Except for extremely small d/L values or for waves near breaking, 

 equation (2) approximates the shoaling coefficient for waves traversing 

 gentle bottom slopes. Most laboratory experiments have used structures 

 fronted by uniform water depths (formed by the tank floor) . In other 

 experiments with slopes fronting the structures, the wave height usually 

 was measured in the uniform water depth of the flat part of the wave 

 tank. In both situations the transformation of the wave height from 

 measured height to deepwater height is particularly applicable using 

 the linear theory shoaling coefficient (eq. 2) because of the relatively 

 large tank depth in most cases. Some researchers use the wave height, 

 H, at a given depth (usually the structure toe) to define relative 

 runup. The drawback in using this approach to describe wave height is 

 that on sloping beaches the wave may break before reaching the toe of 

 the structure, and the resulting broken wave is not easily related to 

 the nonbreaking wave characteristics. 



Data were compiled for regular waves and uniform structure slopes 

 according to the variables d s , W' 0> h a , k r , I, R, T, g, e, v, and g, 

 from which the following dimensionless variables were derived: 



Hi 



gT 



d 



h; 



H j 



12. 

 k v 



■"s^s 



wave steepness 



relative depth at structure 



relative runup 



structure slope 

 beach slope 



relative roughness 



depth Reynolds number, Rg 



I 



relative horizontal length of beach slope 



gT 2 



— relative core height 



