Zr 



1.47 



H„ 



tan/3 



Jho/Lo 



(17) 



The coefficient of determination was 75 percent for 32 cases for which the 

 height of the active profile could be distinguished. 



Equilibrium berm volume 



288. In the LWT experiments, volume of the berm increased with time to 

 approach an equilibrium value attained when the profile was in balance with 

 the incident waves, thereby dissipating wave energy without significant 

 changes in shape. Seventeen cases exhibiting some kind of foreshore buildup 

 were identified in the CE and CRIEPI data sets. However, only eight of these 

 cases showed strong berm buildup with onshore transport occurring during most 

 of the run. In some CRIEPI cases, accretion on the foreshore started to occur 

 only at the very last few profile surveys, and equilibrium was reached almost 

 immediately (for example, Cases 4-2 and 5-2). Profiles of this type were 

 erosional , but these cases had a moderate wave climate and a gentler initial 

 slope, allowing for a small amount of onshore transport on the foreshore as 

 the breakpoint bar system approached equilibrium. In Figure 29(a and b) , the 

 berm volume as a function of time is displayed for the CE and CRIEPI experi- 

 ments . 



289. To estimate equilibrium berm volume, an expression similar to 

 Equation 7 was least-squares fitted to the data for the eight cases. The 

 number of cases was too small to derive reliable empirical relationships 

 between berm volume and wave characteristics and beach profile properties. 

 Some tendencies noted may be of interest for indicating which factors appear 

 to control equilibriiam berm volume. Berm volume showed the greatest dep- 

 endence on sand fall speed, with a greater fall speed implying a larger berm 

 volume. This phenomenon seems reasonable because the tendency for onshore 

 transport increases with greater fall speed for the same deepwater wave 

 steepness (Figure 6). Within the range of grain sizes used in the experi- 

 ments , coarser material often experienced more marked onshore transport than 

 the finer material. In contrast, the finer material, for the cases where berm 

 buildup occurred, had a less dominant transport direction, thus resulting in 



109 



