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further refine Noda's scale relationship. An experimental evaluation of the 

 scale model relationship was also performed. 



The results showed that the effects of graip shape and size distribution are 

 varied. In many cases there was little or no measurable effect; in others, 

 particularly for smaller wave steepnesses, marked differences were apparent. 

 These included multiple bars on profiles consisting of sediment with a bimodal 

 sediment-size distribution and an unstable bar on profiles consisting of 

 sediment with a very narrow unimodal size distribution or a spherical grain 

 shape. Recommendations are made to avoid such sediments as possible model 

 materials. 



The experiments showed that the initial profile slope influences the final 

 stable profile shape. Under identical experimental conditions, the position 

 of the longshore bar on the final stable profile varied between experiments, 

 indicating that defining the "equilibrium profile" is not as straightforward 

 as has been assumed. "Rocklite," a manufactured, lightweight ceramic sediment, 

 was a potentially useful model material. 



Tlie model evaluation tests were only partially successful. The slope of the 

 foreshore was reproduced in scale, but the shape of the offshore and surf zones 

 and the movement of the shoreline were not reproduced. The general results 

 tend to confirm the difficulties of obtaining successful beach models in 

 similitude . 



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