event, since entirely different assumptions were made in their development. 

 An obvious example is the difference in surge duration; nevertheless, one 

 type of comparison of the models can still be made. This comparison is 

 accomplished by examining the sensitivity of both models using the percent 

 changes in predicted volume of erosion which occur as a result of similar 

 percentage changes in equivalent input parameters. Table 5 presents several 

 of these comparisons which were computed from the data presented in Figures 

 18 through 22 demonstrating that both models are stable for the parameter 

 range tested. The Vellinga model is most sensitive to the surge level used 

 and the grain size. The Kriebel model is less sensitive to changes in most 

 parameters . 



Table 5 

 Sensitivity Testing 



Percent Increase in Erosion 



Figure Change in Variable Above Surge Level 



Number Constants Variable From To Percent Vellinga Kriebel 



i 0.40 60 130 



190 

 80 



18 



S 



_ 



2.5 







H os 



= 



6.0 



D 50 



18 



° 5 § 



= 



0.35 







= 



2.5 



H os 



19 



H os 



= 



6.0 







D 50 



= 



0.35 



S 



19 



S 



= 



3.0 







D 50 



= 



0.35 



H os 



20 



Dur 



- 



60 







S 



= 



3.0 







A 



= 



0.21 







D 50 



= 



0.73 



H os 



21 



H os 

 Dur 



- 



6.0 

 60 







S 



■ 



3.0 



A 



21 



^os 



m 



6.0 







Dur 



= 



60 







A 



= 



0.15 







D 50 



= 



0.33 



S 



21 



H os 

 Dur 



* 



6.0 

 60 







A 



= 



0.21 







D 50 



« 



0.73 



S 



22 



H | 



" 



6.0 

 3.0 







A 



I 



0.15 







Dsn 



m 



0.33 



Dur 



0.079 0.214 171 



100 



110 



108 80 



Units: H os and S in m, duration (Dur) in hr, D 50 in mm, and 



A in m 



1/3 



62 



