Lake Superior fell last month, expected to rise in April

NEWS RELEASE

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 1,470 cubic meters per second (m3/s) (51.9 thousand cubic feet per second (tcfs)) for the month of April, effective April 1, 2011.

This is the outflow recommended by the regulation plan for the month of April and is the same as the March outflow.

The April outflow will be released by discharging about 1,368 m3/s (48.3 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 supply to the Lake Superior basin was below normal while that to the Lakes Michigan-Huron basin was above normal.

Lake Superior is currently 34 cm (13 inches) below its chart datum level.

The level of Lake Superior is expected to rise in April.

Currently, the Lake Superior level is about 37 cm (15 inches) below its long-term average beginning-of-April level, and is 22 cm (9 inches) lower than the level recorded a year ago.

This past month the level of Lake Superior fell 4 cm (2 inches), while on average it falls 2 cm (1 inch) in March.

The level of Lakes Michigan-Huron rose 6 cm (2 inches) this March, while on average it rises 5 cm (2 inches) during March.

The level of Lakes Michigan-Huron is now about 49 cm (19 inches) below its long-term average beginning-of-April level, and is 25 cm (10 inches) lower than it was a year ago.

Currently Lakes Michigan-Huron are 16 cm (6 inches) below their chart datum level.

The level of Lakes Michigan-Huron is expected to rise in April.

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.

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