| 摘要: |
| 基于南汇南滩水域2011 年12 月和2012 年6 月洪、枯季大潮的现场水文观测资料及2003 年2月枯季大潮、2004 年9 月洪季大潮的历史观测资料, 分析潮流历时、流速、优势流和含沙量等水沙现状和变化特征, 探讨近年来该水域水沙变化的主要影响因素。结果表明: (1)目前, 南汇南滩水域洪季大潮落潮流占主导优势, 枯季大潮涨潮流占主导优势; (2)东海大桥及其周边促淤围垦工程后, 洪季大潮落潮优势增强, 涨潮垂线平均含沙量减少, 落潮垂线平均含沙量增多; 枯季大潮落潮优势减弱, 涨、落潮垂线平均含沙量均减少; (3)近岸工程建设是南汇南滩水域洪季落潮优势增强、枯季落潮优势减弱的主要影响因素; 涨、落潮垂线平均含沙量的变化主要与工程建设、流域来沙量减少、近岸沙体变迁等作用有关。可为河口河槽治理提供理论依据。 |
| 关键词: 南汇南滩 水沙变化 近岸工程 特征分析 长江河口 |
| DOI：10.11759/hykx20131216001 |
| 分类号: |
| 基金项目:国家自然科学基金专项基金项目(41340044); 国家自然科学基金面上项目(41476075); 国家自然科学基金中荷合作专项(51061130544) |
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| Recent variations in tidal current and suspended sediment concentration in the Nanhui south Shoal of the Changjiang Estuary |
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| Abstract: |
| According to the hydrological data observed at the Nanhui south Shoal of the Changjiang Estuary during the dry season in December, 2011 and flood season in June, 2012, and using the method of tidal range's proportion conversion to assimilate the measured field data of current velocities in 2003 and 2004, this paper analyzed the variations in average fluctuation-tide duration, current velocity, preferential flow and suspended sediment concentration (SSC). The influence of typical engineering projects at the Changjiang Estuary such as the East China Sea Bridge and land reclamation on the ebb and flood tidal current and SSC in the Nanhui south Shoal for the last 10 years was discussed. The results showed that (1) around the Nanhui south Shoal the ebb tide dominated during flood season and the flood tide dominated during dry season at spring tide at the present time, which are mainly contributed to intensifying ebb tidal current with decreasing depth-averaged flood SSC during flood season while decreasing ebb tidal current and depth-averaged ebb SSC during dry season after the construction of the typical projects; (2) the controlling parameters of the intensive ebb tidal current in flood season and attenuated ebb tidal current in dry season are those large-scale engineering projects around the Nanhui south Shoal; variations of the depth-averaged flood and ebb SSC may be related to the reduction of basin annual sediment load, large-scale nearshore projects, and sand ridge migration. These results provide a theoretical basis for the estuarine river channel management. |
| Key words: the Nanhui south Shoal changes in tidal current and suspended sediment concentration nearshore projects characteristics analysis the Changjiang Estuary |
