The water levels of the Great Lakes have gone down significantly in the past few months. Part of that is the natural annual lowering of water levels in most fall seasons and part is because of the lack of rain in the past couple months. (pic. above is me at the Mackinac Bridge in Oct. 2024 – it was a windy, but pleasant day).
Here’s a graph of the water level of Lake Superior. The level is down 3″ in the last month and 7″ in the past year. The level is 7″ below the November average level, but still 12″ above the lowest November lake level reached in 1925.
From Sept. 1 – Nov. 2, Duluth had only 22% of average rainfall. During that period, S. Ste. Marie had 53% of average rainfall and Marquette had 55% of average rainfall. We also had well above average evaporation, due to near record amounts of sunshine, dry air and brisk winds.
Because of the lower water level, the outflow from Lake Superior down the St. Marys River into Lake Huron has fallen to 58,900 cubic feet per second. That’s just 75% of the average flow of 78.800 cfs. The lower water levels have not had a significant negative affect on Great Lakes shipping.
The water level of Lake Michigan/Huron (one lake for lake-level purposes, as they are joined at the Straits of Mackinac) is down 4 inches in the last month (that’s a lot – Each inch of water on Lake Michigan is 390 billion gallons. So that means the lake(s) lost 1,56 trillion gallons of water in just one month. The water level is down 7″ in the past year, but is only 2″ below the average November level. The level is 28″ above the lowest recorded November level reached in 1964.
Rainfall from Sept. 1 – Nov. 3 in Grand Rapids was only about 1/3rd of average (34%). During that period, Kalamazoo had about half of average rainfall (52%).
The water level of Lake Erie is down 5″ in the past month and down 4″ year-to-year. The level is still 7″ above the November average and 40″ above the lowest level reached in 1934.
The water level of Lake Ontario is down 8″ in the last month and down 7″ in the last year. The level is 4″ below the November average level, but the level is still 28″ above the lowest November level in 1934.
The water level of Lake St. Clair is down 8″ in the last month an down 7″ in the last year. The level is still 4″ above the average November level. It’s also 34″ higher than the lowest November level, also reached in 1934.
Streamflow as of 11/7 PM – rivers have gone up this week due to rainfall: The Grand River in Grand Rapids has a streamflow of 2,280 cubic feet per second. The average flow for Nov. 8 is 2,390 cfs, so that’s 95% of average flow.
The Kalamazoo River at Comstock has a flow of 835 cfs, compared to an average flow for early November of 736 cfs. The St. Joseph River at Niles has a flow of 2,140 cfs and that compares to an average flow of 2,350 cfs. The Muskegon River at Croton has a flow of 1,850 cfs which is almost exactly the average flow of 1,860 cfs.
On the east side of the state, the Tittabawassee River at Midland has a flow of 871 cfs compared to an average flow of 1,010 cfs.
In Wisconsin, the Fox River at Oshkosh has a flow of 5,790 cfs, compared to an average flow of 3,900 cfs. Green Bay had 1.54″ of rain in the first week of November and that was 1.05″ above average.
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