smaller equilibrium berm volumes. An increase in wave height produced a 

 larger berm volume, whereas wave period seemed to be a negligible factor. 

 However, wave period influenced the rate at which equilibrium berm volume was 

 reached, with a longer wave period producing more rapid berm buildup. 

 Maximum berm height 



290. Maximum berm height Z^ defined with respect to the initial 

 profile showed development with time similar to berm volume. Figure 30(a and 

 b) shows the growth of maximum berm height as a function of time. If accre- 

 tion on the foreshore occurred in cases with predominant offshore transport, 

 equilibrium berm height was attained quickly, as seen in Cases 200, 3-1, and 

 4-2. Equilibrium maximum berm height was estimated from a least-squares fit 

 of the data from each case (eight cases used in total), with an expression of 

 the form of Equation 7. Grain size emerged as an important variable for the 

 same reasons as discussed for equilibrium berm volume. Breaking wave height 

 appeared as a considerably more decisive factor than deepwater wave height, 

 probably because runup is more closely related to breaking wave height. The 

 ratio between maximum equilibrium berm height and breaking wave height had a 

 relatively small range. The average value of the ratio was 0.5, ranging from 

 0.3 to 0.8 for the eight cases analyzed. The standard deviation was 0.16. 



291. Berm height, normalized by some appropriate length scale (wave 

 height or wavelength) , showed no correlation with dimensionless sand fall 

 speed. This occurrence is not surprising since this quantity is generally 

 believed to characterize suspended transport which is not the dominant 

 transport mode on the foreshore. For a specific grain size, berm height 

 divided by breaking wave height was found to be weakly dependent on the surf 

 similarity parameter, but a clear overall relationship could not be obtained. 

 Runup height is usually expressed in terms of the surf similarity parameter 

 (see Hunt 1959), so this dependence is expected; however, the present data 

 sets on berm growth are too limited to conclusively verify such a 

 relationship . 



Berm slopes 



292. If a berm formed on the foreshore, its seaward face slope steep- 

 ened and a positive slope developed on its shoreward face. Average seaward 

 berm face slope was relatively constant, with a slight tendency to increase 



111 



