intersect before the undiffracted waves adjacent to the structure reach the 

 shore. 



e. Tidal Ran ge . It is extremely difficult to predict the exact effect 

 of a large tidal range on the shoreline response to the construction of an 

 offshore breakwater. Generally, a large range (typically more than 1.5 

 meters) will tend to hinder tombolo formation, especially if the structure is 

 significantly overtopped during high tide. In addition, the cuspate spit will 

 probably not attain a smooth equilibrium shape. An example of a segmented 



Circular Diffracted Wave Crests 



I 



C= Vgd 



Incident Wave Crests 



Figure 5-28. 



Diffraction at a breakwater, assuming linear wave theory is 

 valid. 



Distorted Diffracted Wave Crests 



Large Waves 



Large Waves 



4 



C=yg(d+H) 



Incident Wave Crests 



Figure 5-29. 



Diffraction at a breakwater, including effects of amplitude 

 dispersion. 



5-66 



