and periods are relatively low. 



Significant Wave Analysis 



Visual Swell Observation 



Wave Period 



Wave Height 



Direction in 



Range 05° -l6k° 



Mean 



1st Mode 

 (sec) 



Mean 

 (ft.) 



1st Mode 

 (ft.) 



(True W) From Which Swells Come 



(sec) 



Direction 



Percent of Total 

 Swells 



5.3 ^.0 



1,7 2.0 



k3°-3k° 30.0 



85°-.9^° 20.0 

 1350_i^^o 18.0 



A hreakdown of the 15 most-frequent associations of wave period, height, 

 and angle of approach at the Chesapeake Lightship is given in Harrison 

 and Wilson (1965), together with details of the refraction of these wave 

 fronts as they move into the study area. 



Surf statistics at the Virginia Beach Life Boat Station, 1.6 miles 

 north of Rudee Inlet (fig. IC), have heen complied by Helle (I958). Three 

 years ' records, for observations every four hours, reVeal that surf is k 

 feet or higher 10^ of the year, 3 feet or higher 50^ of the year, and 2 

 feet or higher 95^ of the year. Surf tends to be highest in early fall 

 when the angle of wave approach tends to be from the east (or ENE) . Surf 

 is also high in January, when it is largely out of the northeast. The 

 average period of the surf tends to be greatest April through July (around 

 6.0 seconds) . 



Wind data from the U. S. Weather Bureau's Cape Henry station (fig. 

 IB) for- a 16-year period is summarized in the Virginia Beach, Va., Erosion 

 Control Study (U. S. Congress, 1953^ plate 5). Analysis of these data 

 shows that whereas prevailing winds are from the southern quadrants, vel- 

 ocities and total wind movements are greater from the northern quadrants. 

 Northeast winds tend to be most common in September. 



METHODS 



Measured Variables 



A list of the variables measured in the beach-ocean-atmosphere 

 system at Virginia Beach is presented in table 1, and descriptions of the 

 techniques used in their measiirement are given in Appendix A. Of all of 

 the measurements used in this study, most were taken in the months of 

 February, June, and July. Some were taken in March and April. Thus, a 

 winter and a summer set of data were available for combination and study. 

 (Only summer data were used in the evaluation of the dependent variables 

 J-f and Kf ) . 



