Barrier Island Ecology of Cape Lookout National Seashore and Vicinity, North Carolina
NPS Scientific Monograph No. 9
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Finally, some general suggestions for the management of barrier islands as recreational areas are in order. Much of what will be said here has already been incorporated into the Master Plan for Cape Lookout National Seashore (Fig. 133), where we hope it will help National Park Service Managers avoid the difficulties with which the Superintendents of more developed seashores are saddled (Fig. 134).

Fig. 133. Black skimmers taking off from a spoil island rookery beside the Cape Lookout channel. Marine birds are among the many plants and animals that are part of the wild and increasingly valuable natural barrier island system that is Cape Lookout National Seashore.

Fig. 134. Schematic responses of natural and stabilized barrier islands to storms. (click on image for an enlargement in a new window)

1. Both A and B are essentially alike at the start. Both have a wide berm, low, open dune system, grasslands, and can be overwashed,

2. In B, money has been spent to build a road and a dune to protect it; the island has been "stabilized."

3. A moderate storm strikes both islands and overwashes A. B cannot be overwashed because of the continuous dune, but there is severe erosion of both beach and dune. The erosion narrows the beach and creates deeper water nearshore, which causes more wave damage to the dune. In B there is little or no dune erosion although the beach has retreated.

4. Following the storm, the overwash terrace in A has become vegetated, and new dunes are forming. No damage can be seen. However, in B, the stabilized dune is badly eroded, and the berm markedly narrower. A new beach has been formed on both islands by gentler waves following the storm. Note that shrub vegetation has increased along the road and behind the dune in B. Strong winds from the lagoon side of the island are creating waves in the lagoon, which erode the edges of the salt marsh.

5. A severe storm with winds blowing across the lagoon has flooded the backshore of both islands. In A these flood waters can flow out to sea across the island. In B they are trapped by the man-made dune, and flood the road and other facilities. In A the flood waters remain shallow on the island and last for only a short time. In B they become deep and stand on the land for a long time. Some dune erosion may result on the backside of the dune.

6. The effects of the storm are not evident on the natural island. All vegetation zones are alive and healthy, although the edge of the salt marsh has eroded more. In B, repair work is being done to the back of the dune line. The marsh edge also has eroded. Plants not tolerant of long-term flooding have died. Further attempts to protect the main dune line have been started, with bags of sand being placed along the eroding base of the dune. The problems in B have resulted in major expenses.

7. A severe storm strikes the islands, with different effects on the two islands. In A a sheet of water sweeps completely across the barrier, carrying sand onto the backshore and into the lagoon. A relatively uniform overwash layer has been spread over the island; the beach has retreated. In B, however, the storm resulted in massive erosion of the beach and dune line. The storm waves piled up against the dune-dike and finally broke over the top. The resulting torrent severely damaged the rear of the dune, buried the road deep in sand, and eroded the back of the island as it swept across.

8. Following the storm, the islands are very different. In A, all signs of the storm are gone. All vegetative zones have redeveloped on the overwash layer, including a new salt marsh. New dunes are forming on the beach. The main change is a slight retreat of the barrier. In B, massive projects, at great cost, are underway to rebuild the barrier in the same place. A beach nourishment project is pumping sand from behind the barrier to rebuild the beach and the dune. (Such lagoon-side dredging operations for fill are no longer carried out on National Park Service land because of the ecological damage to the lagoon and the generally poor quality of the sediment. Recent nourishment sources have been accreting spits or inlets.) Once the dune has been built, it will be grassed. Even though the beach has been temporarily restored, the next storm will create difficulties again. Because of the lack of overwash sand, there has been no backshore elevation increase nor any sediment for new marshes in the lagoon. The edge of the marshes continues to erode. More and more effort will be needed to maintain B, while A will continue its natural cycle in equilibrium with the oceanic forces.

The main point is not to try to fight the dynamic nature of barrier-island systems but to accept the fact that the sea level will go on rising and the islands will continue to roll back, eroding here and accreting there. These islands are no place for permanent, expensive structures, which instead belong on the mainland. Anything built on the islands should be in a sheltered, accreting area or up on pilings or both, and in any case should be simple, cheap, and expendable, and possibly movable. The only roads should be sand roads, and these should be planned so that they do not become overwash channels.

The natural stability of some islands has already been destroyed; for example, Portsmouth Island is a low, bare flat which overwash erodes rather than builds up. In such cases a program of grass-planting could help a great deal. Spartina alterniflora would be appropriate where the bare flats are intertidal, and S. patens and Uniola on higher ground. New dunes should be built not in a solid line but scattered so that overwash water may flow between. It would be best to use native grasses and allow natural succession to take place, so that fertilizing and insect control will not be needed.

Returning artificially stabilized sections of National Seashores, such as Cape Hatteras, where long lines of vulnerable barrier dunes have been built, to the natural flexibility of wild barrier islands may be more difficult and is certainly more controversial. However, such a policy is feasible along certain undeveloped sections where the highway is far from the beach. In these areas, natural breaks through the dunes can be tolerated. Once overwash occurs, there need not be an immediate rush to fill the gap artificially. Instead, allow natural revegetation of the overwash fan or, if necessary, plant grasses on the overwash deposit so there will be vegetation and small dunes to slow down the next storm surge. The basic philosophy is to allow a natural, irregular dune line with overwash passes to develop. This is not to suggest that the practice of maintaining dunes be abandoned entirely, but rather that it be modified to follow natural patterns.

On some islands there is already expensive or historically interesting development which it is considered necessary to protect. It is hard to make recommendations for protection which will not lead to more trouble in the long run, and one should consider carefully whether the expense of protection is really justified. If beach nourishment is considered necessary—and it should be avoided as much as possible—the sand should be taken from an accreting section of the beach itself, not from the sounds; nourishment will be a short-term solution at best. Sea walls, etc., can be built if one is willing to spend the money, but if an isolated location is thus reinforced and the rest of the system is allowed to retreat naturally, the final result will be a fortified island at sea, with the rest of the barrier migrating away. In some cases it might be cheaper just to move everything back away from the beach. Paved roads, where we must have them, will simply have to be cleared of sand when necessary, and eventually moved back along with the buildings. Groins are too often a snare and a delusion and should be avoided unless one is quite sure what their effect will be and that it will be useful.

The importance of inlets to the maintenance of the islands and sounds has been mentioned; the creation of new inlets for navigation may be quite acceptable ecologically. The sand removed, however, should be added to the littoral drift or should be spread out at the right level in back of the islands and planted with Spartina alterniflora, such as was done when the U.S. Army Corps of Engineers opened the new Drum Inlet in 1971. This latter is also the best thing to do with spoil from dredging channels; to put such fine-grained material on the beach is to waste it.

Livestock and other undesirable feral animals should be removed from the islands where they remain. If feral horses are considered esthetically desirable, the size of the herd should be kept well within the carrying capacity of the land.

Recreation on the barrier islands will have to be compatible with the island environment; trying to make the islands meet all desired uses will destroy the resource. It also should be recognized that not all types of recreation can be pursued at the same time in any given place. For instance, there are those who would be angered if not allowed to use the barrier beaches solely as a highway for beach buggies. On the other hand are those who cannot be happy except on a pristine strand devoid of any evidence of man, even their fellow purists. Surf fishing, swimming, and surfing are all healthy outdoor sports, but they cannot be safely combined on the same beach. Perhaps different times and places should be allocated to different groups of users, the philosophy being "each to his own within the limits of the environment."

Off-road vehicles are often damaging to barrier island ecosystems and their use should be closely supervised on the islands. There should be requirements that all vehicles taken out to the islands must be returned. Bridgeless, roadless islands should be kept that way, and some system of public ferries and over-sand transportation should be devised to transport visitors with minimum ecological impact. All vehicles, public or private, should be strictly limited as to where they may be driven and should be prohibited from bird rookeries and feeding areas, as well as from beach vegetation.

The abandoned cars already on the islands, the shacks, and as much solid waste as practical should be removed, which will be quite an undertaking. Perhaps a program of public education would encourage people to be more careful on the islands and to locate mainland dumps out of reach of high tide.

Camping on the Outer Banks will present problems during insect season, which is nearly any time but winter. To help relieve pressure for spraying programs, which we consider ecologically unacceptable, camping areas should be located where the prevailing winds will tend to blow away the insects, and visitors should be warned of the situation.

Finally, and perhaps most importantly, while we allocate pieces of the islands to various purposes, we should not forget to set aside substantial areas as wilderness. The most representative and undamaged examples of each habitat type should be included. Such a plan is perfectly compatible with the Recreation Area concept when we consider that wilderness sections will be available for comparison with the parts of the islands we are using. Thus we can determine whether we are damaging either the recreational resources or the general health of all the various ecosystems associated with barrier islands.

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Last Updated: 21-Oct-2005