Erosion of Shorelines Essays

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Erosion of Shorelines The erosion of shorelines is a natural process that can have beneficial or adverse impacts on the creation and maintenance of habitats. Sands and gravels eroded from the shores of coastal bays maintain the beach as a natural barrier between the open water and coastal wetlands. Beaches move back and forth onshore, offshore and along shore with changing wave conditions. The finer-grained silts and clays derived from the erosion of shorelines are sorted and carried as far as the waters of wetlands or tidal flats, where benefits are derived from addition of the new material. However, excessively high sediment loads can smother submerged aquatic vegetation beds, cover shellfish beds and tidal flats, fill in riffle…show more content…
The longshore drift shapes the coastline by carrying sand from sites of high wave activity to those of low wave activity. The volume of sand carried away from or delivered to different points along the coast can be as much as 2,000 cubic meters per day (71,000 cubic feet), enough sand to fill an Olympic-sized swimming pool (Nepf). The seepage of ground water and the overland flow of surface water runoff also contribute to the erosion of shorelines (http://www.epa.gov/OWOW/NPS/MMGI/Chapter6/ch6-4.html). The role of ground water is most important wherever permeable subsurface layers of sand are exposed in high bluffs along coastal bays. In these areas, the seepage of ground water into the waterway can cause erosion at the point of exit. The surface flow of upland runoff can also dislodge sediments through the creation of rills and gullies on the shoreline banks and bluffs (http://www.epa.gov/OWOW/NPS/MMGI/Chapter6/ch6-4.html). Some amount of natural erosion is necessary to provide the sediment for beaches in estuaries and coastal bays. However, excessive erosion has occurred in the past due to development. Industrial and private development along the world’s coastlines has increased dramatically since the 1970s (Nepf). Developers and builders completed much of this construction without taking into account the effects of coastal erosion. New buildings were often placed too close to the existing shoreline so that

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