| 谢卫明,何青,张迨,朱磊,郭磊城,王宪业.河口潮滩地貌和沉积物对人类工程的响应特征[J].海洋学报,2019,41(5):118-127 |
| 河口潮滩地貌和沉积物对人类工程的响应特征 |
| The response of morphplogy and sediment characteristics to human modification in an estuarine tidal flat |
| 投稿时间：2018-06-22 |
| DOI：10.3969/ji.ssn.0253-4193.2019.05.011 |
| 中文关键词: 潮滩 地貌 沉积物 人类工程 长江口 |
| 英文关键词:tidal flat geomorphology sediment human impact Changjiang River Estuary |
| 基金项目:国家重点研发计划项目（2016YFE0133700）；国家自然科学基金项目（51739005，51320105005，41406094，41506105）；上海市科委项目（17DZ1204800，16DZ1205403）。 |
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| 中文摘要: |
| 河口潮滩受径潮流的共同作用，在自然环境与人类活动的影响下处于不断的动态调整中，其中大型人类工程往往对其短期地貌变化和沉积物特征产生巨大影响。2013年底至2014年5月，长江口崇明东滩北部开展大规模互花米草治理工程，本文基于地面三维激光扫描技术、植被点云数据滤除算法、沉积物取样以及室内粒度分析等手段，对比了工程前后潮滩地貌与沉积物特征。研究发现：（1）完工后研究区域靠海及南侧区域出现明显冲刷，北侧虽出现淤积，但整个区域平均冲刷幅度仍达4 cm；（2）工程前研究区域沉积物平均中值粒径为29 μm，工程完工后沉积物平均中值粒径则增大到38 μm；（3）工程完工后沉积物靠海及南侧区域明显粗化，北侧沉积物则变细。结果表明，围垦工程会造成邻近潮滩大幅冲刷以及表层沉积物粗化，但潮滩不同区域地貌和沉积物特征对工程的响应仍存在空间差异性。研究揭示尽管河口潮滩长期演变过程受流域来沙条件影响，但围垦工程等局部影响因素会短期内显著改变潮滩动力地貌过程。 |
| 英文摘要: |
| The estuarine tidal flats are always under the influences of both river inputs and tidal currents. The morphological statuses of estuarine tidal flats are always being dynamic due to both human impacts and natural variations. The human modifications particularly show a strong influence on the short-term morphological changes and sediment characteristics in estuarine tidal flats. A huge embankment was construct in the eastern Chongming tidal flats in the Changjiang River Estuary from 2013 to 2014. Based on Terrestrial Laser Scanner system, non-ground points fitering method, sediment samples and laboratory analyses, this study aim to explore the response of morphplogy and sediment characteristics to human modification in an estuarine tidal flat. The results show that:(1) significant erosion occurs in the southern part while even though light deposition appears in the northern part, the entire tidal flat still experiences significant erosion after the completion of the embankment, with a average decrease of 4 cm in elevation; (2) the median particle size of the sediments increases from 29 μm to 38 μm after the construction; (3) after the completion of the embankment, sediment particle size in the southern part and the flat front increases while decreases in the northern part. The results indicate that human modifications would lead to severe erosion and surficial sediment coarsening, but the response of morphological changes and sediment characteristics still varies in different zones of tidal flats. This study also finds that even though it is riverine sediment input that plays a dominantly role in long-term evolution of estuarine tidal flats, human modifications could change short-term tidal flat morphodynamic processes remarkably. |
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