Morphodynamic modeling of tidal inlets and embayments

Abstract

Tidal inlets and embayments constitute navigation routes and they control the stability of adjacent shorelines and the exchanges of water, sediment and dissolved material between the ocean and back-barrier lagoons. Tidal inlets are thus of critical and growing socio-economical and environmental importance worldwide. They are often exceptionally dynamic, due to the combination of tide- and wave-driven processes. This intense dynamics drives fast and large morphological changes, which make their behavior hard to predict and their sustainable management difficult to achieve. To address this problem, the development of morphodynamic modeling systems has emerged over the last decade as the most promising perspective to understand their behavior and predict their evolution. Morphodynamic modeling systems, whose development and successful application to tidal inlets has been growing over the last decade, couple a set of modules to simulate hydrodynamic circulation, wave propagation, sediment transport and bottom evolution. This chapter provides in introduction a synthesis of the existing quantitative methods to investigate tidal inlets and points out the advantages and limitations of morphodynamic modeling systems compared to physical, empirical and analytical models. The next section describes the main principles of morphodynamic modeling systems and explains how the different modules are coupled together. The following section illustrates through three selected applications the capabilities of morphodynamic modeling systems to simulate morphological changes of tidal inlets at various time scales, but also to investigate the mechanisms that control their development. The final section provides some conclusions and perspectives regarding the morphodynamic modeling of tidal inlets.