ABSTRACT
In addition to their ocean coasts, the United States and Canada enjoy tremendous inland seas, the five Laurentian Great Lakes: Superior, Michigan, Huron, Erie, and Ontario (Figures 1 and 2).1 These lakes and their connecting channels make up the largest freshwater system in the world, extending some 750 miles (1200 km) from east to west and linking the interior of the North American continent to the Atlantic Ocean. Together they represent about 95% of the total freshwater supply in the United States, as well as about 80-90% of North America’s and about 18% of the world’s freshwater supply. In addition to freshwater consumption, they provide a major natural resource for transportation, industry, power, tourism and recreation.
