WASHINGTON, D.C. — International regulators say they plan to release “slightly more water” from Lake Ontario this fall in a move that could make sure lake levels continue to decline after nearly three years of record-high water.
Lake Ontario water levels at last measurement were 246.03 feet, or roughly 5 inches above the 245.60 feet average water level for this time of year. Though water levels have been above average for all of 2020, the widespread flooding that plagued the Lake Ontario shoreline in recent years never materialized.
The International Joint Commission (IJC) — the U.S.-Canadian body that oversees shared waterways between the two nations — announced Friday the International Lake Ontario-St. Lawrence River Board (LOSLRB), which is overseen by the IJC and sets outflows from Lake Ontario through the Moses-Saunders Dam near Massena, would adjust its outflow strategy to allow Lake St. Lawrence water levels to decline to “the normal navigation season minimum” after the Labor Day weekend.
The IJC said the move would “allow for slightly more water to be released from Lake Ontario during the fall.” The IJC’s water management strategy known as Plan 2014 has been blamed by many for the flooding in 2017 and 2019 but it’s unclear if that is an accurate placement of blame. Shoreline property owners and elected officials in recent years have argued regulators did not take advantage of opportunities to release more water in the fall months.
Water levels across the Great Lakes have been at or near record highs for much of the past three years, and the Lake Ontario shoreline experienced record-setting flooding in 2017 and again in 2019. Lake Ontario reached a more than 100-year high of 249.09 feet in early and mid-June last year after setting the previous record high of 248.92 feet in mid-May 2017.
Some shoreline property owners and elected officials were quick to criticize the IJC and Plan 2014, which went into effect in January 2017. Plan 2014 dictates, along with many other responsibilities, the pace of outflows from Lake Ontario through the Moses-Saunders Dam. The dam is the only waterway for emptying the the Great Lakes through the St. Lawrence Seaway and into the Atlantic Ocean.
Despite starting 2020 higher than any of the previous three years, Lake Ontario waters receded significantly throughout the year. IJC officials said Friday the low and declining levels on Lake Ontario, combined with the high outflows through the Moses-Saunders Power Dam, are resulting in very low water levels on Lake St. Lawrence that are anticipated to continue. Despite high Lake Ontario levels, regulators said this was the fourth straight summer of “well-below-average levels of Lake St. Lawrence. As the forebay to the dam, Lake St. Lawrence responds more rapidly and significantly to changes in outflows compared to the larger Lake Ontario, according to the IJC.
During a May 22 meeting, LOSLRB agreed to use accumulated water removed from Lake Ontario, if needed, to maintain levels on Lake St. Lawrence above 239.50 feet. That’s 16 inches above the usual navigation-season low limit.
Lake Ontario outflow was decreased slightly last week to allow Lake St. Lawrence levels to increase. Regulators noted, however, as fall weather approaches, recreational boating activity begins to decrease.
High inflows continue from the upper Great Lakes and Lake Ontario levels remain about 5 inches above their long-term average value for this time of year, so the board decided to cease the maintenance of levels on Lake St. Lawrence. Those levels areexpected to decline following Labor Day, regulators said, so residents and other recreational boaters are encouraged to remove all of their associated equipment from the waterfront on or prior to the September long weekend.
Lake Ontario levels peaked early this year at 247.38 feet on May 5, roughly 4 inches below the general flood stage and more than 20 inches lower than the peak of 2019. Lake levels are expected to continue their seasonal decline through the end of summer, and have fallen to date roughly 16 inches from the crest.