Safety of river courses of middle and lower mainstreams of the Yangtze River and measure study

Xu Quanxi; Jin Zhongwu

doi:10.3969/j.issn.1000-1123.2024.22.013

Abstract：Safety of the middle and lower reaches of the Yangtze River relates directly to flood control,water supply,navigation and ecology of the basin.After years of practices,great achievements have been made in improving river regime,flood control safety,ecology and navigation.Key issues were examined including failure to ciontrol high flood peak due to insufficient storage and discharge capacity,unstable conditions of local rivers and mainstreams caused by erosion and sedimentation,water level drops during dry seasons,and degradation of water environment that fail to meet the water quality requirements specified for water function zones.New situations in the new stage and under new water-sediment condition are examined.First,high-quality development of the Yangtze River Economic Belt makes new and higher requirements for the safety of the river.Second,erosion and sedimentation of the middle and lower reaches and the relationship between river and lake have undergone changes and will continue to be adjusted in the long term in the future.Further analysis was conducted on the characteristics of water and sediment change since the operation of the Three Gorges Dam and the evolution pattern and impact of different river type.Future trend of water and sediment and changes of river lake relationship were analyzed.In response to the existing problems,fully considering the trend of strategic adjustments in the new period,and focusing on the multi-objective synergy needs,a series of main measures have been implemented to ensure river safety,including formulating relevant laws and plans,upgrading river and canal regulation and dredging projects,improving the river lake administration and supervision system,strengthening the coordinated operation of reservoir groups,and promoting the construction of digital twin Yangtze River.