Drought to Blame for Shrinking Lake Superior
DETROIT _ Wild rice fields have dried up in Wisconsin; sandy islands have appeared in the Duluth, Minn., harbor; Marquette’s beaches are broader; and freighters are lightening their loads and avoiding some ports altogether.
Lake Superior, the deepest and largest of the Great Lakes, is down, way down _ victimized by drought that has brought levels down more than a foot since last year, the equivalent of about 6 trillion gallons.
“That’s unprecedented,” said Cynthia Sellinger, deputy director of the Great Lakes Environmental Research Laboratory, part of the National Oceanic and Atmospheric Administration.
Levels are 2 feet lower than they were a decade ago.
Scientists are predicting that levels next month will be the lowest ever for September _ breaking a mark set during a drought in 1926 _ and are likely to continue setting records through the fall.
The lake’s tourism, fishing and shipping industries are all at stake. But the rapid loss of water has implications for all the Great Lakes waters downstream _ including Lakes Michigan, Huron and St. Clair _ that rely on Superior’s flow.
The biggest problem is drought. The area that drains into Superior has been in a moderate to severe drought since May 2006, meaning less rainfall and less melting snow are reaching the lake. The lake’s l evels have been low since April 1998, said Scott Thieme, chief hydrologist for the U.S. Army Corps of Engineers in Detroit.
What is alarming is the speed with which the lake, which is larger than the combined states of Vermont, Massachusetts, Rhode Island, Connecticut and New Hampshire, has dropped, Sellinger said.
Besides the drought factor, Superior has been evaporating more rapidly because warmer temperatures over the past decade have led to less ice cover.
The amount of water available from last winter’s snowpack was 60 percent below average, and last year’s precipitation was 6 inches below normal.
Thieme said if conditions continue through the fall and winter, they could lead to record low levels on L akes Michigan and Huron next year. The lakes are about 9 inches above their record lows.
Thieme said the Army Corps makes 6-month forecasts and sees nothing through January that might cause Superior’s level to rise.
Global warming could be an underlying cause, but the scientists said it’s too soon to know. “We need to do more tracking,” Sellinger said.
The last time Lake Superior was so low was November and December 1925 and January through September 1926, during a long drought that preceded the Dust Bowl.
Lower levels cost the shipping industry money. On average, for every inch water levels drop, cargo ships must reduce their loads by 50 to 270 tons.
Donna Holmstrom, business manager for the Keweenaw Convention & Visitors Bureau in Calumet, said she can’t remember a time when more beach was exposed.
She said Keweenaw residents are having a difficult time launching boats at ramps where the water is suddenly shallow. Others have moved portable docks to deeper water.
Rich Jamsen, 61, former manager of Copper Harbor Lighthouse Ferry Service, grew up in the area.
“The water’s the lowest in my lifetime,” he said.
Jamsen, who still assists the ferry business, said it kept the boat operating in low water this summer by putting more passengers in front. “That way the propeller had less of a chance of dinging the rock,” he said.
Jon Saari, president of the Upper Peninsula Environmental Coalition, said Superior beaches have gained 20 to 50 feet of shoreline. Although that’s not all bad for beachgoers, Saari said he’s concerned about what low water is doing to the shore habitat.
“We don’t know if this is a chronic situation connected to global warming or whether it’s a shorter cyclical pattern,” he said.
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