ri 























/ 





I 



























/ 

































/ 

































/ ( 









• 























J 





























□ 





/ 





























[l 





/ 











1 



















■ 



= V 



• 







• 

























/. 

















)-=■- 













1} 



/ 



/ ■ 



1 























— 







-/- 







— 





























1 



A " 























































] u 











0/ 



» 































/ 







Shoreline 

















/ 







Retreat Advance 









o 







/ 



• 







CE 



)■'- 







< 



^ 



/ 



/ 









CRIEP 



1 1— hn 



D 



h+++- 



1 



2x10 ■ 



10 



(Hq/wT) tan P> 



10" 



Figure 11. Criterion for distinguishing shoreline retreat 



and advance by use of wave steepness, dimensionless fall 



speed, and initial beach slope 



criterion derived from the large-scale tests is not applicable to the small- 

 scale data using the coefficients given in Equation 2. By modifying these 

 coefficients it would be possible to obtain a crude delineation with the 

 quantities in Equation 2. However, the dimensionless fall speed is probably 

 of less significance in distinguishing bar/berm profile response in small- 

 scale laboratory experiments than in prototype -scale experiments. This is 

 attributed in great part to the mode of transport, the main transport mode 

 probably being bed load in these types of experiments, with less significant 

 contributions from suspended load as under higher waves as occur in the field. 



232. Therefore, in small-scale laboratory experiments, use of the 

 parameter H^/D instead of H^/wT should provide a better basis for profile 

 classification since it expresses a relationship between the force exerted by 

 the waves and the resistance offered by the grains (Nayak 1970). This 

 interpretation is closely connected with the mechanism of bed load transport, 

 where the main driving force is the horizontal component of the water particle 



76 



