The Evolution of the North Branch of Yangtze River Estuary Characterizedby Being Narrower and Shallower

The evolution of the North Branch Channel of the Yangtze River Estuary from 1958 to 2009 year has been analyzed in great detail based on GIS technology and underwater survey data.The result showed that the north branch of Yangtze River estuary waterways tend to be narrower and be shallower,and its development characterized by narrowing the channel width,shallower depth,water area reduced and smaller channel volume.The natural reason of this trend is the river adjustment on 1955 to 1958,and the artificial reason is the land reclamation projection along the river.This trend increases the risk of saltwater and sediment intrusion to the South Branch of Yangtze river and other negative effects.In this regard,it is recommended to build dams,water gates and other water conservancy facilities,to full use of the value of the North Branch of waterways,and to reduce the downside risks.