Shoreline Evolution of North Assateague Island, Maryland

Leatherman, Stephen

A shoreline mapping procedure, termed metric mapping, has been recently developed in order to quantify historical shoreline changes with high accuracy (meets or exceeds national Map Accuracy Standards) and relatively low cost. The Atlantic coast of Maryland is split into two different types of shore management zones.The entire Maryland portion of Fenwick Islandhas become urbanized with the development of OceanCity, Maryland, while the remaining two-thirds of thecoastline (Assateague Island) has remained in a morenatural state as coastal parklands (Fig. I). These twocoastal sectors are also physically separated by theOcean City Inlet jetties, which have served to compartmentalizea system that was previously connectedby longshore sand transport.While the present shoreline situation at Ocean City,Maryland has been recognized, the evolution of thenorthern portion of Assateague Island has been largelyoverlooked. Following stabi lizat ion of Ocean CityInlet, Maryland with jeu ie in 1934-5, there has been apronounced alteration of the adjacent shorelines. Updriftof the jetties at south Ocean City, a large amountof sedimentation has occurred. This shoreline progradationhas necessitated the lengthening of theOcean City fishing pier, and the north jetty isimpounded to capacity.A large portion of the sand moving southward in thelittoral drift system is being swept seaward by the ebbtidal jet to form an enormous shoal (estimated volumeof 8,000,000 cubic yards)." The average annual netlongshore transport is estimated to be 150,000 cubicyards to the sout h.'? Since little of this sand is presentlybypassing Ocean City Inlet and reaching Assateague,the northern portion of this island is being sedimentstarvedand driven Ia nd wa rd." This area probablyrepresents the most severe case of downdrift beach erosiondue to shoreline engineering structures along theU.S. coast.

Shoreline Evolution of North Assateague Island, Maryland

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