NEWS RELEASE
INTERNATIONAL LAKE SUPERIOR BOARD OF CONTROL
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The Board expects the total St. Marys River flow in March to be 1,610 m3/s (56,900 cfs), as prescribed by Regulation Plan 2012. Actual hour-to-hour and day-to-day flows may vary depending on hydrologic conditions, as well as variations in flow from the hydropower plants.
The gate setting of the Compensating Works will be maintained at the typical winter gate setting (Gate #1 and Gates #7 through #10 open 20 cm each) equivalent to approximately one-half gate open. Therefore, the average St. Marys Rapids flow in March is expected to be approximately 83 m3/s (2,900 cfs). Gate #1 will remain at its typical setting which supplies a flow of about 15 m3/s (500 cfs) to the channel north of the Fishery Remedial Dike. The Poe Lock is scheduled to reopen for the shipping season on or before March 25, 2025.
Water level changes over the month of February
Water supply conditions were drier than average in both Lake Superior and Lake Michigan-Huron basins in February.
- Lake Superior declined by 6 cm (2.4 in) last month while the seasonal long-term average pattern is for Lake Superior to decline by 4 cm (1.6 in) in February.
- Lake Michigan-Huron declined by 3 cm (1.2 in) last month, while the seasonal long-term average pattern is for Lake Michigan-Huron to decline by 1 cm (0.4 in) 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 18 cm (7.1 in) below the seasonal long-term average (1918-2023) and 14 cm (5.5 in) below the level of a year ago.
- At the beginning of March, the lake-wide average water level of Lake Michigan-Huron was 20 cm (7.9 in) below the seasonal long-term average (1918-2023) and 29 cm (11.4 in) below the level of a year ago.
Forecast outlook
Water level changes based on water supplies over the month of March.
- If weather and water supply conditions are near average, Lake Superior may decline by approximately 1 cm (0.4 in.) and Lake Michigan-Huron may increase by approximately 4 cm (1.6 in).
- If conditions are much wetter than average, Lake Superior may increase by approximately 6 cm (2.4 in) and Lake Michigan-Huron may rise by approximately 12 cm (4.7 in).
- If conditions are much drier than average, the water level of Lake Superior may drop by as much as 6 cm (2.4 in), and Lake Michigan-Huron may decrease by as much as 3 cm (1.2 in).
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