Study on the Influence of River Side Bar on Bifurcated River Reach

On the basis of previous studies,a simple flume experiment on Yaojian reach in the middle Yangtze River was carried out,and the evolution rule of braided channel was studied under the condition with/without river side bar.The results indicated that the variation trend of the thalweg with side bar was the same as that without aide bar,except that the former bed elevation was slightly lower than the latter's;as to the region of separated flow,the lowest points of the river sections would lean to the right bank when the flow of the case with river side bar leaned to the right bank.As to the region of bifurcated river reach and river outlet,the flow and the cross-section would lean to the left bank;river side bar played an important role in the evolution process of the river island,and the river island volume would be smaller than that with no side bar.