| 引用本文: | 周美蓉,夏军强,邓珊珊,毛禹.三峡工程运用后长江中游河床调整沿程变化特点.湖泊科学,2023,35(2):642-649. DOI:10.18307/2023.0220 |
| Zhou Meirong,Xia Junqiang,Deng Shanshan,Mao Yu.Longitudinal variation of channel evolution along the middle Yangtze River after the operation of the Three Gorges Project. J. Lake Sci.2023,35(2):642-649. DOI:10.18307/2023.0220 |
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| 摘要: |
| 三峡工程运行后,坝下游河道发生持续冲刷。本文研究了长江中游(955 km)不同河段沿程演变差异及其原因。总体而言,河床形态调整幅度自上而下减弱,这是因为在河床持续冲刷过程中,水流含沙量沿程恢复,故越往下游冲刷相对缓慢。平面形态方面,长江中游岸线崩退及洲滩变形的强度均呈沿程减弱趋势,且在荆江河段最为显著。断面形态方面,河床冲深幅度在宜枝下段＞荆江河段＞宜枝上段＞城汉河段＞汉湖河段。理论上距离三峡工程最近的河段冲刷应最为剧烈,但由于宜枝上段床沙粗化显著,限制了冲刷的进一步发展。过流能力方面,宜枝河段由于距洞庭湖较远,并未受到入汇顶托作用,故其平滩流量的调整基本由进口水沙条件控制,并随着河床冲深下切而增大;对于荆江、城汉和汉湖河段,河床冲刷虽显著,但支流或湖泊的入汇顶托对平滩流量产生的影响大于前者,故平滩流量总体随上下游水位差同步波动。 |
| 关键词: 河床形态 过流能力 沿程变化 长江中游 三峡工程 |
| DOI：10.18307/2023.0220 |
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| 基金项目:国家自然科学基金项目(U2040215, 52109098, 52009095)和中国博士后创新人才支持计划项目(BX2021228)联合资助。S |
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| Longitudinal variation of channel evolution along the middle Yangtze River after the operation of the Three Gorges Project |
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Zhou Meirong, Xia Junqiang, Deng Shanshan, Mao Yu
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State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, P. R. China
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| Abstract: |
| Significant degradation have occurred in the middle Yangtze River since the operation of the Three Gorges Project. In the current study, longitudinal evolution differences of different reaches along the middle Yangtze River were quantitatively compared, and the main reasons were investigated. In terms of planform geometry, the intensity of bank retreat and central-bar deformation showed a decreasing trend along the reach, and it was most significant in the Jingjiang Reach. With respect to cross-sectional geometry, channel degradation developed gradually from the Yizhi Reach to downstream reaches. It is uncommon that the adjustments of bankfull channel geometry in the upper Yizhi Reach were smaller than those in the downstream reaches. The reason is that the significant coarsening of bed-material composition in the upper Yizhi Reach hindered the development of channel degradation. In terms of discharge capacity, the variations of reach-scale bankfull discharge in the Yizhi Reach were mainly controlled by the incoming flow and sediment conditions, and it increased with the process of channel degradation. In the other subreaches, the variations of bankfull discharge were mainly influenced by the backwater effects owing to the confluences of tributaries and lakes. |
| Key words: Channel geometry discharge capacity longitudinal evolution middle Yangtze River Three Gorges Project |
