E,^ = tan6 / (H/L„Y' = surf similarity or Iribarren parameter 

 H, = significant wave height which is equal to if ,/3 



T„ = mean wave period 



Van der Meer's breaking wave tests were performed with a traditional 

 multi-layer rubble mound where the notional permeability was f = 0.5. This 

 permeability is an empirical parameter without any regard to the flow throughout porous 

 media. Using this value of P, Equations 3.7 and 3.8 suggest that 5 is approximately 

 proportional to Hf and Nj^-^. Because the number of waves is defined as A'^^,= t/r„, 

 where t^ is the total run time, these formulations indicate that damage increases with the 

 square root of time. But because the Iribarren parameter is raised to a negative constant 

 in Equation 3.7 but raised to a positive power of P in Equation 3.8, the effect of wave 

 period is not clear. It is clear that damage progression is very sensitive to wave height. 



Equations 3.7 and 3.8 are of limited practical use for depth-limited breaking 

 waves primarily because the supporting breaking wave experiment was extremely 

 limited in scope. These equations are essentially the same as Van der Meer's 

 nonbreaking wave equations except the Rayleigh wave height distribution assumption 

 of//, = H2crJlA has been substituted. Van der Meer included the structure slope in the 

 Iribarren or surf similarity parameter (Battjes 1974), but the beach slope is critical for 

 depth-limited breaking waves. Van der Meer conducted experiments for only one beach 

 slope and used a very narrow range of wave periods. Therefore, the effect of varying 



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