基于2016—2019年长江防汛与河道查勘新实践、长江中下游洪水与河势的新变化与新形势,以及以往研究基础与成果,总结提出了2016洪水⁺长江中下游防洪与治河10大新问题,即流域水沙变化、河流情势变化、水文节律改变、河道洲滩演变、干流槽蓄变化、江湖关系影响、水位流量关系、防洪布局调整、河湖治理技术,以及河流管护研究。采用“原因Ⅰ-响应Ⅱ-影响Ⅲ-对策Ⅳ”4级体系,对10大新问题进行了体系分类、关系构建、课题分解与研究探讨,构建了“之字形层次驱动”和“田字形关联影响”2组关系。研究增进了三峡工程对长江中下游洪水与河势影响的辨识,强化了对变化条件下长江中下游防洪与治河问题的“层次化”与“系统化”梳理。

According to new practices of flood control and river survey of the Yangtze River during 2016-2019, changes and new situations of river floods and river regime, as well as previous researches and achievements, the author presents ten key issues on flood control and river regulation for the middle and lower Yangtze River after the 2016-type flood. Such key issues include: variation of river discharge and sediment load; change of river regime; change of hydrological rhythm; fluvial processes; change of river storage; relationship of river and lakes; relationship between stage and discharge; adjustment of flood control strategy; technology of river regulation; and research on river management and protection. The ten issues are sorted and decomposed into a four-step framework, namely, Cause-Effect-Impact-Response. The four-step framework contains two sets of relations (a z-shaped driving mode relation and a square-shaped intercorrelated relation). The research finding enhances understanding on the impacts of the Three Gorges Project on river flood and river regime in the middle and lower Yangtze River, and also helps strengthen the hierarchical and systematic understanding on issues of flood control and river regulation.