About 12 cars were stuck on the flooded Don Valley Parkway in Toronto after torrential rain caused the Don River to overflow at the Dundas Street bridge.Melissa Tait/The Globe and Mail
Elliott Cappell is PwC Canada’s national climate change leader. He previously served as Toronto’s chief resilience officer.
On June 29, 2017, against the backdrop of a flooded Toronto lake shore, then-mayor John Tory asked me to find solutions to urban flooding. In response, I convened a working group of 18 experts from across Southern Ontario, sought advice from more than 50 cities globally and detailed our recommendations in Toronto’s first Resilience Strategy.
So when, just over seven years later, following the July 16 deluge in Canada’s biggest city, Mayor Olivia Chow asked City of Toronto staff to “identify how we can … avoid costly floods” as a “critical component to our City’s resilience strategy,” it sounded awfully familiar.
If we had many of the answers to flooding in Toronto in 2017, why are we in a similar place in 2024?
It’s because all these urban-flooding resilience solutions – the ways – come with costs, and Toronto is just one of many cities around the world that haven’t figured out the means. “Ways” and “means” are the fundamental building blocks for addressing urban flooding in Canada.
First, the way we think about flooding needs to change. North American cities have historically been planned with a “keep the water out” mindset, artificially moving water away from development, usually using concrete. By contrast, cities that successfully manage urban flooding plan and manage infrastructure with an uber-Dutch mantra: “let the water in.” They think of flooding as an inevitability, best addressed with a mix of nature, infrastructure, urban planning and social policy.
“Letting the water in” means everyone needs to think of themselves as someone who will get flooded; it’s not a matter of if, but when and how. It requires all of us to accept that roads, trains, buildings and electrical equipment are going to be flooded – which is basically what happened in Toronto.
North America’s most successful urban-flood resilience projects apply a Dutch approach. The Big U – a multibillion-dollar, award-winning project to protect lower Manhattan from flooding after Hurricane Sandy in 2012 – is explicitly about “living with water.” The Big U is designed to flood, and built to withstand a “once-in-100-years” flood. Unsurprisingly, the Big U’s roots were drawn from the designs of a Dutchman, the flood expert Henk Ovink.
Letting the water in to Canadian cities would require a range of capital projects and policy changes. Green infrastructure projects would have to be scaled massively, swapping out impermeable surfaces with trees and green spaces. Cities would also need to upgrade standards for the wetter climate we know is coming, as opposed to the current practice, by which we plan based on observed weather from the drier past. For example, under today’s standards, a new building in Toronto needs to be able to retain 25 millimetres of rain on site over a 24-hour period. On July 16, 25 mm of rain fell in just 10 minutes.
A transformative flood-resilience program would likely take 20 years from start to finish. It might sound ambitious, but cities such as Copenhagen are great models for Canada. Copenhagen is approximately 10 years into a 30-year Cloudburst Management Plan, which is designed to protect the city from 100 mm of rain. (For reference, Toronto’s Pearson Airport received approximately 98 mm of rain on July 16.)
While the ways are relatively clear, the means are less so. As a starting point, cities need to determine how much to invest in resilience. This starts with summing up the financial costs of a July 16-type event, quantifying how those costs may rise with climate change over the next 30 to 50 years, and then comparing those estimates to the costs of a Copenhagen-style Cloudburst plan. In some cases, such an investment will make sense; in other cases, it may be better to accept some level of flooding and focus spending on a quick cleanup.
There are four parties who principally pay for urban-flooding cleanup: taxpayers, property owners, insurers and infrastructure owners. Those groups will either have to pay now or pay later, so they should have a say in whether and how to pay for resilience. But the most common method is the implementation of a stormwater management fee, which effectively charges property owners for their role in urban flooding. But such fees are politically controversial, which is why Toronto’s “means” have been stuck for several years. I am not necessarily advocating for the “rain tax” – but one way or another, we will need to find the means for the ways.
As Bob Marley wrote, “Some people got hopes and dreams, some people got ways and means.” If Canada’s city planners and mayors want to seriously address urban flooding, they will need to be in the latter group.