Rainfall overpowers tidal forcing in driving upper tidal flat erosion and channel evolution

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology Pub Date : 2025-08-20 DOI:10.1016/j.geomorph.2025.109977

Shang Yu , Fan Xu , Weiming Xie , Xianye Wang , Chunyan Zhu , Qing Yuan , Haisheng Yu , Zhonghao Zhao , Yijie Zhang , Zhengbing Wang , Giovanni Coco , Qing He

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引用次数: 0

Abstract

Tidal flats are critical coastal ecosystems, with their geomorphic characteristics traditionally understood to be primarily influenced by tidal, wave, and storm forces. This study investigates the impact of rainfall on the morphodynamics of upper tidal flats by combining hydrodynamic-sediment data, meteorological rainfall records, and video monitoring at the Chongming Dongtan tidal flat in the Yangtze River Estuary, China. We show that rainfall significantly increases suspended sediment transport and accelerates tidal channel elongation. Notably, rainfall events—though occurring during only 25 % of observed tidal inundation periods—accounted for 62 % of cumulative net sediment transport. This disproportionate efficiency compared to tidal forcing stems from the rainfall-induced hydraulic connectivity between expansive supratidal areas and tidal channels, where concentrated runoff convergence intensifies scour dynamics. These findings challenge the traditional view of tidal flat dynamics, suggesting that rainfall is a more influential driver of morphodynamic change than previously recognized.

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降雨在驱动上潮滩侵蚀和河道演变方面胜过潮汐强迫

潮滩是重要的沿海生态系统，其地貌特征传统上被认为主要受潮汐、波浪和风暴力量的影响。本文结合长江口崇明东滩潮滩的水动力-泥沙资料、气象降水记录和视频监测资料，探讨了降雨对潮滩形态动力学的影响。研究表明，降雨显著增加了悬沙输运，加速了潮汐通道的延伸。值得注意的是，降雨事件——尽管只发生在观测到的潮汐淹没期的25%——占累积净沉积物输运的62%。与潮汐强迫相比，这种不成比例的效率源于降雨引起的膨胀的潮上区域和潮汐通道之间的水力连通性，其中集中的径流汇聚加剧了冲刷动力学。这些发现挑战了潮坪动力学的传统观点，表明降雨对形态动力学变化的影响比以前认识到的更大。

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来源期刊

Geomorphology 地学-地球科学综合

CiteScore

8.00

自引率

10.30%

发文量

309

审稿时长

3.4 months

期刊介绍： Our journal''s scope includes geomorphic themes of: tectonics and regional structure; glacial processes and landforms; fluvial sequences, Quaternary environmental change and dating; fluvial processes and landforms; mass movement, slopes and periglacial processes; hillslopes and soil erosion; weathering, karst and soils; aeolian processes and landforms, coastal dunes and arid environments; coastal and marine processes, estuaries and lakes; modelling, theoretical and quantitative geomorphology; DEM, GIS and remote sensing methods and applications; hazards, applied and planetary geomorphology; and volcanics.