WATERTOWN — Regulators of Lake Ontario and St. Lawrence River water levels say they are “optimistic” that weather conditions for the remainder of the winter into spring won’t cause a “damaging rise” in lake levels this year.
That hasn’t prevented the International Lake Ontario-St. Lawrence River Board from dictating system outflows above limits prescribed in Plan 2014, the basic plan the board follows to regulate lake and river levels by means of outflows at the Robert Moses-Robert H. Saunders Power Dam in Massena and Cornwall, Ontario.
Adherence to Plan 2014 has been widely criticized for contributing to flood conditions along the lake and river in 2017 and 2019. The International Joint Commission, which sets the outflow strategies implemented by the board, has allowed the board to deviate from Plan 2014 for months, with latest authority granted to continue deviations due to expire Feb. 28.
While the deviation authority can subsequently be extended past that date, the board said in a statement Friday that the deviations, which have helped maximize outflows, have resulted in three additional inches of water removed from Lake Ontario than would have been achieved under strict adherence to Plan 2014.
The deviations, along with somewhat drier than usual weather conditions over the past several months and favorable ice conditions on the river, has helped lower Lake Ontario levels to a few centimeters below its seasonal long-term average. Stable ice formation allows outflows to be increased. Without the stable formation, ice dams can result, which can produce flooding. A series of freezes and thaws that prevented a stable formation, which limited outflows, has been cited as a factor contributing to flooding in spring 2019.
The board says the risk of high water on Lake Ontario this year “remains a moderate possibility,” but less likely than at this point last year. The board said while water levels on Lake Erie and the upper Great Lakes are all lower than a year ago, they remain high. This will mean inflows into Lake Ontario from Lake Erie will remain high in the coming months. Coupled with yet-to-be-determined seasonal factors, such as precipitation and snowpack runoff, the board said a moderate risk of a high-water event on the lake during the spring remains.
The board said it will continue to monitor conditions and appropriate deviations from Plan 2014 will be applied should conditions worsen. The board said that given the lower risk of flood levels on Lake Ontario this year compared to the same time last year, it does not expect its deviation strategies to interrupt or negatively impact commercial navigation on the St. Lawrence River.