DWHAWB increased. The seiche wave amplitude was computed by first calculating 



the H associated with seiche. This (e \ was calculated by taking 



mo \ moj . , 



seiche 



the total H measured in the tank (single Gage 4) and then subtracting from 

 mo 



it the wind wave H measured on Goda Array 2 (Gages 5, 6, and 7). Using 

 mo 



this (r \ , the seiche amplitude a . , was then computed: 



\ mo/ . , seiche 



seiche 



2 



(h Y - (H ) = (H r (CI) 



\ mo7 ^ , V mo/ . , \ mo/ . , 

 total wind seiche 



(h ) 



\ mo/ 



seiche ^ (^,2) 



seiche 4 



Some of the seiche in the tank now can be accounted for by changing the form 

 of Equation 3 (main text) to the following: 



Q- = exp [c^F' + I (C3F' - C2)] 



(C3) 



where 



Q' = dimensionless overtopping rate made dimensionless by 



{ 3 V/2 

 dividing Q by I gH ) , where g is the accelera- 



mo 

 tion of gravity 



C^ , C„, C„ = dimensionless regression coefficients 



F' = dimensionless relative freeboard parameter 



F = average freeboard in feet 



a = amplitude of the seiche wave in feet 



Figure C5 is a plot of the measured overtopping rate during Phase II seawall 

 tests versus the predicted overtopping rate using Equation C3 . Figure C5 

 shows that the predicted rates agreed well with model results. Figure C6 

 shows the physical model data again with the predicted Q values from 

 Equation C3 represented by darkened circles. Although the predicted Q values 

 of Figure C6 do not correspond exactly to the measured data values, the figure 

 indicates that much of the data scatter is attributed to seiches in the wave 

 tank. Figure C6 should give the reader confidence in the data collected and 

 should calm any fears created by the data scatter. 



C6 



