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Tales of the Coast
America's Coasts

Great Lakes: Lake Michigan

The most notable characteristic of the Lake Michigan shoreline is its variability. Sandy and coarse beaches dominate the geomorphology of the far northwestern shoreline. Along the sheltered shoreline of Green Bay in northern Wisconsin, beaches are mixed with cohesive bluffs and wetlands. Beaches and cohesive bluffs continue to alternate down the coast of Wisconsin and Illinois, except at the cities of Milwaukee and Chicago, where artificial structures and hardened shorelines prevent sediment movement. Along the coast of Indiana, at the southern end of Lake Michigan, intensive industrial development dramatically altered the shoreline with harbors and structures; the only exceptions are the Indiana Dunes National Lakeshore and Indiana Dunes State Park, which are designated as natural areas and feature huge sand dunes.

Along the eastern shore of Lake Michigan, beaches and erodible, cohesive bluffs again alternate as the predominant geomorphic types. Navigational harbors are very common in the southern portion of the state of Michigan, and the jetties, channels and dredging at these locations have changed the natural sediment transport processes. In northern Michigan, however, sandy beaches become common from Grand Traverse Bay to the Straits of Mackinac, which connect Lake Michigan with Lake Huron.

Chicago Harbor and Lock

Southerly break water, Chicago Harbor, Ill.
Source: USACE

Shoreline Changes

Erosion and accretion rates along the Lake Michigan shoreline are highly variable, due to the constantly shifting geomorphology and different levels of development. Some shorelines, such as hardened coasts at cities like Chicago, do not change at all, while others, such as erodible cohesive bluffs in western Michigan, are undergoing permanent erosion.