Empirical Geomorphic Approach to Complement Morphodynamic Modeling on Embayed Beaches

In a coastal engineering project, hydrodynamic models are used to study wave transformations and impacts on structures, while morphodynamic models are applied to calculate the response and evolution of sedimentary beaches. Conventionally, laboratory experiments and numerical modeling have been called to investigate beach changes, particularly those resulting in the formation of an embayed beach. The former is undertaken in a wave basin, necessitating a huge outdoor facility to fit a project with large dimensions, numerous instrumentations, and manpower, while the latter is performed by powerful numerical models on a desktop, requiring only the advent of computing power and professional skills. Conventionally, both approaches have successfully achieved the expected outcome, though differing in cost and time frame. On the contrary, an efficient empirical geomorphic model for headland-bay beaches has been available since 1989 for assessing the planform stability of a crenulated beach in static equilibrium. The model can readily produce a graphic display of the static bay shape aided by a supporting software within a shorter time frame (in a couple of minutes), instead of in hours or days in laboratory tests and numerical modeling. Several practical examples drawn by the software MeePaSoL for the empirical model are presented to complement the results of a morphodynamic model in a wave basin, as well as to guide the modeler to terminate the programming when equilibrium is reached. We believe this alternative approach could be helpful for the experimentalists and numerical modelers on large engineering projects associated with shoreline beach evolution and shore protection, especially for time-saving and reducing manpower and cost.