Water Quantity


Water levels in the Ottawa River fluctuate naturally throughout the year in response to rain and snow melt. However, the operation of dams can also affect water levels in the river.

The Ottawa River is a highly regulated river with over 50 major dams throughout the watershed and 13 principal reservoirs. Given the importance of coordinating the operation of the dams, the Ottawa River Regulation Planning Board (ORRPB) was established in 1983 by the governments of Canada, Ontario and Quebec to ensure integrated management of the principal reservoirs in the watershed. The goal of the ORRPB is to provide protection against flooding along the Ottawa River and its tributaries, while maintaining the interests of its various users and hydro-electric energy producers. The Planning Board also works to ensure downstream communities, such as Montreal, have sufficient water supply at times of low flow.

Water Level Measurements

The Ottawa River Regulation Planning Board reports on the water levels at various locations along the Ottawa River. The reports are updated daily during the spring and once a week during the rest of the year. On the Planning Board’s website, you can also view Monthly and Annual Mean Discharge Records from 1964-present for various locations along the Ottawa River.

Water Survey of Canada (Environment Canada) has a few sites in the Ottawa River Watershed that monitor real time hydrometric levels. Tip: it’s best to search by basin (e.g., St. Lawrence River Basin).