WAVES file corresponding to the start of the simulation. In most verifi- 

 cations and in all predictions, contemporaneous measured wave data do not 

 exist for the simulation interval, and the input file WAVES is viewed as 

 holding representative wave data for a number of typical years. Therefore, it 

 is the number of years, starting from a particular month and day (season) that 

 is usually important, not the actual date of the year. Simulation results for 

 a beach fill placed in late spring or early summer will probably be much 

 different than if the fill were placed under stormy winter waves. By begin- 

 ning the simulation at the appropriate month and day, the phase of seasonality 

 is preserved. It is a happy day in a modeler's life if gage or hindcast wave 

 data are available over the full calibration or verification interval. If so, 

 these data should be used. 



246. The modeler will normally specify the date of the start of the 

 WAVES file (i.e., WDATS) such that the simulation will begin at the first 

 month and day occurring in that file. If it is desired to start the simula- 

 tion in a year other than the first year appearing in the WAVES file, then the 

 starting date of the WAVES file should be changed to move the starting pointer 

 to the required year, month, and day. As a specific example, if the modeler 

 wants to start the simulation in the second year of the wave data set rather 

 than the first year, the starting date of the WAVES file should be set to one 

 year later. The effect of seasonality in the wave data on shoreline response 

 can be investigated by starting the WAVES file in different months. 



C. Beach 



247. Line C.l: D50 GENESIS uses the median diameter of the sand 

 D50 (called "d 50 " in the main text) to compute an equilibrium profile shape. 

 The profile shape determines the distance from the shoreline to the point of 

 wave breaking at each grid cell and hence the effective zone of longshore sand 

 transport. The location of breaking also determines whether diffraction will 

 take place, as sources of diffraction must lie seaward of the breaker zone. 

 Figure 7 can be consulted for selecting an appropriate value of d 50 . 



248. Line C.2: ABH . The average berm height ABH (called "D B " in 

 the main text) above the mean water level or the datum used in the modeling 

 is entered here. 



110 



