Mesoscale Model for Morphologic Change at Tidal Inlets

Abstract

A mesoscale modeling system (time step of hours, space step of 100 m) for bathymetric change at tidal inlets is described. The Mesoscale Inlet Morphology modeling system is composed of a linked two-dimensional (depth-integrated) hydrodynamic module, a wave transformation module, a shoreline change module, and a sediment transport module. A hybrid modeling scheme is employed, featuring a microscale (time steps of minutes) hydrodynamic module within a mesoscale model. Sediment transport is assumed to be as bed load outside of the surf zone, driven by the mean wave- and tide-induced flow. The Mesoscale Inlet Morphology modeling system was applied to Price Inlet, S.C. A two-year simulation of the morphologic changes at Price Inlet was performed using measured wave data and tidal stages predicted from harmonic analysis coefficients, and results compared to measured bathymetric and shoreline changes. Predicted bathymetric changes are similar in sign and location to observations, but the model tends to underpredict the magnitude of the changes. Predicted shoreline changes exhibit similar trends.