450. The depth of the beach profile is obtained as an implicit function 

 of the location across shore according to 



2 5 r^ pg^'^ 



- f" 



«; 3 8D 



eq 



h = X 



(45) 



The corresponding wave height distribution is given by 



H = 



8D„ 



+ r^'h^ 



L >^P% 



1/2 



(46) 



451. As seen from Equation 45, a smaller value of the wave decay 

 coefficient k gives a flatter shape of the equilibrium beach profile and 

 thus requires redistribution of a greater amount of sand before equilibriiom is 

 attained. On the other hand, a smaller value of the stable wave height 

 coefficient F gives a steeper equilibrium beach profile, resulting in a 

 smaller equilibriiom bar volume, since less material has to be moved from the 

 inshore to attain equilibrium. 



452. Figure 65 shows the effect on bar volume of varying the stable 

 wave height coefficient, supporting the qualitative result as predicted by 

 Equation 45. The influence of changes in parameter values in the breaker 

 decay model on maximum bar height was less pronounced compared with the effect 

 on bar volume. The stable wave height coefficient affected the equilibrium 

 maximum bar height only slightly, and the development in time was very similar 

 during the initial phase of a simulation. The wave decay coefficient had a 

 somewhat greater influence on the equilibrium maximum bar height, in which a 

 smaller value implied a larger bar height. 



Influence of equilibrium energy dissipation 



453. Equation 45 also reveals the importance of the magnitude of the 

 equilibrium energy dissipation, which was shown to be a function of grain size 

 by Moore (1982). A change in grain size causes a marked change in the shape 



188 



