改造黄河下游游荡型河道可能性的思考

Possibility for Meandering Reach Modification of the Lower Yellow River

首先基于河床演变理论及实际经验分析了游荡河型形成的4个条件,它们是堆积性、坡降大,河道宽浅、滩槽差小,流量变幅大、洪水暴涨暴落。其次,根据三门峡水库运用初期1960—1964年黄河铁谢—裴峪段游荡性已基本消失的实测资料,和丹江口水库汉江下游由游荡性分汊河道转化为单一河道的趋向,论证了局部河段游荡性减弱和消失的可能性。为了实现长河段游荡性消失,提出的主要措施是:完成水沙调控体系特别是古贤和碛口水库的建设;大范围调水调沙,使黄河下游河道不淤,同时避免暴涨暴落;减缓坡降,使断面趋向窄深,并加大滩槽差,稳定主槽。再结合其他措施,黄河下游河道游荡性有可能消除。最后,指出了消除游荡性的难度。

Based on the theory of fluvial process and experience of sedimentation engineering the four conditions for forming meandering reach was analyzed firstly in this paper, those were ： aggradations of river reach ; large slope ; wide and shallow cross section with small difference of height be- tween bank and channel; and large variation of flow discharge caused by flush flood and fall. According to the measured data from 1960 to 1964 at the reach from Tiexie to Peiyu downstream of Sanmenxia Reservoir at the Yellow River the meandering reach was disappeared. Moreover some local meandering braided reach downstream the Danjiangkou Reservoir at the Hanjiang River had the tendency to turn to single river channel. In order to change the meandering pattern of large scale reach of the Yellow River the paper presented the main measures to be adopted, including constructing the Guxian Reservoir and Qikou Reservoir to complete engineering projects for control flow and sediment discharge; regulating flow and sediment discharge in a large scale to keep the downstream fiver reach out of deposition and avoiding the flush flood and fall; decreasing slope to keep the section riarrow and deep, enlarging the difference between bank and channel and stabilizing the main channel. In addition to the other methods the meandering pattern of lower Yellow River might die away. In the end the paper also pointed out the difficulty for eliminating meandering pattern.