i^ > 2.0 (4) 



X 



Diffraction patterns interfered and reduced longshore currents for a 

 lower range of the ratio. Beach response was observed to be either 

 a salient if bed load was the dominant transport mechanism (fall 

 velocity parameter, H^/VT < 1.5 , where H^ is the deepwater wave 

 height, V is the sediment fall velocity, and T is the wave 

 period) , or a more complex feature if suspended load transport 

 dominated (H^/VT > 1.5): 



^<0.4 to 0.5 (5) 



X 



d. Noninterfering currents strong enough to transport material resulted 

 in tombolo formation for an intermediate ratio value: 



— ^ = 0.67 to 1.0 (6) 



17 . Gourlay makes the following observations about beach response to 



prototype breakwaters based on performance of structures in California, Japan, 



and Israel: 



a. Tombolo formation can only occur if the structure is inside the surf 

 zone and 



^ > 0.67 (7) 



b. For cases in which the structure is outside the surf zone, the 



seaward extent of the beach response (salient) is determined by the 

 breaking point location. 



Rosen and Vadia (1982) 



18. Rosen and Vadja (1982) graphically present relationships to predict 

 the equilibrium salient and tombolo size based on structure and site parame- 

 ters. Relationships to predict salient formation are based on a physical 

 model study of beach response (0.64-mm sand) to an impermeable breakwater 

 under normal wave incidence conducted by Rosen and Vadja, including laboratory 

 data measured by Shinohara and Tsubaki (1967) and prototype data from Israeli, 



11 



