| 引用本文: | 李少希,杨云平,张华庆,朱玲玲,朱玉德,张明进.三峡工程运行前后的长江中游河段冲淤变化(1975-2017年).湖泊科学,2021,33(5):1520-1531. DOI:10.18307/2021.0520 |
| Li Shaoxi,Yang Yunping,Zhang Huaqing,Zhu Lingling,Zhu Yude,Zhang Mingjin.The scouring and siltation in river channels of the middle reaches of the Yangtze River (1975-2017) before/after the Three Gorges Project*. J. Lake Sci.2021,33(5):1520-1531. DOI:10.18307/2021.0520 |
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| 三峡工程运行前后的长江中游河段冲淤变化(1975-2017年) |
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李少希1, 杨云平1,2, 张华庆1, 朱玲玲3, 朱玉德1, 张明进1
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1.交通运输部天津水运工程科学研究所, 工程泥沙交通运输行业重点实验室, 天津 300456;2.河海大学, 水文水资源与水利工程科学国家重点实验室, 南京 210098;3.长江水利委员会水文局, 武汉 430010
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| 摘要: |
| 气候变化和流域人类活动等综合影响改变了河道演变的自然进程，尤其是流域大型水库的影响，深刻改变了下游的水沙通量与河道演变过程及趋势.以三峡工程为对象，研究坝下游水沙通量及河道演变过程对三峡工程运行的响应关系，可加深大型水利枢纽运行对下游河道演变影响的认识.本文以长江中游河段（宜昌-湖口河段）为研究对象，分析1975-2017年河道冲淤变化，结果表明：近40年来，长江中游河床已发生了累积性的冲刷，近坝段砂卵石河段冲刷强度先增强后减弱，沙质河段冲刷强度呈增强态势.三峡工程运行后不同河型演变特征归纳为：分汊河段江心洲以冲刷为主，上荆江河段内实施的航道整治工程稳定了江心洲形态，但面积受清水下泄的影响呈减小态势，枯水期主汊分流比呈减小态势，部分汊道发生了主支汊交替变化；下荆江及下游分汊河段江心洲面积虽然交替变化，整体上航道整治工程控制了江心洲规模；弯曲河段凸岸侧边滩以冲刷为主，急弯段的凹岸侧深槽淤积，微弯段凸岸边滩冲刷，对应的凹岸侧深槽相对稳定. |
| 关键词: 河道冲淤 时空特征 影响因素 三峡工程 长江中游 |
| DOI：10.18307/2021.0520 |
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| 基金项目:国家重点研发计划项目（2018YFB1600400）、国家自然科学基金项目（51809131，51979132）和中央级公益性科研院所基本科研业务费项目（TKS20200404，TKS20200312）联合资助. |
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| The scouring and siltation in river channels of the middle reaches of the Yangtze River (1975-2017) before/after the Three Gorges Project* |
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Li Shaoxi1, Yang Yunping1,2, Zhang Huaqing1, Zhu Lingling3, Zhu Yude1, Zhang Mingjin1
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1.Key Laboratory of Engineering Sediment, Tianjin Research Institute for Water Transport Engineering, Ministry of Transport, Tianjin 300456, P. R. China;2.State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, P. R. China;3.Hydrology Bureau of Changjiang Water Resources Commission, Wuhan 430010, P. R. China
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| Abstract: |
| Climate change and human activities in river basins have jointly altered the natural course of river channel evolution. In particular, large reservoirs have profoundly changed the water and sediment fluxes and river evolution processes and trends downstream. Considering the Three Gorges Project as an example, this study examined the impact of the operation of the Three Gorges Dam on water and sediment fluxes downstream as well as on river evolution. The findings can improve the understanding of the influence of water conservancy projects on river evolution downstream. In this study, variations in river scouring and siltation in the middle reaches of the Yangtze River (Yichang-Hukou) from 1975 to 2017 were studied. The results showed that the riverbeds in the middle reaches of the Yangtze River have undergone cumulative scouring in the past 40 years. The scouring intensity in riverbeds composed of sand and pebbles near the dam first increased and then weakened, whereas that for sandy riverbeds increased. This was mainly due to the combined effects of local hydrological and sediment transport conditions, the adjustment of the river and lake relationships in the sections, and human activities. In general, different evolutionary trends were noted for different river types and can be summarized as follows. Scour was dominant at the alluvial islands of the branching stream sections. The shapes of the islands have been stabilized with the help of the channel improvement project in the upper Jingjiang section, but the island areas have decreased owing to the discharge of clean water. The branching ratios in the dry season have decreased, and some of the main branching channels have changed into minor streams, and vice versa. Although the areas of the alluvial islands in the lower Jingjiang section and the downstream section have fluctuated, the channel improvement project is generally effective at controlling the sizes of the islands. For curved sections, scouring was dominant on the convex sides. On the concave sides of the sharply curved sections, siltation occurred in deep channels. For moderately curved sections, beach scouring was noted on the convex sides, whereas there were stable deep channels on the concave sides. |
| Key words: River scouring and siltation temporal and spatial characteristics influencing factors Three Gorges Project middle reaches of the Yangtze River |
