dt* 



Figure 3. Breakwater and nearly symmetric tombolo (incident waves 

 normal to shore) , Tel-Aviv, Israel 



it is symmetrical and concave on either side. However, if a salient forms, it 

 will have a more rounded, convex shape. The diffracted waves may not be 

 exactly normal in the vicinity of the salient apex, but in this region forces 

 resulting from the waves diffracted by each of the breakwater heads will be in 

 balance. No longshore current will be driven, and the longshore transport is 

 zero. 



10. Waves that arrive at an oblique angle will generate a net longshore 

 transport rate that is maintained some distance updrift and downdrift of the 

 breakwater. The shoreline near the structure will tend to adjust so that the 

 same transport rate is achieved everywhere and dynamic equilibrium is again 

 attained. To do so, smaller waves behind the structure must transport as much 

 sediment alongshore as the larger waves adjacent to the structure. This situ- 

 ation will occur when the beach planform behind the breakwater has adjusted 

 through the formation of a salient. The bathymetry of the salient causes the 

 smaller, diffracted waves behind the structure to break at a more oblique 

 angle than those waves outside the shelter of the structure. After tombolo 



10 



