Forecast for 2023-05-03

River conditions forecasts posted on 2023-05-03 by Ottawa River Regulating Committee

Flows and levels on the Ottawa River continue to rise due to increased runoff from significant rainfall over the entire basin received over the last few days. Levels are expected to peak in all locations today or tomorrow from Mattawa down to Lake Coulonge, and on Thursday or Friday from Chats Lake down to the Hawkesbury / Grenville area. Levels should remain below the historical levels of 2019 (by as much as: 60-70 cm in Mattawa, 20-30 cm in Pembroke, 30-40 cm in Lake Coulonge, 35-45 cm in Chats Lake, 25-35 cm in Lake Deschenes, and 50-60 cm along the reach between Ottawa – Gatineau and the Hawkesbury-Grenville area). Please refer to the forecast section of our website for more information about the expected peak levels. Water levels and flows are expected to stabilize into the weekend and should start to decline slowly into next week with the return of sunny and drier weather. Reservoirs in the northern part of the watershed, which are being used to store runoff and minimize flooding downstream, are rapidly filling. Once reservoirs are full, they will have little capacity to reduce river flows in downstream areas. Levels will therefore remain susceptible to further rise should additional significant rainfall occur over the coming few weeks.