Experimental Investigation on Flow Configuration in Flexible and Rigid Vegetated Streams

Riparian vegetation could be an appropriate solution for the flood control and sustainable river management technique as it is useful for the energy dissipation of the stream flows. The present experimental investigation is conducted to understand the flow configuration and energy dissipation of stream flows considering the flexible and rigid vegetation. The laboratory-based physical models are tested in a rectangular flume to observe the flow field in the upstream and downstream of both the vegetations. In this study, rigid vegetation is considered of wooden dowels of equal height and almost uniform diameter whereas for flexible vegetation paddy plants were used. Acoustic Doppler Velocimeter is utilized to observe the velocity profiles at different sections and then it is compared with and without the vegetation. It is noticed that around 24% reduction in stream velocity occurs due to introduction of rigid vegetation whereas 90% reduction happens due to flexible vegetation in the channel. Additionally, energy dissipation at all the sections of both vegetation types was found to give a more comprehensive understanding of the flow field. Overall, the present study provides an insight into the fact that with the help of flexible and rigid vegetation one can restore the ecological balance in the river. The vegetation with high density, height and flexibility will be useful for the dissipation of energy in effective manner. This study also suggests that flexible vegetation will be an effective tool in river management by decreasing scouring in the channel, thereby reducing erosion and sediment discontinuity.