additional tests conducted after Task C listed as C+. The data set for this 

 effort is given in Table 12. 



Dimensionless variables that yielded the best results were similar to 

 those used in the regression analysis of Task B, above. Dimensionless 

 overtopping was defined in the same way, and the repeating variable was 

 again seawall freeboard (distance between seawall crest elevation and 

 swl). Dimensionless beach elevation used in Task B was replaced with 

 the dimensionless difference between seawall crest elevation and beach 

 elevation, and PI4 was deleted because beach slope for the 1978 profile 

 was constant. Wave period was a factor, and was characterized by deep- 

 water wavelength. Depth in the flume and swl differed by a constant; 

 therefore, they could not both be used and swl was selected for PIS. The 

 dimensionless variables are listed below. 



Q' = Q/i8*fy^ 

 pii = (f-b)/f 



PI2 = Hlf 

 PI5 = swl// 



PI6 = L If 



o-' 



The dimensionless variable P/3 {d/dlOOO) used in Task B was not in- 

 cluded because data for J2000 were not available for conditions in Task C. 



In conducting the analysis, one point was found to lie outside the gen- 

 eral trend. In the set of six tests conducted as Task C+, the measured over- 

 topping from the test with an swl of 15.0 ft was substantially greater than 

 predicted. This data point yielded an unacceptable influence on the re- 

 sults, and was therefore deleted from the analysis. For the remaining 

 data, the selected regression model is given below. 



Q' = -0.000338 + 0.002530*/'/l'^ - 0.004788*^/5^ 



+ 0.001912*PI2^ - 0.000322*P/2^ 



+ 0.0000002 12*^/6^ - 6.92016* 10"'2*/j/64 



This model was selected by weighting the analysis by wave period, 

 thereby increasing the significance of longer period waves. 



This model had a correlation coefficient of 0.992 (R^ = 0.984), and the 

 correlation coefficient of dimensional overtopping (measured to predicted) 

 was 0.970. Sum squares of the residuals of dimensional overtopping was 

 0.3106 for the 60 tests; therefore, the average error was 0.072 cfs/ft. 



Chapter 3 Research Tasks A, B, and C 



39 



