At its meeting on June 30th, the International Lake Ontario – St. Lawrence River Board agreed to continue releasing an outflow of 10,400 cubic metres per second (m3/s) (367,300 cubic feet per second), as conditions allow, in order to help lower the level of Lake Ontario, and provide all possible relief to riparian residents while considering the impacts throughout the Lake Ontario –St. Lawrence River system. This outflow continues to be the highest ever released from Lake Ontario on a sustained basis.
The Board reviewed current conditions of Lake Ontario and the St. Lawrence River, and despite efforts to provide relief by releasing record-high outflows, recent wet conditions continue to sustain high water levels, causing continued severe impacts to Lake Ontario and St. Lawrence River property owners, recreational boaters, businesses and tourism.
Lake Erie remains well above average, and combined with significant rainfall during the past month, the total inflow to Lake Ontario was the 2nd highest recorded in the month of June since 1900.
Yet despite the near record-high inflows and notwithstanding a slight rise in levels following especially heavy showers and thunderstorms on June 22nd, Lake Ontario levels fell 9 cm (3.5 inches) overall last month, 8 cm (3.1 inches) more than average and the 11th largest decline in June since
1918.
On the St. Lawrence River, levels near Montreal and further downstream had been declining in general, but rose to near record highs in recent days following a series of storm events. The Board continues to monitor and assess conditions in consideration of the impacts that these exceptionally high levels and flows are having in Lake Ontario and the upper and lower St. Lawrence River on all stakeholders, including commercial navigation.
Furthermore, based on information provided to the Board by the St. Lawrence Seaway on navigation conditions at high flows, the Board concluded that an outflow of 10,400 m3/s (367,300 cfs) is the maximum outflow that can be released from Lake Ontario with present river levels, that would
still allow continued, though restricted, safe commercial navigation in the St. Lawrence River.
The Board noted that while wet weather has maintained high levels recently, warmer and drier summer conditions are likely to return, and
allow water levels throughout the system to resume their decline.
As levels decline, a gradual reduction in outflows will be required to prevent the velocities in the St. Lawrence River from exceeding the limits for
safe navigation. However, the Board expects the flow of 10,400 m3/s (367,300 cfs) can safely be maintained for some time to come, and will continue to re-evaluate this on a daily basis at least until its next meeting.
The Board is drawing on all of its resources and available technological support to provide the best information and allow it to review options to reduce water levels as fast as possible while considering all interests in the Lake Ontario-St. Lawrence River system.
Outflow changes, photos, and graphs are posted to the Board’s Facebook page at https://www.facebook.com/InternationalLakeOntarioStLawrenceRi
verBoard (English), and more detailed information is available on its website at http://ijc.org/en_/islrbc.
Contacts: Derrick Beach: (905) 336-4714; derrick.beach@canada.ca
Arun Heer: (513) 684-6202; Arun.K.Heer@usace.army.mil
