The wave reflection analysis as used assumed a flat sea bottom and that 

 linear wave theory was valid. But the bottom of the flume sloped at 1 V:20H and the 

 waves were clearly nonlinear. An analysis was done to determine the sensitivity of the 

 wave analysis method to selection of gage location and therefore beach slope. Using the 

 depth at the center of the gage array in the reflection analysis, rather than the depth at 

 Gage 1, resulted in no difference for //„„, 2-percent difference for H^ and 7-percent 

 difference for //2%- The difference in depths between Gage 1 and the array center was 

 12 percent. H^ and //„„ were more stable than H2% in this analysis. H^ and //„„ for Gage 

 1 closest to the toe were approximately the same for repeated tests. This is important, as 

 the damage was shown to be approximately proportional to the fifth power of the wave 

 height in the previous chapter, exaggerating any errors in wave height measurement. 

 Therefore, the more stable values oiH^ and //„„ are relied on in the analysis that 

 follows. Comparison of measured wave heights with breaker index curves, such as 

 Figure 7-2 of the SPM, showed that the maximum H^^q would just break at the mean 

 period in the depth of the shallowest wave gage, approximately 1 m from the structure 

 toe. 



The Iribarren parameter or surf similarity parameter (Battjes 1974) is 

 defined as 



r tanO 



I = 



H_ (4.9) 



72 



