Ottawa’s climate is changing. Gradually, the weather is getting wetter, hotter and more severe. Our city is subject to more frequent intense weather events such as flooding, heatwaves, severe thunderstorms, ice storms and snowstorms.
This past spring, hundreds of homeowners temporarily abandoned their homes to the rising waters, highways were eroded and closed, and the Canadian Forces were sent in to aid with emergency efforts. The city is struggling to keep up with infrastructure repairs – from violent storms, freeze-thaw cycles and record rainfall events.
It’s clear Ottawa’s climate is changing, but what can we do about it?
In nature, most of the rain that falls is intercepted by living things such as trees and other vegetation, but when a forested area is turned into a city, everything changes, and so should the way we build our landscape.
Ottawa needs to adapt and prioritize solutions that integrate living and built systems designed to slow down, soak up and filter rainwater.
Slowing down and soaking up rainwater prevents it from pooling, flooding our homes and damaging our creeks, streams and built infrastructure. Filtering rain before it enters our waterways keeps out many harmful chemicals and toxins from our driveways, sidewalks and roads. Basically, we need our landscape to be more absorbent and permeable, ensuring that rainwater filters through the landscape rather than allowing it to run off hard surfaces like paved roads into storm sewers.
Absorbent landscapes, like parks, can reduce runoff by up to 10 times compared to impermeable surfaces like roads or parking lots.
This type of landscape is called green infrastructure, and Ottawa needs more of it, now!
There are many forms of green infrastructure, from parks, to street trees, to permeable pavements, to green roofs, bioswales, rain gardens and stormwater ponds. Green infrastructure, also referred to as low impact development, can include living systems (e.g., trees, green roofs, bioswales, rain gardens) as well as green technologies (e.g., porous pavements, rain barrels and cisterns). Green infrastructure treats stormwater at source by filtering it through the natural water table rather than funnelling it to our waster water treatment plant. But just because it’s “green”, doesn’t mean it’s green infrastructure. For example, the soil in parks can become heavily compacted from use, which reduces the amount of water that can filter through the soil. Another example is when street trees are only given a small soil volume under the sidewalk to grow from. Not only will they not grow very big, but their capacity to slow down, soak up and filter stormwater becomes negligible at best.
Don’t dismay! We have solutions and a clear way forward.
The City of Ottawa has several plans in place, but one, in particular, is called the Greenspace Master Plan which outlines quite clearly the importance of green space and the integration and implementation of green infrastructure at a municipal scale. The City of Ottawa even mentions how “green streets” could be a way to connect dedicated greenspaces – such as our parks and park network– and filter rain where it falls, rather than directing it to our already over-burdened sewage treatment system. In its multi-million dollar Ottawa River Action Plan, the City of Ottawa also started to identify green infrastructure as a way to increase urban permeability through street renewals and neighbourhood-level pilot projects.
This sounds good, so what’s the problem?
The City of Ottawa has all the tools and knowledge it needs to roll out green infrastructure at scale. They know green infrastructure is fundamentally important for the future of our city, and they are getting their toes wet with local-level pilot projects such as the Sunnyside traffic calming project, the Stewart Street Bioretention project, and the more recent (and ongoing) Pinecrest Neighbourhood Rain project. The problem is that the rate at which climate change is hitting our city means that we need to get more than our toes wet, we need to jump in!
We need to move past local-level pilot projects and towards the integration of green infrastructure on a city-wide scale. The science behind green infrastructure is already out there. Many municipalities across Canada are directly incorporating green infrastructure into their climate change resiliency plans. For example, Vancouver’s new rainfall management plan argues that if we have both grey and green infrastructure working together, we will have more efficient stormwater resiliency.