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Summer vacation researching lakes
The Journal Gazette (8/25)
Steve Park, a seventh-grade science teacher from Riverview Middle School in Huntington, Ind. spent a portion of his summer on an Environmental Protection Agency research vessel.

Senators announce funding for University of Michigan project
WKZO - Washington, D.C. (8/25)
Senators Debbie Stabenow and Carl Levin say that a grant for the University of Michigan will help develop models to protect Lake Erie from the effects of algal blooms.

Residents get hands-on lesson about Maumee River conditions
WTVG 13 ABC - Toledo, OH (8/25)
More than two dozen people took a two-hour look at the Maumee River and nearby facilities that impact its condition. The tour, hosted by the Lake Erie Waterkeeper, was especially important this year because of the growing algae bloom in Lake Erie.

Save the River looks to boost its education program
TWC News - Syracuse, NY (8/20)
A volunteer for a non-profit dedicated to protecting the St. Lawrence River has published a book to benefit the cause.

Great Lakes Bay Regional Alliance aims to raise awareness of Bay City's schooner Appledore, other STEM teaching tools
MLive (8/20)
Great Lakes Bay Regional Alliance ambassadors and board members, joined Bay City, Mich. area educators and members of the media for a STEM excursion aboard the schooner Appledore IV.

Local teachers travel to study lakes
The Journal Gazette (8/4)
An Indiana high school teacher and his brother were among the group of educators who took part in a weeklong summer program at Michigan Technological University in Houghton, Mich., as part of the Great Lakes Teacher Institute.

TEACH Calendar of Events
What's going on in your neighborhood this month? Meet other people and learn together at recreational and educational events! Our new dynamic calendar is updated daily with current educational events.
Water levels on the Great Lakes

table of contents
Introduction
Three types of water level fluctuations
History repeating itself: Hydrographs illustrate historical levels
How levels and flows are measured
Effects of lake level fluctuations
References and more information

Water levels on the Great Lakes

Click to see larger image. Water levels are part of the ebb and flow of nature.

The difference between the amount of water coming into a lake and the amount going out is the determining factor in whether the water level will rise, fall or remain stable. When several months of above-average precipitation occur with cooler, cloudy conditions that cause less evaporation, the levels gradually rise. Likewise, prolonged periods of lower-than-average precipitation and warmer temperatures typically result in lowering of water levels.

The recent decline of Great Lakes' water levels, now at lows not seen since the mid-1960s, is due mostly to evaporation during the warmer-than-usual temperatures of the past three years, a series of mild winters, and below-average snowpack in the Lake Superior basin.

Because the major factors affecting the water supply to the lakes--precipitation, evaporation and runoff--cannot be controlled or accurately predicted for more than a few weeks into the future, the influence of man-made regulation of lake levels is very limited. Nature has most of the control, adding water through snow and rain, and taking it away through evaporation.

Graphic: Lake Superior's south shore, April 2000.

Detailed Map: The Great Lakes-St. Lawrence River system


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