Scientists say higher water levels are good for the region's wetland vegetation, birds and fish.
Cynthia Sellinger is a hydrologist for the National Oceanic and Atmospheric Administration's Great Lakes research lab. She says the area had a wet fall and an unusually wet May.
Levels at the other Great Lakes are up, too. Erie is up six inches, Superior is up five inches, Ontario is up three inches and Huron is up a foot.
The overall depth in August was measured as 578.7 feet above sea level.