近50年来长江中下游河道演变分析表明,河道演变具有如下特点:河道总体河势基本稳定,局部河势变化较大;河道总体冲淤相对平衡,部分河段冲淤幅度较大;荆江和洞庭湖关系调整幅度加大;人为因素未改变河道演变基本规律;坐崩是长江中下游岸线崩退和护岸工程崩毁的主要形式;人为因素对长江口河道演变的影响增加。

The analysis on fluvial processes of Middle and Lower reaches of Yangtze River in recent fifty years shows that:(1)the river regime of all reaches as a whole is table,but there are relatively obvious changes in some reaches;(2)the erosion and siltation of all reaches is in a state of relative equilibrium,but variatio in some reaches are rather noticeable;(3)the regulating ranges of relation between Jingjiang River and Dongting Lake increased;(4)the regularity of fluvial processes has not been changed under human activities;(5)rotational slip is a major mode of banks failure and river bank protection works;(6)the impact of human activities on the fluvial processes of the Yangtze River estuary is increasing.