New National Standards to reduce the risks of flooding from climate change
With extreme weather on the rise, flooding is now the fastest-growing source of disaster-related costs in Canada; in eleven of the twelve years leading up to 2020, property and casualty insurance payouts have exceeded $1 billion per year. These events have devastating impacts on Canadian households, businesses, and communities, and drive up home insurance premiums and costs to governments for disaster assistance and recovery.
Many of these damages, however, can be avoided with good community-level planning, design, and management. Two new National Standards of Canada have now been published to guide municipalities in reducing flood risks in light of climate change:
- CSA W210 Prioritization of flood risk in existing communities, which provides an evidence-based, systematic framework to help prioritize flood mitigation measures within a community or municipality, and
- CSA W211 Management standard for stormwater systems, which provides guidance on how municipalities can more effectively manage their stormwater systems, increasing the systems’ capacity to absorb the impacts of extreme weather events such as short-duration, high-intensity rainfall.
Flood risk
Flood risks in existing communities can vary greatly depending on a neighbourhood’s physical characteristics, the era of its development, underlying land use policies and regulations, and the level of service for flood risk mitigation that is incorporated into the area’s historical infrastructure design standards.
CSA W210 Prioritization of flood risk in existing communities supports the integration of flood risk management in the municipal infrastructure planning process, serving as a tool to inform decisions about flood-related resource allocation. The implementation of this standard along with other related policy instruments are critical for flood protection measures in existing communities to be effective. It presents a three-tiered risk assessment methodology that overlays various flood hazards and proxy risk factors to score and determine areas within a community at highest risk of flooding.
“CSA W210 offers a systematic flood risk assessment framework for municipalities, watershed organizations, and other stakeholders,” said Barb Veale, Director, Planning and Watershed Management, Conservation Halton and Chair of CSA Technical Committee that developed CSA W210. “Given extreme flooding events recently experienced across Canada, it is an invaluable, timely, and easily applied standard to assess flood risk. The application of this tool will provide valuable insights for informing management decisions and solutions and help communities more effectively address flooding issues and related socio-economic impacts.”
Management of stormwater systems
Building climate resilience into stormwater systems is an iterative process that requires all aspects that intersect with the system be accounted for and included in a management plan. Beyond infrastructure, the management of a stormwater system needs to include processes such as emergency management, competency of personnel, and a robust description of the system. Key to the success of a management plan is the commitment of top leadership and a process for continuous improvement.
CSA W211 Management standard for stormwater systems provides guidance that identifies key policies, processes and procedures needed to be in place to effectively manage a stormwater system. It identifies roles and responsibilities for each aspect and explicitly calls for the endorsement by top leadership or decision makers. It is adaptable for any sized system but will be of particular value to owners and operators of systems with limited capacity to identify what is needed in a management plan for their system.
“Stormwater management is being brought to the forefront with the publication of this standard,” said Carl Yates, Interim CEO Atlantic First Nations Water Authority Inc. and Vice Chair CSA Technical Committee that developed CSA W211. “In the context of ongoing and recent flood events on the Pacific and Atlantic coastlines, many professionals are trying to ensure resilient stormwater systems are developed and managed. This standard serves as a baseline for that goal.”
Expanding the toolkit of climate-resilient standards and guidance
Developed by CSA Group, the publications are the latest in a suite of standards and guidance funded by SCC’s Standards to Support Resilience in Infrastructure Program, a five-year federally funded initiative to adapt Canadian infrastructure to the current and future impacts of climate change.
"In light of the devastating floods and other disasters that Canada experienced in 2021, it is more important than ever to make better decisions that help us avoid the worst impacts of climate change,” said Chantal Guay, CEO of the Standards Council of Canada. “These two new National Standards of Canada represent state-of-the-art knowledge and best practice. They should be part of the toolkit of every community in Canada, large and small.”
Both CSA W210 and CSA W211 are available via free view-access to Canadian IP addresses, or downloadable purchase, in the CSA Store.