specified on Line G.5 in the START file to cross the right-hand boundary and 



if, at the same time, a diffracting groin is located in cell number N+l on 



Line E.4 in the START file. The error is remedied in three ways: 



a. Replace the diffracting groin with a nondiffracting groin. 



b. Extend the diffracting groin to the detached breakwater, specify 

 that the detached breakwater does not cross the left-hand 

 boundary by setting IDBN = on Line G.5 in the START file, 

 and at the same time specify that the detached breakwater ends 

 in cell number N+l on Line G.6 in the START file. 



c. Move the diffracting groin so that it will no longer be inside 

 the detached breakwater, which means that IXDG(NDG) (last 

 diffracting groin) on Line E.4 in the START file must be smaller 

 than or equal to IXDB(NDBTP) (last detached breakwater tip) on 

 Line G.6. 



7. ERROR. DETACHED BREAKWATER CAN ONLY CONNECT TO A GROIN AT THE GROIN 

 TIP. Two of the basic structural elements in GENESIS, the jetty and the 

 detached breakwater, may be combined to produce complex configurations, e.g., 

 spur jetties. However, one requirement is that the structures attach only at 

 tips. This error will appear if a detached breakwater is connected to a 

 diffracting groin other than at its tip and is remedied by moving the detached 

 breakwater tip to the end of the groin or by moving either of the two struc- 

 tures to separate them. 



8. ERROR. DETACHED BREAKWATER ENDING ON OPEN LEFT-HAND BOUNDARY NOT 

 ALLOWED. Although GENESIS permits almost arbitrary placement of structures, 

 there are restrictions. One basic restriction is that a detached breakwater 

 cannot end on a grid boundary. Such placement implies that the first (or 

 last) energy window is outside the calculation grid and that wave energy 

 entering through it could not be determined. This message will appear if a 

 breakwater tip is in cell number 1 on Line G.6 in the START file and is 

 remedied by either considering the detached breakwater as being semi -infinite 

 by setting IDB1 = 1 on Line G.4 in the START file or by specifying the first 

 cell number to be 2 or higher, as given on Line G.6 and setting IDB1 =0 on 

 Line G.4 in the START file. 



9. ERROR. DETACHED BREAKWATER ENDING ON OPEN RIGHT-HAND BOUNDARY NOT 

 ALLOWED. Although GENESIS permits almost arbitrary placement of structures, 

 there are restrictions. One basic restriction is that a detached breakwater 

 cannot end on the grid boundary. Such placement implies that the first (or 



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