Progress of research on the relationship between the Yangtze River and its connected lakes in the middle reaches

The complicated changing water-sediment exchange relationship between the Yangtze River and its naturally connected lakes,Lake Dongting and Lake Poyang,have affected regional flood disaster control,water resources and water environmental protection and maintenance of water ecological security,which has become the core of water problems in the middle reaches of the Yangtze River.The progress of research on river-lake relationship between the Yangtze River and its connected large lakes was systematically reviewed from the point of view of the concept and connotation of river-lake interaction,the evolution process,the influencing factors and effects of changing river-lake relationship.Based on the problems in current research,the following research issues were proposed:how to define a comprehensive index for the river-lake relationship is the premise to correctly understand the relationship between rivers and lakes;how to quantify the effects of human activities and climate change contributions is the emphasis and difficulty of research on the river-lake relationship;it is a long-term task to track the impact of the Three Gorges Project on the river-lake relationship;and it is the ultimate goal to maintain healthy river-lake system pattern in the middle reaches of the Yangtze River which benefits both the Yangtze River and its connected lakes based on the optimization and controlling principles on joint operation of hydraulic engineering group for large river-lake water systems.