Lake St. Clair begins ‘seasonal decline’

By: Kristyne E. Demske | Metro | Published November 5, 2021

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METRO DETROIT — After the record high water levels set on Lake St. Clair in 2019 and 2020, forecasts from the U.S. Army Corps of Engineers show the lake’s levels in a decline, which will likely continue through the winter.

“During the fall and early winter, water levels typically decline as a result of increased evaporation,” said Keith Kompoltowicz, Detroit District Watershed Hydrology Section Chief of the U.S. Army Corps of Engineers in the corps’ “On the Level” video. “Evaporation is highest during this time of year as a result of the colder air that enters the region and moves over the relatively warm waters of the lakes.”

Lake Superior is the only lake forecasted to remain below average levels. The other Great Lakes and Lake St. Clair are expected to continue their seasonal decline and be below the record high levels, but still slightly above average, over the next six months.

As of Oct. 22, Lake St. Clair’s current level is 4 inches below the level measured in September and 6 inches below the level measured in October 2020. It is still 45 inches above chart datum, however. Projections show the lake will likely lose 6 inches by Nov. 22, 2021. The six-month forecast shows the lake will lose anywhere from 2 inches to 2 feet in depth by March 2022.

“Lakes Michigan-Huron and St. Clair are also forecasted to continue their seasonal declines into the late winter while, similarly to Lake Erie, remaining above average but below record high levels,” said Watershed Hydrology Section Physical Scientist and lead water level forecaster Dee Apps.

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