2. Differing Profile Response to Specific Storm Events . 



During the study, the study beaches were additionally surveyed 

 after eight storms. (Actually a total of 9 storms, including the 3 to 

 4 December 1974 storm which was surveyed during a regular monthly pro- 

 file session.) The storms of 1 July 1975 and 10 August 1976 were 

 tropical storms; the other seven were extratropical . The dates of 

 the storm surveys were 15 and 20 March, 1 July, 3 September, and 

 25 November 1975; and 12 March, 10 April, and 10 August 1976. The 

 most devastating storm effects were surveyed 25 November 1975, and the 

 second worst erosion occurred from Hurricane Amy, surveyed 1 July 1975. 

 Table 9 describes qualitatively the highly variable effects of each 

 storm at each survey location. Appendix D details the various para- 

 meters of each storm, and Appendix I presents the precise surveyed 

 volume and MSL intercept changes. 



The first storm event surveyed was 15 March 1975; this storm appeared 

 to be the least eventful and least damaging of the nine storms involved. 

 Five profile lines (1 at Fort Story, 6 and 7 in Dam Neck, 10 in 

 Sandbridge, and 12 in Back Bay) actually showed net sand volume accre- 

 tion, especially in the area between the base of the dune and the berm. 

 Four profile lines [4 in Virginia Beach, and 11, 13, and 14 in Back 

 Bay) appeared to be virtually unchanged from the preceding surveys in 

 February. The remaining profile lines were erosional, but only to a 

 minimal degree, and this erosion was mostly confined to the area of the 

 berm seaward to MSL. 



The second March storm was surveyed 20 March 1975, and was of greater 

 intensity than the first, but the effects were certainly not devastating. 

 Four profile lines (7 at Dam Neck, 9 at Sandbridge, and 14 and 15 at 

 Back Bay) were slightly accretional. Profile line 4 (Virginia Beach), 

 6 (Dam Neck), and 18 (False Cape) remained virtually unchanged from 

 the previous measurements. The other 11 profile lines were erosional. 

 Profile line 3 (Virginia Beach) was the most dramatically affected; 

 it was erosional over the entire length of the profile line (-12.3 cubic 

 meters per meter) . The remaining profile lines were mostly erosional 

 over the entire profile length, but to a lesser extent. 



Hurricane Amy passed through the study area 28 to 30 June and the 

 beaches were surveyed 1 July 1975. Although winds were recorded at 

 22 knots (App. D) , the high seas were probably the most influential 

 factor affecting beach erosion. Only profile line 1 at Fort Story 

 showed any accretion, although there was a fairly significant 

 amount of erosion below the berm area. However, there was also a 

 significant amount of accretion in the backshore area. Only profile 

 line 11 in Back Bay showed very little change from the previous sur- 

 vey in June. All other locations showed a significant amount of 



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