Forecast for 2026-05-01

River conditions forecasts posted on 2026-05-01 by Ottawa River Regulating Committee

Spring runoff remains very high in the northern part of the basin due to recent rain and melting snow.  The Ottawa River water levels and flows continue to increase gradually in Mattawa, and more slowly in Pembroke.  Elsewhere, water levels are starting to stabilize.  With less rainfall received than expected in the central portion of the basin over the last few days, water levels and flows in locations downstream of Pembroke, from Lake Coulonge down to the Montreal region, are expected to stabilize over the next few days, and slowly start declining later next week.  Levels are not expected to exceed the maximum values shown in the four-day forecasts on our website over the next few days. 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.