RESULTS AND INTERPRETATIONS 



Profile Modifications 



Winter Months. An idea of the expectable wintertime profile changes 

 in a region of essentially unmodified foreshore and dune at Virginia Beach 

 is shown in Figure 2. The period of destructive winter northeaster storms, 

 is roughly November through March. The envelope of altitudinal variations 

 (Figure 2) at stations along the profile at 61st Street shows that the 

 greatest winter month changes can be expected in the intertidal zone and 

 that the beach there may fluctuate in altitude through a distance of 3 to 

 5 feet. This range would have been slightly greater had the silt beds 

 (Figure 2) been missing. The silts are eroded with difficulty and, in 

 fact, are recognized as the sediments that determine the position of the 

 coastline today. 



These deductions about profile changes in the foreshore area of 61st 

 Street are based on measurements that are believed representative of the 

 natural beach response to the existing forces over the period of study. 

 Watts (1959, p. 3) indicates that during all of 1956 only 1,000 cubic 

 yards of beach fill were placed artificially along the beach from Rudee 

 Inlet to 42nd Street (Figure 2). In 1957, however, 89,000 cubic yards 

 were placed along the shore in this area, but the pumping did not exceed 

 a few thousand cubic yards by April 6, 1957. 



Changes in the dune profile (Figure 2) were minor, the greatest 

 changes coming near the dune crest on the steep seaward slope where 

 stabilization by vegetation was absent. The remainder of the dune was 

 only poorly stabilized. 



Summer Months. The summer months, April through October, show some- 

 what similar changes in the envelope of altitudes at 61st Street, although 

 the envelope is not presented here. Both winter and summer profile changes 

 at five stations are plotted on Figure 3. There is a difference only in 

 the rapidity of change as noted in qualitative observations, the more 

 rapid changes occurring in the winter months. Summer changes in the profile 

 envelope can be deduced from Figure 3. 



Yearly . Data (Figure 3) from 23 consecutive months suggest a gradual 

 increase in the volume of foreshore sand above MLW (November 1956 - June 

 1958) at 61st Street. This can very probably be related to the large 

 amounts of sand pumped on the beach from the Owl Creek hydraulic dredge 

 during 1957 - 1958 (Watts, 1959, p. 3). Watts notes (1959, p. 2) that 

 available evidence indicates a northward drift of beach material in the 

 area in the summer months. Thus, the beach at 61st Street, which was 

 definitely downdrift from the zone of artificial nourishment in the summer 

 months, would be expected to build up. This is borne out by the curves of 

 Figure 3. 



