Forecast for 2026-04-30

River conditions forecasts posted on 2026-04-30 by Ottawa River Regulating Committee

Recent rain and snowmelt in the northern part of the basin have increased spring runoff, causing water levels and flows on the main stem of the Ottawa River to continue rising slowly from Mattawa to Pembroke. Levels in Mattawa are now slightly above the major flood level, while levels in Pembroke are expected to remain below this threshold.  With less rainfall received than expected in the central portion of the basin, water levels and flows in locations downstream of Pembroke, from Lake Coulonge down to the Montreal region, are expected to rise only slightly, reach a plateau over the weekend, and then slowly decline later next week.  Levels are not expected to exceed the maximum values shown in the four-day forecasts on our website. Because a large volume of water is still expected to come from northern regions, water levels are expected to remain generally high along the main stem of the river over the next two weeks. The risk of further increases in levels over the coming weeks due to high spring runoff from the northern portion of the basin is higher from Mattawa to Lake Coulonge.