Lake Superior shoreline exposed
By Anna Liisa Schourek
The Mining Gazette
Published May 2, 2007
HOUGHTON — Lake Superior is 12 inches below its water level this time last year and the U.S. Army Corps of Engineers expects it to stay below last year’s levels through September.
The expected water level for April 27 was 600 feet, only six inches above the lowest recorded monthly mean level for April in 1926, according to the Corps. The drop is attributed to a combination of decreased surface water runoff and increased evaporation during the winter.
The Great Lakes region has been experiencing a drought for the past couple of years, which has lessened runoff and precipitation, said Marcia Cronce of the National Weather Service. Most of the runoff for Lake Superior comes from northeastern Minnesota and Ontario, Canada.
Cronce said the temperature is slightly above normal, but drought is the main contributor to decreasing water levels.
This long period of low precipitation is not the only factor contributing to lower water levels.
“Lack of ice cover has allowed for a tremendous amount of evaporation,” said George Madison, fisheries supervisor for the Michigan Department of Natural Resources’ Western U.P. Management Unit. “Billions of gallons are evaporated every winter.”
Madison explained cold and dry Canadian air masses sweep across the lake, pick up a lot of moisture from the exposed water, and then release the moisture as precipitation outside of the Great Lakes watershed.
Water levels do typically rebound in the spring. All of the Great Lakes, except for Lake Erie, are forecasted to rise 1 to 3 inches over the next month, according to the U.S. Army Corps of Engineers.
It is still possible that Lake Superior is approaching a record low, which may hit mid-summer, Madison said.
The negative effects of decreased water levels include dangerous and inconvenient conditions for boaters and the shipping industry. Sandbars, rocks and other obstacles that are normally deep beneath the water can be hazardous.
Low water levels also pose a hazard to animal habitats, as it may become difficult for fish like walleye and northern pike to spawn, Madison said.
On the positive side, less erosion, like bank failures, will occur on lakefront property.
Water loss occurs every year and normally fluctuates between 12 and 24 inches, according to the U.S. Army Corps of Engineers. Extremely low water levels did occur in the mid 1920s, mid-’30s and early ’60s. Historically, those dry periods were followed by high water levels, and Madison believed that trend would continue.
“Water levels are cyclic,” he said.