Morphodynamics of Complex Meander Bends on Large Rivers

大河复杂曲流的形态动力学

• 批准号: 0952065
• 负责人: Jorge Abad
• 金额: $ 6.81万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2015-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0952065&HistoricalAwards=false
• 关键词: Morphodynamics; Complex; Meander; Bends; Large

This project will combine state-of-the-art techniques in field measurement and mathematical modeling of river processes to explore the interactions among flow, sediment movement and channel change in complex meander bends along large rivers. The research will address questions of how the complexity of bend shape affects flow and sediment transport, how these effects vary with different flow levels, and how these effects combine to determine long-term changes in the shapes of large meander bends. The Wabash River on the border of Illinois and Indiana, one of America's last virtually unregulated free-flowing meandering rivers, will serve as the field site. The research will measure, using new acoustic technologies, three-dimensional patterns of water movement, sediment transport and changing riverbed morphology within meander bends of different shape over a range of flow levels. Field measurements will be used to develop, calibrate and test advanced computational models that will allow numerical simulations of meander bend dynamics over a wider range of meander shapes and flow levels than is possible in the field. Meanders are one of the most recognizable and common features of river landscapes, and have fascinated scientists, artists and writers for centuries. The floodplains of large meandering rivers are also among the most populated areas in the world, and management of human infrastructure in these locations is often of critical importance. Additionally, rocks formed from the deposits of meandering rivers may contain economically-important quantities of oil, gas, water and minerals, and reconstruction of these past environments relies on knowledge of processes in modern meandering rivers. At present, most knowledge concerning patterns of flow, sediment movement and channel change in meandering rivers stems from studies of small bends, in the laboratory and field, and bends that have relatively simple shapes. The project will transform our understanding of the form and dynamics of large, complex-shaped, river meanders and allow testing of hypotheses concerning channel geometry that have been long-proposed for smaller river meanders, but never tested in large river bends. The research will quantify the three-dimensional movement of water, transport of sediment and evolution of river bends in the large Wabash River (c. 250m wide, 10m deep), and use this data to develop and test numerical models of meander bend flow and erosion. This combined field-numerical approach will be of direct use in explaining how complex river bends have evolved and how they may behave in the future. This will have significant impact in many realms of social and applied science concerned with the management of infrastructure and populations located within the floodplains of large meandering rivers, and in future predictions of bank erosion, channel migration and meander abandonment.

该项目将结合最先进的实地测量技术和河流过程数学建模，探索大河流复杂曲流弯道中水流、沉积物运动和河道变化之间的相互作用。该研究将解决弯曲形状的复杂性如何影响水流和沉积物输送、这些影响如何随不同流量水平而变化，以及这些影响如何结合起来确定大型曲流弯曲形状的长期变化等问题。伊利诺伊州和印第安纳州交界处的沃巴什河是美国最后几条几乎不受管制、自由流动的蜿蜒河流之一，将作为实地考察地点。该研究将使用新的声学技术来测量水运动的三维模式、沉积物输送以及在一定流量水平范围内不同形状的曲流弯内变化的河床形态。现场测量将用于开发、校准和测试先进的计算模型，这些模型将允许在比现场更广泛的曲流形状和流量水平上对曲流弯曲动力学进行数值模拟。曲流是河流景观中最显着、最常见的特征之一，几个世纪以来一直让科学家、艺术家和作家着迷。大型蜿蜒河流的洪泛区也是世界上人口最多的地区之一，这些地区的人力基础设施管理往往至关重要。此外，由蜿蜒河流沉积物形成的岩石可能含有具有重要经济意义的石油、天然气、水和矿物质，而这些过去环境的重建依赖于对现代蜿蜒河流过程的了解。目前，大多数关于蜿蜒河流的水流模式、泥沙运动和河道变化的知识都源于对实验室和野外小弯道以及形状相对简单的弯道的研究。该项目将改变我们对大型复杂形状河流曲流的形式和动态的理解，并允许测试有关河道几何形状的假设，这些假设长期以来一直针对较小的河流曲流提出，但从未在大型河流弯曲处进行过测试。该研究将量化大沃巴什河（约 250m 宽、10m 深）中水流的三维运动、泥沙输送和河湾演变，并利用这些数据开发和测试曲流湾流和河湾的数值模型。侵蚀。这种现场数值相结合的方法将直接用于解释复杂的河流弯道如何演变以及它们未来的表现。这将对涉及大型曲流河流漫滩内基础设施和人口管理的社会和应用科学的许多领域产生重大影响，并对未来河岸侵蚀、河道迁移和曲流废弃的预测产生重大影响。