Poor flood-risk maps, or none at all, are keeping Canadian communities in areas prone to flooding

Wednesday, April 24, 2019

Cartographic depictions of areas most likely to flood under certain conditions are invaluable resources for Canadians. But unfortunately, the vast majority do not have access to such maps

Flood maps – cartographic depictions of areas that are likely to flood under certain conditions – are invaluable sources of information for homeowners and civic officials. In the United States, England and France, one can enter a postal code into a government website and quickly assess a property’s susceptibility to flooding. Had Mr. Coochey possessed such information, he could have taken steps to protect his property – or never purchased the home in the first place. Various studies have determined that every dollar spent on flood prevention is worth many times that amount in property replacement costs.

Yet the vast majority of Canadians do not have easy access to such maps. Partly due to government cutbacks – and the reluctance of municipalities to discourage development – all too often the best many homeowners can do is visit a local government office and dust off a decades-old relic intended for engineers or hydrologists.

Professor Jason Thistlethwaite and colleagues at the University of Waterloo recently completed a study of almost 700 Canadian flood maps. “The results are not impressive,” he said. Many were old, few had been digitized and most were not publicly accessible.