As the images of flooding and damage in Houston from Hurricane Harvey continue on the front pages of newspapers and on social media, it’s a good moment to think about how ready Canadian cities are for managing extreme weather.
As we wrote about in our Resilient Parks, Resilient City park solutions brief last month, climate change in Canada is leading to more and more extreme weather, causing stress on our urban environments. This includes droughts and heat waves, but also heavy rainfall that can lead to flash floods and long-lasting damage to our cities.
Toronto just experienced what climate change means in a very real way when heavy spring rain caused flooding that closed Toronto Islands for most of the summer. Parts of Montreal have also experienced flooding from heavy rainfall this year. And only a few years ago, Calgary experienced severe flooding that caused the evacuation of neighbourhoods and killed several people.
All of this was on my mind when I went to the City Parks Alliance’s Greater Greener conference in Minneapolis/St. Paul at beginning of August where I was able to hear Lykke Leonardsen speak. Leondardsen works in sustainability at the City of Copenhagen and spoke about that city’s climate adaptation plan (well worth a read) and cloudburst management strategy which relies heavily on green infrastructure investments.
We covered green infrastructure and its different elements in the Resilient Parks park solutions brief, so I won’t go into detail about that here. But I do want to share a bit about what I heard from Leonardsen at the conference and the amazing, forward-thinking work that Copenhagen is doing to climate-proof their city by rethinking their streets, parks, and other public spaces to transform stormwater from a liability into a celebrated resource. There is much we can learn in Canada from Copenhagen’s approach.
Build parks to flood
By now people are likely familiar with the idea of parks being designed as places that can also capture and hold water during storms or protect a city from flooding. We have some great examples in Toronto, including Corktown Common, which we covered in our Resilient Parks, Resilient Cities report.
But Copenhagen is taking this a step further, engineering public spaces, both hard-surfaces and soft green areas, to hold water and use it as a resource in the park. Their newly built Tasinge Plads (title picture) captures not just the rain water that falls on the park, but water from the surrounding neighbourhood during storms. This helps reduce flooding, but it also creates a unique park where large upturned umbrellas capture additional rainwater and create a playful element.
A park built to flood doesn’t have to be green, however. It can be a hard-surface plaza, basketball court, or other playing surface that is designed to capture water during a storm, transforming it into a kind of reflecting pool while the water drains away–like Copenagen’s Enghave Park.
Create rivers out of streets
Part Copenhagen’s plan calls for Cloudburst Boulevards, which, despite being beautifully poetic, perform a very important function when it rains. These boulevards are designed with depressions, like bioswales, and other graded-areas that essentially become small streams during heavy rainfall events, slowing down, soaking up, and guiding rainwater.
It also has the added benefit of creating what could be a really delightful amenity from the water that we usually see rushing down the gutter, picking up cigarette butts and other garbage along the way, before pooling around clogged drains on city streets. Apologies for the poor image quality below, but this is a picture I took during Leondardsen’s presentation of a Cloudburst Boulevard in action. You can see more images in this presentation.
Find a win-win-win solution
Finally, all of this will actually save Copenhagen money. And not just a little bit, but a huge amount. Forget for a moment the cost of damage from storms (although it can be huge–Toronto’s July 2013 storm caused $1 billion in property damage insurance claims), which this plan will surely help mitigate. Focus instead on the cost of just implementing the infrastructure improvements to cope with extreme weather and increased rainfall. Copenhagen’s plan, which relies on a combination of green infrastructure elements and more traditional “grey” infrastructure (like pipes and treatment plans), will cost less than half of what it would have cost to implement a plan based entirely on grey infrastructure.
That’s an impressive saving. But there’s more. Because green infrastructure also usually results in new and improved public spaces and parks, you get the added benefit of a stormwater infrastructure investment that also provides a visible public recreational and aesthetic benefit.
Save money, build infrastructure, improve public space. That’s a nice set of wins.