近年黄河下游输沙功能的时空变化及其影响因素分析

黄河下游河道输沙功能受自然和人为因素的扰动,对黄河的入海泥沙通量产生深远影响。为探明近年来黄河下游河道输沙功能的演变及其主导因素,基于黄河下游河段各站点2007—2020年实测径流与泥沙资料,计算历年黄河下游河道输沙功能,并结合流域降水、水土保持和引水引沙的变化情况讨论了各因素对输沙功能演变的影响。结果表明:黄河下游河道输沙功能指标在2007—2020年显著下降了约57%,其中花园口—高村段输沙功能指标和其降幅均高于高村—艾山段和艾山—利津段; 黄河下游河道输沙功能演变的主导因素是河床粗化、水土流失综合治理面积增加和引水量增大,三者的相对贡献率分别达37.6%,21.6%,17.5%。河床粗化与引水量增大使输沙功能减弱,与水土流失综合治理对输沙功能的增强作用相反,三者综合作用下黄河下游河道输沙功能近年来呈退化趋势。

Study on the Temporal-Spatial Variation of Sediment Transport Function in the Lower Reaches of the Yellow River and Its Influencing Factors in Recent Years

The sediment transport function of the lower reaches of the Yellow River is disturbed by natural and anthropogenic factors, which has the profound influences on the sediment flux of the Yellow River into the sea. To investigate the evolution of the sediment transport function of the lower reaches of the Yellow River and its effect factors in recent years, based on the measured data of runoff, sediment, precipitation, water-soil conservation and water-sediment diversion from 2007 to 2020, the annual sediment transport function was calculated and its dominant factors were discussed. The results show that the sediment transport function index of the lower reaches of the Yellow River decreased by 57% from 2007 to 2020, and the sediment transport function index of Huayuankou—Gaocun section and its decline rate were higher than those of Gaocun—Aishan and Aishan—Lijin sections; moreover, the main reasons for the evolution of the sediment transport function in the lower reaches of the Yellow River were the riverbed armoring, soil-water conservation, and water diversion, which contributed 37.6%, 21.6%, and 17.5% to the changes of sediment transport function, respectively. The riverbed armoring and the increase in water diversion had weakened the sediment transport function, while the increase in soil and water conservation had the opposite enhancement effect. The sediment transport function of the lower Yellow River has been degraded in recent years under the combined effects of the three dominant factors.