水沙变化背景下黄河三角洲动力地貌过程研究进展

Advances in understanding the geomorphological processes of the Yellow River Delta under changing water and sediment conditions

  • 摘要: 黄河三角洲的动力地貌演变机制是揭示河口沉积演化与维持生态稳定的关键科学问题,对区域防洪安全和湿地保护具有重要意义。与20世纪下半叶相比,2000年以来黄河入海径流量下降约40%,输沙量减少超过80%,表明入海水沙供给显著衰减,海洋动力在沉积-侵蚀过程中的相对作用日益增强。本文系统梳理了自20世纪80年代以来黄河三角洲在水沙变化背景下的典型动力地貌过程研究进展:入海口与流路演变方面,拦门沙发育与通道改道形成正反馈,驱动叶瓣式演化周期;滩槽系统调整表现为边壁坍塌频发、潮沟拓宽及地貌结构复杂化;岸线演变呈现现行河口淤进与废弃河口蚀退并存特征,受临界输沙阈值控制;植被格局方面,互花米草入侵导致盐沼生态系统单一化与碎片化,湿地演替格局显著重构。未来研究应加强对冻融过程下泥沙输运与生态反馈机制的认识,量化多尺度冲淤平衡阈值及其对系统稳定性的约束作用,并揭示人类活动与极端气候叠加的非线性响应规律,从而为黄河三角洲地貌演化预测与生态修复提供科学支撑。

     

    Abstract: Understanding the morphodynamic evolution of the Yellow River Delta is a key scientific issue for elucidating deltaic sedimentary processes and sustaining ecological stability, with significant implications for regional flood control and wetland conservation. Compared with the latter half of the 20th century, the mean annual river discharge entering the Yellow Sea has decreased by approximately 40%, while the sediment load has declined by more than 80%, indicating a marked reduction in fluvial sediment supply and an increasing dominance of marine dynamics in sediment–erosion processes. This paper provides a comprehensive review of research progress since the 1980s on the major morphodynamic processes of the delta under changing water and sediment regimes, including mouth-bar and channel evolution, tidal-flat and creek adjustments, shoreline dynamics, and vegetation succession. Mouth-bar development and channel avulsion exhibit positive feedbacks that drive lobe-building cycles; tidal-flat systems are characterized by frequent bank collapses and progressive creek widening; shoreline evolution shows coexistence of accretion at the active delta lobe and erosion at abandoned lobes, governed by a critical sediment-supply threshold; and vegetation communities, particularly following the invasion of Spartina alterniflora, have undergone significant homogenization and fragmentation. Future studies should aim to deepen understanding of sediment transport and ecological feedbacks under freeze–thaw processes, quantify multi-scale thresholds of erosion–deposition balance and their constraints on system stability, and elucidate the nonlinear responses arising from the combined impacts of human regulation and extreme climatic events, thereby providing scientific guidance for predicting delta evolution and promoting ecological restoration in the Yellow River Delta.

     

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