Bob McDonald's blog

Mitigating flood risks in your own backyard

A new report details ways local communities can boost their resiliency to extreme weather events

A new report details ways local communities can boost their resiliency to extreme weather events

Brantford residents were being evacuated due to flooding along the Grand River after an ice jam upstream of Parkhill Dam sent a surge of water downstream in February 2018. (THE CANADIAN PRESS/Aaron Vincent Elkaim)

A new report out of the University of Waterloo summarizes a five year, cross-Canada project to demonstrate how local communities can make small improvements to the landscape that could make big differences during floods.

As extreme weather events become more common, flooding is an increasing threat, causing more than a billion dollars in economic losses to Canadians every year. Familiar images of sandbags piled high to protect buildings are last minute attempts to direct rising waters away from homes and offices during a flood. But relatively simple actions taken ahead of time to direct water back into the ground before a flood can prove to be more effective.

The Intact Centre on Climate Adaptation is an applied research centre within the faculty of the environment at the University of Waterloo that works with homeowners, communities, governments and businesses to identify and reduce the impacts of extreme weather and climate change. Between 2012 and 2017, a series of 11 community-based projects were carried out across the country to demonstrate how relatively easy and practical changes to local water management — from backyard improvements to local waterways — can go a long way to reducing the effects of flooding.

Paved surfaces means the water has nowhere to go

The biggest contributor to flooding is the fact that excess water from heavy storms has nowhere to go. As our urban areas grow, we have covered what was once porous forest floor or plant-covered land with pavement, sidewalks, driveways and patios. Rainwater that was once able to sink into the soil now runs across the surface, accumulates into large volumes and overwhelms storm sewer systems. The result is a flood and costly property damage.

Flooded tennis courts are shown as the Toronto Islands were threatened by rising water levels in 2017. Areas that used to be covered in vegetation, that are now paved over, are problematic when flooding occurs. (THE CANADIAN PRESS/Nathan Denette)

One solution is to make the urban landscape more porous, so the water can sink into the ground rather than accumulate on the streets and in basements. The project ranged from single home modifications to community-based tree-planting to shoreline improvements.

Potential ways to mitigate flood damage

Among the 11 projects: experts visited 100 homes in Calgary as part of an education program to look at simple solutions for the household such as changing the angle of the downspouts, so water doesn't fall close to the foundation of the house; 30 "Depave" projects in Ontario and Alberta replaced pavement with porous material for water absorption; in Quebec, a green alley was created in one community, while trees were planted in a storm runoff area in another.

Sometimes the scale of change seems overwhelming, such as the transition from fossil fuels to cleaner forms of energy. But little changes, carried out by a lot of people is a positive move in the right direction as we adapt to living on a changing world.- Bob McDonald, Quirks & Quarks

On a larger scale, local wetlands were created to not only capture water, but filter it and provide a habitat for wildlife. And finally, shorelines along estuaries and creeks from Nova Scotia to British Columbia were improved to prevent erosion.

The beauty of these projects is that they were mostly community-based. People were willing to give their time and muscle power to rip up pavement, dig in the dirt, plant trees or gardens because they realized it was an investment in the safety of their own homes and businesses. It also improved the aesthetics of the regions by adding more greenery.

Volunteers plant a rain garden in Alton, ON (Credit Valley Conservation)

It is a harsh reality that we need to adapt to a changing planet. Sometimes the scale of change seems overwhelming, such as the transition from fossil fuels to cleaner forms of energy. But little changes, carried out by a lot of people is a positive move in the right direction as we adapt to living on a changing world.

About the Author

Bob McDonald

Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.

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