Erosion of the Long Island Shore Line
In the United States, extensive barrier beach systems occur along major portions of the Atlantic and Gulf coasts. These fragile coast lines are in a continual state of flux. Beach erosion and accretion can result from both natural and man made causes. Sea level change, storms, and development may all significantly impact these environments. On Long Island, New York, beach stabilization has repeatedly been attempted. Such efforts typically meet with varied success. In fact, many believe that the island's past stabilization projects have actually contributed to its current erosion problems. Geologically, Long Island consists of moraine sediments deposited by glacial drift. This mixture of crystalline gravel and boulders was scraped up in New England, carried several miles, and then dumped along the glacier's frontal margin. The northern coast of the island, which borders on Long Island Sound, consists of long sandy beaches, marshes, and harbors. In contrast, the south shore stretching 120 miles from Mantauk Point to Norton Point, Coney Island contains both headlands and beaches. The headlands occur along the island's eastern 30 miles; whereas, the sandy barrier beaches with their lagoons are further south (U.S. Army, 1936, p. 4).
Over the years, the Long Island has undergone considerable erosion. This phenomenon, however, is not restricted to New York. Coastal erosion is generally occurring on a global scale. For example, along northern New Jersey, 11 shore line surveys were conducted between 1853 and 1985. Analyses of that data has revealed that the area's beaches are retreating at a mean rate of 0.8 meters/year (Gorman & Reed, 1989, p. 122). Invasion of the land by the sea, or marine transgression, may occur as a result of either sea level rise or coastal subsidence. It has been estimated that mean sea levels in the United States are rising at a rate of ab...