Modeling tidal dynamics in a mangrove creek catchment in Delft3D

Modeling tidal dynamics in mangroves is of great use in studying the effects of changes in e.g. vegetation cover or tidal forcing. Process based models, taking into account vegetation drag and turbulence, have not yet been applied to study tidal dynamics in mangrove forests. We compare three different model representations of vegetation in Delft3D-FLOW for their accuracy and efficiency in modeling tidal dynamics in a schematized mangrove creek catchment: (i) a threedimensional model taking into account vegetation induced momentum loss and turbulence generation and dissipation (3D-DPM); (ii) a two-dimensional depth-averaged model taking into account the vegetation induced momentum loss (2DH-DPM); and (iii) a two-dimensional depth-averaged model applying an adjusted bed roughness and an artificial term for momentum loss (2DH-Baptist). All models predict flow velocities, suspended sediment concentrations and sediment deposition rates of the same order of magnitude as observed in the field. Compared to the 3D-DPM model which resolves all vegetation impacts, the 2D-DPM model predicts resembling hydro- and sediment dynamics, but at a significantly increased computational efficiency. This efficiency is useful when modeling real mangrove wetlands, requiring high grid resolution due to great spatial topographic variability. Increased model efficiency also enhances the feasibility of sensitivity analyses of the short- and long-term development of mangroves under changing conditions.