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U-M divers retrieve 8,900-year-old piece of wood from Lake Huron
Annarbor.com (12/12)
University of Michigan researchers announced they have found a 5 1/2 foot long, pole-shaped piece of wood that is 8,900 years old in Lake Huron.
RIVERKEEPERS: Tending the waterways
Niagara Gazette (2/6)
The goal of the Buffalo Niagara Riverkeeper is two-fold: protecting the water quantity and the quality, as well as connecting people to the waterfront.
Internationally renowned ‘Ocean Doctor’ to speak in Grand Rapids
MLive.com (2/3)
Known as the “Ocean Doctor,” David Guggenheim will speak in Grand Rapids, Mich., about the many similarities between the threats to the oceans and to our Great Lakes.
SUNY Fredonia to lead Great Lakes pollution study
Wall Street Journal (2/3)
Plastic pollution in the Great Lakes will be the focus of a study this summer. Led by the State University of New York at Fredonia, researchers will try to quantify the amount of plastic polluting the fresh water Great Lakes.
SSC students taking part in marine science bowl
Arenac County Independent (1/31)
Teams of Michigan high school students will be heading to Ann Arbor this weekend to take part in the annual Great Lakes Bowl, a quiz event that focuses on questions about marine and freshwater systems and biology.
No aquarium for Windsor
CBC News (1/31)
Aquariums in Cleveland, Toledo, and Chicago prove to be too much competition for Windsor.
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.
2 | Three types of water level fluctuations
Water levels on the Great Lakes change seasonally each year and can vary dramatically over longer periods. Short-term changes are generally of greater magnitude than the monthly averages.
Short-term changesSome water level fluctuations are not a function of changes in the amount of water in the lakes, but are due to winds or changes in barometric pressure. These short-term fluctuations, often due to storms or ice jams, can last from a couple hours to several days and can be very dramatic.
One such phenomenon, known as wind set-up or storm surge, occurs
when sustained high winds from one direction push the water level up at one end of a
lake, which makes the level drop by a corresponding amount at the opposite end. Changes
in barometric pressure can add to this effect. When the wind abruptly subsides or
barometric pressure changes rapidly, the water often oscillates until it stabilizes again.
This oscillation is called seiche (pronounced "sayshe"). These events are most common on Lake Erie
due to its east-west orientation in an area of prevailing westerly winds and its generally
shallow western end.
See also: Great Lakes Facts and Figures
Seasonal changes
In the fall and early winter, when the air above the lakes is cold and
dry and the lakes are relatively warm, evaporation from the lakes is greatest.
Consequently, water levels decline to their seasonal lows.
As the snow melts in the spring, runoff to the lakes increases. Evaporation from the lakes is also least in the spring and summer when the air above the lakes is warm and moist and the lakes are cold. With more water entering the lakes than leaving, water levels rise to their peak in the summer. In the early fall, evaporation and outflows again begin to exceed the amount of water entering the lakes.
The range of seasonal water level fluctuations on the Great Lakes averages about 12 to 18 inches from winter lows to summer highs. Seasonal rises begin earlier on the more southern lakes that experience a slightly warmer climate. Lake Superior, the northernmost lake, is generally the last to peak, usually in August or September.
Long-term changes
Long-term fluctuations occur over periods of consecutive years.
Continuous wet and cold years will cause water levels to rise. Likewise, consecutive warm
and dry years will cause water levels to decline. Over the last century, the range from
extreme high to extreme low water levels has been nearly 4 feet for Lake Superior and
between 6 and 7 feet for the other Great Lakes.
Graphic: Lake profile showing wind set-up.
