中文摘要：

黄河下游河道在人类长期抗洪斗争和河道历史演变的共同影响下，形成了两个平面形态宽窄不同的河段。本文根据实测资料，论述了宽窄河段形成的历史背景，宽河段洪水传播及水沙运行的规律；分析了1950—1985年285场洪水在宽窄河段内的冲淤关系及宽河段的水沙运行对窄河段内防洪、河道冲淤的影响，提出了水库调水调沙应该注意的问题。

英文摘要：

The Lower Yellow River has two reaches in plane geomorphology, the wide channel and the narrow channel. The wide reach plays a great role in regulating the incoming flood and sediment, which remarkably affects the flood and channel deformation in the narrow reach. After the regulation of the incoming flow and sediment in the wide reach, the flood discharge decreases, which is beneficial to the flood prevention for the river, but the prolonged flood propagation is much harmful to the safety of the embankments in the narrow reach. The decrease of sediment concentration especially for the large floods in the wide reach will enhance the channel erosion in the narrow reach. Therefore, how to create the favorable flow and sediment conditions in the wide reach to increase the channel erosion or decrease the channel deposition in the narrow reach is an important task for the planning and design of water and sediment management of the reservoirs on the upper and middle reaches of the Yellow River, which should be studied in the near future.