Mayor Raymond Bélanger has terminated the state of emergency for Mattawa, as the risk of floods subsides. He signed the papers on the morning of May 29, and the notice was posted on the Town’s Facebook page the following day.
BayToday reached out to Mayor Belanger for additional comment, but he did not respond in time for publication.
The entire municipality was under the state of emergency, which Mayor Bélanger declared on May 2 as the water was continuing to rise and more rain was in the forecast. At that time and in the following days, Mayor Bélanger noted “people are starting to get nervous.”
See: Mattawa declares state of emergency as rivers rise
Fearful of a repeat of the terrible flood in 2019, the town banded together to fill sandbags preparing for rising water. Overall, damages were minimal for most, although rising groundwater also affected a lot of homes and businesses near the rivers and low-lying areas.
Thankfully the worst of the river didn’t come to Mattawa, and currently, there are no Flood Warnings or Flood Watches for the town, as issued by the North Bay-Mattawa Conservation Authority.
When BayToday arrived in Mattawa on May 3, a few residents asked about the management of the river, concerned about the control of the water flow. Some questioned why the dam further downstream wasn’t opened more to give the water pooling in Mattawa a place to go.
See: Mattawa binds together under state of emergency
Admittedly, the physics of flowing rivers is outside of most daily conversations, save for flooding season. Thankfully, Manon Lalonde, a principal engineer at the Ottawa River Regulation Planning Board, provided an explanation to address the resident’s concerns of those downstream dams, and how some people noticed some of the reservoir areas below were practically dry.
She noted that the dam downstream of Mattawa on the Ottawa River is the DesJoachims Dam, also known locally as the Swisha Dam. “The reservoir above the dam is typically full between mid-May and the end of February. During that period, people are used to seeing the water coming close to the edge of the roadway from their viewpoint on Highway 17 near Deux-Rivières.”
During the spring flood period, “when the reservoir is either empty or only half full, people see the dry flat riverbanks from their viewpoint on the highway and wonder why the river is not flowing,” Lalonde said.
“They don’t realize that the Ottawa River is still flowing very swiftly, but further away from the highway where they can’t see the water current. The perception is that the dam is restricting the flow, when it’s the opposite. The dam is actually opened and passing the water that arrives from the upstream section of the river.”
This spring, a large amount of runoff surged through the watercourses, causing high waters levels in the Ottawa River. When this amount of water “flows through natural narrows and rapids in the river, such as those located near the vanished village of Klock’s Mills, water levels rise in the river located above the river restriction.”
“Just like water flowing through a funnel, water flowing through narrows is restricted and backs up as flows increase. The effects of such natural river narrows impact upstream river sections and can extend upwards of more than fifty kilometres.”
Lalonde also mentioned people can learn more about the river’s management on the Ottawa River Regulation Planning Board’s website at ottawariver.ca.
David Briggs is a Local Journalism Initiative reporter who works out of BayToday, a publication of Village Media. The Local Journalism Initiative is funded by the Government of Canada.
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