How does your (rain) garden grow? A mosaic about really green infrastructure

You might recall that climate change is going to mess with precipitation trends (I made a mosaic about it a while back) and, as a result, some areas of the world will experience more intense downpours. In cities, which tend to be covered with a high percentage of impermeable surfaces (think roads, rooftops, parking lots, etc.), this water can’t soak in, so we have to direct it somewhere using man-made solutions, like storm sewers. When our storm sewers get overwhelmed by a big rainfall event, we can end up with flooding in our streets and our basements.

As these downpours become more intense and cities continue to expand (thereby increasing the surface area covered by concrete, asphalt, and the like), local officials are finding that they’re having to deal with increasing stormwater runoff. One option is to build bigger and bigger storm sewers, but that sort of hard infrastructure can get pretty expensive and you’ll always be playing catch-up as the climate continues to change. A better (and complementary) option is to manage the rain where it falls. Slow it down. Let it soak in. And what’s naturally built to do that? Plants are! Leaves slow down the falling rain, while roots and the soil let it soak in. Not only does this help redirect water away from our storm sewers and avoid overburdening them, but it also helps recharge our groundwater.

Back when I worked on adaptation (which seems like ages ago but in reality was less than a year ago), I had a huge crush on green infrastructure. It just makes sense: it’s cheaper, it comes with a whole bundle of co-benefits, and it actually gets stronger / appreciates with age. Now, when I say “green infrastructure” I’m talking about really green infrastructure (natural infrastructure), like trees and plants and things, not “green infrastructure” the way the current federal government is using the term (to mean environmentally beneficial infrastructure, like public transit or energy efficient housing). Not that there’s anything wrong with the latter definition, I just find coopting an already-established term a bit…confusing. Anyway, we’re talking plants here and using them to solve a problem we’ve created by letting them just do what they do.

There are lots of ways to team up with nature to deal with climate change impacts, like extreme precipitation, heatwaves, and drought, as well as reaping other benefits, like expanding wildlife habitat, creating recreation opportunities, improving air quality, etc. But the specific focus of this mosaic was how rain gardens (and bioswales, which are kind of just big rain gardens but with a much cooler sounding name) can help deal with extreme precipitation.

Rain gardens are pretty much what you think they are: gardens designed to soak up rain. They’re typically located in lower-lying spots / depressions in your yard where the rain would tend to pool naturally and/or in line with your downspout so they can catch the water coming off your roof (rain barrels are also good for this). You can dig the area out and add soil or other filler that will allow it to better soak up the rainwater like a sponge, and then you add plants that are water-loving. It’s as easy as that! (The City of Guelph has a good little primer / guide here.)

In this mosaic, these low-lying areas—prime candidates for rain gardens—are represented through an undulating surface full of swells and valleys. The lines swirl away from the asphalt sections at the tops of the undulations (where the water can’t soak in), running downhill and getting greener and wetter as you move toward the pools at the bottoms of the depressions.

In the KW area, if you’re looking for help with this sort of undertaking, check out REEP Green Solutions. They offer information and workshops on building your own rain garden and on other green living solutions. They’re a fantastic local resource and you can actually see many sustainable solutions in action at the REEP House for Sustainable Living. And, if you live in Kitchener or Waterloo (and a growing number of other municipalities), you can even reduce the stormwater charge you pay to the city if you install a rain garden (or other stormwater management features).

In short: rain gardens look pretty, help your community deal with stormwater (including keeping your basement dry), and save you money. Not a bad deal!