Lake Superior Still On Upswing

Lake Superior's water levels continue to climb, with the lake clocking in a four-inch rise in June – an inch above average.

Though Lake Superior's water levels have been on the rise this spring and early summer, the lake is still about 11 inches below its long-term average beginning-of-July level. Even so, the lake is one inch higher than water levels recorded a year ago and the level of Lake Superior is expected to rise in July.

This past month water inputs to the Lake Superior basin and the Lakes Michigan-Huron basin were above normal. The level of Lakes Michigan-Huron rose three inches in June, while on average it rises two inches in June. The level of Lakes Michigan-Huron is now about 12 inches below its long-term average beginning-of-July level, and is one inch higher than it was a year ago. The level of Lakes Michigan-Huron is expected to remain steady in July.

The International Lake Superior Board of Control continues to monitor conditions both on Lake Superior and downstream and will be advising the International Joint Commission accordingly on those conditions.

Lake Superior's outflow was set by the board of control to 1,720 cubic meters per second for the month of July. This is an increase of almost 100 cubic meters per second from June and is to accommodate sea lamprey trapping tests.

The lake's outflow occurs through three hydropower plants and through a control structure at the head of the St. Marys Rapids.