By SooToday.com Staff
Friday, September 02, 2011
Update on Lake Superior outflow
The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission, has set the Lake Superior outflow to 1,650 cubic meters per second (m3/s) (58.3 thousand cubic feet per second (tcfs)) for the month of September, effective September 2, 2011.
This is a decrease from the August outflow which was 1,750 m3/s (61.8 tcfs).
This outflow is as prescribed by Plan 1977-A.
The September outflow will be released by discharging about 1,538 m3/s (54.3 tcfs) 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 existing setting equivalent to one-half gate open (four gates open 20 centimeters (cm), or about 8 inches each).
There will be no change to the setting of Gate No. 1 that supplies the Fishery Remedial Works.
This past month the water supplies to both the Lake Superior and Lakes Michigan-Huron basins were below normal.
Lake Superior is currently 6 cm (2 inches) above chart datum level.
The level of Lake Superior is expected to remain steady or rise slightly in September.
Currently, the Lake Superior level is about 28 cm (11 inches) below its long-term average beginning-of-September level, and is 5 cm (2 inches) higher than the level recorded a year ago.
This past month the level of Lake Superior fell 2 cm (1 inch), while on average it rises 1 cm (0 inches) in August.
The level of Lakes Michigan-Huron fell 8 cm (3 inches), while on average it falls 4 cm (2 inches) in August.
The level of Lakes Michigan-Huron is now about 35 cm (14 inches) below its long-term average beginning-of- September level, and is 2 cm (1 inch) lower than it was a year ago.
Currently Lakes Michigan-Huron is 18 cm (7 inches) above its chart datum level.
The level of Lakes Michigan-Huron is expected to drop in September.
The board continues to monitor conditions both on Lake Superior and downstream and will advise the International Joint Commission accordingly on those conditions.
Major General John W. Peabody, Commander, Great Lakes and Ohio River Division, U.S. Army Corps of Engineers, is the United States Board Member.
Mr. David Fay is the board member for Canada.