Lake Superior drops four inches
By David Helwig
Published December 31, 2005
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 1,960 cubic metres
per second (m3/s)(69.2 thousand cubic feet per second
(tcfs)) for the month of January.
This is the outflow recommended by the regulation plan
for the month of January and is a decrease from the December
outflow of 2,110 m3/s (74.5 tcfs).
The January outflow will be released by discharging about
1,850 m3/s (65.3 tcfs) through the three hydropower plants
and passing most of the remaining flow through the control
structure at the head of the St. Mary's rapids.
The gate setting of the control structure will be maintained
at the existing setting equivalent to one-half gate open
(four gates open 25 cm, or about 10 inches each).
There will be no change to the setting of Gate #1 that
supplies the Fishery Remedial Works.
This gate setting is expected to be maintained until
at least April.
This past month the water supplies to the Lake Superior
basin and the Lakes Michigan-Huron basin were below their
respective long-term averages for December.
Currently, the Lake Superior level is about 13 cm (5
inches) below its long-term average beginning of January
level, and is 11 cm (4 inches) below the level recorded
a year ago.
This past month the level of Lake Superior declined by
about 9 cm (4 inches), while usually it declines by 8
cm (3 inches) during December.
The level of Lakes Michigan-Huron declined by about 6
cm (2 inches), which is more than the 4 cm (2 inches)
decline in levels that is typical in December on these
The level of Lakes Michigan-Huron is now about 48 cm
(19 inches) below its long-term average beginning of January
level, and is 20 cm (8 inches) lower than a year ago.
The Board continues to monitor conditions both on Lake
Superior and downstream and will advise the International
Joint Commission accordingly on those conditions.
Brigadier General Bruce A. Berwick, Commander, Great
Lakes and Ohio River Division, U.S. Army Corps of Engineers,
is the United States Board Member.