泥沙淤积对黄河下游中小洪水风险影响评价

Risk evaluation of medium and small flood in the lower Yellow River induced by sediment deposition

泥沙淤积导致黄河下游中小洪水灾害发生次数及损失大小发生了变化。利用90系列洪水资料,分析了小浪底水库和黄河下游河道系统不同组合条件下滩区中小洪水风险变化特点。水库和下游河道淤积都导致了黄河下游中小洪水漫滩淹没损失发生的次数增多、损失值变大。在维持黄河下游平滩流量4 000m3/s条件下,泥沙淤积导致滩区中小洪水漫滩次数由小浪底水库拦沙运用初期的年均0.10次增大到拦沙运用后期的年均2.18次,相应的洪水灾害损失值也由年均0.220亿元增大到年均2.400亿元。

To evaluate the disaster quantitatively caused by sediment deposition in the lower Yellow River,risk analysis method is adopted in this paper. By using the 90 series flood data,risk characteristics of middle and small flood in the floodplains of the lower reaches of the Yellow River are analyzed under different combinations of reservoirs and river channels. Sediment deposition in the reservoirs or the river channels both resulted in growth of inundation loss in the Yellow River floodplain. To maintain the downstream bankfull discharge of 4000 m^3/ s,sediment deposition resulted in middle and small flood disaster increased from 0. 1 times to2. 18 times per year from the early period of Xiaolangdi reservoir blocking sand to the late period. Correspondingly,flood disaster loss value has increased by an average 0. 22 million yuan to 2. 40 million yuan per year.