Coastal erosion and weathering are natural processes that occur along all shorelines. Breaking down and removal of sediment is a constant process. These processes may become destructive to an island or beach if the rate of erosion increases and new sediment is not deposited fast enough to replace it.
Waves cause much of the weathering to coastal rocks. Constant motion against these rocks carve out sediments from rocks and remove sand. Rocks made up of different types of materials will weather at different rates, creating interesting structures.
Tides occur as a result of the moon's gravitational pull. Each day, the tide rises and falls. This constant change of water level erodes the beach and breaks down other materials, such as rocks and vegetation.
Longshore drift is the process that transports sediments along the beach. Waves approach the beach at an angle and pick up sediment. They retreat horizontal to the beach and redeposit the sediment during the next approach. This zigzag motion constantly moves sediment south along the coast.
Creation of Sand Bars
Other sediment is deposited offshore. This can build up and create formations parallel to the coast known as sand bars. Sand bars that grow large may become permanent barrier islands.
Factors That Increase Erosion
Climate change, storms and man can affect the rate of erosion. Storms can remove large amounts of sediment at one time. Man-made structures on the beach can interfere with the normal longshore drift process. This prevents new sediments from replacing removed sediments.