A modeling-based assessment of tidal inlet classification

Abstract

The economical and ecological importance of tidal inlets have fostered the development of empirical tools for inlet management during the last century. This study aims at confronting these empirical theories with recent process-based numerical models. The 2DH process-based morphodynamic modeling system MORSYS2D is applied to an idealized tidal inlet/lagoon system with six different combinations of significant wave height, tidal range and tidal prism. The model predictions are compared to natural morphologies and then to the empirical models of Hayes, O’Brien and FitzGerald. The results present good accordance with observation as well as with some key behaviors predicted with the empirical theories. The predicted morphologies satisfy the relation of O’Brien between the tidal prism and crosssectional area, model results reproduce the conceptual model of sand by-passing of FitzGerald and the energetic classification of Hayes is partly respected. However some inconsistencies between model results and Hayes prediction appears, which highlights the limitations of the classification, that only considers the yearly-averaged significant wave height and tidal range.