小浪底水库对下游河道的冲刷效果及趋势预测

Scouring Effect and Trend Predicting of Xiaolangdi Reservoir on Downstream River

对小浪底水库对黄河下游河道的冲刷效果及趋势进行了分析和预测,结果表明:①小浪底水库投入运用以来,通过水库拦沙和调水调沙,黄河下游冲刷效果明显,至2010年10月,黄河下游河道累计冲刷泥沙19.4亿t,2 000 m3/s同流量水位下降1.6 m左右,下游河道主槽最小过流能力由2002年汛初的不足1 800 m3/s提高至4 000 m3/s;②在小浪底水库主要拦沙期的2008—2020年,下游河道基本不淤积,2020年以后下游河道快速回淤,在2028年左右回淤量达到建库前水平,届时小浪底水库拦沙期恢复的4 000 m3/s左右的中水河槽将难以维持。建议尽早开工建设古贤水利枢纽,争取在2025年前后建成生效。

The paper analyzed the scouring effect of Xiaolangdi Reservoir on downstream river and predicted its trend.The results show that since the operation of Xiaolangdi Reservoir,the erosion on the lower reaches of the Yellow River is obvious through water and sediment regulation.As of October 2010,the accumulative sediment erosion of the lower reaches of the Yellow River have reached 1.94 billion tons,the water level under the same flowrate of 2 000 m3/s discharge drops about 1.6 m,and the minimum discharge capacity of the main channel in downstream river increases to 4 000 m3/s from less than 1 800 m3/s in the very beginning of flood season in 2002.During the main sediment storage periods of Xiaolangdi Reservoir from 2008 to 2020,the downstream river remains basically no deposition.While after 2020,it backs fast to silting.Thus,around 2028 the deposition amount accounts to the former level before the building of the reservoir,with the discharge 4 000 m3/s will be difficult to maintain.The paper suggests Guxian Project should be built as early as possible and operated in about 2025.