Birkemeier (1985) discuss use of the model and present a computer program for 

 making the computations. Bruun (1984) and Vellinga (1984) address specific 

 aspects of the model, including the possibility of a universal erosion 

 profile shape for both sand and rock beaches. Vellinga (1984) also compares 

 the profile shape equation developed for the Dutch method to the equilibrium 

 equation used by the Kriebel model (Equation 1). 

 Governing equations 



67. Figure 12 is a schematic cross section of the predicted Vellinga 



LEGEND 

 . PORTION OF E 



n p 



STORM SURGE LEVEL. S 







°or ^~4i\ x 



MEAN SEA LEVEL 



n 



EROSION '^^>^. 









DEPOSITION — ^ L "^£v^~t v ^ 



/EROSION PROFILE 



a? 





INITIAL PROFILE -^"^ 













^i 1 



Figure 12. Schematic representation of the Vellinga predicted 

 profile (Vellinga 1983b) 



storm profile. The shape of the erosion profile is based on the following 

 equation: 



y(x) = 0.47(x + 18) 



0.5 



(2) 



where x is the seaward distance in meters from the foot of the poststorm 

 dune (x = 0, y = 0) and y is the depth below the surge level in meters. 

 This equation is based on model profiles (generated with irregular waves) and 

 has been derived for "reference storm" conditions with a deepwater wave 

 height H os of 7.6 m, a wave period T of 12 sec, and a median grain size 

 of 0.225 mm. The tests simulated a duration of 5 hr with a constant water 

 depth at the storm surge level. This 5-hr duration is typical of the fast 



34 



