PART III: WAVES 



38. This section presents summaries of the wave data. A discussion of 



individual major storms is given in Part IX, and Appendix B contains hourly 



wave data for times when the heights H exceeded 2 m at the seaward end of 



mo 



the FRF pier. Appendix C (published as Volume II) provides summaries of the 

 data for each gage, including height and period distributions, wave direction 

 distributions, persistence tables, and spectra during storms. Signals from 

 the wave gages were routinely sampled in accordance with guidelines indicated 

 in paragraph 1 1 . 



39. Daily wave height and period values for Gage 630, located 6 km from 

 shore, and Gage 625, located at the seaward end of the FRF pier, are presented 

 in Figures 9 and 10, respectively. The annual mean wave height (measured at 

 the seaward end of the FRF pier) is 0.9 m, with a standard deviation of 0.6 m. 

 Although the portion of the North Carolina coast in the vicinity of the FRF 

 experiences a fairly low frequency of occurrence of direct hurricane strikes 

 (on the average of once every 42 years) , more frequent near-misses can cause 

 high wave conditions at the FRF. Wave height in excess of 2 m can be expected 

 to occur 7 percent of the time, or 600 hr per year. 



40. Wave periods generally vary between 6 and 12 sec, with an annual 

 mean peak spectral period of 8.8 sec and a standard deviation of 2.8 sec. 



Wave periods tend to be longest during the fall and shortest during the summer. 



41. Wave directions (similar to wind directions) at the FRF are season- 

 ally distributed. Waves approach most frequently from north of the pier in 

 the fall and winter and south of the pier in the summer, with the exception of 

 storm waves which approach twice as frequently from north of the pier. Annu- 

 ally, waves are approximately evenly distributed between north and south (re- 

 sultant wave direction being almost shore-normal) . 



Measurement Instruments 



Staff gages 



42. Two Baylor Company (Houston, Tx.) parallel cable inductance wave 

 gages (Gage 645 at sta 7+80 and Gage 625 at sta 19+00 (Figure 2)) were mounted 

 on the FRF pier. Rugged and reliable, these gages require little maintenance 

 except to keep tension on the cables and to remove any material which may 



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