3. The expected annual, or long-term average annual, damages are esti- 

 mated by the following formula, given the parameters which define the incident 

 wave climate by an annual cumulative probability distribution of significant 

 wave heights FlHg) as follows: 



if^}-^f'4 



dF(H ) 

 s_ 



dH' 



dH 



(D2) 



where 



E{7oD/yr} = the expected annual damage 



X = the Poisson parameter or average number of extreme 

 events per year 



[dF(H )/dH ] = the probability density function corresponding to 

 F(H3) 



4. The relation above implicitly assumes that H^ is a significant 

 wave height representing some design sea state since its probability of ex- 



\%' 



ceedance in any year and that of all higher values of Hg in 

 determined by a distribution of significant wave heights. It further assumes 

 that the number of extreme events per year is a random variable which can be 

 represented by a mean value and is independent of the individual significant 

 wave heights representing the intensity of these storms. BWDAMAGE requires 

 the user to input X and the e and cj) parameters of the Extremal Type I 

 cumulative probability distribution of incident significant wave heights where 



[(.-H^)/«] 



F(H ) 

 s 



(D3) 



The associated probability density function is thus 



dF(H ) F(H ) r(e-H )/^-\ 

 s s L s J 



dH 



(D4) 



Input of the design significant wave height 'H^ and X the average number of 



extreme events per year X are required so the expected annual damages can be 

 estimated as 



■ H 



y^/ H, \"d/L ^"s J ^ 



(D5) 



D2 



