Flow and Topographic Changes in Compound Meandering Rivers

Flood flow in compound meandering channels exhibits flow storage and attenuation of peak discharge. A sufficient understanding of these characteristics is essential for river design projects that include assessment of dam reservoir and capacity flood relief schemes. Laboratory experiments in a compound meandering channel were performed and flood data from Ota River were analyzed. Results of comparison of the experimental and Ota River data indicated similar characteristics of flood flow storage. Assessing both channel storage capacity and peak discharge attenuation mechanism, a new concept of flood control plans is presented. Additionally, for the evaluation of the structure of flows and river bed topography in a compound meandering channel, a three dimensional numerical model was developed. The numerical model can evaluate and reproduce accurately the features of the flow field and bed topography observed in compound meandering channels. It was considered that the use of a non-hydrostatic pressure model is necessary for evaluating the deformation in a compound meandering channel with high relative depth values. The numerical analysis has shown the importance of secondary flow structures in the formation of the bed features