CSA Group report calls for wider use of nature-based solutions for flooding, erosion

In 2021, Abbotsford, B.C., experienced one of Canada’s largest flooding disasters when the Nooksack River overflowed and breached its dike. Photo credit: edb3_16,

The CSA Group has released a new report designed to help governments shift from traditional grey or engineered infrastructure, such as walls and dikes, to nature-based solutions like restoring forests and wetlands, to manage flooding and erosion.

Authored by the Intact Centre on Climate Adaptation at the University of Waterloo, the report reviews watershed management practices within provinces, as well as trends in federal funding for flood risk projects. It also identifies existing best practices and opportunities for improvement when nature-based flood solutions are applied at the watershed-scale.

Floods continue to be the costliest natural disaster across the country.

The report, Managing Flooding and Erosion at the Watershed Scale: Guidance to Support Governments Using Nature-Based Solutions, notes that approximately 1.5 million homes, representing 10% of the Canadian residential housing market, are located in high-risk zones where they are ineligible for flood insurance.

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“This research supports the addition of new nature-based solutions standards that enhance an already robust set of existing standards to mitigate flood risk,” announced Michael Leering, CSA Group director of environmental and business excellence, in a statement. “We are encouraged by the growing momentum at regional levels to adopt new flood resilient standards, and this research is the latest tool to support all levels of government,” Leering added.

Nature-based solutions can contribute to flood and erosion management by storing, slowing, and reducing flood waters in the upper and middle watershed, using native vegetation where possible. These solutions can also improve connectivity of watercourses with their flood plains, creating space for water and room for the river. They also preserve and restore sediment processes.

The report has three primary recommendations that CSA Group suggests could be supported by the development of future standards. First, the report states that it’s important to develop consistent provincial approaches to integrated watershed management, as nearly all provinces other than Ontario focus on habitat quality and biodiversity rather than flood and erosion risk objectives.

Second, the report notes that funding should be prioritized for river flood management of high-risk watersheds, as funding directed to municipal governments may often not have jurisdiction to implement nature-based solutions at the watershed scale.

Lastly, the CSA report suggests that governments should routinely consider nature-based solutions for river flood and erosion management alongside built infrastructure, and should see them as viable long-term strategies with benefits to people and nature. Currently, these options are underutilized, the report’s authors warn.  Funding procedures should be updated to more often than not consider nature-based solutions as the “default solution”, they suggest.

“We are seeing increased awareness of the need to work with, rather than against nature, in tackling flooding in Canada,” announced Joanna Eyquem, lead author of the report and managing director of climate-resilient infrastructure at the Intact Centre on Climate Adaptation. “However, to deliver these flood solutions, we need to work at the scale of natural systems, which in the case of rivers is the watershed,” she added.

CSA Group said the release of the report is timely as the federal government looks to define the role of the new Canada Water Agency and finalize a National Adaptation Strategy.

The report offers a breakdown of each province’s watershed management approach and analyzes the effectiveness of federally funded flood and erosion risk management projects such as those under the Disaster Mitigation and Adaptation Fund.

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