长江口的演化与发展趋势

随着长江上游干支流众多大型水利工程的修建,特别是三峡大坝和南水北调工程陆续完工并投入运行,以及退耕还林和水土保持工程的实施,使得长江入海泥沙量急剧减少,导致长江三角洲淤涨速率减缓,并可能使长江三角洲出现逐渐退化和萎缩现象。论述了长江三角洲的形成过程,分析了上游水利工程、海平面上升、地面沉降和人类活动等对长江三角洲的影响,提出了目前仍在实施的围海造地是有效防止或缓解长江口三角洲免遭侵蚀的有效途径。

Estuarine Evolvement of the Yangtze River and Its Developing Trend

With the construction of many hydro-projects in both the trunk stream and tributary the upper reaches of the Yangtze River,especially the Three Gorges Project and the South-to-North Water Diversion Project,and the implementation of converting farmland into forest and grass as well as soil and water conservation,sediment discharge into the sea in the Yangtze River is declining quickly.This reduces the silting rate of the Yangtze River Delta and might degenerate the Yangtze River Delta as well.Formation process of the Yangtze River Delta is discussed,and the impacts of upstream hydro-projects,rising sea level,land subsidence and human activities upon the Yangtze River Delta are analyzed.It is put forward that the coast reclamation which is still being carried on at present is an effective way to prevent the Yangtze River Delta from erosion.The result from the study has some guiding significance to the practice.