Great Lakes Water Levels Fall a Little Bit

Bill's Blog

Water levels on the Great Lakes fell a little bit over the past month, which is typical for this time of year. Levels of the Great Lakes (except Lake Ontario) remain well above average. The above pic. was taken at 8 am Thursday from the Chicago Water Intake (GLERL camera).

Graph of the water level of the Great Lakes over the last 102 years.

The water level of Lake Superior fell one inch in the last month. It’s down 3″ from one year ago. The lake is 10″ above the November average, but is now 7″ below the all-time November highest level, which occurred in 1985.

The level of Lakes Michigan and Huron is down 2″ in the last year and 3″ year-to-year. The level is still 32″ above the November average, but is also 7″ below the all-time November highest level which occurred in 1986.

Lake Erie fell 2″ in the last month and is one inch lower than last November. The lake is 25″ above the average for November, but 8″ below the highest November level, which was reached in 1986.

Lake Ontario is down 4″ in the last month and is down a healthy 18″ since Nov. 2019. The lake is only 3″ above the November average level and is a full 22″ below the November record level of 1945.

Lake St. Clair is also down 4″ in the last month and down 3″ year-to-year. The lake is 28″ above the November average level, but also 7″ below the November record level set in 1986.

St. Clair River – (pic. from the Army Corps of Engineers

All the rivers that connect the Great Lakes have above to much above average flow. The St. Marys River at Sault Ste. Marie has a flow of 97,300 cfs, compared to an average flow of 80,700 cfs. The St. Clair River at Port Huron has a flow of 249,000 cfs compared to an average Nov. flow of 181,000 cfs.

Inland rivers are a mix. The St. Joseph River at Niles has a flow of 1,710 cfs, compared to an average flow of 2,450 cfs. The Kalamazoo River at Comstock has a flow of 892 cfs, compared to an average flow of 772 cfs. The Grand River at Grand Rapids has a flow of 2,920 cfs, compared to an average flow of 2,520 cfs. The Muskegon River at Croton has a flow of 1,640 cfs – average for mid-November is 1,820 cfs.

This is interesting, the flow on the Saginiaw River at Saginaw was -2,520 cfs. That’s right, the river was flowing backwards. That can happen when there is a strong northeast wind at that location. The wind pushes water from Saginaw Bay back into the river. That can happen (will happen on Sunday 11/15) to the rivers in West Michigan that empty into Lake Michigan when there is a strong west wind. The average flow at Saginaw is 2,700 cfs. Upstream, the Tittawabassee River had a flow of 1,180 cfs, compared to an average of 1,090 cfs.

The Fox River at Appleton has a flow of 10,000 cfs, compared to an average flow of 4,250 cfs. Green Bay is 5.51″ above average precipitation for 2020 after a record wet year in 2019, so rivers in NE Wisconsin have been high for a long time.

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