probability level of 90 percent. Notably these limits are not confidence 

 limits on the estimator function but are probability intervals for individual 

 predictions of overtopping for a given swl. 



32. A table of overtopping calculations throughout the length of each 

 storm was developed (Table 5) . Dates and times are listed in the first two 

 columns with storm surge levels, in feet above NGVD, in the next column. The 

 prototype storm hydrographs were for peak surge levels of +6.7 and +8.7 ft 

 NGVD for the extratropical storm and hurricane at Virginia Beach, respec- 

 tively. To adjust or scale them to the +7.0-, +8.0-, and +9.5-ft surge levels 

 (swl) used in the physical model tests, linear scaling was applied. These 

 scaled water levels (in feet) are shown in column four. Column five is the 

 deepwater wave height (in metres) calculated for each hour of the storm using 

 the storm wave hindcast model (Part III) . The next column is the percent of 

 maximum wave height at that time during the storm. Figure 8 illustrates the 

 time series of the hindcast storm wave hydrograph relative to the measured 

 storm surge hydrograph for both storms. 



Table 5 



Overtopping Calculations 



1933 Hurricane 















Regr 



ession ( 



Zurve 















Over 



topping 



Rates 







Swl 

 ft 



Swl* 

 ft 



H ** 







cfs/ft 





Date 



Time 



m 



Percent 



Qr 



^u 



Ql 



Aug 23 



0600 



4.6 



— 



4.4 



91 



0.0 



0.0 



0.0 





0700 



5.0 



— 



4.5 



93 



0.0 



0.0 



0.0 





0800 



5.6 



5.2 



4.6 



95 



0.0 



0.0 



0.0 





0900 



6.2 



5.7 



4.6 



95 



0.0 



0.0 



0.0 





1000 



6.8 



6.3 



4.7 



98 



0.0 



0.14 



0.0 





1100 



7.5 



6.9 



4.8 



100 



0.09 



0.33 



0.0 





1200 



8.2 



7.5 



4.8 



100 



0.30 



0.53 



0.08 





1300 



8.7 



8.0 



4.8 



100 



0.45 



0.66 



0.25 





1400 



8.1 



7.5 



4.8 



100 



0.27 



0.50 



0.05 





1500 



7.3 



6.7 



4.8 



100 



0.03 



0.27 



0.0 





1600 



6.2 



5.7 



4.5 



93 



0.0 



0.0 



0.0 





1700 



4.3 





4.1 



85 



0.0 



0.0 



0.0 



* Scaled to design storm elevations. 

 ** H = 4.82 m. 



mo 

 max 



22 



