Table 8 (Concluded 





Profile 

 No. 



Storm 

 Hour 



SWL 

 ft, mlw 



Depth in 

 Flume, ft 



Wave 



Height 



ft 



Wave 



Period 



sec 



Seawall 

 Crest 

 Elev. 

 sec 



Base of 

 Seawall 

 ft, mlw 



Over- 

 topping 

 cfs/ft 



Cotan 

 Beach 

 Slope 



Elev at 

 2,000 ft 

 Offshore 

 ft, mlw 





30 



16.6 



18.79 



8.70 



15.9 



20.7 



20.3 



0.5093 



14.0 



-5.41 





31 



15.0 



17.19 



9.10 



15.9 



20.7 



20.3 



0.1329 



14.0 



-5.41 





32 



13.4 



15.59 



9.01 



15.9 



20.7 



20.3 



0.0258 



14.0 



-5.41 





42 



13.9 



16.09 



8.90 



15.9 



20.7 



20.3 



0.0396 



14.0 



-5.45 





43 



13.4 



15.59 



8.15 



15.9 



20.7 



20.3 



0.0155 



14.0 



-5.45 





45 



10.0 



12.19 



9.02 



15.9 



20.7 



20.3 



0.0000 



14.0 



-5.45 



5 



31 



15.0 



13.83 



8.30 



15.9 



20.4 



19.1 





14.5 



-1.40 



4 



42 



13.9 



14.59 



9.90 



15.9 



20.3 



19.1 





19.5 



-3.57 



3 



42 



13.9 



15.37 



7.30 



15.9 



20.5 



18.2 





15.5 



-2.23 



coefficients (typically 10 percent for this study) were retained in the 

 selected models. 



The model that best fit the data in Task B was: 



Q' = -0.0190100 + 0.113943*PI1 - 0.074790*/'/l2 



-I- 0.114503*^/32 - 0.072397*P/34 



- 0.007017*P/4 -f 0.0001 99*-P/42 



- 0m6809*PI5 + Omi60l*PI5^ 



While this equation was somewhat tedious, it fit the data with a correla- 

 tion coefficient of 0.991 (R^ = 0.983), and the sum of squares of differ- 

 ences between the overtopping rates (dimensional) and measured 

 overtopping was only 0.074. There were 38 data points in the analysis; 

 therefore, the average difference between calculated and measured over- 

 topping was ± 0.044 cfs/ft. 



It should be emphasized that regression models presented in this report 

 are site-specific and are only valid at Revere Beach and within the range 

 of conditions tested. The range of variables used, both dimensional and 

 nondimensional, is given in Table 9. 



It seemed unreasonable to delete wave height (PI2) from the model, es- 

 pecially when a correlation analysis revealed that Q' was more highly cor- 

 related with dimensionless wave height than any other single variable. 

 However, there was a very high correlation between dimensionless wave 

 height and dimensionless water depth (P/2 and PIS, 76-percent correlation). 



34 



Chapter 3 Research Tasks A, B, and C 



