wave height than a constant value of y b , Smith and Kraus (1988) developed a 

 power law equation for wave height decay as 



/* "L *\ 



H = 7 b h b < 48 > 



Ub J 



where n was empirically determined through regression analysis from 

 previously acquired data of Kuo (1965), Horikawa and Kuo (1967), Saeki and 

 Sasaki (1973), Sasaki and Saeki (1974), Van Dorn (1977), Mizuguchi (1981), 

 Maruyama et al. (1983), and Stive (1985). Multiple regression of the data 

 gave: 



0.043 7b 0.0096 



n = 0.6577 b + + 0.032 (49) 



m m 



The value of 7 b was calculated from Singamsetti and Wind (1980) 

 (Equation 29) . 



69. Sallenger and Howd (1989) conducted field experiments in the 

 vicinity of a longshore bar at Duck, North Carolina, in 1982 and 1985. They 

 determined that wave energy became saturated at H^g/h =0.32 in the inner 

 surf zone independent of H . However, all wave data were collected seaward 

 of an inner bar, and measured values of H^/h included broken and unbroken 

 waves . 



70. Irregular wave decay models have been developed by Battjes and 

 Janssen (1979), Dally (1980), and Thornton and Guza (1983) applying monochro- 

 matic decay models to a distribution of wave heights. 



Summary 



71. Several expressions and models have been developed for wave decay. 

 This abbreviated and selective review of the considerable wave decay litera- 

 ture was made to illustrate the different methods used to predict wave decay. 

 The methods may be complex and may attempt to physically explain energy 

 dissipation in the surf zone, or they may be as simple as applying a constant 

 multiplier to the water depth to estimate wave height. 



39 



