ing slopes found in the field, attributed to the monochromatic waves and 

 constant water level used in the experiments. Berm face slopes were typically 

 in the range of 6-8 deg on the seaward side and 2-4 deg on the shoreward side. 



542. Properties of the cross-shore transport rate were investigated by 

 integrating the mass conservation equation between consecutive profiles in 

 time. This methodology provided a picture of the net average transport rate 

 distribution between two surveys. The magnitude of the net transport rate 

 distribution decreased with time as the profile approached an equilibrium 

 shape and less material moved along the profile. Decrease of peak transport 

 rates was best described by a function which showed an inverse dependence with 

 elapsed time, not with an expected exponential decay with time. This dif- 

 ference was attributed to randomness of microscale processes and slight 

 unsteadiness in forcing conditions, which produce a perturbation on the 

 idealized mean behavior. Decrease of the peak transport rate was more rapid 

 for accretionary profiles than erosional profiles. 



543. By comparing the initial and final profile surveys, an "equili- 

 brium transport distribution" was defined and calculated, which indicated how 

 sand was redistributed along the profile to achieve an equilibrium configura- 

 tion. Equilibrium distribution could be classified into three characteristic 

 shapes in a majority of the experimental cases; Erosional (Type E) , Accretion- 

 ary (Type A), and mixed Accretionary-Erosional (Type AE) . Type E distribu- 

 tions showed transport directed offshore along the entire profile, whereas 

 Type A distributions showed transport directed onshore along the entire 

 profile. Type AE distributions were characterized by a mixed response with 

 offshore transport along the shoreward portion of the profile and onshore 

 transport along the seaward portion of the profile. 



544. The profile was divided into four different zones to interpret and 

 quantify properties of the cross -shore transport rate distribution, in analogy 

 with recent findings from nearshore wave dynamics. These zones were: pre- 

 breaking zone (I), breaker transition zone (II), broken wave zone (III), and 

 swash zone (IV). For Zone I, the LWT experiments showed that the net trans- 

 port rate was well approximated by an exponential decay with distance from the 

 break point, with a spatial decay coefficient (average value of 0.18 m"'^) 

 proportional to the ratio of the grain size to the breaking wave height for 



233 



