INTERNATIONAL LAKE SUPERIOR BOARD OF CONTROL
************************* 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 1,560 cubic meters per second (m3/s) (55.1 thousand cubic feet per second (tcfs)) for the month of May, effective May 3, 2011.
This is the outflow recommended by the regulation plan for the month of May and is an increase from the April outflow, which was 1,470 m3/s (51.9 tcfs). The May outflow will be released by discharging about 1,456 m3/s (51.4 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 eight 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 the Lake Superior basin and the Lakes Michigan-Huron basin were above normal.
Lake Superior is currently 24 cm (nine inches) below its chart datum level.
The level of Lake Superior is expected to rise in May.
Currently, the Lake Superior level is about 35 cm (14 inches) below its long-term average beginning-of-May level, and is 10 cm (four inches) lower than the level recorded a year ago.
This past month the level of Lake Superior rose 10 cm (four inches), while on average it rises eight cm (three inches) in April.
The level of Lakes Michigan-Huron rose 20 cm (eight inches) this April, while on average it rises 11 cm (four inches) during April.
The level of Lakes Michigan-Huron is now about 40 cm (16 inches) below its long-term average beginning-of-May level, and is six cm (two inches) lower than it was a year ago.
Currently Lakes Michigan-Huron is 14 cm (six inches) below its chart datum level.
The level of Lakes Michigan-Huron is expected to rise in May.
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.