In Spring 2017, Toronto has rain on the brain. Our gardens may be beautifully lush, with twice our usual rainfall in May, but Lake Ontario is at its highest levels in a 100 years, shorelines have moved inland, and flooding has shut down the Islands till at least July 31.
Who’ll stop the rain? Let’s have a little chat about rain gardens. Specifically, one we’ve been watching since it was installed by the City as a pilot project for the Toronto Green Streets initiative (project described on pages 48 and 49 of PDF) on Fairford Avenue at Coxwell.
In July 2015, when we tweeted about the project underway in our east-end nabe, project designer Sheila Boudreau tweeted back to say that she and her team would be there the next day. She offered to meet us to talk about it.
What had started 2012 as a traffic-control measure, to remove an awkward road stub at this bend in the upper leg of Gerrard at Fairford, by 2013 had become an opportunity to experiment with bioremediation. Construction started in 2014, replacing a big triangle of asphalt with a trench rain system and rain garden. The goal was to capture rainwater, including some from roads, and to filter it as much as possible before returning any overflow to the rainwater system. According to this PDF, it can capture as much as 198,000 liters of storm water a year.
All together, 400 square meters of asphalt was removed. In its place, nearly half is now permeable green space, filled with shade trees and over 2,000 pollinator plants. The new paving is high-albedo concrete – meaning its lighter-coloured surface reflects sunlight (and its heat) rather than absorbing it like darker asphalt does. Along with the greenery and soil, this cools the area by an estimated 7˚C. There’s seating and improved lighting, too. It’s a parkette. For people. And it actually came in under budget.
Open grillwork (above) helps people like us see what’s happening to the storm water. I walked down on a rainy day earlier this month to see it in action. I wouldn’t say that rain from the street gushed into the parkette, but the “rain (captured) on the plain” was clearly evident. The soil elevation is like a mini valley, and materials beneath the surface are designed to retain and filter rainwater. Limestone blocks at the end of the grill drain seemed like they were placed to control erosion at point of entry.
Above, (left to right) you can see the new lighting, and the garden in July and September of 2015, then just this month in May 2017. (Click any image to enlarge and see the slideshow.) Many plants are natives. Later in July, purple spikes of Liatris bloom. By September, they’ve turned into architectural brown pillars, and plants like Rudbeckia take over. When snows recede after winter, the ornamental grasses look pleasantly tufted.
Is the parkette successful as a rainwater diversion project? When you consider lake water levels in 2017, changing this small patch of the city landscape might seem like a drop in the bucket. But in terms of naturalizing the concrete jungle, it enhances the corner far more than a patch of asphalt. I know I’ve never crossed the street as often – on purpose – just to look at this wedge of land before. By that measure alone, it’s a success.
And more good news: Coxwell is getting a second Green Streets parkette to replace a similar road stub, a short walk south at Dundas. This one has the fancier name Raindrop Park. I look forward to seeing it happen.