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New stewardship programs aim to teach students how to care for Great Lakes
Upper Peninsula Second Wave (10/15)
The Upper Great Lakes Stewardship Institute is the newest among several regional hubs across Michigan with the goal to educate students on good environmental stewardship for the Great Lakes and their watersheds.

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.
TEACH Questions & Answers

Do the Great Lakes have tides?
from Jean in Milton, Massachusetts and Thor in Davisburg, Michigan

The same forces are at work on lakes as on oceans -- the moon pulls on inland lakes, too. However, you won't find large tides on lakes as you do on oceans; lakes just don't have enough water in them for large tides to occur.

Dr. David Hollander -- a specialist in lake systems at Northwestern University -- was asked about tides on inland lakes. He said that the Great Lakes sometimes experience slight changes in water levels over short time scales, and in spring, there's a substantial influx of water due to melting of winter snows farther north. Yet, none these changes in water level can be called a true tide.

Click to see larger image. However, there is some disagreement on the subject. According to the Canadian Hydrologic/Hydrographic Service, the Great Lakes experience tides from 1 to 4 cm, the strongest being on Lakes Superior and Erie. These tides are often masked out by meteorologically induced phenomena, such as a seiche (pronounced "sayshe"). When wind pushes down on one part of a lake, the water surface rises in another part, producing waves (most noticeable on Lake Erie because the lake is so shallow).

Read TEACH's segment, Great Lakes water levels, for more information; if you'd like a more in depth explanation, download the Great Lakes Commission's Living with the Lakes brochure.

Thank you both for your question!


Answered on October 1, 2000

 

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