ABSTRACT:

Vegetation patches are commonly found in channels with high-permeability beds, such as gravel channels, floodplains, and wetlands. The current knowledge on patch-scale hydrodynamics is largely based on the assumption of impervious bed. It has been shown that the hydrodynamic characteristics of the river channels without vegetation are affected by bed permeability. The aim of this study is to reveal the effect of bed permeability on the hydrodynamic characteristics of vegetated channels and its mechanism. A Laser Doppler Anemometer (LDA) was used to investigate the wake structure of an emergent vegetation patch over a high-permeability bed.