PART VI: WATER DEPTH AND WAVE BREAKING CONSIDERATIONS 



49. The outer buoy location water depth is about 77 m. For linear 

 waves with periods of 12 sec and longer, this does not constitute deep water. 

 The deepwater assumption holds for h/Lo > 0.5 where h = water depth and 

 Lo = deepwater wavelength. Values for h/Lo with h = 77 m and periods 

 of 12 sec and longer are h/Lo < 0.34 ; thus, the waves traveling from deep 

 water will be somewhat affected by the water depth. Corrections for this 

 are available in wave tables (Skovgaard et al. 1974) that report the ratio 

 of wave height to deepwater wave height as a function of h/Lo . Values for 

 this ratio are listed in Table 22 for the range of wave periods of interest. 

 Wave breaking limits were computed using a controlling depth of 7.5 m for the 

 area between Puffin Island and Popov Island. It was found that for the ex- 

 treme waves of this study the attenuation factor does not need to be modified 

 using an upper limit of significant wave height. 



Table 22 



Ratio of Wave Height Over Deepwater 



Wave Height for a Water Depth 



of 77 m Versus Wave Period 



Wave Period H_ 



sec Ho 



14.0 0.932 



14.3 0.929 



14.5 0.929 



14.8 0.926 



15.0 0.923 



15.3 0.920 



15.5 0.920 



15.8 0.918 



16.0 0.916 



16.3 0.916 



16.5 0.914 



16.8 0.914 



17.0 0.913 



50. The peak wave period that most accurately represents the local 

 weather conditions comes from the WIS hindcast data set. The WIS hindcast 

 period for the 20-year event is 14.3 sec. This value is also sufficient for 



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