| 长江口横沙北侧岸坡冲刷特征与趋势分析 |
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| 引用本文： | 姜泽宇,程和琴,华凯,石天,唐明,滕立志,颜阁.长江口横沙北侧岸坡冲刷特征与趋势分析[J].海洋通报,2020,39(2):249-256. |
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| 作者姓名： | 姜泽宇 程和琴 华凯 石天 唐明 滕立志 颜阁 |
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| 作者单位： | 华东师范大学河口海岸学国家重点实验室,上海200062;华东师范大学河口海岸学国家重点实验室,上海200062;崇明生态研究院,上海200062 |
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| 基金项目： | 国家自然科学基金委 （NSFC） 与荷兰科学研究组织 （NWO）、英国研究理事会 （RCUK） 合作研究项目 （51761135023）；中国地质调查局项目 （DD20160246） |
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| 摘 要： | 根据2018年多波束测深系统、双频ADCP获得的横沙岛北侧岸坡水下地形与水动力实测数据,并结合历史地形资料分析该区域冲刷特征与发展趋势。结果表明:横沙北侧岸坡存在近岸冲刷坑,最大冲深约7 m;2002—2018年期间,冲刷坑附近河床经历冲-淤-冲的演变模式,整体呈冲刷状态;2007年后冲刷坑开始形成,并向下游延伸。这主要是因为青草沙水库工程的建设导致北港上段束窄,下段主流南移贴岸,使得近岸河床冲刷加剧。另外,横沙东滩促淤圈围工程抑制了北港与北槽间的水量交换,横沙岛近岸水域水动力进一步增强,也是岸坡冲刷的原因之一。分析表明大潮期间水流处于次饱和状态,岸坡表层泥沙起动流速略小于落急时刻水流流速,横沙北侧岸坡的冲刷可能会继续发展。
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| 关 键 词： | 近岸冲刷坑 多波束测深系统 长江口 人类工程活动 |
| 收稿时间： | 2019/5/17 0:00:00 |
| 修稿时间： | 2019/8/2 0:00:00 |
Study on scour along the north bank of Hengsha Island in the Yangtze Estuary |
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| JIANG Zeyu,CHENG Heqin,HUA Kai,SHI Tian,TANG Ming,TENG Lizhi,YAN Ge.Study on scour along the north bank of Hengsha Island in the Yangtze Estuary[J].Marine Science Bulletin,2020,39(2):249-256. |
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| Authors: | JIANG Zeyu CHENG Heqin HUA Kai SHI Tian TANG Ming TENG Lizhi YAN Ge |
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| Institution: | State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;;State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China;Institute of Eco-Chongming, Shanghai 200062, China |
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| Abstract: | Multi-beam eco-sounder system and dual-frequency ADCP were applied to survey the subaqueous topography and hydrodynamics of the north bank of Hengsha Island in 2018. Combining with historical topographic data, the scour characteristics and development trend of the area were discussed. Results indicated that there was a nearshore scour pit on the north bank of Hengsha Island with a maximum scour depth of 7 m. It was formed and developed downstream since 2007, and the riverbed near the scour pit are eroding on a whole although the riverbed evolved in a pattern of erosion, deposition and
erosion cycle during the period of 2002 -2018. This evolution is mainly due to the construction of Qingcaosha Reservoir, which leads to the narrowing of the upper section of North Channel and the southward movement to shore of the main flow of lower section, aggravating the scouring of the nearshore riverbed. In addition, the siltation promotion and enclosure projects of Hengsha East Beach restrain the water exchange between North Channel and North Passage and further enhance the hydrodynamic force of nearshore waters, which is also one of the reasons for bank scour. Analysis showed that the water is subsaturated and the incipient velocity of surface sediment on the bank slope was slightly lower than the velocity of water flow at the downrush time, and the scour of the north bank of Hengsha Island will probably continue to deteriorate. |
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| Keywords: | nearshore scour pit multi-beam sounding system Yangtze Estuary human intervention |
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