Coupled barrier island-resort model: 2. Tests and predictions along Ocean City and Assateague Island National Seashore, Maryland

The fate of coastlines and their human settlements under the effects of global climate change will depend critically on the nonlinear dynamics of and feedbacks between shoreline processes and human agency. This hypothesis is explored on the barrier island coastline of Ocean City and Assateague Island National Seashore, Maryland, using a model-coupling natural coastal processes, including erosion, accretion, island overwash, alongshore sediment transport, dune growth and migration, inlet migration and ebb tidal delta growth to economics of tourist resort development through storm damage and beach and dune replenishment. Initiating the model in 1845, the RMS difference between model and measurements of the shoreline position in 2001 is 84.97 m compared to a net onshore migration of 472.2 m and the RMS difference between modeled and measured hotel room density in 2001 is 2950 rooms km(-1) compared to a net gain of 28,824 rooms km(-1). Simulations to year 3400 for a rate of sea level rise of 3.5 mm a(-1) show a steady state barrier island position 158 m further offshore and 0.54 m lower in elevation compared to its natural counterpart. Changing the rate of sea level rise to 10.5 mm a(-1) increases these differences to 288 m and 0.76 m. Changing storminess by increasing the standard deviation of storm size 50% diminishes coupling between resorts and barriers, bringing the natural and coupled attractors into near coincidence. These results suggest that predicted increases in the rate of sea level rise will lead to enhanced vulnerability for Ocean City.