330. Detached breakwaters . Figure 32 illustrates detached breakwater 

 parameters that may be varied. Detached breakwaters are defined in the 

 modeling system by specifying pairs of ends or tips of the structures in the 

 START file section. (Wave transmission coefficients must also be given. ) As 

 a summary, as long as detached breakwaters do not overlap (except for two tips 

 having the same grid cell), the modeler is free to vary the length, trans- 

 mission coefficient, orientation, distance offshore, and, in the case of 

 segmented breakwaters, the gap width between structures. Detached breakwaters 

 or their equivalent, such as a portion of a harbor jetty, may cross a grid 

 boundary, although this is an unusual and complex case and should be modeled 

 with caution. A groin cannot be placed at the boundary if a detached break- 

 water crosses it. GENESIS Version 2 will not allow the shoreline to grow to 

 meet a detached breakwater (tombolo formation not simulated). If the shore- 

 line approaches very close to a detached breakwater, the model will fail. 



MULTIPLE DETACHED BREAKWATERS 

 LENGTH ARBITRARY 



GAP WIDTH 

 ARBITRARY 



\ 



ORIENTATION 

 ARBITRARY 



TWO TIPS AT 

 ' SAME CELL 



Y///////A 



fy vzmn 



v^r 





J, 



. TRANSMISSION 



V 



iJ 



BREAKWATER 

 ACROSS BOUNDARY 



24 30 35 50 



DISTANCE ALONGSHORE/GRID CELL NUMBER 



Figure 32. Parameters associated with detached breakwaters 



142 



