The effects of climate-change-induced catastrophic infrastructure damage can be measured in ways large and small.
The Intact Centre on Climate Adaptation at the University of Waterloo in Ontario reports the tally for catastrophic insurable losses in the property and casualty insurance sector from January to May 2018 exceeded $800 million, according to the Insurance Bureau of Canada.
The Intact Centre also estimates basement flooding causes impacted homeowners to miss an average seven days of work and results in an average repair bill of $43,000, not to mention significant emotional distress.
In an effort to build new resilience into Canadian communities, the CSA Group and the Intact Centre have developed a new national standard called Flood-Resilient Design for New Residential Communities based on a report prepared by the Intact Centre identifying 20 best practices for mitigating damage caused by flooding in new residential communities.
The Intact Centre consulted with over 100 municipal stormwater experts, engineering consultants, developers, homebuilders and other stakeholders, wrapping up its report last fall. The new standard, funded by the Standards Council of Canada, is currently being finalized for publication in October 2019.
Natalia Moudrak, the director of Intact’s Infrastructure Adaptation Program and vice-chair of the technical committee preparing the standard, said the uptake of the 20 best practices has been swift, considering the initial report only came out last fall.
“On the ground we are seeing some municipalities take the best practices report and start cross referencing their stormwater management guidelines for new developments,” Moudrak said, noting developers and homebuilders are also taking steps to incorporate the best practices into their guidelines.
“Imagine a homebuilder who wants to have a competitive advantage and showcase their brand in the face of this risk, you say, not only is this community certified to be flood resilient, you as a homebuyer are getting greater piece of mind and annually you benefit by lower insurance rates on the home.”
Key elements of the new standard include discouraging building in floodways; increasing storm-sewer capacity in new communities; designing streets to channel rainfall to safe discharge areas; elevating homes above potential water levels that follow extreme rainfall events; and rethinking the location of water treatment facilities to reduce sewage backup into homes.
The threats are climate change combined with ill-advised building practices, the spread of development and other factors such as aging infrastructure. Seventy-three per cent of wetlands have been lost due to development, said Moudrak.
“In addition to microbursts when a month’s worth of rain is falling in a matter of hours in a localized fashion, we have been losing pervious surfaces,” she said. “It used to be wetlands could act as a sponge and retain some of that rainwater, rather than it spilling into basements.”
As for aging infrastructure, Moudrak commented, “In many older communities in Canada, systems were designed to only withstand one- and two-year events. What will they look like if we have these extreme downpours, if we have some operational failures, maybe with debris in the river causing blockage and spillage?”
The report notes flooding also stresses the mortgage market, gives rise to lawsuits and affects municipal insurance costs and bond ratings.
Other benefits of implementing the best practices are said to include reduced liability, improved local co-ordination and planning, clarity for developers, improved construction quality and more public awareness.
The new standard will operate alongside other guidelines including upcoming changes to building codes being implemented by the National Research Council. That process takes four or five years while the new standard can be adopted by various stakeholders right away, Moudrak noted.
Among stakeholders from the construction and engineering sector that have contributed to consultations are Stantec, Amec Foster, Aecom, the Canadian Home Builders’ Association, Mattamy Homes, Lion’s Gate Homes and Brookfield Residential. The final workshop involved 25 stakeholders who ranked a long list of suggestions and came up with the final 20 best practices that met the twin criteria of technical feasibility and cost effectiveness.
“We kept the ideas that scored the highest, meaning the most practical ones on the ground right now to drive flood resilience forward, the most material ones,” Moudrak explained, saying the participants selected the “low-hanging fruits that can materially reduce flood risks.”
Moudrak acknowledged the Intact Centre benefits from funding from the Intact Financial Corporation, an insurance provider, but said the research is independent and balanced.
“From a standpoint of who wins from the standard, everyone wins,” she said. “Homebuyers have safer houses and reduced insurance premiums, municipalities win because they can show due diligence in following good storm management guidelines, and homebuilders and developers can demonstrate due diligence in designing communities in accordance with nationally recognized standards of resilience.”
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