modeled. The user must input only the part of the beach fill that appears 

 inside the portion of the beach presently being modeled. GENESIS transforms 

 the coordinates from the total coordinate system covering the whole beach to 

 the local system covering only the portion of beach. This error will appear 

 if the recalculated grid cell numbers fall outside the range of the local 

 grid. If the entire fill lies outside the grid, the error is remedied by 

 omitting corresponding values on Lines I. 4-1. 8. If the fill is only partially 

 outside the grid, the error is remedied by setting IBFS on Line 1.6 equal to 

 the grid cell number where the simulation starts, if the right side of the 

 beach fill is outside the grid, or by setting IBFE equal to the grid cell 

 number where the simulation ends, if the left side of the seawall is outside 

 the grid. 



5. ERROR. BOTH SEMI -INFINITE DETACHED BREAKWATER AND A DIFFRACTING 

 GROIN ON LEFT-HAND BOUNDARY NOT ALLOWED. Although GENESIS permits almost 

 arbitrary placement of structures, there are restrictions. One basic restric- 

 tion is that diffracting structures may not overlap. This means, for example, 

 that it is not possible to place a diffracting groin between two tips of a 

 detached breakwater. This error will appear if a detached breakwater is 

 specified on Line G.4 in the START file to cross the left-hand boundary and if 

 at the same time a diffracting groin is located in cell number 1 on Line E.4 

 in the START file. This error is remedied by any of three alternatives: 



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 IDB1 = on Line G.4 in the START file, 

 and at the same time specify that the detached breakwater starts 

 in cell number 1 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(l) on Line E.4 

 in the START file must be greater than or equal to IXDB(l) on 

 Line G.6. 



6. ERROR. BOTH SEMI -INFINITE DETACHED BREAKWATER AND A DIFFRACTING 

 GROIN ON RIGHT-HAND BOUNDARY NOT ALLOWED. Although GENESIS permits almost 

 arbitrary placement of structures, there are restrictions. One basic restric- 

 tion is that diffracting structures may not overlap. This means, for example, 

 that it is not possible to place a diffracting groin between the two tips of a 

 detached breakwater. This error will appear if a detached breakwater is 



C2 



