Prediction on Evolution Trend of Different Reaches in Middle of Yangtze River

Abstract

It is described herein the general rule complied with by different forms of rivers by calculation of evolution trend of selected typical reaches of Ouchikou, Wakouzi and Yaojian which are appeared in the middle of Yangtze River, representing respectively the straight branch, minor bending branch and bending branch. The evolution for reaches of straight branches are mainly characterized with moving backward of side shoal by washout, increased swing of main flow, becoming shallow of riverbed and displacement of navigation trough. For minor bending branches, they generally have unstable water courses, frequently swinging thalweg, washout on head part and left and right rims of heart shoal and extended downward of deposit at the end. Because of reduced sand content, main courses and branches are in the trend of washout. As for bending branches, it is generally stable because of shore protection projects and the navigation condition is better than other type of river reaches unless there is sharp cutting of protruding side shoals.