". . . like a foolish man who built his house upon the sand. And the rain descended and the floods came and the winds blew and burst against that house and it fell and great was its fall." Matthew 7: 26-27 (NAS)
In 1996, the nation's attention was seized by one of the most lopsided contests ever covered by the news media. It was not the title bill in some Las Vegas arena, it was Hurricane Fran vs. Topsail Island, NC. This small island off the coast of North Carolina, less than ten feet above sea level, was swept from end to end by a twelve foot storm surge generated by Fran. The devastation and the community's subsequent efforts to rebuild were feature stories on nightly newscasts and in editorials. Once again, the relationship between humans and the environment was the subject of debate and discussion nationwide.
The coastal zone of the U.S. (which includes barrier islands and the coastal plain that lies behind them) is home to nearly two-thirds of the population; and barrier islands such as Topsail make up eight of the shoreline of North America. The barrier islands have been valued as hunting grounds, fisheries, agricultural lands, and, most recently, as recreation areas. What is it about barrier islands that makes them so important to coastal communities?
The continental coastlines are dynamic areas where three environmental zones - land, air and water - come together. The processes that shape the features of the coastlines are powerful and relentless. With storms like Fran and with the everyday rush of tides, the landscape is constantly being remade. Yet, one of the most striking features of the coastlines of North America is the slender, fragile-seemingly slivers of sand and vegetation that form the barrier island system along the Atlantic and Gulf Coasts. Stretching 2700 kilometers from Fire Island, New York, all the way to Padre Island, Texas, this chain of islands has been the scene of a geological and biological drama for centuries.
At the end of the last ice age, the water flowing into the oceans from the retreating ice caps and glaciers caused a steady rise in sea levels, flooding coastal river valleys as the oceans advanced inland. It is thought that the first barrier islands along the Eastern United States formed on the higher ground which once surrounded the now-drowned river valleys. Today, barrier islands are built and maintained by the complex interaction of rivers, sediment, ocean currents and wind. The rivers bring sediment from inland areas. Ocean currents move and deposit it along the coast, and winds build the deposited material into dunes. If they are stable enough, the dunes may be colonized by a variety of plants whose roots help anchor the dunes in place and resist the erosional action of ocean tides and storms. In the end, it is usually the sea that seems to "win," eroding the islands away. However, the very forces that wash the sand away from the islands are the same forces that deposit it elsewhere, and island-building process begins anew.
Before European settlement, Native Americans harvested the abundant terrestrial and marine resources found on barrier islands. When the Europeans began settling the coasts, they used the islands primarily as pastures for their animals. In the late 1600's and early 1700's, the islands were notorious as the haunts for pirates. But it wasn't until the 1900's, particularly after World War II, that intensive development began on the islands. The barrier islands provided amazing recreational opportunities, and by the 1980's, 6,000 acres of barrier island land a year were being lost to development.
Because of these characteristics, the barrier islands are the "young and restless" of the coast: young geologically (the Outer Banks in North Carolina are less than 5,000 years old) and restless (always shifting and sliding in response to the ocean currents, winds and the available sediment). For example, the barrier islands comprising the Virginia Coastal Reserve have moved 100 kilometers west over the last 10,000 years. Hog Island, in this reserve, is losing five meters of shoreline a year on the southern end, while it is growing on the northern end at a rate of more than five meters a year. Because of the dynamic nature of barrier islands, researchers that work there have referred to them as "high speed real estate."
Despite their seemingly transitory existence, these barrier islands are an important part of the coastal zone. About one-half of the 20,000 known species of fish feed or reproduce in the coastal zone. The barrier islands also protect the productive marshes and estuaries from the ocean's energy, while still allowing the renewal of the nutrient base as the ocean waters pass through inlets and breaches.
The barrier islands are instructive examples of the importance of scale in environmental problems. Viewed at the local scale, groins may be effective at reducing beach erosion; from the regional scale, groins may have exacerbated the regional erosion problem. Most environmental problems require scientists, mangers and local stakeholders to look at many levels of a problem before environmentally and economically responsible decisions can be reached.
While the engineering required to build homes on islands is fairly well-understood, there is no engineering that can permanently change the basic nature of the barrier islands. People want to build on the islands because of the tremendous recreational opportunities available there, and they continue to maintain their own property even when they are fully conscious of the personal and property risks they are facing. In the past, these risks have been easier to absorb because property owners on these islands have been eligible for federal emergency aid and for subsidized flood insurance. With the new legislation, land owners on these islands are concerned about their ability to protect their assets and their rights to develop their land.
Many advocates of coastal zone development point to engineering structures such as groins (rock jetties extending out into the ocean) and seawalls as possible answers to barrier island stabilization problems. Groins preserve beaches by interrupting offshore currents and by causing more sand to be deposited behind the groin. Seawalls, at least in theory, block the erosive action of the waves on beaches. Groins can be very effective locally in maintaining beaches; the effectiveness of seawalls is more difficult to evaluate. Both offer benefits in saving the functional usage of island barriers for the environment.
The USACE and beach "nourishment"- The U.S. Army Corps of Engineers spends millions of dollars annually to dredge offshore sand and transport it to beaches to combat erosion. Such projects, as the Miami Beach restoration, help protect beaches and coastal property which may be very important to local economies. However, there is no clear evidence that most of these projects stabilize beaches in the long term.
Many taxpayers think it is wasteful for tax dollars to pay insurance claims for individuals who build homes on such unstable landscapes. This view is increasingly shared by the federal government, which has been gradually limiting its involvement in insuring these flood and storm-prone properties (see regulations).
Critics of groins consider them extremely damaging to beach areas down current of the groin. While the local area around the groin may become more stable, all of the beaches and islands in an area draw from a common "sand savings account" for replenishment. Artificial stability in one area may result in increased erosion in another. Once groins are constructed, down current areas may build groins to try to stabilize their eroding beaches and the process repeats itself up and down the coast. Assateague Island, famous for its wild ponies, has seen its shoreline erosion rates accelerate to seven meters a year in places. Some researchers believe this is the result of upshore jetties placed at Ocean City, Virginia. Critics of seawalls believe that these structures actually increase erosion by preventing sand replenishment. When storms wash the sand away, the sand may accumulate in sand bars offshore and slowly wash in. Seawalls may interfere with this process.
The cost of restoring a beach is up to 1 million dollars per square mile. Part of restoring the Miami Beach, Florida project cost 60 million dollars. With many of these restorations, a series of storms may undo millions of dollars worth of work in a few months. Other Corps activities, seemingly unrelated to the coastal zone, may also have a negative effect on barrier islands. Some researchers think that the levees and flood control structures maintained by the Corps along the Mississippi are interfering with sediment transport in river. As a result, many gulf barrier islands are "under-nourished' and may become unstable.
In response to a growing concern about the health of the barrier island system, Congress passed the Coastal Barrier Resources Act in 1982. This act protected 453,000 acres of undeveloped barrier islands; an additional 700,000 acres were added in the Coastal Barriers Improvement Act in 1990. Perhaps, the most important piece of legislation was tucked into the larger Budget Reconciliation bill in 1981. In that bill, Congress was prohibited from issuing flood insurance to new developments or "substantially improved" property on barrier islands. Without guaranteed insurance, fewer developers were willing to risk building on the islands.
Information on how ecosystems, like barrier islands, function can be found on pages 29-40. Consult the fold-out map (beginning on page 42) in the text to see a good pictorial representation of how the terrestrial and oceanic zones meet to form the coastal zone. Chapter 17 gives a good overview of public policy issues and how public, private and governmental groups seek to solve problems.
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