Conservationists work to update flood risk map along Ottawa River

·3 min read
By assessing the flood and erosion risk along the Ottawa River, developers will be able to use the data to better plan and build safely.  (Denis Babin/CBC - image credit)
By assessing the flood and erosion risk along the Ottawa River, developers will be able to use the data to better plan and build safely. (Denis Babin/CBC - image credit)

A conservation authority is working to update flood hazard maps for parts of eastern Ontario, which will help municipal governments assess the risk of flooding when planning for the future.

The South Nation Conservation (SNC), an organization dedicated to the protection and restoration of ecosystems in the region, is leading the efforts to update the maps, which hasn't been done for many years.

United Counties of Prescott and Russell
United Counties of Prescott and Russell

The organization is surveying the Ontario side of the Ottawa River between the city of Clarence-Rockland and the Quebec-Ontario border, east of Chute-à-Blondeau, along with areas crossed by Bear Creek, east of downtown Ottawa.

Since the end of the summer, a SNC team has been scanning the river and creek to measure their depth and width, as well as the dimensions of bridges and culverts built along the two water bodies.

An analysis of the data collected in the field will help determine which areas are the most likely to flood and be affected by soil erosion.

"This will allow us to establish the limits of the flood zones, that is to say the extent of land that can be occupied by water in the event that [the Ottawa River and Bear Creek] overflow," Jason Symington, an environmental technician with the SNC told Radio-Canada.

Incomplete portrait

Funding for the surveys comes from the federal government's Natural Disaster Mitigation Program, along with the City of Ottawa and the United Counties of Prescott and Russell (UCPR).

According to Louis Prévost, director of urban planning and forestry with the UCPR, the overhaul of the flood risk maps is long overdue and will fill in a large piece of the Ottawa River puzzle.

"We basically have flood plain mapping for all of the other major watercourses within the counties. We've got good coverage, but the Ottawa River was lacking big time," he said.

Prévost said the mapping will be a "tremendous tool" for city planners. Once the flood plains are identified in the official county plan, that information will be used to create local zoning bylaws to eliminate any potential developments in flood-prone areas, he said.

Denis Babin/CBC
Denis Babin/CBC

Valuable tool for municipalities

With access to precise data, municipalities in the region will be better able to plan any prospective development.

Jeanne Charlebois, the former mayor of Hawkesbury, Ont., said not having flood plain information readily available is holding back commercial and residential development along part of the city's waterfront — what she calls a "prime piece of land."

"We will be able to tell the people who own land on the waterfront and want to develop it, 'Here you go. Here's step one. Step one is you're no longer in a flood plain, or sadly you are in a flood plain and this is what you're going to have to do,'" she said.

Charlebois said Hawkesbury's future growth lies in the city's west end, and the sooner the municipality has the information to safely develop, the better.

Drafts of the planning maps are expected to be completed by March 2022 and shared during public consultations.

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