Anglers on St. Marys urged to be wary of waterflows, levels

Anglers and other users of the St. Marys River will need to be cautious of changing flows and water levels in the rapids in June.

That's the word from the International Lake Superior Board of Control, which is responsible for managing the control works on the St. Marys River and regulating the outflow from Lake Superior into Lake Huron and Lake Michigan. 

The board said Gate #16 will be opened to a setting of 5 cm this Thursday, June 6 to facilitate sea lamprey trapping.

Then later this month, to facilitate underwater inspections of the International Bridge piers, gates will be temporarily changed to a setting equivalent to one-half gate open, the board said in a release.

A supplementary news release will be issued once inspection dates and gate settings are finalized, the board said.

Following the inspections, it is expected that the gates will be returned to a setting equivalent to approximately four gates fully open.

The average St. Marys Rapids flow is expected to meet the Plan 2012-prescribed flow in June in light of capacity restrictions at the hydropower plants, the board said.

The board's report says water supply conditions were drier than average in the Lake Superior basin and wetter than average in the Lake Michigan-Huron basin in May.

• Lake Superior rose by 7 cm (2.8 in) last month while the seasonal long-term average pattern is for Lake Superior to rise by 10 cm (3.9 in) in May.
• Lake Michigan-Huron rose by 10 cm (3.9 in) last month, and the seasonal long-term average pattern is for Lake Michigan-Huron to rise by 8 cm (3.1 in) in May.

Water levels as of the beginning of June:

• At the beginning of June, the lake-wide average water level of Lake Superior was 5 cm (2 in) below the seasonal long-term average (1918-2023) and 31 cm (12.2 in) below the level of a year  ago.
• At the beginning of June, the lake-wide average water level of Lake Michigan-Huron was 8 cm (3.1 in) above the seasonal long-term average (1918-2023) and 7 cm (2.8 in) below the level of a year ago.

The lakes are expected to continue their seasonal rise over the coming month:

• If weather and water supply conditions are near average, Lake Superior may rise by approximately 8 cm (3.1 in.) and Lake Michigan-Huron may rise by approximately 4 cm (1.6 in).
• If conditions are much wetter than average, Lake Superior may rise by as much as 16 cm (6.3 in) and Lake Michigan-Huron may rise by as much as 12 cm (4.7 in).
• If conditions are much drier than average, the water level of Lake Superior is expected to rise by approximately 1 cm (0.4 in), and Lake Michigan-Huron is expected to decrease by approximately 1 cm (0.4 in).