Distinct patterns of interactions between vegetation and river morphology

Modelling vegetation and morphodynamics is often one-way traffic that either takes into account the effect of vegetation on morphodynamics or vice versa. The few models that do incorporate an interaction have until now represented vegetation as cylinders causing hydraulic resistance that do not change over time. We coupled a morphodynamic model to a dynamic vegetation model, tested two vegetation scenarios with different functional trait sets and compared them to a control scenario without vegetation. Vegetation was modelled as either static softwood forest or dynamic riparian trees of different age, dimensions, density, settling conditions and flooding/desiccation tolerances. Results show that vegetation restricts lateral migration and static vegetation also restricts longitudinal migration. Dynamic vegetation results in more realistic vegetation patterns and fluvial morphology than static vegetation. This shows the importance of including dynamic vegetation in morphodynamic models.