Weathering the Storm: Developing a New Flood Risk Standard for Canadian Communities

Toronto, ON (Jan. 18, 2019) – Flooding within urban centres is Canada’s costliest and fastest-growing extreme weather challenge. Insurable claims in Canada have risen from an average of $405 million per year between 1983 and 2008 to an average of $1.8 billion per year between 2009 and 2017 (in $2017), with flooding contributing the greatest proportion of this increase.

Against the backdrop of unavoidable climate change, the need to limit this risk will only grow. In an effort to alleviate future flood risk, a new report from the Intact Centre on Climate Adaptation, University of Waterloo, highlights a range of solutions that can be deployed practically and cost-effectively within communities and households.

This report was supported financially by the National Research Council of Canada, the Standards Council of Canada and the Intact Financial Corporation, with the objective to fund the development of a National Standard of Canada by SCC-accredited standards development organizations. It features a unique framework for screening flood hazards and vulnerabilities to select areas within communities that should be targeted for flood-resiliency retrofits – a result of an extensive, year-long consultation with municipal experts, engineering consultants, conservation authorities and industry representatives from across the nation.

“Extreme weather caused by climate change is both a societal issue and an economic priority – there is a role for all of us to play in building a more resilient society. The Intact Centre “Weathering the Storm” report provides Canada with clear, practical steps to protect our communities against flood damage. Being resilient means adapting to our new climate reality – build in the right place, build right the first time, and build back better,” said Monika Federau, Chief Strategy Officer at Intact Financial Corporation.

The report, Weathering the Storm: Developing a Canadian Standard for Flood-Resilient Existing Communities, includes such measures as:

  • Proactive maintenance of flood control structures such as culverts, bridges, dykes and channels to ensure that they perform as intended during storm conditions;
  • Construction of strategically placed stormwater storage tanks and stormwater ponds within and around communities;
  • Removal of snow from critical overland flow path locations prior to forecasted flood events;
  • Clearing of leaves and debris from catch basins, particularly during Fall and Spring;
  • Re-grading of lots and roadways to carry water away from properties and onto streets and right-of-ways;
  • Installing backwater valves (sometimes called a backflow or sewer backup valve) on sewer line within basements, and disconnecting downspouts from weeping tiles, to limit sewer backup flooding;
  • Sealing manhole covers in low-lying areas where water accumulates and has a higher risk of causing sewer backup flooding;
  • Implementing stormwater diversion projects such as piping that can direct excess stormwater away from flood vulnerable areas; and
  • Delivering public education programs on flood prevention and maintenance activities to homeowners, municipal staff, insurance brokers and real estate agents.

As extreme weather becomes more severe and frequent due to climate change, every effort must be made today to better protect existing communities from future damage and destruction. This aligns well with the climate commitments made by Canada as a signatory to the Paris Agreement, the United Nations’ Sendai Framework for Disaster Risk Reduction, and the Pan-Canadian Framework on Clean Growth and Climate Change.

“The Standards Council of Canada (SCC) is leading the way in recognizing the impact of flooding and by working with the Intact Centre on Climate Adaptation, and our accredited standards development organizations, SCC is laying the foundation for a new national standard that will ensure flood resilience in Canadian communities,” said Chantal Guay, CEO of the Standards Council of Canada. “This collaboration is another example of how standardization strategies can strengthen Canadian infrastructure against climate change—and protect vulnerable communities across the country.”

“The National Research Council is committed to the continued support of partners like the Intact Centre on Climate Adaptation, the Canadian Commission on Building and Fire Codes, and standards development organizations,” said Philip Rizcallah, Program Director, National Research Council of Canada. “This support ensures that climate change adaptation and resiliency measures introduced into Codes, standards and guides are based on the latest science and research to protect Canada’s critical infrastructure, homes and buildings, providing a safer environment for all Canadians.”

Executive Summary

In recent years, the financial and social costs of natural catastrophes in Canada have escalated beyond historical levels. Residential flooding has been a key driver behind this trend, which has led to upward pressure on residential insurance premiums, mental health stress for homeowners impacted by flooding, potential increases in residential mortgage defaults, and lawsuits directed to builders and municipalities that fail in their fiduciary duty to anticipate and mitigate flood risk.

Fortunately, a range of practical solutions can be deployed to reduce and limit risk of flooding across a variety of circumstances. These include proactive maintenance of flood control structures, re-grading of lots and roadways, constructing new or upgrading stormwater storage facilities, and many other measures.

Public engagement and education programs on flood prevention and maintenance activities can also drive the uptake of flood-resilience initiatives in existing communities, particularly for “lower cost” solutions that depend on homeowner participation and support.

To effectively prioritize these different approaches to mitigating flood risk, a flood hazard and vulnerability screening framework can help identify areas in existing residential communities that require the most immediate attention. Drawing on extensive engagement with key stakeholders across Canada, this report outlines such a framework, consisting of the following key considerations:

  • Age of development: in the absence of major retrofits, older areas in Canada (e.g., pre-1970’s) are typically more flood-prone, compared to newly-built subdivisions;
  • History of flooding: in absence of major retrofits, where municipal records (e.g., flood reports) indicate that repeated floods have occurred, these areas may be the most flood-prone;
  • Design standards: areas where community design standards were less stringent (e.g., permitting development in the floodplain) are typically at a higher risk of flooding;
  • Proximity to the floodplain: areas located closer to the floodplain are typically at a higher risk of flooding;
  • Topography: lower-lying areas are typically at a higher risk of flooding;
  • Land use changes and intensification rates: areas where significant urbanization and growth has occurred, and where natural capacity to absorb rain water has diminished (e.g., as a result of losing permeable areas to development), are at a higher risk of flooding;
  • Sewer system types: areas with combined sewer systems (CSS) (e.g., systems that carry sanitary and storm water in one pipe), or partially-separated sewers, compared to fully separated systems, are typically more flood prone; and
  • Presence of critical infrastructure, essential services and social vulnerabilities: each of these criteria would prompt more urgent response to the identified flood-hazard areas.

Application of the framework will enable communities to make better-informed decisions when prioritizing areas for flood-resiliency programming. The purpose of the report is to serve as a seed document for a future National Standard of Canada, to be developed based on this framework.

Guidance in this report has been well-vetted, as it draws heavily on the insights of municipal planners, engineers, consultants, conservation authorities, developers, homebuilders, insurance industry representatives and stakeholders across Canada.

The report was supported financially and technically by the Standards Council of Canada (SCC) and the National Research Council (NRC), in response to commitments made by Canada as a signatory to the Paris Agreement1, the United Nations’ Sendai Framework for Disaster Risk Reduction (DRR)2, and in support of the Pan-Canadian Framework on Clean Growth and Climate Change. Consistent with the intent of these international and national commitments, this report serves to help Canadians weather not only the storms of today, but to also ensure a more flood-resilient and climate-ready tomorrow.

Read or download the full report: Weathering the Storm: Developing a Canadian Standard for Flood-Resilient Existing Communities (PDF).

About Intact

Intact Insurance is Canada’s largest home, auto and business insurance company, the choice of more than four million consumers. Its coast-to-coast presence and its strong relationship with insurance brokers mean the company can provide the outstanding service, comfort and continuity customers deserve. Intact Insurance is a member company of Intact Financial Corporation (TSX: IFC), the largest provider of property and casualty insurance in Canada. For more information, visit

The Intact Centre for Climate Adaptation (ICCA) was developed after five years of research and discussions with the University of Waterloo. The ICCA is a national applied research centre focused on bringing practical and cost-effective solutions to address climate change and extreme weather events. Every Canadian has felt the effects of climate change in recent years. The ICCA serves as an incubator to promote new ideas on how we, as a country, can adapt to the ever-changing weather.

SOURCE: Intact Centre on Climate Adaptation, Faculty of Environment, University of Waterloo

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