The Great Lakes are a chain of five large freshwater lakes that form the largest lake group in the world, covering an area of 95,000 sq miles. This is about the same size as the state of Wyoming, the 10th largest state in the US. They are the largest surface freshwater system on the Earth. They contain about 84 percent of North America’s surface fresh water and about 21 percent of the world’s supply. Only the polar ice caps contain more fresh water.
Nearly 25 percent of Canadian agricultural production and 7 percent of American farm production are located in the Great Lakes basin. More than 30 million people live in the region – roughly 10 percent of the U.S. population and more than 30 percent of the Canadian population.
For more information on that data for these calculations see this site
In spite of their large size, the Great Lakes are sensitive to the effects of a wide range of pollutants. Major stresses on the lakes include toxic and nutrient pollution, invasive species and habitat degradation. Sources of pollution include the runoff of soils and farm chemicals from agricultural lands, waste from cities, discharges from industrial areas and leaching from disposal sites. The large surface area of the lakes also makes them vulnerable to direct atmospheric pollutants that enter the system as rain, snow, or dust on the lake surface. The amount of water that leaves Great Lakes annually is relatively small (less than 1 percent per year) in comparison with the total volume of water. Pollutants that enter the lakes are retained in the system and become more concentrated with time.
In the early years of Canada and the United States the waterways were vital to fur trading and regional development. In modern times they remain a significant transportation route for iron ore, steel, petroleum, grain, American automobiles, and other products.
The names of the lakes are Superior, Michigan, Huron, Erie, and Ontario.
Lake Superior at 31,698 sq miles, is the largest fresh water lake in the world. It is about 350 miles long and 160 miles at its widest point. The deepest point is 1,332 ft, while the average depth is 500 ft. The shoreline is 2,730 miles including islands.
Lake Huron is 23,011 sq miles and is 206 miles long and 183 miles at its widest point. The deepest point is 750 ft, while the average depth is 195 ft. The shoreline is 3,830 miles including islands.
Lake Michigan is 22,316 sq miles and is the largest freshwater lake that is totally contained within the United States. It is 307 miles long and 118 miles at its widest point. The deepest point is 925 ft, with an average depth of 279 ft. The shoreline is 1,640 miles including islands.
Lake Erie has an area of 9,922 sq miles. It is 240 miles long and 38 to 57 miles wide, depending on the location. The deepest point is 210 ft, while the average depth is 48 ft. The shoreline is 871 miles including islands.
Lake Ontario, at 7,320 sq miles, is the smallest of the Great Lakes. It is about 193 miles long and 53 miles at its widest point. Because of low elevation above sea level and shallow depths (500 to 800 ft in some places), it doesn’t freeze in winter, unlike the other lakes in the chain. The deepest point is 802 ft, while the average depth is 283 ft. The shoreline is 871 miles including islands.
Sources
http://www.worldatlas.com/webimage/countrys/namerica/greatlk.htm
http://epa.gov/greatlakes/basicinfo.html
For additional information and facts see these sites
Great Lakes Information Network
Environment Canada, Our Great Lakes
Great Lakes Environmental Research Laboratory
Great Lakes Science Center: US Geological Survey
Also, new photos of the Sleeping Bear Dune region on the Photos tab
