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Drinking Water Week
American Water Works Association (5/6)
Drinking Water Week, May 4-10, is a unique opportunity for water professionals and the communities they serve to join together to recognize the vital role water plays in our daily lives.
American Wetlands Month
U.S. Environmental Protection Agency (5/2)
This May will mark the 18th anniversary of American Wetlands Month, a time when EPA and its partners celebrate the vital importance of wetlands to the Nation's ecological, economic, and social health. It is also a great opportunity to discover and teach others about the important role that wetlands play in our environment and the significant benefits they provide.
Great Lakes Regional Research Information Network (GLRRIN)
GLIN's May 2008 Site of the Month (5/1)
Established in 2006 by NOAA Sea Grant, GLIN and regional partners, GLRRIN provides a powerful means to foster collaboration, acquire funding, highlight research needs and issues, and increase the overall impact of Great Lakes research. GLRRIN is a free service and offers research-related news and upcoming events, and profiles of Great Lakes researchers and their current projects.
Mother Earth Water Walk
(4/28)
Two Anishinawbe Grandmothers, and a group of Anishinawbe Women and Men have taken action regarding the water issue by walking the perimeter of the Great Lakes. The 2008 Lake Michigan walk kicked off April 26.
Shipwrecks and Maritime Tales of the Lake Erie Coastal Ohio Trail
Ohio Sea Grant (4/24)
The shipwrecks within this website are a mere sampling of the hundreds of shipwreck sites located in the depths of Lake Erie. The goal is to make the visitor aware of the rich maritime history which lies beneath the surface of Ohio's Lake Erie.
Michigan Wildlife Conservancy
(4/21)
The Michigan Wildlife Conservancy provides the technical and financial assistance that landowners and managers need to restore and maintain wildlife habitat on their own land.
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 | Prehistoric glacial movements
Early drainage from these lakes flowed southward through the present Illinois River Valley toward the Mississippi River, through the Trent River Valley between present lakes Huron and Erie and through the Lake Nippissing-Ottawa River Valley from Georgian Bay on Lake Huron downstream to the present Montreal, Quebec, area.
Without the immense weight of the glaciers-thousands of feet thick in places- the land began to rebound. Even today, virtually all of the land in the Great Lakes basin continues to rise. Southern parts of the basin are rising slightly, less than 3 inches per century. The northeastern corner of the Lake Superior basin, however, is rebounding in excess of 21 inches per century.
Graphic: Prehistoric glacial movements and lake shapes
Since the retreat of the glaciers, water levels continued to undergo dramatic fluctuations, some in the magnitude of hundreds of feet. These extremes were caused by changing climates, crustal rebound and natural opening and closing of outlet channels. Within the last 1,000 years, evidence suggests that lake levels exceeded the range of levels recorded since 1865 by an additional five feet on lakes Michigan and Huron. As a consequence of these recent fluctuations, shoreline position and environments have dramatically changed. Dunes, baymouth barriers, embayments and river mouths have all been modified by the forces of water. Many dune formations-some hundreds of feet thick-were established during glacial periods. The tops of these dunes have been continuously sculpted by winds to form the majestic structures now visible.
Today, rebounding of the earth's crust, erosion, and changes in climate continue to alter the shapes and sizes of the Great Lakes. As one of the youngest natural features on the North American continent, the lakes remain a dynamic, evolving system.
