PART V: RESULTS 



22. Coastal processes are constantly at work modifying the beach pro- 

 file and the sediment distribution across the profile with each wave. Daily 

 changes during fair weather waves are small. Storm- induced changes can, how- 

 ever, be significant and can occur over the period of one to five tidal 

 cycles. The longer term changes in the profile shape and sediment distribu- 

 tion are a function of the frequency of storm- induced changes. The cyclic 

 variation in this storm frequency leads to a general seasonal cycle of erosion 

 typical to the winter months due to increased extratropical storm occurrence. 

 Accretion is more likely in the more quiescent summer months, barring tropical 

 storm impacts. The key forcing functions are the frequency and duration of 

 storm activity. The present study covers a period of 17.8 months, from March 

 to September, which spans this seasonal time frame. Several storm events were 

 also bracketed with surveys and samples . This unique data set allows for 

 analysis of long-term changes in the profile and sediment distribution under 

 varying wave conditions . 



Profile Changes 



23. A general description of long-term profile changes that occurred at 

 the FRF are described from 1981 to 1984 in Birkemeier (1985). This present 

 study extends that data set into 1985. The general morphology of the beach at 

 the FRF includes the dune, initially bulldozed by man and now under the influ- 

 ence of eolian transport; the berm, or dry beach, under the influence of wave 

 transport only during high-water conditions; the foreshore or intertidal area, 

 changed daily by the uprush and backwash during each tidal cycle; the bar/ 

 trough region where the wave breaks and reforms into a bore in the surf zone; 

 and the nearshore area seaward of the bar and breaker zone. 



24. The profile at the FRF is most active during storms and is charac- 

 terized by an dynamic bar/trough movement zone. The inner bar, located at a 

 depth of -0.6 to -1.5 m (Birkemeier 1985), moves offshore in response to the 

 storm waves. During fair weather periods, the bar migrates back onshore. 

 The berm and foreshore change along with the bar movement, typically eroding 

 as the bar moves offshore and accreting as the bar moves onshore. 



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