'Above-average' flooding could hit Ottawa region this spring

A City of Ottawa task force is monitoring water levels ahead of the spring thaw and says there's no major flooding in the immediate forecast — but that could change in the weeks ahead.

Water levels are currently normal or close to normal, according to the joint Thursday memo from public works general manager Alain Gonthier and Kim Ayotte, general manager of emergency and protective services.

"As members of council are aware, the Ottawa River basin experienced above average amounts of rainfall and snowpack during the peak of the freshet in past years, and as a result, the [city] experienced prolonged flooding events," their memo said.

A freshet is a large increase in water discharged into a river during the spring, caused by melting snow and sometimes rainfall. The city has established a freshet task force each year since major floods hit the Ottawa area in 2017.

Heavy flooding again struck the region in 2019, prompting the city to declare a state of emergency and call for help from the Canadian Armed Forces.

Levels already rising in some upriver lakes

The Rideau Valley Conservation Authority (RVCA) is one partner currently working with the task force.

In a statement Thursday, the RVCA said an unusually mild and snowy winter has caused water levels to rise in some lakes upriver of Ottawa.

The current snowpack varies across the Rideau Valley watershed but is heaviest in the Ottawa area, according to the RVCA.

"Based solely on the fact we have above-average snow water content and above-normal water levels in some upper watershed lakes, there is potential for above-average flooding this spring," the statement said.

Any floods would likely impact low-lying areas with a history of flooding, the authority added. But the melt is unlikely to begin immediately, as the first half of March is forecast to be cold and dry.

City crews have already begun the annual ice removal on the Rideau River between Rideau Falls and Bronson Avenue.