338. It should be noted that all values in a column must refer to the 

 same fill . This means that the values on a row may not always appear in 

 consecutive or chronological order. 



Time-Varving Structure Configurations 



339. In many modeling projects, structures are built, modified, 

 removed, or destroyed during the course of a shoreline change simulation 

 period. The simulation must be performed in stages in such a case. A START 

 file with the initial configuration would run GENESIS until the time step of 

 the change in a structure; the SHORC file (calculated shoreline) from this 

 first stage would then be copied to a SHORL file (initial shoreline) for the 

 next stage of the simulation, and another START file describing the new 

 configuration would be used to continue. This procedure can be chained for 

 describing any number of modifications in structure configurations and boun- 

 dary conditions. Most computer systems allow creation of a batch file to 

 automate the chaining of calculation segments. 



148 



