700 



Shoreline position (ft) 



Measured 10/24/77 

 Calculated 10/09/78 



Measured 10/09/78 



w/////////////\ 



400 600 800 1000 



Distance alongshore (ft) 



1200 



Figure 42. Result of model calibration 



396. Aerial photographs indicated that the shoreline in the small 

 pocket beach on the east side of the east groin had receded, almost doubling 

 the distance from the shoreline to the seaward end of the groin between 1978 

 and 1979. Therefore, for the verification, YG1 was increased from 70 ft 

 used in the calibration to 128 ft for the verification, as read from the 

 photographs . 



397. The model was then run for the verification period by using the 

 1-year wave field, and reasonable agreement was obtained between calculated 

 and measured shoreline position. Subsequent sensitivity testing indicated 

 that better results could be obtained if the wave height were increased by on 

 the order of 10 percent. Therefore, the value HCNGF = 1.1 was entered on 

 line B.l in the START file. Other than changing YG1 and HCNGF , all other 

 input values were the same as for the calibration. The verification result is 

 shown in Figure 43. Similar to the case of the calibration, the measured and 

 calculated shoreline positions for the verification are in good agreement. 



168 



