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Anglers enlisted in water fight
Great Lakes Echo (6/29)
A recent study by researchers at Cornell University, in N.Y., revealed that anglers in the Great Lakes region are aware of and concerned about the threat of aquatic invasive species (AIS).

Stone Lab hosts series of experts to discuss lake
Port Clinton News Herald (6/28)
In Ohio, people looking to learn more about the issues facing Lake Erie will have several opportunities this summer to hear firsthand from the experts in the field who deal with those issues every day.

Goal of UWM habitat study is to help restore fisheries in river
Milwaukee Journal Sentinel (6/25)
Led by University of Wisconsin-Milwaukee's School of Freshwater Sciences, a habitat study's goal is to identify habitat that supports estuary fish and recommend strategies to protect, encourage and connect these habitats in harbor revitalization and habitat restoration plans.

Funding milestone reached for Aquatic Research Lab expansion
The Sault Ste. Marie Evening News (6/13)
Both houses of Michiganís legislature have approved nearly $9 million in funding for an expansion of Lake Superior State Universityís successful Aquatic Research Lab (ARL).

Students dive, document Sheboygan shipwreck
Sheboygan Press (6/13)
A team of budding nautical archaeologists from East Carolina University dove below the waves of Lake Michigan to discover what treasures lay hidden on the sandy bottom.

Island living and working at Thousand Islands Biological Station in Clayton
The Syracuse Post-Standard (6/8)
Many apply, but few are chosen for the limited number of scientific research positions each year at the Thousand Islands Biological Station (TIBS). The SUNY ESF research facility is located on Governor's Island in the St. Lawrence River in Clayton, NY.

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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