Doctoral Dissertation Research: Curvature-Migration Relations and The Planform Dynamics of Meandering Rivers

曲流河的平面动态一直是河流地貌学家和工程师的基本兴趣，因为这些动力学的复杂程度，平面变化在滩地发育和景观演变中的作用，以及侧向河道迁移的经济和社会后果。理解曲折河流动力学的理论方法试图将横向迁移率与河道曲率和河道几何形状联系起来。尽管基于这些方法的模型通常会对弯曲不对称和弯曲平移模式产生相当现实的预测，但基本的方程尚未经过严格的经验评估。此外，这类模型不能复制复杂形式的弯曲展开，例如双头弯曲或复合弯曲。本博士论文研究项目的总体目标是通过详细探索河道曲率的空间扩展模式与局部横向迁移速率之间的关系，促进对曲流河横向迁移空间结构的理解。为了确定一组曲折河流研究河段的河床曲率模式和横向迁移率，将进行基于地理信息系统(基于地理信息系统)的历史航空摄影分析。该项目将具体侧重于开发一种方法，将自然曲折河流的平面曲率作为一个连续而不是离散的函数进行数学表征。然后将曲率值与测量的横向迁移率相关联，以得出经验曲率迁移率函数。估算公式和理论公式将进行比较，以评估理论函数的有效性，经验函数将用于完善曲流河运移理论模型的预测能力。这一博士论文的研究成果将有助于了解和预测曲流河平面动力学的空间结构，这是河流地貌学的一个基础研究问题。从科学角度来看，研究结果将评估平面形态迁移理论模型的基本假设的有效性，并提高准确预测蜿蜒河流平面形态变化的能力。从实用的角度来看，提高预测能力很重要，因为蜿蜒河流的横向运动可能会破坏财产和农田，破坏建筑物，降低水质，减少水生栖息地，并降低审美质量。该博士论文奖也将提供支持，使有前途的学生建立一个强大的独立研究事业。

The planform dynamics of meandering rivers have been of fundamental interest to fluvial geomorphologists and engineers because of the intriguing complexity of these dynamics, the role of planform change in floodplain development and landscape evolution, and the economic and social consequences of lateral channel migration. Theoretical approaches to understanding the dynamics of meandering rivers have attempted to relate rates of lateral migration to channel curvature and channel geometry. Although models based on these approaches generally yield fairly realistic predictions of bend asymmetry and patterns of bend translation, the underlying equations have not been rigorously evaluated empirically. Moreover, such models are incapable of reproducing complex forms of bend development, such as double-heading or compound looping. The overall goal of this doctoral dissertation research project is to advance the understanding of the spatial structure of lateral migration of meandering rivers by exploring in detail the relationship between spatially extended patterns of channel curvature and local rates of lateral migration. To identify patterns of channel curvature and rates of lateral migration for a set of study reaches along meandering rivers, geographical information system-based (GIS-based) analysis of historical aerial photography will be conducted. The project will focus specifically on the development of a methodology for mathematically characterizing planform curvature of natural meandering rivers as a continuous, rather than discrete function. Curvature values will then be related to measured rates of lateral migration to derive empirical curvature-migration functions. Estimated and theoretical formulations will be compared to evaluate the validity of the theoretical functions and the empirical functions will be used to refine the predictive capabilities of theoretical models of meander migration. The results of this doctoral dissertation research will contribute to understanding and predicting the spatial structure of planform dynamics of meandering rivers, a fundamental research problem in fluvial geomorphology. From a scientific perspective, the results will evaluate the validity of underlying assumptions of theoretical models of planform migration and improve the capacity to accurately predict planform change along meandering rivers. Improved predictive capability is important from a practical perspective because lateral movement of meandering rivers can obliterate property and agricultural land, damage structures, reduce water quality, diminish aquatic habitat, and degrade aesthetic quality. This doctoral dissertation award will also provide support to enable a promising student to establish a strong independent research career.