Summary 



15. Breaker type is a function of the bottom slope and deepwater wave 

 steepness. Spilling waves occur if the beach slope is flat and wave steepness 

 is large. Plunging breakers are expected for either small wave steepness on 

 mild slopes or large wave steepness on steep slopes. Collapsing and surging 

 breakers occur if wave heights are low in relation to wavelength and slopes 

 are steep. 



16. Dimensionless parameters based on beach slope and deepwater wave 

 steepness were developed by Galvin (1968) and Battjes (1975) to quantify 

 breaker type. These parameters are also used to predict other wave breaking 

 properties, such as breaker indices, plunge distance, wave reflection, and 

 runup, as will be discussed. 



Wave Reflection 



17. A structure may dissipate or reflect wave energy, or both. The 

 structure may be natural, such as beaches, bars, and reefs, or engineered, 

 such as breakwaters, jetties, and seawalls. Wave reflection is quantified by 

 the reflection coefficient K„ , which is defined as 



K r = 



(7) 



in which H r and R L are the heights of the reflected wave and incident 



wave, respectively, at a specified point. 



Review 



18. Miche (1951) developed a theoretical relation for K r for smooth 

 plane slopes. He assumed that the portion of wave energy that was reflected 

 corresponded to a critical deepwater wave steepness and that wave energy that 

 exceeded this critical value was dissipated. The wave reflection coefficient 

 was expressed as : 



-l 



K„ = 





'H ^ 





'Ho' 



H 



> 



'Ho 





I Lo J 



cr 



I L o J 



Lo 



[ Lo 









Ho 



fH 





1 





< 















L 



1 L 



(8) 



17 



