Update on Lake Superior Outflows and Expected Conditions

International Lake Superior Board of Control

The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission (IJC), has set the Lake Superior outflow to 2320 cubic metres per second (m3/s) for the month of November, effective November 3rd. The November outflow is expected to exceed the combined capacities of the hydropower plants on the St. Marys River, which will be approximately 2185 m3/s in November, and most of the excess flow will be released through the control structure at the head of the St. Marys Rapids.

The gate setting of the control structure will be reduced from November 3rd to 5th. This will be done in stages to allow flow measurements to be conducted in the St. Marys Rapids and to accommodate underwater inspections of the international railway bridge piers, and will also result in a gradual reduction in flows and water levels prior to winter. As of Thursday, November 5th, the gate setting is expected to have been reduced from the current setting equivalent to approximately three gates open, to the equivalent of one-half gate open. This will be achieved by partially lowering Gates # 7 to 10 to a setting of 20 centimetres (cm) each, and closing Gates #2 to 6 and Gates # 11 to 16. 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 November outflow of 2320 m3/s is 270 m3/s less than that prescribed by Regulation Plan 2012, in accordance with the Board’s approved deviation strategy. The Board continues to adjust the outflow of Lake Superior to accommodate expected maintenance at the hydropower plants and reduce the potential for adverse consequences of high and fluctuating flows and water levels in the St. Marys Rapids. Flows less than Plan 2012 were released in May and June of this year, followed by flows greater than Plan 2012 being released in July and August. The Board again began releasing flows less than Plan 2012 starting in September, and this will continue through the end of November, at which point the Board’s deviation strategy will be completed.

The net water supplies into Lake Superior were below average in October. The level of Lake Superior declined 9 cm last month, while on average the lake falls 3 cm in October. The Lake Superior level at the beginning-of-November is 9 cm above average, 13 cm below the level recorded a year ago at this time, and 38 cm above its chart datum level.
The net water supplies to Lake Michigan-Huron were also below average in October. The level of Lake Michigan-Huron declined 11 cm last month, while on average the lake falls 7 cm in October. The level of Lake Michigan-Huron is 16 cm above its long-term average beginning-of-November level, 1 cm higher than it was a year ago, and 55 cm above its chart datum level.

The levels of Lake Superior and Lake Michigan-Huron are both expected to continue their seasonal declines in November.

Mr. Jaymie Gadal is the Board Member for Canada. Brigadier General Richard Kaiser is the U.S. Board Member.

For further information, please contact Mr. Jacob Bruxer, Canadian Regulation Representative, International Lake Superior Board of Control, by phone at (613) 938-5862 or by e-mail at [email protected]

Additional information can also be found at the Board’s homepage: http://ijc.org/en_/ilsbc
Or on Facebook at: https://www.facebook.com/InternationalLakeSuperiorBoardOfControl