700 



Shoreline position (ft) 



Verification 

 HCNGF - 1.2 



Decreased transm. 

 ZCNGA - -10 



400 600 800 1000 



Distance alongshore (ft) 



1200 



Figure 45. Model sensitivity to changes in K T 



HCNGF , and ZCNGA 



increased recession of the shoreline behind the gaps between structures. As a 

 whole, the decreased wave transmission simulation produced net accumulation in 

 the area. 



405. An increase in wave height of about 10 percent, produced by 

 changing HCNGF from 1.1 used in the verification to 1.2, had almost the same 

 effect as an increase of Kl , i.e., a slight increase in volume contained by 

 the project, but the calculated shoreline position shows very little departure 

 from the verification result. Setting ZCNGA = -10 means that the offshore 

 wave direction was uniformly shifted 10 deg to the east. The calculated 

 result confirms the intuitive picture that erosion should decrease on the 

 western side of the project and increase on the eastern side. Again, the 

 calculated results indicate a moderate or low sensitivity of the model to 

 changes in the input parameters. 



172 



