File:COUPLED, HIGH-RESOLUTION STORM SURGE MODELING OF AN INLET SYSTEM (IA coupledhighresol1094561254).pdf

Model simulations using an ocean circulation model (ADCIRC) coupled with a wave model (STWAVE) are compared to observations made in the shallow, two-inlet tidal system Katama Bay during Hurricane Irene. Integrating high-resolution grids of this system with the North Atlantic Coast Comprehensive Study (NACCS) performed by the United States Army Corps of Engineers enabled a study of the effect on storm surge modeling accuracy of boundary condition representation of ephemeral inlets and wave model coupling. The high-resolution coupled model reduced error by over 20 percent compared to the NACCS during the peak storm surge period, representing a 14 percent improvement over the high-resolution circulation model simulation alone. Contrary to prior research that shows a lack of setup in the Katama Bay system from wave forcing, this research shows that in extreme wave forcing events, the flux through the Edgartown Channel cannot provide an adequate drainage path to prevent an increased water elevation in the bay. Furthermore, the presence of Katama Inlet in the south enhances the velocity along the entire southern part of Martha’s Vineyard during peak storm conditions by more than a factor of two, highlighting the need for adequate model resolution for local storm surge predictions.