IJC maintaining record outflows for Lake Ontario

Posted 24 June 2019 at 10:42 am

Press Release, International Joint Commission

The board of commissioners for the International Jont Commission is doing everything possible to provide all possible relief to Lake Ontario and upper St. Lawrence River residents, while considering impacts throughout the system.

During its meeting on June 21, the Board decided to maintain outflows at their current record-high levels, 10,400 m3/s (367,270 cfs), for the next week considering there is very little capacity for passing water on the lower St. Lawrence River due to Lake St. Louis flooding conditions. Many areas around Montreal and Lake St. Louis still remain flooded presently.

Significant precipitation over the last few days throughout the system have increased outflow from the Ottawa River into the lower St. Lawrence River. This has caused water levels on Lake St. Louis to rise to 22.42 m (73.56 ft) again, only 6 cm (2.4 in) below the levels causing significant flooding.

Before making their decision to maintain the current outflow, the Board considered the impact of increased currents and flows on multiple stakeholders, and received testimony from various groups, such as shoreline owners, hydropower, municipal and industrial water uses, recreational and commercial navigation, ecosystems, and upstream and downstream conditions.

Even with high outflows, it is expected that Lake Ontario will remain stable or decline slowly for the next several weeks. The Board continues to seek any opportunity to lower Lake Ontario faster than what is presently possible, and will be meeting again this week to review its regulation strategy.

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