Effect of vegetation on hydromorphodynamics

Vegetation can influence river hydrodynamics by changing the turbulent flow field and the averaged velocity profiles in comparison with those that can be commonly found in non-vegetated flows. In this way, vegetation potentially has a relevant effect on flow resistance, sediment transport and bank dynamics (see Table 1).

Table 1. Models for the effects of vegetation on hydromorphodynamics.

Vegetation and flow resistance

Table 2. Summary of model characteristics on vegetation and flow resistance.

Future research is needed on the following topics:

- effect of different types and growth stages of vegetation (rigid or flexible) and different vegetation densities on flow turbulence structure and secondary currents of a stream;

- effect of plant reconfiguration with increasing flow velocity on drag;

- effect of the spatial distribution of vegetation at a reach scale on flow resistance;

- uprooting, breakage of plants during high-flow conditions may give rise to significant changes in flow resistance between the rising and falling limbs of the hydrograph;

- develop suitable parameterization to characterize different species.