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.
