一条河流的河床发育规律,在下游的冲积平原河段同在丘陵山区的河段,二者是完全不同的。但是,在冲积平原上所形成的河床,其一切特征都同上游丘陵山区的地貌,地质和气候等因素有密切的关系。在冲积平原上的河床,经常处于变化之中,对于沿岸居民的关系远比山区丘陵河段影响更大。因此,本文主要是研究平原河段的河流规律。 The law of river bed development in a river is completely different from that in the lower reaches of the alluvial plain and that in the hilly mountains. However, all the characteristics of the riverbed formed on the alluvial plain are closely related to the geomorphology, geology and climate of the upper hilly region. River beds on the alluvial plain are often undergoing changes and have a far greater impact on the coastal residents than on the hilly reaches of the mountains. Therefore, this article mainly studies the law of rivers in plain riverbed.