distance from shore but had a crest 2.5 feet deeper. This indicates that 

 the longshore bars do change. Therefore, it is possible that the August 

 1972 profile was subsequently modified, thereby permitting more wave energy 

 to reach the coast and cause erosion. 



1. Profile Site 12 . Much erosion occurred at this site during 1972-73. 

 Nearly 200 cubic feet was lost from the profile (Table 6) . Longshore bar 

 data indicate that there should be little wave energy reaching the beach. 

 Bars are much shallower and closer to shore than mean values. Only the 

 steep profile lakeward of the beach is conducive to erosion. However, no 

 substantiated explanation can be offered for the extensive erosion at this 

 site. The possibility of changes in nearshore profile must be considered. 



m. Profile Site 13 . On the basis of the nearshore profile, it would 

 be expected that this site is subjected to severe erosion. There is only 

 one longshore bar present and it is more than 12 feet deep and 950 feet 

 from shore. Consequently, it provides little protection for the beach. 

 However, only 59.5 cubic feet of sediment was removed during the third 

 year and a net of only 16.5 cubic feet was lost during the entire 3-year 

 period. Essentially all changes were to the active beach. 



The primary reason for erosion being minimal is in the location of the 

 profile just to the north of a protuberance in the coastline. Net long- 

 shore transport is to the south, and thus much sediment accumulates just 

 north of this protuberance as it would adjacent to a groin. Even if waves 

 reach the till bluffs behind the active beach, there is essentially no 

 erosion due to the resistant nature of the clay till. 



n. Profile Site 14 . As with profiles at sites 11 and 12, the profile 

 at this site experienced much erosion (202.5 cubic feet) although the near- 

 shore profile apparently provided good protection. Bars were shallower 

 and closer to shore than mean values and ephemeral bars were common at this 

 site. There is no reasonable explanation for the erosion at this site 

 other than the possibility of a change in the profile. 



o. Profile Site 15 . Erosion was moderate at this site with a loss of 

 112.5 cubic feet of sediment during the final year. Although an ephemeral 

 bar was present during the August 1972 profile, it is not typical. The 

 first bar is somewhat farther from shore than the mean but it is shallower 

 so that the effects of these parameters cancel one another. The second 

 bar is deeper and much farther from shore than the mean. The overall 

 effect of this on the beach is the ability of waves to rebuild over a 

 broader area and thus import more energy to the beach. 



The beach at this site is narrow, and even during minor storms waves 

 attack the base of the clayey bluff. The clay till is soft and almost 

 quick due to a very high moisture content. Erosion to the toe of the bluff 

 results in mass wasting and much loss of material from the profile. 



p. Profile Site 16 . Erosion at this site was only 62.5 cubic feet of 

 sediment, largely from the active beach. The longshore bars were less than 





58 





