has eroded from the area below the berm seaward. Profile line 18 

 has demonstrated very little change in shape. 



Profile line 1 (Fig. 21) is typical of the longer, accretional 

 beaches. Generally, the profile line surface is horizontal with a 

 slight landward slope from the top of the berm. During erosion the 

 beach face has a concave-upward slope. The beach face may slope 

 convex-upward with formation of a second berm close to the spring 

 high tide swash. 



Profile line 9 (Fig. 22) is typical of the shorter beaches in the 

 study area. It is concave-upward from the dune seaward, and with 

 accretion there is a convex-upward berm covering two-thirds of the 

 profile. The remaining landward one-third remains concave -upward. 



4. Sand Storage . 



Generally, erosion and accretion occurred in the berm area of the 

 beach. On only rare occasions were the dune areas affected; erosion 

 only occurred in these areas during storms involving high winds and 

 high storm tides. The berm appears to be a storage area for sand 

 during quiet periods between storms. When a storm strikes, this area 

 is the most vulnerable to erosion. Most survey locations, which 

 experienced erosion during storm events, eroded either at the berm, 

 or from the berm seaward to the swash zone. Beach recovery after 

 storms was most noticeable in the berm area, usually by the time of 

 the next survey, except after the most severe storms. Accretion after 

 storm recovery was usually about equal to erosion (cumulative volume) 

 during the storm event. 



A specific example of sand loss in the berm area is seen at profile 

 line 9 (Fig. 22) . Computing data from the COMPARE program show that 

 about 15 cubic meters of sand per linear meter of beach was lost from 

 the base of the dune to MLW swash between 6 June and 1 July 1975. 

 Concomitantly, at profile line 1 (Fig. 21) about 17 cubic meters of 

 sand accumulated in the berm area. 



Profile lines 1 (Cape Henry) and 12 (Back Bay) , after almost every 

 storm, experienced accretion in the area immediately landward of the 

 original berm, and erosion from the berm seaward; e.g.. Profile line 1 

 during Hurricane Amy accreted approximately 16 cubic meters of sand per 

 linear meter of beach behind the original berm, and eroded some 4.6 

 cubic meters per meter from the berm to upper swash. This suggests 

 that high water and winds possibly transported sand from the berm and 

 deposited it higher on the beach. After the storm, at these locations, 

 the storm accretion area slowly eroded and the original berm area 



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