Update on Lake Superior Outflows and Expected Conditions

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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 2890 cubic metres per second (m3/s) for the month of July, effective July 1st.

The outflow is expected to exceed the combined capacities of the hydropower plants on the St. Marys River, which will be approximately 2322 m3/s in July, and 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 for the month of July will be maintained at the current setting equivalent to three gates open.

The July outflow is 70 m3/s more than that prescribed by Regulation Plan 2012. The Board expects to continue to adjust the outflow of Lake Superior in accordance with the approved deviation strategy 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. The Board expects to release flows greater than Plan 2012 in July and August, and less than Plan 2012 in September through November.

The net water supplies to Lake Superior were above average in June. The level of Lake Superior rose 13 cm last month, while on average the lake rises 8 cm in June. The Lake Superior level at the beginning-of-July is 18 cm above average, 1 cm below the level recorded a year ago at this time, and 46 cm above its chart datum level.

The net water supplies to Lake Michigan-Huron were below average in June. The level of Lake Michigan-Huron rose 1 cm last month, while on average the lake rises 6 cm in June. The level of Lake Michigan-Huron is 28 cm above its long-term average beginning-of-July level, 12 cm higher than it was a year ago, and 84 cm above its chart datum level.

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

Mr. Jaymie Gadal is the Board Member for Canada. Mr. Stephen Durrett 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