Zhao Xiaolong, Liu Chuanjie, Ren Zhongda, Ding Weijie, Chen Xi, Cheng Heqin, Jin Yang, Zhang Hong, Jia Zhengyang
School of Geographic Sciences, East China Normal University, Shanghai, 200241, China.
ChinaYangtze River Estuary Investigation Bureau of Hydrology and Water Resources, Changjiang Water Resources Commission, Shanghai, 200136, China.
Sci Rep. 2024 Nov 20;14(1):28769. doi: 10.1038/s41598-024-79384-1.
In recent years, as river-borne sediment transport has decreased, land loss in estuarine areas has become increasingly severe. Particularly from 2009 to 2022, due to the reduced sediment load from the upper reaches of the Yangtze River, significant changes in the erosion-deposition conditions at the Yangtze River Estuary have become a critical concern. The suspended sediment concentration (SSC) in the estuary is closely linked to sediment content, and against this backdrop, this study aims to thoroughly explore the response mechanisms of the Yangtze River Estuary's SSC to changes in erosion-deposition conditions, with the goal of providing scientific bases and strategic recommendations for erosion-deposition management. To this end, this research collected historical water depth data for the Yangtze River Estuary, measured vertical distribution of SSC in September 2022, surface suspended sediment concentration (SSSC) data from 2021 to 2023, and 25 factors influencing SSSC, to analyze in detail the changes in the erosion-deposition conditions at the Yangtze River Estuary and the response mechanisms of SSC to these changes. The analysis showed that between 2009 and 2022, the mouth bar area of the Yangtze River Estuary experienced net erosion for the first time since 1958, with an annual erosion rate reaching 63.2 × 10^6 m/yr, and the highest erosion rate occurring in the North Passage area, reaching 83.3 mm/yr. This phenomenon is likely caused by human-induced changes in underwater topography, with the Yangtze River Estuary shifting from deposition to erosion. Between 2021 and 2023, the turbidity maximum zone (TMZ) of the Yangtze River Estuary did not show regular changes in SSSC, which may be related to the frequent occurrence of typhoons and changes in sediment supply in the submerged delta of the Yangtze River Estuary.
近年来，随着河流输沙量的减少，河口地区的土地流失日益严重。特别是2009年至2022年期间，由于长江上游来沙量减少，长江河口冲淤状况发生显著变化，成为备受关注的关键问题。河口的悬浮泥沙浓度（SSC）与泥沙含量密切相关，在此背景下，本研究旨在深入探讨长江河口SSC对冲淤状况变化的响应机制，为冲淤管理提供科学依据和战略建议。为此，本研究收集了长江河口的历史水深数据，测量了2022年9月SSC的垂直分布、2021年至2023年的表层悬浮泥沙浓度（SSSC）数据以及影响SSSC的25个因素，详细分析长江河口冲淤状况的变化以及SSC对这些变化的响应机制。分析表明，2009年至2022年期间，长江河口拦门沙区域自1958年以来首次出现净侵蚀，年侵蚀速率达63.2×10^6 m/yr，侵蚀速率最高的区域出现在北港，达83.3 mm/yr。这种现象可能是由人为引起的水下地形变化导致的，长江河口由淤积转变为侵蚀。2021年至2023年期间，长江河口最大浑浊带（TMZ）的SSSC未呈现出规律性变化，这可能与台风频发以及长江河口水下三角洲泥沙供应变化有关。
