moving North Sea storm surges and is one of the limiting assumptions of the 

 model if intended for general use. 



68. The equation is applied to a distance 200 to 250 m seaward of the 

 shoreline. From the scale relationships used in the model studies, Equation 

 2 can be generalized in terms of H os and fall velocity w as 



2.0 - 0.47 



7.6 

 H 



1.28 



w 



0.0268 



0.56 



+ li 



0.5 



7.6 



H 



(3) 



where x , y , and H os are in meters and w is in m/sec. The profile 

 defined by Equation 3 terminates offshore at 



x = 250 



OS 



7.6 



1.2* 



0.0268 

 w 



0.56 



(4) 



which, substituting into Equation 3, yields 



0.75 H r 



(5) 



69. Constant slopes are used to terminate the profile at the shoreward 

 end (m^ at x = y = 0) and seaward end (1112) of Equation 3 and are defined as 



-1:1 



(6) 



m2 



-1:12.5 



(7) 



Use of this steep poststorm dune face m^ is consistent with field 

 observations, and m2 is arbitrarily fixed in agreement with model tests. 



70. Application of Equation 3 is straightforward. Based on the wave 

 height and fall velocity, a profile shape is computed. The origin of this 

 line, with the two end slopes is placed at the surge level and shifted 

 horizontally landward until the eroded volume equals the deposition. In 

 order to compensate for longer duration storms, Vellinga (1983b) suggests 



35 



