ABSTRACT

Underwater study of oscillation ripples in the nearshore environment of southeastern Lake Michigan indicates that a variety of physical factors control the shape, size, composition and orientation of ripples. With the use of SCUBA (self-contained underwater breathing apparatus) ripples were measured at almost 400 locations along 21 traverses in Allegan and Berrien Counties, Michigan. Ripples range in wave length from 2.5 to 38 inches and are found throughout the sand sized fraction of the sediment.

Wind direction is the ultimate agent in determining orientation of ripple crests although shoreline direction is also a factor. Change in wind direction causes change in ripple orientation and provides criteria for observing the generation of ripples. Topographic position and grain size control the size of ripples. Shape of ripples is primarily a function of relative physical energy and composition.

At 50 feet from the strand line ripple orientation may be 65 degrees from that of the shore. This indicates ripples are not a good criterion for establishing ancient shoreline direction.