U.S. Army Corps of Engineers
Lake Level Bulletin: May 2014
Above-average water supplies to Lake Superior kept the Big Lake above its average level for the second consecutive month. Last month Lake Superior topped long-term average for the first time since 1998.
In April, the Lake's monthly mean was an inch above long-term average and rose 4 inches (an inch more than usual). The U.S. Army Corps of Engineers projects above-average levels all summer long.
In a news release, the International Lake Superior Board of Control said, "The outflow of Lake Superior will be adjusted over the next several months to reduce the risk of unusually high flows forecasted for the months of June through August, and to provide more consistent flow conditions in the St. Marys Rapids."
Anglers Cautioned of High Flows in St. Marys Rapids
The International Lake Superior Board of Control, under authority granted to it by the International Joint Commission, expects to increase the Lake Superior outflow for the month of May. The increased outflow is expected to exceed the capacities of the hydropower plants on the St. Marys River in May, and therefore the excess will be released through the control structure at the head of the St. Marys Rapids.
As a result, beginning on Monday, May 5th, it is anticipated that the gate opening in the control structure at the head of the St. Marys Rapids will be changed from the present setting equivalent to ½ gate open to four (4) gates fully open. Anglers need to be cautious of the changing flows and water levels in the rapids on May 5th and the unusually high flows and levels that will be experienced in the rapids during May. These gate movements will primarily affect water conditions in the main rapids, but with four gates fully open in the control structure, water may overtop the Fishery Remedial Dike along the north side of the Rapids, and may create a hazard. There will be no change to the setting of Gate #1 which supplies water to the channel north of the Fishery Remedial Dike.