Update on Lake Superior Outflow 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 2990 cubic metres per second (m3/s) for the month of November, effective November 1st. The November outflow will be released by discharging about 2225 m3/s through the three hydropower plants and passing most of the remaining flow through the control structure at the head of the St. Marys Rapids.

The gate setting of the control structure will be maintained at the equivalent of approximately five gates open for November. Gates 3 to 15 will remain partially open at the current setting of 80 centimetres (cm) each. There will be no change to the setting of Gate 1 which supplies water to the channel north of the Fishery Remedial Dike, and Gates 2 and 16 will remain closed.

The November outflow is 510 m3/s greater than that prescribed by Plan 1977-A. In April 2014, the Board requested and received approval from the IJC to temporarily deviate from Lake Superior Regulation Plan 1977-A to reduce the risk of unusually high flows expected in the St. Marys Rapids this summer. To offset some of the effects of releasing flows less than Plan 1977-A from June through September, flows greater than Plan 1977-A were released in May, and flows greater than Plan 1977-A are expected for the remainder of 2014, at which time the net effect on lake levels resulting from this deviation strategy is expected to be negligible.

According to preliminary data, the monthly mean water level of Lake Superior in October was 183.71 m. This is 21 cm above the long-term (1918-2013) October average and the highest October level since 1996.

For the tenth consecutive month, the net water supplies to Lake Superior were above average again in October. The level of Lake Superior remained at about the same level last month, while on average the lake declines 3 cm in October. The preliminary Lake Superior level at the beginning-of-November is 21 cm above average, 28 cm above the level recorded a year ago at this time, and 50 cm above its chart datum level.

The monthly mean water level of Lake Michigan-Huron in October was 176.54 m. This is 11 cm above the long-term (1918-2013) October average and the highest October level since 1998.

As was the case in September, the net water supplies to Lake Michigan-Huron were well above average in October. According to preliminary data, the level of Lake Michigan-Huron rose 3 cm this past month, while on average the lake declines by 7 cm in October. The level of Lake Michigan-Huron is 16 cm above its long-term average beginning-of-November level, 56 cm higher than it was a year ago, and 55 cm above its chart datum level.

The levels of both lakes Superior and Michigan-Huron are expected to begin their seasonal decline 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 Jacob.Bruxer@ec.gc.ca

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