长江泥沙调控与干流河床演变及治理中的关键科学技术问题与预期成果展望

长江流域面积180万km2,人口和国民生产总值均超过全国的40%,是我国水资源配置的战略水源地、水电开发的主要基地、连接东中西部的“黄金水道”和珍稀水生生物的天然宝库,在我国经济社会发展中具有重要的战略地位。近些年来,在自然条件和人类活动的双重影响下,长江泥沙时空分布与产输过程发生了重大变化,给河流开发利用与保护均带来了显著影响,而沿江经济社会快速发展和生态文明建设不断对长江泥沙提出调控要求。同时,河流工程建设和泥沙资源化利用的发展也使长江泥沙调控具备了基本条件。但泥沙兼具灾害性与资源性,泥沙调控与河流功能发挥之间存在着矛盾与统一,需要深入研究。国家重点研发计划项目“长江泥沙调控及干流河道演变与治理技术研究”以揭示长江泥沙输移分布与河流开发及保护之间的耦合作用关系,研究提出满足沿江经济社会和生态环境需求的长江泥沙调控、河道演变与治理的基本理论和关键技术为总目标。重点研究长江泥沙来源与时空分布变异规律和趋势,河道演变对水沙输移变化的响应机制,控制性水利水电工程联合运用下长江干流和洞庭湖、鄱阳湖的水沙输移规律,河床重塑过程与驱动机制及其防洪、航运和岸滩利用等多重效应,长江泥沙多维耦合与协同调控的理论和方法,并研发多尺度、多目标与多过程泥沙联合调控技术和河道治理技术。通过本项目研究,预计将揭示多因素影响下长江来水来沙时空变异特征与趋势、水沙输移与河道演变的响应机制;定量预测控制性水库联合运用下长江和洞庭湖、鄱阳湖泥沙输移与冲淤过程,揭示长江河道的重塑过程、相对平衡状态与驱动机制,阐明河流系统再造的防洪、航运及岸滩利用等多重效应;构建长江泥沙调控的理论框架,建立泥沙调控指标体系、方法和模型;研发江河湖库多尺度、多目标与多过程泥沙联合调控技术和河道综合治理技术,并予以示范。本项目的研究将推动河流动力学学科发展,促进长江水沙资源利用与保护,为流域社会经济发展和河流生态保护提供基础保障,具有显著的社会经济与环境效益。

Key Technical Problems and Expected Achievements in the Sediment Control of the Yangtze River and the Bed Evolution of Its Mainstream

The basin area of the Yangtze River is 1.8×10⁶ km² with 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.