A study released this month by the Intact Centre on Climate Adaptation at the University of Waterloo examined the financial impacts of wetlands on rural and urban flooding.

“With the flooding events in recent history, it has become clear that that the human and financial costs of these events are substantial,” said Professor Blair Feltmate, the head of the Intact Centre and an author on the report, When the Big Storms Hit: The Role of Wetlands to Limit Urban and Rural Flood Damage. “With the ever-increasing financial burden of flooding to Canadians, it is remarkable that a practical and cost-effective means to alleviate flood risk is readily available—that is, simply leave natural wetlands natural.”

The research focused on two Southern Ontario pilot sites, one rural and one urban. For both sites, computer models simulated a major autumn flood and compared flood damages under conditions where wetlands were maintained in their natural state and where they were replaced with agricultural land use. The researchers found that flood damages were lower if wetlands were maintained in their natural state, with financial cost savings of 29 and 38 per cent in rural and urban areas, respectively.

At the rural pilot site, if existing wetlands were maintained in their natural state, flood damages would have been $8.9 million. This was $3.5 million, or 29 per cent, lower than the $12.4 million cost that would have been realized if wetlands had been replaced with agricultural development.

For the urban pilot site, the cost of flood damages would be $84.5 million, if existing wetlands were maintained in their natural state. This compared to the $135.6 million cost that would be incurred had wetlands been replaced with agricultural development.

If the modeling assumed that wetlands were replaced by impervious surfaces, such as buildings, roads and parking lots rather than agricultural development, their respective value for avoiding flood damages would exceed the range of 29–38 per cent.

“We know wetlands help to reduce the impacts of flooding,” said Lynette Mader, Ontario manager of Ducks Unlimited Canada. “The Intact Centre research illustrates quantitatively that wetlands conservation offers a fiscally responsible means to address flooding that should factor prominently into infrastructure development going forward.”

The researchers concluded based on their findings that wetlands conservation is a cost-effective means to reduce flood risk in Canada. As such, they have determined that their findings are consistent with directives outlined in the Wetland Conservation Strategy for Ontario, the Province of Ontario’s Climate Change Action Plan, and the Government of Canada’s Pan-Canadian Framework on Clean Growth and Climate Change.

The report was generated through the efforts of the Grand River Conservation Authority, Credit Valley Conservation, and Ducks Unlimited Canada in conjunction with the Intact Centre on Climate Adaptation.


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