Coastal Processes

Shabica & Associates, Inc.

Sustainable Coastal Solutions

Coastal Processes

Current Lake Michigan Water Level — 577.08’ IGLD (1985), February 2010

As the shore erodes, the beach narrows, sometimes becoming non-existent and waves begin to cut the base of the bluff. In Illinois, Lake Michigan’s shoreline is located in a highly erosional area due to reduced sand quantities moving along the shore caused by historic armoring of the bluffs and construction of groin fields over the last 100 years.

1860 to 2008 Yearly Lake Michigan Average Lake Levels (IGLD 1985)

Shore Erosion: the group of natural processes that includes weathering, dissolution, abrasion, corrosion, and transportation, by which natural material is worn away from the earth’s surface.

Text Box: “Great Lakes water levels have fluctuated throughout their historical record. Levels of Lakes Michigan and Huron, for example, reached record highs in both 1886 and 1986. Lakes Michigan and Huron’s record low water levels coincided with climatic events such as the Dust Bowl of the 1930’s, a multi-continental severe drought of 1964 (which is the record low for the two lakes), and the most recent and strongest El Nino on record of 1997.” Taken from: Water Levels of the Great Lakes, NOAA Great Lakes Environmental Research Laboratory, July 2007

Who is Affected by Fluctuating Lake Levels?

As many Chicagoans remember, record high lake levels of 1986 affected many residents and businesses along Lake Michigan. Portions of Lake Shore Drive and Sheridan Road had to be closed from invading stormwaves, and dozens of high-rise buildings along the lakeshore suffered from flooded basements and lobbies. The problem was so serious that Chicago’s Mayor Harold Washington mailed letters to all riparian homeowners along the lake with instructions on how to properly fill and install sandbags on the beach to protect their properties (at the right).