汛期与非汛期水沙条件对黄河下游不同河段过流能力的影响  

Effects of flood and non-flood flow and sediment regimes on the flood discharge capacity of different reaches in the Lower Yellow River

作　　者：曹玉芹 夏军强[1] 周美蓉[1] 程亦菲 陈建国[2] CAO Yuqin;XIA Junqiang;ZHOU Meirong;CHENG Yifei;CHEN Jianguo(State Key Laboratory of Water Resources Engineering and Management,Wuhan University,Wuhan 430072,China;State Key Laboratory of Watershed Water Cycle Simulation and Regulation,China Institute of Water Resources and Hydropower Research,Beijing 100038,China)

机构地区：[1]武汉大学水资源工程与调度全国重点实验室,湖北武汉430072 [2]中国水利水电科学研究院流域水循环模拟与调控国家重点实验室,北京100038

出　　处：《水科学进展》2024年第4期617-628,共12页Advances in Water Science

基　　金：国家自然科学基金资助项目(U2243237,U2243238)。

摘　　要：20世纪80年代以来黄河下游水沙输移特性显著改变,下游河道经历强来沙作用下的持续淤积与小浪底水库调控下的持续冲刷过程。基于黄河下游1986—2020年实测水沙数据与固定断面地形,计算了河段尺度的平滩流量,量化了汛期与非汛期水沙过程对各河段过流能力的相对贡献。结果表明:①小浪底枢纽运行前水流冲刷强度随时间减弱,下游河道呈汛期淤积、非汛期冲刷的整体淤积态势,平滩流量持续减小,最小过流能力小于2000 m^(3)/s。②小浪底枢纽运行后水流冲刷强度显著增大,尤其在非汛期,对河床冲刷产生重要影响;各河段过流能力显著恢复,其中游荡段恢复最为迅速。③各河段平滩流量与前5 a汛期、非汛期平均水流冲刷强度呈良好的幂律关系,该关系能较好地反映汛期与非汛期累积水沙过程对过流能力的综合影响。④小浪底枢纽运行后,非汛期水沙条件对平滩流量的贡献率增大,尤其是对游荡段具有重要影响(占比53%),对过渡段与弯曲段贡献则较小(占比不到20%)。Since the 1980s,the flow-sediment regime entering the Lower Yellow River(LYR)has altered significantly.The channel in the LYR continuously experienced aggradation under the heavy sediment load and degradation by the operation of the Xiaolangdi(XLD)Reservoir.Based on the measured flow-sediment data and the topography at fixed sections from 1986 to 2020,the reach-scale bankfull discharges were calculated,and the contributions were quantified of flow-sediment regime during the flood and non-flood seasons to the flood discharge capacities in different reaches.Results show that:①In the pre-dam period,the fluvial erosion intensity decreased temporally,leading to a predominance of channel aggradation with deposition in flood seasons and erosion in non-flood seasons.Consequently,the bankfull discharge decreased continuously with the minimum value less than 2000 m^(3)/s.②In the post-dam period,the fluvial erosion intensity increased significantly especially in the non-flood seasons,contributing greatly to the channel degradation.The flood discharge capacity recovered remarkably,with the most rapid recovery occurring in the braided reach.③There was a close power law relationship between the bankfull discharge and the 5-year average fluvial erosion intensity during the flood and non-flood seasons,reflecting the cumulative impact of flow-sediment regimes in the flood and non-flood seasons on the flood discharge capacity.④Owning to the upstream damming,the contribution of the flow-sediment regime in non-flood seasons to the flood discharge capacity increased especially in the braided reach(53%),while it was lower in the transitional and the meandering reaches(less than 20%).

关 键 词：平滩流量 水沙条件 非汛期 汛期 不同河型 黄河下游 

分 类 号：TV143[水利工程—水力学及河流动力学]