一、引言在設計三門峽水庫时,很自然地会發生下面一系列問題:由于三門峽水庫所引起的水力、泥砂因素的改变,將促使黄河下游河床演变过程發生何种变化?这些变化將引起何种后果?如何進行控制?提出这些問題不是偶然的。以永定河为例,官廳水庫修成后,下游防洪問題并没有全部解决。由于河床發生剧烈的 I. INTRODUCTION The following series of questions naturally occur when designing the Sanmenxia Reservoir: What changes will occur in the evolution of the river bed in the Lower Yellow River due to changes in the hydraulic and sediment factors caused by the Sanmenxia Reservoir? What will these changes cause? Consequences? How to control? It is not by chance that these issues are raised. Taking Yongding River as an example, after the completion of Guanting Reservoir, the flood control problems in the lower reaches have not been fully solved. Due to the dramatic river bed