论黄河下游河道的改造与“二级悬河”的治理

本文对黄河下游滩地分布和“二级悬河”的发展过程、现状及其形成原因进行了深入分析，指出水沙条件变化是形成“二级悬河”的主要原因，生产堤和河道整治工程的修建加速了“二级悬河”的发展，要立足于下游、着眼于全流域，从水沙优化配置、人与自然和谐相处、社会经济发展与黄河治理开发协调发展的战略高度，探讨“二级悬河”的治理。在系统分析和总结“二级悬河”和下游河道治理各种设想和措施的基础上，指出今后黄河下游河道治理的方向是进行河道的改造。下游河道治理已进入宽河道与窄河道相结合、综合治理滩区．逐步向窄河道发展的时期，“二级悬河”的治理是其中的组成部分，具体设想是：通过下游河道的改造，滩区的综合治理，形成由现有宽河道、改造后窄河道和窄深主河槽三者相结合的输水输沙和滞洪淤沙系统。并提出了下游河道改造与“二级悬河”治理的具体措施和技术指标，以及需要研究的关键技术问题。

A preliminary study on alteration of watercourse and improvement of the"secondary perched river" in the lower Yellow River

The authors analyzed distribution of fluvial flat and evolution,current situation and formation cause of the "secondary perched river" in the lower Yellow River.The change of inflow of water and sediment was considered to be the primary cause.Embankment for crop production and harnessing projects in rivercourse accelerated the development of the secondary perched riverbed.Based on systemic analysis,the authors envisaged various improvement countermeasures and pointed out that alteration of watercourse would be the direction of river regulation in the lower Yellow River.The lower Yellow River should be transformed into a system of combination of existing watercourse,narrow channel after alteration and deepened main course in order to play functions of flood detention, sediment siltation,as well as water and sediment transportation.The measures and guidelines about the alteration of watercourse and the improvement countermeasure of "the secondary perched river" were discussed and some key technical issues were presented for further research work.