三门峡水库运行模式对黄河下游水环境的影响

根据黄河下游在三门峡水库20世纪70年代投入运行后的实测资料，考虑水库的不同运行模式以及下游支流的入汇作用，研究了水库对黄河下游的水环境的影响。注意到黄河灌溉用水的主导作用，以河水中离子总量为指标，分析了三门峡水库运行对黄河下游水质的影响。考虑到断流是黄河下游最为突出的生态问题，以全年断流总长度为指标，分析了三门峡水库运行对断流严重程度的影响。研究表明，黄河下游各站离子总量与三门峡水库运行模式以及三门峡-花园口间支流入汇条件有着密切的关系，而且断流严重程度主要受到水库运行模式的控制，据此提出了有利于降低离子总量和减轻断流严重程度，同时又兼顾发电和防洪的三门峡水库推荐运行模式。

Impact of operation mode of Sanmenxia Project on ecological environment in lower reaches of Yellow River

The impact of Sanmenxia Hydro Project on water quality and desiccation of lower reaches in Yellow River is studied according to the monitoring data accumulated since the Project was put into operation. The total ion content (TOC) is taken as the major index for assessing the water quality and the length of desiccated river section in the lower reaches of Yellow River is taken as the index for evaluating the level of desiccation. The effects of operation mode and incoming flow from tributaries are analyzed. It is found that the TOC is remarkably varies with the output discharge of the Project and incoming water quality, and the desiccation level is not only related to the output discharge of the Project but also the in coming flow from tributary. An optimized operation mode for reducing the TOC in flow and mitigating the river desiccation is proposed.