Lake level changes close to seasonal average

Despite what has been on unusual winter, water level changes in our big lakes over the past month have been business as usual and around average, according to the International Lake Superior Board of Control.

In a news release, the board said water supply conditions were slightly below average in the Lake Superior basin and slightly above average in the Michigan-Huron basin in February.

Lake Superior declined by 6 cm last month, while the seasonal long-term average pattern is for Lake Superior to decline by 5 cm in February.

Lake Michigan-Huron declined by 2 cm last month, while the seasonal long-term average pattern is for Lake Michigan-Huron to decline by 1 cm in February.

Water levels as of the beginning of March:

• At the beginning of March, the lake-wide average water level of Lake Superior was 3 cm below the seasonal long-term average (1918-2022) and 24 cm below the level of a year ago.
• At the beginning of March, the lake-wide average water level of Lake Michigan-Huron was 9 cm above the seasonal long-term average (1918-2022) and 2 cm below the level of a year ago.

Depending on water supplies, both lakes may rise or fall in the upcoming month, the board said.

• If weather and water supply conditions are near average, Lake Superior may decline by approximately 1 cm and Lake Michigan-Huron may rise by approximately 4 cm.
• If conditions are wetter than average, Superior may rise by 6 cm and Lake Michigan-Huron may rise by as much as 12 cm.
• If conditions are drier than average, the water level of Lake Superior is expected to decline by as much as 6 cm, and Lake Michigan-Huron is expected to decline by as much as 4 cm.

The board said the gate setting of the Compensating Works at the head of the St. Marys Rapids will be maintained in March at a setting equivalent to approximately one-half gate fully open.  

Meanwhile, the MacArthur Lock has been closed and will reopen April 24. The Poe Lock has also been closed for the winter and will reopen on March 25. These closures are routine for winter and allow for maintenance work, the board said.

Additional information can be found at https://ijc.org/en/lsbc.