影响黄河下游河道决溢的环境因素（一）

影响黄河下游地上河决溢的环境因素十分复杂。在流域多沙和人工堤防束范的决定因素下，全球变化，河流地质构造活动，河床演变和人类活动剧的相互作用，以及堤防工程存在多种隐患的影响，是引起下游河道泥沙不断堆积，地下河道逐渐隆起和河道决溢潜在危险的重要因素。依据近年来对下游的考察及对已有资料进行认为，目前下游决溢潜在的环境因素可归纳为河道水利环境背景，河床演变趋势和堤防工程隐患等三大方面。

Environmental Impacts on the Lower Yellow River Breach

There are complicated environmental components affecting the breach of the suspected lowerreaches of the Yellow River. Under the decisive circumstance of silt-laden flow and man-made dykes.such factors as global change, riverine tectonic movement, channel evolution and human activitiesinterrelates to each other and the dykes represent so many snakes in the grass that deposition in thelower reaches keeps increasing and that the suspended channel becomes higher and higher above theground' All these are the main cause of potential river breaches. As the macro and all-round analysisbased on downstream investigations over the recent years and the available date, the environmentalimplications on the downstream breach can be divided into adverse environmental background of thechannel, river bed evolution tendency and hidden problems of the dykes.