Update on Lake Superior Outflows and Expected Conditions – February 2022


Weather and water supplies to Lakes Superior and Michigan-Huron were much drier than average in January. 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 1,540 m3/s (54 tcfs) in February, 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. The navigation locks have been closed for the winter.

Based on preliminary estimates, water supplies to the Lake Superior basin set a new, record low in January. As a result, Lake Superior declined 12 cm (4.7 in), while on average the lake declines 7 cm (2.8 in) in January. Similarly, because of the dry conditions, Lake Michigan-Huron declined 10 cm (3.9 in) last month, while on average the lake declines 2 cm (0.8 in) in January.

At the beginning of February, Lake Superior is 12 cm (4.7 in) below the long-term average water level (1918 – 2020) and 30 cm (11.8 in) below the level of a year ago. Lake Michigan-Huron is 26 cm (10.2 in) above average, 44 cm (17.3 in) below the level from last year, and 72 cm (28.3 in) below the record-high level set at this time in 2020.

Lake Superior and Lake Michigan-Huron water levels typically continue to decline in February. Depending on the weather and water supply conditions during the next month, Lake Superior may decline by as much as 10 cm (3.9 in) in February. Lake Michigan-Huron water levels may rise slightly or could decline by as much as 10 cm (3.9 in).

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