Record-breaking natural conditions have exceeded the capability of water level regulation to prevent the wide-spread flooding and coastal impacts experienced across the Lake Ontario – St. Lawrence River basin. Gradually decreasing inflows from Lake Erie, drier weather and record-setting outflows on the St. Lawrence River have resulted in a steadily declining Lake Ontario, down 45 centimeters (17.7 inches) below the peak.
The International Lake Ontario-St. Lawrence River Board will continue to prescribe the most aggressive outflows with the goal of reducing Lake Ontario as quickly and safely as possible. The board met August 15 to assess current conditions, hydrologic forecasts and review the ongoing impacts of high water levels and flows throughout the Lake Ontario – St. Lawrence River system.
Outflows continue at 9,910 m³/s (350,000 cfs) until midnight, August 18 and then lowered slightly to 9,870 m3/s (348,600 cfs), which will remain the highest flow ever recorded at this time of year.
High outflows remain necessary to provide relief to those affected by this year’s high water levels on Lake Ontario, but the decrease is necessary to balance the impacts to navigation and other interests in the St. Lawrence River. Ottawa River flows into the St. Lawrence River have decreased and, while levels of Lake St. Louis (near Montreal) continue near record highs for this time of year, they are now below flood levels.
The unprecedented outflow from the Moses-Saunders Dam has however, resulted in the lowest water levels experienced on Lake St. Lawrence (near Cornwall, Ontario and Massena, New York) since 1998.
Falling water levels will result in increased currents and potentially hazardous navigation conditions for all in the international section of the St. Lawrence River.
The board will continue to maximize outflows in consideration of impacts to public water uses, riparian landowners and businesses, commercial shipping and recreational boating. Water levels are expected to continue to decline rapidly into the fall throughout the system.
The board, in conjunction with its staff, continues to monitor and reassess conditions on an ongoing basis. Information on hydrologic conditions, water levels and outflows are posted to the board’s Facebook page www.facebook.com/InternationalLakeOntarioStLawrenceRiverBoard.
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