Types of Coastline
The "type" of beach also plays a role in determining if and how the shoreline will be affected by erosion, and North Carolina has a variety of different coastal areas.
Barrier Islands are found on coastlines all over the world, but are most noticeable along the eastern coast of North America, where they extend from New England down the Atlantic Coast, around the Gulf of Mexico and south to Mexico. North Carolina is home to one of the longest strings of barrier islands on the East Coast, beginning with the Northern Outer Banks, extending through Cape Lookout National Seashore, and culminating at the Southern Cape Fear region at Wilmington. Most barrier islands are popular vacation spots and are home to a number of vacation homes and properties. However, these islands are fragile, constantly changing ecosystems that are important for coastal geology and ecology. Development has posed dangers to these ecosystems and has also increased the risk of property damage every year from hurricanes and Nor'easters.
Barrier islands are long, narrow, offshore deposits of sand or sediments that lie parallel to the coastline. Some barrier islands can extend for 100 miles (160 kilometers) or more, and the islands are separated from the mainland by a shallow sound, bay or lagoon. Barrier islands are often found in chains along the coastline and are separated from each other by narrow tidal inlets.
The formation of barrier islands is complex and not completely known. The current theory is that barrier islands were formed about 18,000 years ago when the last Ice Age ended. As the glaciers melted and receded, the sea levels began to rise and flooded areas behind the beach ridges at that time. The rising waters carried sediments from those beach ridges and deposited them along shallow areas just off the new coastlines. Waves and currents continued to bring in sediments that built up, forming the barrier islands. In addition to this process, rivers washed sediments from the mainland that settled behind the islands and helped build them up.
Barrier islands consist of three parts, including the beach, the dune, which protects the rest of the island from the beach and is naturally stabilized with plants, and the barrier flat, or the backbone, which is the remaining part of the island. Formed by sediments that get pushed through the dune system by storms, such as hurricanes, grasses grow and stabilize these areas. Barrier islands also serve two main functions. First, they protect the coastlines and mainland from severe storm damage. Second, they harbor several habitats that are refuges for wildlife.
Some wave-dominated coasts do not contain estuaries and have no barrier island system. These coasts, however, do have beaches and dunes and may even have coastal marshes. The term "strand plain" has been applied to coasts of this sort. Examples include parts of western Louisiana and eastern Texas. In most respects, they are similar in morphology to barrier islands, but simply lack inlets.
North Carolina is also known for its miles of wetlands, from the sound surrounded areas off Roanoke Island and Manteo, to the miles of wetlands that play a key role in attracting birds to the Pea Island National Wildlife Refuge north of Rodanthe, to the miles of scenic wetlands just south of Cedar Island. Because the North Carolina coast is dominated with barrier islands and inlets, wetlands thrive in this coastal environment.
A wetland is an area between dry land and water that is regularly saturated with surface or ground water. In fact, it is inundated with this water so consistently that vegetation and animals that thrive in wet conditions take up residence there. Wetlands host a wide variety of plant and animal life. They also provide water storage and filtration, and give mainland areas protection from floods.
Many of North Carolina's coastal wetlands are flooded on a regular basis from storm surges from sounds, rivers and inlets, but this helps the wetlands thrive. Composing of species that don't mind the salt and freshwater mix, wetlands perform very well with a salty marsh base and a fresh rainfall. Because of our climate and the nature of our coastline, wetlands are common and do very well in North Carolina.
Unfortunately, the main threat to our wetlands has nothing to do with natural erosion, but with human interference. Up until the mid-1980s, wetlands were viewed as wild areas that needed to be controlled. The U.S. Army Corps of Engineers spent a lot of time draining wetlands for future development or agriculture, and even today, new coastal developments are filling in wetlands to make room for new communities. This is treacherous to our coastal environment for a number of reasons. These new communities displace countless species of wildlife that formerly lived in the wetland area, and because these areas have a history of being flooded, homes in these communities are in a precarious position from the day they are built. In addition, flood waters that used to simply seep into the wetlands and intermingle with the marshy areas are displaced as well, and may affect and flood other neighboring communities.
During the 1970s, people did begin to recognize the benefits of wetlands, and beginning with The Clean Water Act of 1972, the U.S. Federal Government began instituting a series of laws and acts that would protect wetlands from further degradation. Unfortunately, the majority of wetlands in this country are located on private land, so the government can only do so much, and North Carolina's wetlands continue to deteriorate as new coastal communities are built.