volume from measured wave heights and inferred or "measured" transport rates 

 from the LWT data was about 1.1 10"^ m''/N. In contrast, Moore (1982) and 

 Kriebel (1982) obtained a value of 2.2 10"^ mVN by making comparisons between 

 calculated and measured profile change. This value was revised by Kriebel 

 (1986) to become 8.7 10"^ m''/N. The coefficient K is not entirely compar- 

 able between the models, since the structures of the models are different. 

 The value of e was found to be on the order of 0.0006 mVsec (Part V). 



411. The equilibrium energy dissipation was determined by Moore (1982) 

 by fitting Equation 1 to 40 field and laboratory profiles. Beach material 

 ranged in size from boulder (30 cm) to fine sand, and D^^ was related to the 

 mean sand diameter. Moore's analysis provided the best fit to profiles both 

 with and without bars. These values were used in the numerical model and 

 found to give reasonably accurate estimates of D^^ in regions of broken 

 waves. However, in the present study, in order to obtain optimal agreement 

 between model simulations and measured profile change, values of D^^ as 

 specified by Moore had to be reduced by 25 percent, as discussed later. 



412. By adding the slope term in Equation 33, the shape of the equi- 

 librium profile will be somewhat gentler, since a profile with a specific 

 grain size will be able to withstand a lower energy dissipation per unit 

 volume. The shape of the equilibrium profile, derived from Equation 33 in 

 analogy to Dean (1977), may be written 



hjh 



24 

 A^'^ X (36) 



K 5pg^/V 



413. In Equation 36 water depth is an implicit function of the cross- 

 shore distance. The effect of incorporating beach slope is only noticeable 

 close to the shoreline for the values of e used in the model. Further 

 seaward the profile agrees with Dean's (1977) equilibrium profile. 



414. In the numerical model, regions of fully broken waves are identi- 

 fied at each time-step, and transport rates are determined from Equation 33. 

 Waves are considered to be fully broken from the plunge point to the shoreward 

 end of the surf zone or to the point where wave reformation occurs . The 

 location of the plunge point is defined with respect to the break point to 



169 



