2018年黄河宁夏段洪水分析

Flood Analysis of Ningxia Section of the Yellow River in 2018

自1986年龙羊峡、刘家峡水库联合调度以来,黄河宁夏段大流量洪水相对较少,洪水期洪水要素研究分析大多局限于1981年大洪水资料。本文以2018年洪水资料为基础,综合考虑2012年、1981年洪水特征,计算分析不同流量等级下洪水传播时间、洪水比降、河道冲淤变化、对排水沟回水影响。分析结果表明:黄河宁夏段自上游至下游流速随比降的减小而逐渐减小;卫宁段洪水期河滩地较主槽冲刷明显,青石段兴庆区石坝至平罗五堆子河道冲刷程度大于卫宁段;青铜峡灌区排水沟受回水顶托影响明显,致使水位抬高,严重影响农业生产及防汛减灾。

Since the joint operation of Liujiaxia Reservoir in Longyangxia in 1986,there had been relatively little flood with large flow in Ningxia section of the Yellow River.Based on the flood data of 2018 and the flood characteristics of 2012 and 1981,the influences of flood propagation time,flood gradient,channel erosion and deposition on backwater of drainage ditch were calculated and analyzed under different discharge grades.The results showed that the flow rate from the upper reached to the lower reaches of the Yellow River in Ningxia decreases with the decreasing of the gradient,and the floodplain of the Weining section is scoured more obviously than that of the main channel in the flood period Qingshi section Xingqing District Shiba to PingluoWudaizi river erosion degree than Weining section,Qingtongxia irrigation ditch by backwater jacking effect obvious,resulting in high water level,serious impact on agricultural production and flood prevention and disaster mitigation.