Great Lakes’ water levels dropping, but still just about average

• Drier conditions and the lack of precipitation have caused the water levels of the Great Lakes to decline 
• Despite the decline, water levels are just about the same as they were this time last year 
• Water levels in the Great Lakes tend to drop during the winter but rise again in the spring after the snow melts 

Autumn in Michigan not only means falling leaves; it also marks the start of the seasonal drop in water levels on the Great Lakes.

The U.S. Army Corps of Engineers, in a report issued late last week, said that by the second week in November, it expects water levels to drop 5-6 inches on lakes Erie and Ontario and 2-3 inches on lakes Superior, Michigan and Huron.

New estimates are due to be released in the coming days.

According to the agency, water levels tend to drop in fall and early winter “due to an increase in evaporation as temperatures decline and cold air moves over the relatively warm lake waters.”

Low water levels can create access issues for certain boats.  Recreational boating, for example, may be difficult because some vessels are not suited for lower water levels.

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According to Great Lakes Integrated Sciences and Assessments — a joint project of the University of Michigan and Michigan State University — high or low water levels can impact fisheries, commercial shipping, hydropower generation, recreational boating, shoreline flooding and coastal erosion.

“The variability of Great Lakes water levels is necessary for the continued health of the Lakes but can create challenges for waterfront communities and homeowners,” the Michigan Department of Environment, Great Lakes, and Energy explains on its website.

Historical perspective

Water levels in the Great Lakes have declined in recent years, but experts say it’s not as bad as it seems. 

Precipitation is the main determinant of water levels in the Great Lakes. This year, the state experienced drier-than-normal conditions due to a lack of rainfall, causing abnormally dry and even drought conditions in some parts of the state. 

But lake levels don’t just depend on rainfall totals in a specific area. Many of the rivers and streams across the state that feed into the lakes also impact lake levels. 

“The more areas that have drainage channels into the lakes, the more those areas are below average or in drought conditions, generally, the greater tendency for those lake levels to slowly decline over long periods of time,” said Kevin Kacan, meteorologist of the National Weather Service’s Detroit office. 

While low precipitation has had a slight impact on water levels in the Great Lakes, long-term data show that the current lake levels are just about average. 

“While the levels have dropped significantly in the last four or five years, they're not quite to a place where we would call them low yet,” said Keith Kompoltowicz chief of hydraulics for the U.S. Army Corps of Engineers, Detroit district. “They're near average, and that's just simply because it's been so dry, especially recently.” 

The water levels in the Great Lakes are just about the same as they were this time last year, except for Lake Superior, where the average water level is down compared to last year. 

As of Oct. 11, the average water level was about:

• 601 feet for Lake Superior
• 579 feet for lakes Michigan and Huron
• 572 feet for Lake Erie
• 245 feet for Lake Ontario.

Water levels in the Great Lakes dropped to record lows beginning in 2012 and 2013. However, the levels began to quickly increase in 2022 and are now starting to average out. 

“This stretch of weather that we've had across the Great Lakes, with the exception of a couple of rainy days here and there, has been just remarkable with tons of sun,”  Kompoltowicz said. “Very dry conditions have allowed the lakes to decline because of the lack of water being put into the system and that's a natural thing.” 

Typically, the lakes reach low levels during the winter but will rise again once the snow melts and spring rain occurs. But when there are consecutive dry seasons, water levels will decline to below-average levels. 

“If we see a very healthy snowpack on the ground in the Great Lakes followed by a very wet spring that would lead us to believe that levels might increase from where they were a year ago,”  Kompoltowicz said. “But if we continue these very dry conditions with very minimal snow, very minimal spring rains next year, then levels would continue to maybe even dip a little bit further and fall below average.”