Because of its location, fetch is an important factor in the wave climate 

 of the area. The fetch varies from about 400 kilometers to the north, to only 

 60 kilometers to the southwest. 



The effect of fetch is also shown by the hindcasted design wave character- 

 istics given for the study area in Resio and Vincent (1976). They determined 

 design wave heights and periods for waves from three directions (shore-normal, 

 and greater than 30° to the right and to the left) for each season, and for 

 return periods of 5, 10, 20, 50, and 100 years. For example, using the 50- 

 year return period and the winter season, the deepwater design wave heights 

 are given in Table 3. As expected, the largest waves are along the longest 

 fetch. Interestingly, the characteristics of the design storm and the hydrog- 

 raphy are such that waves normal to the beach (west-southwest to northwest) 

 will be nearly as high as waves from the longest fetch, while the waves along 

 the shortest fetch will be significantly lower. 



Table 3. Winter deepwater desi 



gn waves for a 



50-year storm. 



Wave direction 



Height 





Period 



Avg. fetch 





(m) 





(s) 



(km) 



NW. to NNE, 



6.6 





11.4 



280 



WSW. to NW. 



6.0 





10.7 



118 



SW. to WSW. 



2.8 





7.3 



80 



Because the wave characteristics in Table 3 are for deepwater conditions and 

 for extreme events (with a probability of occurrence once every 50 years), they 

 are significantly different from the average breaking conditions in Table 2. 



3. Storms. 



The low-pressure storm systems which affect the study area generally move 

 through the Great Lakes from west to east. The combination of this path and 

 counter-clockwise circulation around the low center produces strong winds from 

 the north and northwest usually following passage of the storm. Seibel (1972), 

 Maresca (1975), and Davis (1976) have investigated the wind and wave climate of 

 the study area and the characteristics of the storms which affect the eastern 

 shore of Lake Michigan. 



Seibel (1972) determined that the annual number of low-pressure systems 

 passing through the Great Lakes between 1938 and 1970 averaged about 43, though 

 the number varied from 31 to 67. The number of storms did not appear as impor- 

 tant in determining bluff recession as the intensity of individual storms. 



Although many storms occurred between November 1970 and November 1974, one 

 of the most significant storms occurred 16 to 18 March 1973. The storm caused 

 some of the highest winds of the study period with windspeeds at Muskegon, 

 Michigan, averaging 41 kilometers per hour from the northwest for 2 days. At 

 the powerplant, an anemometer recorded windspeeds as high as 72.4 kilometers 

 per hour. The highest recession rates measured during this study occurred at 

 reaches A and B during 16 November 1972 to 20 March 1973 (just 2 days after the 



