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采用时间序列分析方法对黄河下游河道断面形态参数变化趋势及其变异点进行了系统分析,结果表明:从20世纪50年代以来,断面形态参数发生了趋势性变化,表现为主河槽呈逐年萎缩的态势,且这种趋势在未来仍将延续;黄河下游主河槽萎缩的主要特征是平滩流量和平滩面积的显著下降,相应的平滩河宽、平均水深、最大水深等出现不同程度的下降,同时还伴随着平滩水位和宽深比的上升.提出了黄河下游河道主河槽萎缩的判别参数与判别标准,分析认为下游河道主河槽在70年代开始初步萎缩,90年代以后进入严重萎缩期;提出了三门峡出库水沙过程不协调指数,表明三门峡水库修建后水沙过程不协调性呈增加的趋势;建立了下游河道主河槽萎缩参数与三门峡水库出库水沙过程的响应关系,指出通过水库调控进入下游的水沙过程,特别是调控出库水沙不协调指数,可以缓解和改善下游河道主河槽的萎缩状况,恢复与维持下游基本的输水输沙通道.
The time series analysis method was used to systematically analyze the trend and variation of morphological parameters of the section of the lower Yellow River. The results show that the trend of the section parameters has been changed since the 1950s, And the trend will continue in the future. The main characteristics of the main channel trough in the lower reaches of the Yellow River are the flat beach discharge and the flat area of the beach, and the corresponding flat width, average water depth and maximum water depth of the flat beach decrease in varying degrees, Meanwhile, along with the increase of water level and width-to-depth ratio of the flat beach, the discriminant parameters and criteria for the atrophy of the main channel in the lower Yellow River are proposed. The analysis shows that the main channel of the lower reaches of the lower reaches of the river started to shrink initially in the 1970s and entered a severe period of shrinkage after the 1990s. The uncoordinated index of water and sediment discharge process in Sanmenxia Reservoir is proposed, which indicates that the incoordination of water and sediment process tends to increase after the Sanmenxia Reservoir is constructed. The response relationship between the shrinkage parameters of the main channel and the water and sediment discharge in Sanmenxia Reservoir is established. Reservoir regulation into the downstream water and sediment process, especially the regulation of the out of library water and sand incoordination index, can ease And to ameliorate the atrophy of the main channel of the lower reaches of the river and restore and maintain the basic channel for transporting water and sediment downstream.