近期长江河口横沙通道冲淤变化与微地貌特征

于2015年2月1~7日利用多波束测深系统对长江口横沙通道河槽进行走航测量，结合人类活动强干扰下的海图水深数据及河槽表层沉积物资料分析近期长江河口横沙通道河槽冲淤变化与微地貌特征，探讨河槽冲淤演变和床面微地貌之间的相关性以及河口河槽冲淤演变过程和微地貌特征对人类活动的响应。结果显示：近年来横沙通道河槽持续受到冲刷，2002~2013年泥沙净冲刷量为0.86 × 108m3，平均每年冲刷0.08 × 108m3，其原因可能与三峡蓄水工程、北槽深水航道治理工程和北港青草沙水库工程的实施有关。而横沙通道的河床冲刷对圆圆沙航槽和北槽航道的泥沙回淤具有一定的贡献；其底床上除发育平滑床底外，还广泛发育凹坑和冲刷痕等侵蚀性微地貌，且河槽受到冲刷导致底沙推移质运动增强，促进了沙波微地貌的发育。

Recent Morphological Changes and Micro topography Features in the Hengsha Passage of the Yangtze River Estuary

Bedforms were observed in February 2015 with the acoustic multi beam bathymetric. Chart data and surface sediment samples were collected. Based on these data, the recent morphological changes and micro topography features in the Hengsha Passage of the Yangtze River Estuary were studied in this paper. The correlation between the morphological changes and micro topography in the Hengsha Passage was explored in this paper, and the response of the morphological changes and bedforms of the channel beds to the human activities was also explored. Results showed the channel of Hengsha Passage experienced significant erosion because the construction of Three Gorge Dam, the Qingcaosha Reservoir project and the Deepening Waterway Project may have indirectly affected the morphology of the Hengsha Passage. From 2002 to 2013, net volume loss and average annual net volume loss reached 0.86 × 108 m3 and 0.08 × 108 m3 yr-1 in the Hengsha Passage, respectively. A large amount of the eroded sediment from the south entrance of the Hengsha Passage was trapped, resulting in substantial accretion in the Yuanyuansha Waterway and the upper reach of the North Passage. In addition to smooth bed floors, there were erosive micro topography in the Hengsha Passage, such as hollow and scour mark etc.. Due to the channel experienced erosion will lead to enhanced of bed load movement, which can promote the development of dunes. Consequently, there was a large area of dunes developed in the Hengsha Passage.