The basin area of the Yangtze River is 1.8×106km2with more than 40% ratio of population and GDP in China.This area is the strategic region of water resources,the main base of hydropower development,the connection of waterway and rare aquatic natural resources in east-midwest of China,which both natural conditions and human activities,significant changes had taken place in the temporal and spatial distributions of sediment production and transports in the Yangtze River,which considerably affected river development and utilization as well as protection.The requirements of sediment control were proposed to meet the rapid economic and social developments and ecological civilization construction.Meanwhile,the basic conditions of sediment control were achieved during the development of river engineering and the utilization of sediment resources.However,sediment is both disastrous and resource so that further investigation is required to solve the contradiction and unity between sediment control and river function.The main goals of the national key research project "the Yangtze River sediment control and river channel evolution and control technology" were revealing the relationship between the distribution of sediment transport in Yangtze River,and river development as well as protection research,and proposing the basic theory and key technology for the needs of sediment control and river evolution in the economic,social and ecological environment along the Yangtze River.This project focused on sediment sources and the variation patterns of spatial sediment distribution in the Yangtze River,response mechanism to the changes of water and sediment transport,the patterns of water and sediment transport of the Yangtze River and Dongting Lake,Poyang Lake River with the control of water hydropower engineer projects,bed restore process and multiple effects of flood,shipping and riverbank,and synergy theory and method of sediment control in the Yangtze River with the developments of multi-scale,multi-target and multi-process control technologies for river sediment control.According to this project,firstly,the variation trend of spatial and temporal patterns of water and sediment,and the response mechanism of river evolution were revealed.Secondly,sediment transport and sedimentation process of the Yangtze River,Dongting Lake and Poyang Lake with combination of reservoirs were quantitatively predicted.Bed restore process,relative balance state and driving mechanism were revealed.Flood control,shipping and riverbank were clarified considering multiple effects of river restore system.Thirdly,the theoretical framework of sediment regulation and control in Yangtze River,as well as the index system,method and model of sediment regulation were established.Finally,the river control technology combined with multi-scale,multi-objective and multi-process sediment modification was proposed,which was applied in engineering projects.The research of this project promoted the development of river dynamics,the utilization and protection of water resources in the Yangtze River,which provided the basis for the development of social economy and the ecological protection of river basin,with great social economic and environmental benefits.
