Erosions

Erosion is a process by which a coastal landscape is altered, mainly through the removal of existing sediment. Sediment reduction in a coastal system is caused by many factors including natural processes like storms, winds, sea-level change, and human activities.

The Eastern Seaboard of the United States is an eroding coastline constantly changing and being reshaped by storms, wave action, and rising sea levels. The Atlantic coast, which accounts for 27% of the nation’s coastline, is eroding at an average rate of 2-3 feet per year. Along the Gulf coast, erosion of the coastline is roughly 6 feet per year (Stewart, 2009). Louisiana is an extreme case with shoreline recession at a rate of 50 feet per year (Stewart, 2009). The majority of this erosion is from wetlands and barrier islands, the loss of which can raise the risk of damage from storm events (Sullivan, 2005).
Coastal erosion and deposition are caused by three interrelated

1. the amount and type of sediment within a coastal area
2. the storm and weather, and wave/tide patterns;
3. changes in sea level

The shoreline recedes when the forces of erosion exceed the amount of sediment supplied to the coast. The greater the deficiency of sand, or the higher the wave forces, the more rapid the rate of erosion. Any of the three factors (storm frequency and energy, sediment, sea level) can vary through time and change the balance. Beach erosion is, however, a natural process and becomes a problem only when man's structures are placed in the path of shoreline recession. Storms alone are not responsible for long-term beach erosion; most beaches can recover in 4-5 years following a storm of any severity (Zhang, Douglas, & Leatherman, 2002).

Human interference in coastal erosion more often leads to long-term erosion, which through time increases the vulnerability of property to storm damage in later events.