黄河泥沙百年演变特征与近期波动变化成因解析

Cause analysis of the centennial trend and recent fluctuation of the Yellow River sediment load

  • 摘要: 黄河泥沙未来变化趋势关系到新时期治黄策略制定,科学认知入黄沙量变化特征,特别是一些典型或极端情况下的沙量变化原因,对于科学研判黄河泥沙未来情势具有重要指导意义。本文在分析百年黄河沙量演变特征基础上,重点解析了2013年和2018年典型"大沙"年份以及2017年典型"极端降雨"年份潼关沙量波动变化原因。结果表明:1919—2018年百年尺度上黄河潼关站输沙量呈"台阶式"减少特征且减少趋势极显著(P < 0.001),尤其2000年以后年均输沙量降至2.44亿t左右;随着黄土高原下垫面土壤侵蚀环境大幅改善,黄河上游相似来水年头道拐—潼关区间流域输沙量减少82%,相似极端降雨情景下流域次洪输沙量平均减少50%~85%,2017极端降雨年并未导致大沙年出现,水土保持生态建设成果在减少入黄泥沙方面发挥了关键作用;2013年和2018年典型"大沙"年潼关站泥沙来源解析表明,河道淤积泥沙冲刷和水库排沙成为新时期黄河潼关站沙量波动变化的主要影响因素。

     

    Abstract: The trend of the Yellow River sediment load in future is related to the development of the river basin management strategy in the new era. It has great significance to clarify the sediment load feature for the determination of future trend, especially under the typical and extreme precipitation. The study emphases on the sediment load fluctuation in the typical large sediment discharge years in 2013 and 2018, and the typical extreme heavy precipitation in 2017, based on analyzing the character and future trend of the sediment load. The result showed that the sediment load discharge decreased extremely in a stage style on century scales from 1919 to 2018, particularly those decreased to 244 million tons after 2000. The sediment load discharge from the Toudaoguai to the Tongguan region decreased 82% than that from the similar upstream rivers years, and the flood discharge decreased around 50%—85% from each extreme precipitation, along with the improvement of the erosion environment in the Loess Plateau. The typical extreme heavy precipitation did not generate the large sediment discharge in 2017 which confirmed that the ecological construction of soil and water conservation played a great significance for reducing sediment into the Yellow River. The fluctuation of the Yellow River sediment load is affected by the deposition from the waterways and the release from the reservoirs by the results of sediment source in 2013 and 2018 in the new era.

     

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