Vegetated dunes accumulate around vegetation, which act as sand- 

 trapping baffles (vertical growth of 0.3 to 1.0 meter per year), and 

 also as an internal skeleton fixing the dunes in place, and result in 

 a characteristic internal geometry containing low-angle dipping beds 

 (mean = 12°) and polymodal dip directions (Goldsmith, 1973; 1975b). 

 The vegetated foredunes are highest and most prominent at Profile 

 line 2 (61st Street, Virginia Beach) , in Back Bay, and in False Cape 

 where they reach elevations of 10 meters. At Cape Henry and in 

 Currituck County, the foredunes are lower in elevation (usually about 

 3 meters) and grade landward into sparsely vegetated eolian flats con- 

 taining multiple lines of sand fencing. 



Medanos are large, isolated unvegetated hills of sand, 10 to 25 

 meters in elevation, and asymmetric in profile. They migrate down- 

 wind up to tens of meters per year by a process which produces char- 

 acteristic slipfaces of unconsolidated sand dipping at the angle of 

 repose on the leeward side of the dune. About a dozen medanos occur 

 in Currituck County, with elevations up to 25 meters (Lewark Hill) 

 and migration rates up to 20 meters per year (Jones Hill, 1955-1975). 

 In total, they represent a significant ai?iount of sand (i.e., many 

 times the annual longshore transport rate) . 



Parabolio dunes , defined by their characteristic planimetric 

 view, are similar to medanos in that they have a slipface formed in 

 direct response to the dominant wind, and a deflation zone within 

 their upwind concave side, but are different in that they have an 

 internal geometry more characteristic of vegetated dunes and may be 

 fixed in place depending on their recent vegetation history. Par- 

 abolics occur prominently in False Cape State Park, and also in 

 Currituck County where their aerial distribution typically grades 

 from vegetated parabolics to transverse dunes (i.e., medanos) in 

 an upwind direction. Parabolics also show in situ temporal changes 

 to other dune types. These dunes are discussed further in Goldsmith, 

 et al. (1977) . 



Ongoing studies at VIMS indicate that sand is blown from beach to 

 dune and back throughout the width of Currituck Spit. The classic 

 idea of sand blowing from the beach landward into the dunes may be 

 overly simplistic to the point of being incorrect. Further compli- 

 cating this matter is man, through the active sand fencing program 

 since the 1930' s, which has built up the foredunes along the area 

 south of Sandbridge. These foredunes, which result from natural 

 processes around an artificially heightened dune, may result in a 

 different type of dune, and unforeseen consequences. Also, as shown 

 by Leatherman (1976), eolian transport of sand from overwashes back 

 onto the foredunes and onto the beach is a very significant process. 

 Artificial heightening of the foredunes in this area has cut off the 



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