Forecast for 2026-05-05

River conditions forecasts posted on 2026-05-05 by Ottawa River Regulating Committee

Spring runoff is slowly decreasing in the northern part of the basin with the melting of the last patches of snow and recent rain. Water levels and flows on the Ottawa River from Mattawa to Pembroke are starting to decline slowly, while levels downstream, from Lake Coulonge to the Montreal Region, continue to decrease. Over the next week, as no major rainfall is forecast on the northern part of the basin, water levels and flows are expected to continue declining gradually from Mattawa to the Montreal Region. However, because large volumes of water continue to come from the northern part of the basin, water levels along the main stem of the river are expected to remain generally high over the next week. The northern part of the basin will remain vulnerable to heavy rainfall in the coming weeks; therefore, further increases in water levels from Mattawa to Lake Coulonge due to high spring runoff cannot be ruled out.