变化条件下长江口沉积地貌系统转型与应对  

Regime shift in morphology of the Yangtze Estuary under changing environment and it’s management

作　　者：何青[1] 朱春燕 郭磊城 侯立军[1] 彭忠 张卫国[1] He Qing;Zhun Chunyan;Guo Leicheng;Hou Lijun;Peng Zhong;Zhang Weiguo

机构地区：[1]华东师范大学河口海岸学国家重点实验室,上海200241

出　　处：《中国水利》2024年第16期12-19,共8页China Water Resources

基　　金：国家自然科学基金(U2040216,42206169,42030411);科技部重点研发项目(2022YFE0136700);上海市科委项目(23590780200,23002400400)。

摘　　要：长江口是径流-潮汐共同影响的大型分汊河口三角洲复合系统,是推动长江经济带发展、长三角一体化发展等国家战略的核心承载区。为深入认识长江口沉积地貌系统演变规律,综合分析了长江口面临的变化条件、沉积环境、地貌演变、问题挑战及应对举措。研究表明,在全球气候变化条件下,长江口面临河流输沙量减少75%~90%、海平面持续上升、人类涉水工程数量增多等多重变化,长江口沉积地貌系统转化开始显现,河口河道窄深化,岸线日益固化,拦门沙地貌淤蚀转变,水下三角洲加速侵蚀,1950—2020年累计减少水域面积约1500 km^(2),由此引起的河道人工渠化趋势,可能导致河流来沙更加难以在河口系统内沉积,加剧减沙环境下的河口侵蚀和洪水灾害风险;河口系统整体呈现“自然淤涨—稳定调整—淤蚀转型—侵蚀萎缩”的演变趋势,长江口面临从泥沙沉积和自然缓慢淤涨过程,向侵蚀冲刷与人类驱动的适应调整转变。未来河口开发治理和保护需加强流域—河口—近海的自然-社会耦合机制研究,发展实时现场监测、中长期地貌数值模拟和数字孪生技术,兼顾生态保护和系统韧性与安全维护,增强河口系统应对洪水、侵蚀等灾害的抵御能力,保障长江口健康可持续发展。The Yangtze Estuary is a large,multi-channel deltaic system controlled by both river runoff and tidal forces.It serves as a ritical area for national strategies such as the Yangtze River Economic Belt and the integrated development of the Yangtze delta.To gain a deeper understanding of the morphological evolution and to support sustainable development of the Yangtze delta,comprehensive analysis of the changing conditions,morphological evolution,challenges and management measures are conducted.The research shows that under the condition of global climate change,the Yangtze Estuary is facing multiple changes such as 75%~90%reduction in river sediment transport,continuous rise of sea level,and increase in the number of human water-related projects,and the transformation of the Yangtze Estuary depositional geomorphic system has begun to appear.It’s found that the channels are deepened and narrowed,the shorelines stabilized,the mouth zone is shifting from sedimentation to erosion,and the delta front is experiencing accelerated erosion.The water area has cumulatively decreased by approximately 1500 km^(2) over the past 70 years(1950-2020).The trend of artificial channelization could lead to reduced deposition in the estuary,exacerbating erosion and flood hazards in a sediment-deficient environment.The entire estuary exhibits four-stage of evolution,namely developing trend characterized by natural siltation—stability with adjustment—accretion to erosion transition—erosion and shrinkage.The present Yangtze Estuary is transitioning from a natural,slow depositional system to one characterized by erosion and human-driven adaptive adjustments.Future estuarine management and protection efforts should enhance the understanding of natural-social coupling mechanisms across river-estuary-coast systems.This includes development of real-time field monitoring,medium and long term geomorphic numerical simulations,and digital twin technologies.Balancing ecological protection,resiliece recovery,and safety maintenance is crucial

关 键 词：长江口 潮汐 泥沙 地貌 转型 人类活动 可持续发展 

分 类 号：TV882.2[水利工程—水利水电工程] P737.121[天文地球—海洋地质]