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Grand Haven students participate in annual fishing event
Grand Haven Tribune (5/15)
In Michigan, Grand Haven Area Public Schools partnered with a nonprofit organization called Pursuing a Dream to give about 300 students with special needs the opportunity to fish and enjoy the outdoors.

NYPA funding aids three St. Lawrence River projects
Watertown Daily Times (5/10)
The St. Lawrence River Research and Education Fund has provided funding for three projects that support environmental education in and around the riverís ecosystem.

Lake Michigan Academy students learn from 'Salmon in School' project
MLive (5/9)
About 100 schools throughout Michigan are selected to take part in the Lake Michigan Academy program that aims to help stock local rivers and support fishing as a leisure activity.

Huron Perth students find Lake Huron threats
Blackburn News (5/1)
Nearly 60 high school students from the public and separate boards in Huron and Perth counties spent one day at the Oakwood Inn in Grand Bend, Ontario, where they were learning about the environmental threats and challenges to Lake Huron.

Bay City tall ship sets sail for season of education, fun
The Associated Press (4/24)
An educational tall ship is back for another season on the Lake Huron waters off Bay City, Mich.

Salmon raised in Guelph classroom soon to swim in Lake Huron
Guelph Mercury (4/22)
Schools in Ontario are participating in the Lake Huron Fishing Club's salmon hatchery program, which aims to rejuvenate a salmon population that has been severely diminished.

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

4 | How levels and flows are measured

Water levels are measured and recorded at many locations around the Great Lakes and on their connecting channels.

Click to see larger image.The National Ocean Service of the National Oceanic and Atmospheric Administration (NOAA) presently operates 31 water level gages on the Great Lakes and 18 gages on the connecting channels. In Canada, the Canadian Hydrographic Service maintains 29 water level gages on the Great Lakes and 27 on the St. Lawrence River. Other agencies, including the U.S. Army Corps of Engineers, New York Power Authority and Ontario Power Generation, also operate recording gages at various locations on the lakes.

See also: Map of Great Lakes Water Level Gauging Stations

Great Lakes water levels are officially measured from the International Great Lakes Datum 1985 (IGLD 1985). This datum is referenced to sea level, as measured at Rimouski, Quebec, near the mouth of the St. Lawrence River. Because the crust of the earth in the Great Lakes region is continuously rising with respect to sea level, and the rate of movement is not uniform throughout the region, the IGLD must be updated every 25 to 30 years.

See also: FAQ about the International Great Lakes Datum

Click to see larger image.The rate of flow, or discharge, in a river or Great Lakes connecting channel is determined by measuring the channel depth and width, and the velocity of the flow. Measurements can be made by boat, from a bridge, or from a cableway strung across the river. With sufficient measurements of flow over a range of water levels, mathematical relationships can be developed between levels and discharges for various points along the connecting channels and the St. Lawrence River. These equations are essential to the coordination of outflow data, particularly related to hydroelectric power usage of Great Lakes waters.

Graphics: Water level gaging station; measuring outflows at the Niagara Cableway.

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