Flood levels on Ottawa River expected to plateau this weekend, decline next week

High water levels seen on the Ottawa River on April 30, 2026. (Brad Quinn/CTV News Ottawa)

The latest forecast for the Ottawa River has water levels holding steady this weekend before a gradual decline next week.

The Ottawa River Regulation Planning Board says recent rain and snowmelt in the north have caused levels and flows on the main stem of the river to slowly rise between Mattawa and Pembroke, but with lower-than-expected rain this week, levels have not increased as much as anticipated in the central part of the basin.

“Levels in Mattawa are now slightly above the major flood level, while levels in Pembroke are expected to remain below this threshold,” the planning board said in its latest update.

“With less rainfall received than expected in the central portion of the basin, water levels and flows in locations downstream of Pembroke are expected to rise only slightly, reach a plateau over the weekend, and then slowly decline later next week.”

Despite an expected decline, the board warns that there is still a lot of water moving through the river and levels will remain generally high for at least another two weeks, with the highest risk areas being from Mattawa to Lake Coulonge.

A flood warning remains in effect for areas between Arnprior and Hawkesbury along the Ottawa River. The Mississippi Valley Conservation Authority says water levels are expected to remain well below historical flood levels on the main stem of the Ottawa River. 

In Gatineau, the city continues to urge residents to be vigilant in case levels rise but said the lower rainfall on Wednesday was good news.

“The amount of rainfall received since (Wednesday) afternoon has been less than the predicted maximums. This appears to be reflected in the water levels, which are currently slightly below anticipated levels,” the city said in a statement, translated from French.

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