Elapsed Time (hr) 



Figure 5. Absolute sum of profile change for selected cases 



amount of sand must be redistributed in the process of reaching equilibrium. 

 Dean (1977) derived a simple analytical expression for the beach profile shape 

 in the surf zone based on the concept of a constant dissipation of wave energy 

 per unit water volume. This expression agrees well with the relationship 

 established by Bruun (1954) on empirical grounds from field data. The 

 equilibrium beach profile shape may be written 



h = Ax2/3 



(1) 



where 



h = water depth 



A = shape parameter 



X = cross-shore coordinate (directed positive in the seaward direction) 

 The shape parameter is mainly a function of grain size, in which a coarser 

 grain size gives a larger value of A and a steeper beach (Dean 1977, Moore 

 1982). Dean (1987) recently reexpressed the curve of Moore (1982) in terms of 



61 



