134. Breaker heights and depths were determined from videotape for 80 

 of the 96 total base tests. Measurements of breaker height and depth were 

 made for all tests in which fi 1 < 20 deg. The values of height and depth 

 represent an average of 10 consecutive waves from each test. 



Breaker depth index 



135. Breaker depth index showed considerable scatter if plotted as a 

 function of £ (Figure 34) . Values of 7 b tend to increase for £ 



< 0.9 , whereas for higher £ -values the breaker depth index appears to 

 decrease more gently with wide scatter in the range 0.9 < £ < 1.6 , shown by 

 vertical lines. Wave breaking for £ > 0.9 was not only influenced by 

 depth, but by a dependent variable involved in the breaking process, the re- 

 turn flow velocity. Breaking waves at higher £ -values were typically of 

 the form shown in Figure 35. A secondary wave shoreward of the main wave 

 crest is created by the return flow, which causes the break point to develop 



Hb/hb 



0.7 



0.5 



3.5 



Figure 34. -y h as a function of | 



86 



