130. Equation 9 is used to calculate the height of breaking waves that 

 have been transformed by refraction and shoaling (Figure 10) : 



^2 - K R K S H ref 



(9) 



where 



H 2 = breaking wave height at an arbitrary point alongshore 



K R = refraction coefficient 



K s = shoaling coefficient 



H ref = wave height at the offshore reference depth or the nearshore 

 reference line depending on which wave model is used 



131. The refraction coefficient K R is a function of the starting 



angle of the ray and the angle of arrival at P 2 , the location of which is 



determined by the breaking depth. K R is given by 



K R = 



COS^i 



cos8* 



11/2 



(10) 



in which 8 2 is the angle of the breaking wave at P 2 . 



132. The shoaling coefficient K s is a function of the wave period, 

 the depth at P x , and the breaker depth and is given by: 



K* = 



J g2 J 



(ID 



in which C gl and C g2 are the wave group speeds at P 1 and the initial 

 break point, respectively. The group speed is defined as 



C„ = Cn 



(12) 



where 



C = wave phase speed = L/T 

 L = wavelength at the depth D 

 n = 0.5[1 + (27rD/L)/sinh(27rD/L)] 



64 



