H. = 0.78h u 

 b b 



(32) 



and 



, 2ifh, 



H. = 0.1 42L. tanh .' 

 b b \ L,. 



(33) 



where 



H^ = breaking wave height 



h b = water depth at breaking 



L^ = wave length at breaking 

 by McCowan (1891) and Miche (1944), respectively, are based on this criterion. 

 Equations 32 and 33 were derived for solitary and periodic shallow-water 

 waves, respectively, in water of uniform depth (Iwata and Sawaragi 1982). A 

 breaking height predictor based on wave energy flux was developed by Komar and 

 Gaughan (1972) and is given by 



<*( g ) 1/5 K 



(34) 



where <* is a dimensional coefficient equal to 0.39. Field and laboratory 

 data have shown this predictor to be quite accurate. Other incipient breaking 

 criteria have been developed by fitting empirical relationships to breaking 

 wave data. These methods are not derived from any theoretical considerations 

 of wave physics, yet results derived using them agree very well with observed 

 data. The most widely used of these criteria are those developed in Equa- 

 tions 35, 36, and 37 by Le Mehaute and Koh (1967), Goda (1970), and Weggel 

 (1972), respectively. These criteria are as follows: 



v-1/4 



H, = 0.76 H , 

 b o 



1/7 



(35) 



where 



L = deepwater wave length 

 m = bottom slope 



H. = 0.1 7L n 

 b of 



exp 



-1.5- r (1 



o 



15(m)) 



4/3 



(36) 



and 



19 



