using primed wave angles. After the wave angle and wave transformation are 

 calculated in the rotated system, the breaking wave angle is converted back to 

 the fixed coordinate system for use in the longshore sand transport rate 

 equation (Equation 2). Thus, in the shadow region, the breaking wave height 

 is calculated as 



H b = K D (« D ,D b )Ki(tfi,D b )Hi 



(19) 



in which Kr = refraction coefficient in the primed (rotated) coordinate 

 system. Use of this contour modification technique significantly improves the 

 accuracy of the internal wave model by giving a more realistic value of the 

 breaking wave angle (Kraus 1983, Kraus and Harikai 1983). The contour 

 modification is calculated automatically by the internal wave model in GENESIS 

 in taking waves from a reference depth to the point of breaking. 



y s 



INCIDENT WAVE 

 DIRECTION 



BREAKWATER 



\///////////////////////////A 



CONTOUR LINE 



X 2 X! 



DISTANCE ALONGSHORE 



Figure 12 . Wave angles in contour modification 

 70 



