WATERTOWN — Lake Ontario’s level has begun its seasonal decline, well below its peak level a year ago, but still well above its long-term average for this point in the year.
The lake’s level typically does not peak until early June, but did so early this year — on May 5 at 247.38 feet. This level is 20 inches below the peak of 2019, a year of widespread shoreline flooding on the lake and St. Lawrence River.
However, it was also just 4 inches below its general flood stage level. The level has since dropped two more inches.
With the decline, the International Joint Commission has withdrawn the International Lake Ontario-St. Lawrence River Board’s authority to deviate from Plan 2014, the basic regulation plan used to determine lake and river outflows. The IJC since early October had allowed the board to release far more water through the Robert Moses-Robert H. Saunders Power Dam in Massena than called for in Plan 2014 in attempt to lower lake levels before spring.
Inflows into the lake from the upper Great Lakes — inflows which account for more than 80 percent of Lake Ontario’s level — remain very high and are expected to remain so for the foreseeable future. In response, Plan 2014 will prescribe continued very high outflows.
The high outflows will, in addition to causing increased currents on the upper St. Lawrence River, have the effect of creating extremely low levels on Lake St. Lawrence, which serves as the forebay for the Moses-Saunders dam. The board plans to maintain levels on Lake St. Lawrence above 239.50 feet, or 16 inches above the usual navigation season low limit, through Labor Day weekend in September.