waves before runup on the foreshore, and is best developed under low-energy 

 conditions. During periods of storm activity the plunge step may not be 

 present as a topographic feature but its location may be indicated by an 

 accumulation of coarse sediment, generally gravel, at that position on the 

 profile. 



Beyond the plunge step the profile slopes gently to the nearshore area 

 where longshore bars and troughs are typically present. These bars are 

 continuous, extending through the eastern Lake Michigan nearshore area; 

 however, their position and depth vary (Hands, 1976). 



The small ephemeral bar may be present, particularly just after storm 

 conditions or during low-energy periods of the summer months. This bar is 

 generally less than 100 feet from the strand line and has less than 3 feet 

 of water over its crest. The bar will migrate shoreward during low-energy 

 conditions and eventually weld to the beach (Davis, et al., 1972). 



Most of eastern Lake Michigan contains two longshore bars although one 

 to three are present at some locations. Although these bars are fairly 

 stable (Davis and McGeary, 1965) , they have been shown to move slowly in 

 response to changing lake level conditions (Saylor and Hands, 1970). They 

 are also rather continuous, based on aerial photos and field surveys. The 

 migration, stability, and storm modifications of longshore bars are gener- 

 ally poorly known. Although the above-mentioned studies have attempted 

 to monitor changes in these bars, there are as yet no good data on modi- 

 fications that might occur during storms. It is apparent that there is 

 little or no change between prestorm and poststorm profiles (Davis and 

 McGeary, 1965; Davis and Fox, 1971). This situation could be quite dif- 

 ferent during a storm. The opinion of the author is that longshore bars 

 are modified during intense wave activity but as the storm subsides there 

 is a return to equilibrium conditions with no apparent changes. 



2 . Processes . 



With the notable exception of significant astronomical tides, there is 

 no general difference between beach and nearshore processes operating along 

 eastern Lake Michigan and those on marine coasts. Studies of both types of 

 coasts have confirmed this (Davis and Fox, 1972a; Davis, et al . , 1972). 

 Waves and currents are the dominant processes, and wind is of only minor 

 significance, except in the formation of the foredune terrace. Currents 

 are primarily of two types: Longshore currents and rip currents. Because 

 of limited fetch in the Great Lakes, swell is not prominent in coastal 

 processes. 



There is an apparent cyclic nature of the processes operating along 

 the eastern coast of Lake Michigan with the most prominent underlying 

 causes being those of pas-sing weather systems and in particular, fluctua- 

 tions in barometric pressure (Fox and Davis, 1970b, 1971). In this lati- 

 tude, weather systems generally move in a west to east path due to the 

 prevailing westerly winds. As a low-pressure system (storm) approaches, 

 the wind is from the southwest in the cyclonic system. This generates 

 waves which approach the coast at an angle open to the north and thus 

 generates northerly- flowing longshore currents (Fox and Davis, 1971). As 

 the storm approaches the eastern coast of the lake there is an increase in 



