The Great Lakes - Superior, Michigan, Huron, Erie and Ontario - are a dominant part of the physical and cultural heritage of North America. Shared with Canada and spanning more than 750 miles (1,200 kilometers) from west to east, these vast inland freshwater seas have provided water for consumption, transportation, power, recreation and a host of other uses.
Lake Erie is the shallowest and the second smallest of the Great Lakes. It was formed by numerous glacial cycles, with ice over 5,000 feet thick that could advance over 200 feet in a year. These heavy, moving sheets of ice pushed across an ancient river valley and gouged out the softer areas of rock. This helps explain the difference in average depth between the deeper eastern part of the lake and the shallow western island region. The retreat of these glaciers opened up the waters of Lake Erie earlier than the more northern Great Lakes as well.
As the North American landscape changed, so did the Lake Erie shore. Once as far inland as Route 84, the current shore is very new in geological terms. This contributes to the dynamic nature of our coastline. Besides glacial rebound, other forces changing the shape of the shore are seasonal water level fluctuations, severe storms and the waves they create, and human influences.
About 80% of the water in Lake Erie comes from the upper lakes. The water that fills Lake Erie comes mostly from the Detroit River. Other major inputs include the Maumee, Portage, Cuyahoga and Grand Rivers. Smaller rivers, such as the Chagrin and Euclid Creek also contribute. The approximately 219,000 cubic feet of water per second flowing into the western end of the lake combine with the prevailing southwestern winds to create a longshore current. This current moves the water in Lake Erie towards Buffalo and Niagara Falls, and unstable shore materials can be carried away as well.
Shore erosion has always happened along the Lake Erie coast, but unusually high water levels in the 1970’s magnified the rates of shore erosion in many places. These high water levels occur when the upper lakes freeze over, preventing evaporation, and when there is an increased input of rainfall and snowmelt. Typically, the energy from waves is spread out over a beach area. However, when the lake level is higher, the waves strike directly at the base of slopes or cliffs. This is a minor issue along rocky shores, but much of the Lake County shore is soft shale or piles of glacial till, both of which are easily eroded. Removal of trees and shrubs from these steep slopes, and runoff from houses and roads built on the top of the slopes also increase vulnerability.
While every Lake County resident has a responsibility to protect water quality, lakeshore landowners have a more direct responsibility and more at stake. Many of the factors discussed above are out of an individual’s control, however a responsible shore landowner should take steps to prevent or slow down shore erosion. The four publications below will explain the natural shoreline process, describe the mechanisms of erosion, illustrate some possible ways to protect a shoreline from erosion, and how to get the proper permits to begin a project.