Predicted Hrms/(Hs)o (A - 0.09) 









n 



(deg) 







n 



O 1.9 (m 



■ 1/30) 







+ 5 

 * 10 







* 



□ 15 





D 



/^O o 







1 



+ 

 4- 



i 



i 





1.2 



1.0 



0.8 



0.6 



0.4 



0.4 0.6 0.8 1.0 1.2 



Measured Hrms/(Hs)o 



Figure 71. Predicted H rms /(H S ) of Goda (1975) 

 (A = 0.09) as a function of measured H rms /(H S ) 



(0! = 15 deg) . Other procedures are clearly required to predict heights over 

 engineering structures having steep faces. 



165. Figures 72 (a— c) to 75 (a— c) show H rms /h as a function of distance 

 from the shoreline, where h is the depth evaluated from SWL. The tests con- 

 ducted with bars show a significant increase of H rms /h over the bar. The 

 increase results from the water depth becoming shallow and waves becoming 

 higher by shoaling and becoming nonlinear in shape over the bar. Wave height 

 to water depth decreases directly shoreward of the bar because water depth is 

 deeper and a majority of the waves broke on the bar. The ratio continues to 

 increase as water depth decreases in the surf zone for all tests, including 

 tests on the plane slope. The plots indicate that wave height does not decay 

 consistently with the decrease in water depth; therefore, H rms /h is not 

 constant through the surf zone for either barred profiles or plane -sloping 

 beaches . 



166. On the basis of their field measurements, Sallenger and Howd 

 (1989) found H rms /h to be constant, independent of offshore wave conditions, 

 and stated that the wave distribution was energy saturated through the inner 

 surf zone. They concluded that offshore migration of nearshore bars is, 

 therefore, not necessarily associated with the break-point processes; however, 



131 



