Despite ample evidence that nature-based solutions to flooding are cheaper and more effective than trying to contain water behind dikes and artificial channels, Canada continues to prioritize a concrete-centric approach, a recent report concludes.
Federal funding for climate adaptation “strongly favoured structural solutions” over the absorption and distribution functions of healthy ecosystems, reports the Globe and Mail, citing research conducted by the University of Waterloo’s Intact Centre on Climate Adaptation for the CSA Group, a national standards development organization.
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The Intact Centre report studied two federal flood mitigation programs: the National Disaster Mitigation Program (NDMP), which funded 460 projects between 2015 and 2022, and the Disaster Mitigation and Adaptation Fund (DMAF), which supported 45 efforts dealing with flooding and erosion between 2018 and 2022.
Only six of the NDMP projects, all in Ontario, used nature-based solutions. Of the DMAF projects, “just six used nature-based solutions, while another nine employed elements of them.”
Often, nature-based solutions involve removing “grey infrastructure” barriers previously put in place to prevent the natural flow of water, the Globe explains. “Some rivers, for example, were straightened historically; reintroducing meanders can slow the velocity of water moving downstream and reduce peak water levels.”
Allowing trees to grow back on previously cleared floodplains is another solution. In a healthy forest, thick loam acts as a “shock absorber” during spring run-off, soaking up water like a sponge, while shade from forest canopy slows down the rate of snow melt.
Without trees, and with the hardpack soil or pavement that remains, snow melts quickly, and water rushes off into surrounding waterways in a torrent, with predictable results.
“With nature-based solutions, what we try to do is soak up the water, allow infiltration, slow down the flow through reconnecting wetlands or natural floodplains upstream,” said report author Joanna Eyquem. Relying on grey infrastructure means “storing up maintenance commitments,” she added, citing the devastation wrought in November, 2021 when a massive atmospheric river swept across British Columbia’s Lower Mainland.
“Grey infrastructure can fail, leading to catastrophic flooding,” Eyquem said. “Whereas if we’re working with natural processes, we’re not subject to those failures, and it costs less to maintain in the long term.”
Flooding is “Canada’s costliest variety of natural disaster, and damages are rising amid pressures from a warming climate, a growing population, and other factors,” the Globe says. But nature-based solutions remain thin on the ground and underfunded by Ottawa. This partly owes to limited experience and lack of hard data on their efficacy, Eyquem said, suggesting that Canada could learn from places like the Netherlands, which has decades of experience dealing with floods.
A further challenge is that nature-based solutions typically focus on watersheds, meaning they can fall outside a single city’s priorities or funding arrangements. “Federal programs have tended to direct money to individual municipalities, which have limited authority to modify entire watersheds,” explained the Globe.
The Intact Centre cited Ontario as a leader in nature-based solutions in Canada, largely because it possesses oversight bodies that are legally mandated to manage water and erosion in entire watershed systems. (The conservation authorities continue to pursue this work despite having their flood management budget slashed 50% by the Ford government in 2019.)
The CSA Group recommended that Ottawa mandate its newly-minted, multi-million-dollar Canada Water Agency to draw up consistent national standards to encourage nature-based solutions to flooding.
