, Ness explained, by examining municipal land use policies and zoning bylaws across Canada to estimate where the 5.8 million homes would be built. Developing in flood-risk areas, the report says, could cost insurance companies and homeowners between $340 million and $2 billion in repairs. 

“The actual risk is probably somewhere in the middle of those two scenarios,” Ness said, adding that the range accounts for the worst- and best-case scenario based on possible flood precautions such as levees and dikes. 

The damage to homes affected by flooding can range from basement floods to complete destruction, according to Glenn McGillivray, managing director of the Institute for Catastrophic Loss Reduction.

“Either they can be washed away completely or they can be so badly damaged that they have to be torn down,” he said. “Lives can be lost, (and) property can be contaminated because floodwaters are often filled with contaminants like fuels, agricultural runoff and sewage.” 

Building flood-resistant homes normally involves retrofitting houses already built in areas later deemed at risk of flooding, McGillivray said. However, houses are not typically built with flood resistance strategies from the get-go, since building codes across the country vary and often don’t account for extreme weather conditions. 

“If somebody lives on the coast, we don’t build in a different way than if they lived inland,” McGillivray said. “This is problematic. We kind of build homes in the same way across the country.”

Mitigating the impacts of flooding, he said, starts with avoiding development in at-risk areas to begin with — something that is possible if building occurs within existing urban areas instead of protected regions such as Ontario’s Greenbelt. 

“I don’t think there’s a shortage of land itself,” McGillivray said. “What we need to do is take good land inventories, find out where we can build and how safe that land is.” 

A LOCAL PROBLEM

Flood mapping — the process of identifying areas affected by floods or potential floods — is a provincial responsibility that often occurs in collaboration with municipalities, so flood mapping and zoning practices are different by province and territory. 

In Ottawa, zoning adheres to Ontario’s regulations prohibiting development within the one-in-100-year flood zone: the area with a one per cent chance of being affected by a major flood event in a given year. 

According to Carol Ruddy, Ottawa’s program manager of zoning and intensification, the municipality goes one step further by using a one-in-350-year flood zone planning tool to avoid building developments in areas that could become a flood zone down the line. 

“It’s just to build some resiliency into communities from the get-go,” she said.

The one-in-350-year recommendation attempts to address the impacts of climate change: “We can’t predict how the weather’s going to change in the future, but we do know we’re having more extreme events,” Ruddy said.

She added that larger municipalities like Ottawa have resources to partner with local conservation authorities for flood mapping, but that’s not the case for all communities. 

Geneviève Thouin, director of adaptation programs with the Federation of Canadian Municipalities, said outdated information is the main barrier for municipalities when avoiding flood zones.

“Most of the country’s flood maps are quite old. They date back to the ’80s or so,” she said. 

“All municipalities face a real challenge in terms of sufficient financing to be able to undertake these types of initiatives: the planning aspect, getting to the data, making sure the risks are known and also undertaking the projects to actually reduce and mitigate those risks,” she said. 

Easy access to updated flood mapping and hiring building specialists would be key to better prepare municipalities, Thouin added. 

“Looking at reducing risks will create more affordability,” she said. “There’s a lot of interest for municipalities across the country in undertaking some of the climate adaptation and resilience work.”