"It is very tempting to draw an analogy between a seawall and an 

 eroding barrier dune. The essential difference appears in their 

 response: static vs. dynamic. Unless a sand dune is essentially 

 structurally controlled by rip-rap or caissons as a seawall, it is free to 

 erode or accrete depending on the environmental conditions. It has 

 long been argued by the U. S. Army Corps of Engineers (1974) that 

 dunes serve as a sand reservoir for beach nourishment in times of need 

 (during storm conditions). In fact, it has been clearly shown that a 

 high sand dune will reduce foreshore erosion during a storm since a 

 greater amount of sand is available to fill the offshore profile and 

 buildup the outer bar to provide sufficient width to dissipate the wave 

 energy (Van der Meulen and Gourlay I 969). 



"The case against barrier dunes, artificially induced or totally 

 natural, is not convincing from either a beach or barrier dynamics 

 viewpoint. Much more work needs to be done along these lines, 

 particularly in the case of storm generated beach dynamics" 

 (Leather man 1979b). 



DUNE STABILIZATION IN THE UNITED STATES 



There exists a long history of the use of vegetation to retard the erosion of dunes in 

 the United States. Attempts at coastal dune stabilization were made as early as 1703 

 when colonists of Cape Cod used grasses to control sand erosion due to their own 

 deforestation of sandy areas (Westgate 1904). 



In the early I900's, intense efforts to vegetate existing dunes along the Pacific 

 Northwest coast began. Primarily, European beach grass, Ammophila arenaria , and 

 American dunegrass, Elymus mollis , were planted. These plantings proved to be 

 successful to the point that the dominant dune plant in the Pacific Northwest is European 

 beach grass. 



Along the Atlantic coast, large scale planting by the Civilian Conservation Corps 

 (CCC) occurred along the North Carolina coast from 1934-36. American beachgrass, 

 Ammophila breviligulata , was planted extensively in the Bodie Island area of the outer 

 banks. Between 1936-40, the CCC and the Works Progress Administration (WPA), under 

 the direction of the National Park Service, erected almost I million meters of sand 

 fencing to create a continuous barrier dune along the outer banks, including Hatteras, 

 Pea, and Bodie islands (Dolan et al. 1973). 



After a series of strong hurricanes impacted the Atlantic coast starting in 1954 

 with "Hazel", new interest in dune erosion control was stimulated. The National Park 

 Service and the Soil Conservation Service began testing various species of grasses on 

 North Carolina's Outer Banks in the late I950's. Beach grasses, especially American 

 beachgrass, have been planted extensively on the outer banks during the I950's and 

 I960's. With the establishment of the Cape Hatteras National Seashore in 1957, the 

 National Park Service felt it was important to protect the dunes making up the park from 

 eroding. Thus, extensive dune plantings continued which augmented the I930's effort at 

 dune construction. After this effort, an almost continuous vegetational cover existed on 

 these barrier islands making up the outer banks. 



190 



