Effects of hypsometry on the morphodynamic stability of single and multiple tidal inlet systems

The advection of the depth-averaged along-channel momentum results in an extra term in the momentum equation. The joint presence of hypsometric terms and this new term instigates a shift of the stable equilibrium cross-section to smaller values. The sole effect of the hypsometry of the inlet cross-section is a larger amplitude of the tidal current, causing a shift of the stable equilibrium cross-section to higher values. Similar conclusions are found in the case of a double inlet system. For this configuration also multiple stable morphodynamic equilibria are found, which strongly depend on the cross-sectional area above the topographic high. It further turns out that the morphodynamic equilibria are sensitive to changes in parameters that break the symmetry of the system, viz. the ratio of the surface areas of the back barrier basins, the ratio of the inlet lengths, the phase difference of the tidal wave and the cross-channel bottom slope of one of the inlets.