V. BEACH CHANGES 



1 . Regional Variations in Beach Volume Changes During VIMS-CERC Study . 



In analyzing 27 months of data from the study area, it became 

 evident that certain areas had usually accreted, some had usually 

 eroded, and some were either stable or fluctuated too much for any 

 discernible trend to be recognized. Appendix I gives the total 

 cumulative volume changes with time for each of the 18 profile lines. 

 Plots of profile line cumulative volume changes with time (18 VIMS- 

 CERC profile lines) are in Appendix B. Figure 13 represents graphi- 

 cally the 27-month total cumulative volume at each profile line, and 

 Figure 14 shows similar data at 9-month intervals, using CERC's 

 volume calculations. All these volume data represent net changes 

 along the profile line between the number 1 pipe and the MSL inter- 

 cept determined by the surveyers, as discussed in Section III, 4. 

 A qualitative description of the 27-month volume trends and major 

 events is presented in Table 6. Statistical analyses of beach 

 trends for the 27-month study and the historical changes are given 

 in Tables 7 and 8, respectively, and are shown graphically in 

 Appendixes B and C. 



Fort Story (Profile line 1) appears to have accreted throughout 

 the study. Even the severest storms did little damage at this 

 survey location. Although the 1 July 1975 storm was followed by 

 significant accretion, the 25 November 1975 storm was followed 

 by minor erosion. However, one factor, whose influence remains 

 unknown, is the occasional leveling of the wide beach area with a 

 road grader by the U.S. Army. 



The Virginia Beach area (profile lines 2, 3, and 4) tended 

 to erode, but this was offset with beach nourishment. The 

 total volume of the profile lines fluctuated considerably and is 

 probably due, to some extent, to sand nourishment. However, it 

 would seem accurate to assume that the area would be erosional, 

 without beach nourishment (see Section VII, 2). Profile line 5, 

 updrift of Rudee Inlet, displayed a slight, statistically non- 

 significant accretional trend. 



In the Dam Neck area, profile line 6 appears to be erosional; 

 while Profile lines 7 and 8 seem to be slightly accretional to 

 no trend because of "very active" volume changes. Profile line 8 

 follows a fence which separates Dam Neck from Sandbridge and obser- 

 vations clearly indicate that the sand levelhas been rising next 

 to the fence above the high tide line, while the beach face has 

 remained the same or slightly eroded during the study. 



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