In arriving at Equation 2, it was assumed that sand porosity was constant 

 across the profile. 



62. By using the initial and final profiles from each case, the total 

 net cross-shore sand transport rate can be obtained, which in a gross sense 

 illustrates how material was redistributed over the profile in the approach to 

 an equilibrium shape. Larson and Kraus (1988b) classified such distributions 

 of the net cross-shore transport rate derived from experiments performed with 

 large wave tanks, and three principal shapes were identified. Most of the 

 cases listed in Table 2 had unipeaked distributions and exhibited either 

 offshore-directed or onshore-directed sand transport along the active profile. 

 Only a few cases exhibited multiple peaks of opposite sign, and one peak was 

 always dominant, except for Case 801 which had two peaks of about the same 

 magnitude. In Case 801 the initial profile was almost stable under the in- 

 cident waves, and little net transport took place. 



63. Figure 15 shows two typical distributions of the total net cross- 

 shore transport rate calculated from initial and final profile surveys, one 

 illustrating bar formation (Case 500) and the other berm buildup (Case 301). 

 Offshore-directed sand transport is positive, since the origin of the coor- 

 dinate system is located at the initial still-water shoreline and the hori- 

 zontal axis points positive offshore. 



Distance from Initial Shoreline (m 



Figure 15. Examples of total net cross-shore sand transport 

 rate distributions, Cases 301 and 500 



35 



