黄河下游游荡型河段河势演变规律

Law Governing Changes in Wandering Plane-Form of the Lower Yellow River

阐述了黄河下游枯水少沙系列、丰水少沙系列河势演变情况,指出了河势演变的特点,并总结了河势演变基本规律:①河势自然演变的程度同来水来沙变幅成正比;②河床的可动性决定河势演变的剧烈程度;③主流线的弯曲系数、弯道半径自上而下呈增大趋势;④河势的演变具有关联性,具体表现为"一弯变、多弯变";⑤主流线有"小水坐弯、大水趋直"的特点;⑥节点及人工边界对河势的演变具有限制作用。

Analysis of the data measured in low flow and sediment load regimes and high flow regime and low sediment load regime in the lower Yellow River leads to the understandings of the law governing the changes in plane-forms of the wandering Yellow River,which are,among others,are a) that the extent of the change of planeform in nature is in direct proportion to the ranges of the flow and sediment load variations;b) that the amplitude of the plane-form change is dependent on the bed erodibility;c) that channel curvature and the bend radii tend to increase downstream;d) that there is a strong linkage between the changes of the downstream and the upstream channels,exemplified by change in one bend leading to numerous changes in the other bends;e) that main streamline tends to get bent during low flow and get relatively straight during high flow;f) that bank nodes and man-made boundary restrain the plane-form changes.