method used to construct the dune. Dunes 

 can be built mechanically with a bull- 

 dozer, hydraul ically with a pipeline 

 dredge, with sand fences, or by a combi- 

 nation of methods. First, consider push- 

 ing up sand with bulldozers. This is 

 actually dike-building and is at best a 

 temporary means of halting the ocean's 

 advance. It is usually resorted to only 

 in emergency situations. During the Ash 

 Wednesday storm of 1962 along the North 

 Carolina coast, personnel of the Cape 

 Hatteras National Seashore worked all 

 night with a bulldozer to keep a barrier 

 dune intact and prevent overwash from 

 flooding a developed area. 



Another option is to use a pipeline 

 dredge to pump sand from a barrow area 

 (e.g., sand spit or lagoon) onto the 

 beach and build a new berrr. and dune 

 system hydraul ically. Placement of sand 

 onto the beach in this manner is called 

 beach nourishment. In 1965, the U.S. 

 Army Corps of Engineers nourished 

 Wrightsville Beach, North Carolina, at a 

 cost of about $468,750/km ($750,C00/mi) 

 of beach. This procedure has been 

 repeated since 1965 at a cost of 

 $1,250,000 to $l,875,000/km ($2 to 3 

 million/mi) of beach. This process may 

 have to be repeated again and again. The 

 economics of the situation in this case 

 might dictate or indicate that beach 

 nourishment, time and again, is the 

 answer in this relatively heavily devel- 

 oped area. A part of the specifications 

 followed by the Corps in a nourishment 

 project is that the upper portion of the 

 nourished area be planted and stabi- 

 lized. Under favorable conditions this 

 will result in dune formation. 



In some situations a dune can be 

 built with sand fence (snow fence) or 

 with sand fence and vegetation together. 

 Under certain conditions, it is possible 

 to plant grass and, as the grass grows, 

 it accumulates sand, and a dune forms. 

 With this technique, the dune is being 

 stabilized as it is being built. 



Whether the dune is pushed up me- 

 chanically, pumped up hydraul ically, or 

 formed by fences or grasses, the sand 

 must be stablized to be a protective de- 

 vice. You can accumulate all the sand 

 you want, but sand can be moved by the 

 prevailing winds unless it is stabi- 

 lized. In underdeveloped areas along 



some coastlines, it is feasible to build 

 a dune just by planting dune grasses. 

 When you consider something like beach 

 nourishment, you are dealing with mil- 

 lions of dollars. A dune can be built 

 in a few years after planting with Amer- 

 ican beachgrass for about $6,250/km 

 ($lC,000/mi). 



Coastal dunes are abused by man, 

 his animals, and his machines. Grazing 

 has been a major problem in the past; 

 traffic, both foot and vehicles, is a 

 major problem now. Almost any dune 

 system along the Atlantic coast or Gulf 

 of Mexico at one time or another has 

 undergone grazing pressure by various 

 domestic animals, including sheep, 

 cattle, horses, pigs, and goats. These 

 animals had a tremendous impact and in 

 many cases completely denuded the 

 coastal dunes. 



Some present-day ecologists say 

 dune systems are in a dynamic equilibri- 

 um even though man has interfered with 

 these systems for several hundred years. 

 Presently, the problem is not grazing 

 but man's impact with foot and vehicular 

 traffic. Dune vegetation is very suscep- 

 tible to damage by traffic. Land manag- 

 ers should control access to beach areas 

 by directing it along wooden, elevated 

 walkways. One of the very desirable 

 features of dune grasses is their capac- 

 ity to reestablish following storm ac- 

 tivity. Traffic interferes with this 

 capability of the vegetation. There is 

 no way that plants can reproduce well in 

 areas used heavily by vehicles. Dune 

 buggies may have their place, but it is 

 not on a frontal dune system along the 

 Atlantic coast. Get them further inland, 

 possibly on certain live dunes. 



The absence of dunes along most of 

 the Atlantic coastline is usually due to 

 a lack of sand or sufficient winds to 

 move the sand onto the vegetation, or 

 due to man's interference through his 

 activities, or his animals' activities. 

 Dunes are natural features. They will 

 develop if there are vegetation and a 

 sand supply. Placement of vegetation 

 about 100 m (330 ft) from the high tide 

 line will result in dune formation pro- 

 vided there is an adequate sand supply. 



Dunes are fragile structures re- 

 quiring protection and stabilization; 

 vegetation is usually the only practical 



59 



