| 摘要: |
| 长江与洞庭湖之间存在复杂的江湖水沙交换关系，水沙变化引起江湖冲淤变化，从而对长江中游区域防洪、水资源利用、航运及水生态环境等产生较大影响。本文利用实测资料较为系统地分析了荆江与洞庭湖水沙输移变化规律，取得了主要认识如下：1955-2021年期间枝城、沙市、螺山站年径流量变化趋势不明显，监利站年径流量增幅为17.4%，三口分流洪道与七里山站均以减少为主；1955-1989年期间枝城与沙市站年输沙量变化趋势不明显，监利站明显增加，三口分流洪道与七里山站明显减少，1990-2021年期间各站均显著减少，其中三峡工程运用后荆江河段、三口分流洪道、洞庭湖出湖及城螺河段年输沙量分别减少90.1%、90.2%、22.5%及76.6%；受水库下泄径流过程改变的影响，荆江河段、荆江三口分流洪道、洞庭湖出湖与城螺河段年内径流过程均呈不同程度的坦化，枯水期平均流量均显著增加，消落期平均流量稍有增加，汛期一定程度减少，蓄水期稍有减少，下泄径流过程坦化、2006和2011年特枯水年引起荆江三口年均分流量分别减少41.2亿m3和32.4亿m3。随着三峡上游水库群陆续建成运用，荆江河段、三口分流洪道、洞庭湖出湖及城螺河段径流量将进一步坦化，由于干流河床泥沙补给逐渐减少，输沙量将进一步减少，预计长江与洞庭湖水沙输移变化规律将基本保持现有变化格局。 |
| 关键词: 三峡工程 长江 洞庭湖 水沙输移 |
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| Variation of water and sediment transport in the Zhicheng-Luoshan Section of the Middle Reaches of the Yangtze River and Three Diversion Floodways from 1955 to 2021 |
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Yao Shiming, Guo Xiaohu
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: Key Laboratory of River and Lake Regulation and Flood Control in the Middle and Lower Reaches of MWR,Yangtze River Scientific Research Institute
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| Abstract: |
| There is a complex exchange relationship between the Yangtze River and Dongting Lake, and changes in water and sediment transport cause changes in river and lake erosion and deposition, which have a significant impact on flood control, water resources utilization, shipping, and water ecological environment in the middle reaches of the Yangtze River. This article systematically analyzes the variation laws of water and sediment transport in Jingjiang and Dongting Lake using the latest measured data, and obtains the following main insights: During the period from 1955 to 2021, the annual runoff at Zhicheng, Shashi, and Luoshan stations showed no obvious trend of change, while the annual runoff at Jianli station increased by 17.4%, and the Sankou diversion floodway and Qilishan station mainly decreased; The trend of annual sediment discharge at Zhicheng and Shashi stations was not obvious during the period from 1955 to 1989, while the Jianli station increased significantly, and the Sankou diversion floodway and Qilishan station decreased significantly. During the period from 1990 to 2021, all stations decreased significantly, with the annual sediment discharge at the Jingjiang River section, the Sankou diversion floodway, the Dongting Lake outlet, and the Chengluo River section decreasing by 90.1%, 90.2%, 22.5%, and 76.6%, respectively, after the Three Gorges Project was put into operation. Due to the changes in the discharge process of the Three Gorges Reservoir, the runoff processes of the Jingjiang River section, the Jingjiang River Sankou diversion floodway, the Dongting Lake outlet and the Chengluo River section showed varying degrees of flattening during the year. The average flow during the dry season increased significantly, the average flow during the drawdown period increased slightly, and the average flow during the flood season decreased to a certain extent. The discharge process flattened and the average annual discharge of the Three Gorges Reservoir in 2006 and 2011 decreased by about 4.12 billion m3 and 3.24 billion m3 respectively. With the gradual completion and operation of the upstream reservoirs of the Three Gorges, the runoff of the Jingjiang River section, the Sankou diversion floodway, the Dongting Lake outlet and the Chengluo River section will further flatten. Due to the gradual reduction of sediment supply in the main stream riverbed, the sediment transport volume will also decrease further. It is expected that the change law of water and sediment transport in the Yangtze River and Dongting Lake will basically maintain the existing pattern of change. |
| Key words: Three Gorges Project Yangtze River Dongting Lake Water and sediment transport |
