The Need for Sand in Ocean City, Maryland
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Along Maryland's Atlantic coast, sand is carried by currents and wind in a north-to-south direction along the beaches. Also, sand moves on and off the beaches seasonally. In the summer, sand moves onto the beach and is stored in dunes. During the winter months, sand migrates off the beach and into sand bars beyond the breakers. The net direction of sand transport is from Delaware, in the northeast, to Virginia, in the southwest. Anything that interrupts the natural flow of sand will cause accelerated erosion. Additionally, Maryland's barrier islands are slowly migrating westward as sea level rises. Development on Fenwick Island has modified cycling of sand on Maryland's coast. A natural dune system no longer exists in Ocean City. In the past, development was permitted up to and beyond the natural primary dune line. This practice essentially removed seasonal dune storage from the cycle. Beach stabilization structures such as groins were place along the beach to retard the southwestward movement of sand. Again, the natural flow of sand was interrupted. The net result of these actions was to accelerate the movement of sand off the beach, and increase the barrier island's rate of landward recession. Additionally, the potential for accelerated sea level rise over the next century posses a further threat to infrastructure stability.
Ocean City Inlet formed during a hurricane in 1933. The jetties built in 1934-35 to stabilize the inlet interrupt the natural flow of sand to northern Assateague Island by trapping sand in shoals around the inlet. The barrier islands' westward progression is shown by superimposing shoreline maps from the last 100 years. The exaggerated recession of northern Assateague Island is apparent from these maps.
To prevent further erosion to the beaches, and costly damage to Ocean City homes and businesses, the U.S. Army Corps of Engineers initiated a study to determine the feasibility of a beach replenishment and protection project for the region (U.S. Army Corps of Engineers, 1980). The study concluded that the most practical and efficient method to protect the island would be to widen the beach and create an artificial dune, with sand dredged from shoals located within state waters. Periodic replenishment of beach sand with offshore sands would be required every four years to maintain the new beach geometry. This study led to the Ocean City beach replenishment project.