Legal positioning of structures 



328. Figure 30 gives examples of legal placement of structures. 

 Nondiffracting groins may be placed behind a diffracting breakwater (but 

 diffracting groins cannot) (upper left sketch) . The other three sketches in 

 this figure show situations involving the tips of two structures sharing the 

 same grid cell. The tip of a detached breakwater and a diffracting groin can 

 be at the same longshore grid cell , as can the tips of two detached break- 

 waters. The tips of one or two detached breakwaters can be located in the 

 same cell and at the same distance offshore as the tip of a groin to form an 

 angled structure such as a spur groin, Y-groin, angled groin, etc. These 

 types of legal patterns of structures may be repeated along the model reach, 

 as required. 



NONDIFFRACTING GROINS 

 BEHIND DETACHED BREAKWATER 



fcr 



TIPS OF ONE DIFFRACTING 

 GROIN AND ONE BREAKWATER 

 IN SAME CELL 



€ 



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TIPS OF TWO BREAKWATERS 

 IN SAME CELL 



Ezzzzzzzz, 



4 



TIPS OF JETTY AND BREAKWATER 

 IN SAME CELL 



DISTANCE ALONGSHORE 



Figure 30. Example legal structure placements 



140 



