Great Lakes Shoreline Erosion - Western Lake Michigan

Three coastal sites of varying topographic and geologic characteristics were selected along the Wisconsin shoreline of Lake Michigan for monitoring the processes and rates of shoreland erosion. Periodic (seasonal) plane surveys revealed that the mean recession rates varied from 0.05 ft (0.015 m)/TDM (thirty-day month) to 2.7 ft (0.082 m)/TDM, the latter having occurred during the fall/winter of 1975/ 76 along a high, steep, clayey bluff near Port Washington. A sinuosity factor S, invoked as a quantitative measure of the planimetric geometry of the bluff crest, provided an indirect evaluation of the compositional uniformity or variability of the bluff deposits. While high lake levels have accelerated the processes which induce failure and slumping, particularly along those shoreline segments having narrow beaches, the entire mechanism of bluff undermining and collapse depends largely on the direct and indirect effects of precipitation including rainfall, sheet & channelled runoff, water table fluctuations, frost action & shore ice.