Since its operation in October 1999,the Xiaolangdi Reservoir has profoundly changed the process of runoff and sediment entering the lower reaches of the Yellow River for 23 years,leading to the reconstruction of the riverbed in the lower reaches.This study is based on multi-source data such as long-term hydrological and sedi-ment,cross-sectional topography,and remote sensing images from 1960 to 2022.It elucidates the impact of the Xiaolangdi Reservoir on the downstream river channel since its operation from three aspects:runoff and sediment,erosion and sedimentation evolution,and morphological adjustment.The results show that:(1)The sediment re-tention effect of the reservoir is significant,with a more uniform distribution of discharged water within the year and a more concentrated sediment amount towards the flood season;the severity and frequency of extreme floods,droughts,and hyperconcentration events have significantly decreased;the adjustment of suspended sediment is not significant,and the coarsening of bed sediment is significant.(2)The trend of continuous sedimentation in the lower Yellow River has been reversed,and the adjustment of erosion and sedimentation mainly occurs in the wan-dering river section from Huayuankou to Gaocun;the erosion efficiency continues to decrease,and the flow capaci-ty of the main channel has been significantly restored.(3)The cross-sectional morphology of the wandering river section has developed towards narrow and deep depths,and the development of secondary suspended rivers has been effectively alleviated.The overall river regime of the river section is in a stable state.The research results have enriched the scientific understanding of the impact of reservoir construction on downstream rivers in sandy riv-ers,and can also provide scientific support for the optimal operation of the Xiaolangdi Reservoir.
关键词
径流泥沙/冲淤演变/形态特征/游荡性河段/黄河下游
Key words
runoff and sediment/evolution of erosion and deposition/morphological characteristics/wandering river sections/lower reaches of the Yellow River
维普
万方数据