Conservation experts maintain that Ontario’s floodplain maps are dangerously outdated and need to be updated before another costly disaster happens.

Conservation Ontario – an umbrella agency for the region’s conservation authorities – estimates that 74% to 78% of the floodplain maps in Ontario are out of date in some way.

“We have some conservation authorities that use mapping that’s on paper,” Conservation Ontario business development and partnerships head Jo-Anne Rzadki told TVO.org. “We have conservation authorities that may have it digitized and on Geographic Information Systems, but they could still update it with new modelling.”

The province’s 36 conservation authorities are responsible for managing the area’s watershed, and thus have to maintain accurate floodplain maps. Conservation Ontario, however, reported that the average floodplain map in the province is from 1991 – which translates into a full 25 years’ worth of missing information.

In 2013, the organization issued a report calling for a comprehensive update to the maps. In the report, Conservative Ontario warned that ““climate change, intensified development, and long term lagging investment in natural hazard structures, tools, and programs . . . impair [the province’s] ability to maintain existing levels of flood protection and deal with emerging threats.”

“Traditional urban development practices are compounding the damaging effects of rainfall intensity and diminishing the capacity of watersheds to slow storm runoff and ease flood flows. Investment in new risk management tools and design standards, particularly for new urban development, is required,” the report added.

The organization projects the cost of such an update to be around $136 million, which it notes is relatively small compared to the costly damage flood can cause.

The Insurance Bureau of Canada (IBC) launched its own mapping project in 2015 to provide a model to insurers looking to offer flood-protection policies. While the project gathered enough data for insurers to rely on, the information is too low-resolution for land use and urban planning purposes, IBC vice-president of federal affairs Craig Stewart explained.


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