Channel Evolution and Regulation of Zhenjiang-Yangzhou Reach of the Lower Yangtze River

The Zhenjiang-Yangzhou reach(hereafter referred to as Z-Y reach) is one of the river sections with the most severe changes in lower Yangtze River.The evolution of this reach is complicated and the river regulation involves great difficulty.Changes of the river in the past century are described as follows: the head of Shiye sandbar collapsed continually and the left branch developed slowly with the mainstream moving towards the right after the confluence.The concave bank of Liuyu bend,which developed towards the downstream afterwards,collapsed constantly since the concave bank and convex bank exchanged.The multi-braided channel at Hechang island developed into a goose-head shaped double-braided channel,and afterwards the main channel exchanged with the branch channel while the left branch developed steadily.The effects of regulation works in this reach is analyzed,and regulation ideas are proposed for the existing problems.