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 3290 cubic metres per second (m3/s) for the month of August, effective August 1st. There will be no change to the current setting of the control structure at the head of the St. Marys Rapids, which is currently set at an equivalent to seven gates open (achieved by setting 14 gates to a partially open setting of 94 centimetres (cm) each). This setting is expected to be maintained for the month of August, and as a result, the August outflow will be 40 m3/s less than the amount specified by Plan 1977-A.
The outflow of Lake Superior continues to be adjusted over the next several months to reduce the risk of unusually high flows expected in the St. Marys Rapids this summer. The Board requested and received approval from the IJC to temporarily deviate from Lake Superior Regulation Plan 1977-A to allow for these adjustments.
According to preliminary data, the monthly mean water level of Lake Superior in July was 183.66 m. This is 16 cm above the long-term (1918-2013) July average and the highest July level since 1997.
This past month the net water supplies to Lake Superior were above average. The level of Lake Superior rose 5 cm last month, while on average the lake rises 4 cm in July. The Lake Superior level at the beginning-of-August is 16 cm above average, and 24 cm above the level recorded a year ago at this time. It is 48 cm above its chart datum level. The level of Lake Superior is expected to begin its seasonal decline during August.
The preliminary monthly mean water level of Lake Michigan-Huron in July was 176.46 m. This is 11 cm below the long-term (1918-2013) July average, but the highest July level since 1998.
The net water supplies to Lake Michigan-Huron were also above average in July. The level of Lake Michigan-Huron rose 4 cm this past month, while on average the lake remains at about the same level through July. The level of Lake Michigan-Huron is 8 cm below its long-term average beginning-of-August level, but 39 cm higher than it was a year ago. Lake Michigan-Huron is now 48 cm above its chart datum level. The level of Lake Michigan-Huron is also expected to begin its seasonal decline in August.
Mr. Jaymie Gadal is the Board Member for Canada. Ms. Deborah Lee is the Alternate 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