小浪底水库拦沙初期黄河下游冲淤效果分析

根据实测资料分析了1999年11月～2007年10月小浪底水库拦沙初期黄河下游河道冲淤变化情况,结果表明:①小浪底水库运用8年来,累计冲刷量为10.549亿m3,其中汛期冲刷量占全年冲刷量的69%,花园口洪峰流量大于2 000 m3/s的洪水冲刷量占总冲刷量的38%,6次调水调沙冲刷量占总冲刷量的20%;②下游河道冲刷量具有两头大、中间小的特征,冲刷强度沿程逐渐减弱,高村以上河段的断面形态调整为展宽和下切同时进行,高村以下河段以下切为主;③下游河床明显粗化,主槽过流能力明显增加;④平滩流量基本为3 650-5 800 m3/s,部分河段仍小于4 000 m3/s的低限标准.

Analysis on Scour and Fill Effects of the Lower Yellow River in Initial Debris Retaining of the Xiaolangdi Reservoir

The paper analyzes the variations of scour and fill of the lower channel of the Yellow River at the initial debris retaining period of the Xiaolangdi Reservoir from November 1999 to October 2007. The outcomes show that a) during 8 years operation of the reservoir, the ac- cumulated scouring is 1. 0549 billion m~3, of which, the scouring in flood season making up 69% of the whole year, the scouring occurred by peak discharge greater than 2 000 m~3/s at Huayuankou making up 38% of the total and the scouring occurred by 6 regulated discharge re- gimes making up 20% of the total; b) the characteristics of scouring of the lower channel are greater at the both ends of the reach and smal- ler in the middle, the scouting intensity getting smaller along the channel, the regulation of cross section shape above Gaocun widened and undercut simultaneously and the section downstream Gaocun mainly undercut; c) the lower fiver bed becomes rough obviously and the flow- ing capacity of the main channel increases remarkably and; d) usually the bankfull discharge is 3 650-5 800 m~3/s, only some sections smaller than the low standard of 4000 m~3/s.