Large-Scale Outdoor Flume Experiments for Interactions Between Flow, Sediment and Vegetation

Feedback between turbulence, sediment transport and morphology is important for natural stream managements. While experimental studies have focused on the mean flow and turbulence with mimic vegetation such as cylinders and bamboo sticks, this study presents preliminary results of mean flow, turbulence and morphological changes in the large–scale outdoor channel with real willow patches, consisting of foliated and leafless vegetation. The mean flow showed the steady wake regions and the velocity gradient near the interface between the vegetation patch and free stream. The large momentum exchange occurred at the shear layer where the Reynolds stress was elevated and it was consistent with enhanced regions of sediment deposition downstream of the patches. These data will be very help to further understand landform process in vegetated channels.