Update on Lake Superior Outflows and Expected Conditions - March 2022
Lake Superior and Lake Michigan-Huron water levels are near their seasonal low point and depending on weather and water supply conditions could begin their seasonal spring rise over the coming weeks. Lake Superior water levels remain below the seasonal long-term average while Lake Michigan-Huron water levels remain above the seasonal long-term average. Lake Superior outflows continue to be set in consideration of water levels upstream and downstream.
The Board expects the total outflow to be 1,570 m3 /s (55.4 tcfs) in March, which is as prescribed by Lake Superior Regulation Plan 2012. The gate setting at the Compensating Works will be maintained at the setting equivalent to one-half gate open (Gates #7 through #10 partially open 20 cm (7.9 in)). There will be no change to the setting of Gate #1, which supplies a flow of about 15 m3 /s to the channel north of the Fishery Remedial Dike.
Water levels of Lake Superior and Lake Michigan-Huron continued to decline in February. Lake Superior declined 2 cm (0.8 in), while on average the lake declines 5 cm (2 in) in February. Lake Michigan-Huron declined 3 cm (1.2 in) last month, while on average the lake remains stable in February.
At the beginning of March, Lake Superior is 9 cm (3.5 in) below the long-term average water level (1918 – 2021) and 28 cm (11 in) below the level of a year ago. Lake Michigan-Huron is 23 cm (9 in) above average, 43 cm (17 in) below the level from last year, and 69 cm (27 in) below the record-high level set at this time in 2020.
Depending on the weather and water supply conditions during the next month, Lake Superior and Lake Michigan-Huron water levels may continue to decline by as much as 10 cm (3.9 in.) in March. Conversely, it is possible that water levels will begin their seasonal rise and could rise by as much as 10 cm (3.9 in.) over the next month.
The International Lake Superior Board of Control is responsible for regulating the outflow of Lake Superior and managing the control works on the St. Marys River. Under any regulation plan, the ability to regulate the outflow from Lake Superior does not mean that full control of lake levels is possible. This is because the major factors affecting water supply to the Great Lakes, precipitation, evaporation, and runoff cannot be controlled, and are difficult to accurately predict. Outflow management cannot eliminate the risk of extreme water levels from occurring during periods of severe weather and water supply conditions. Additional information can be found at the Board’s homepage: https://ijc.org/en/lsbc or on Facebook at: https://www.facebook.com/InternationalLakeSuperiorBoardOfControl