一、前言 大河口区,交通发达,人口稠密,是国家的门户,政治、文化的中心,工农渔业生产的基地.因此河口区的开发和利用,向来为世界各国所重视.长江是我国最大的河流,长江口扼长江的咽喉,又是我国第一大港—上海港的入海航道,如何充分利用和发展长江口的优势,对上海市和长江中下游地区实现四个现代化具有极其重要的意义. 然而,由于长江口的自然条件十分复杂,航道冲淤多变,拦门沙水深不能满足航运 I. Introduction The Dahekou District, with developed traffic and dense population, is the gateway to the country and the center of politics and culture and the base for the production of fisheries and fisheries. Therefore, the development and utilization of the estuarine region has always been valued by all the countries in the world. The Yangtze River, the throat of the Yangtze River and the throat of the Yangtze River are the most important ports in our country. It is of great importance to the four modernizations in Shanghai and in the middle and lower reaches of the Yangtze River to fully exploit and develop the Yangtze River Estuary. However, due to the complicated natural conditions in the mouth of the Yangtze River and the change of scouring and silting in the waterway,