Author ORCID Identifier

https://orcid.org/0009-0007-2840-8568

Date of Award

Spring 2025

Document Type

Thesis (Ph.D.)

Department or Program

Earth Sciences

First Advisor

Carl Renshaw

Second Advisor

Francis Magilligan

Third Advisor

Marisa Palucis

Abstract

The morphology of an alluvial river is the culmination of dynamic processes interacting across scales. When the boundary conditions of a fluvial system are modified, feedback effects among these processes reshape the channel by altering the flow of water and sediment. Environmental stressors, therefore, have the potential to propagate signals of change from watershed to grain scale features in a river channel. I trace the influence of modern climate change across these scales by first quantifying changes in the generation of surface runoff and sediment supply at watershed scales. I then identify how the subsequent changes in hydrological and sedimentological processes affect reach scale channel morphology. Finally, I connect the physical expression of these processes to grain scale changes in sediment transport dynamics, which provides a mechanism for channel restructuring. My analysis reveals that temperature-sensitivity at the watershed scale can be manifested in within-channel structures and hydraulic geometry. As the supply of water and sediment is modulated by external forcings, fluvial processes at the reach scale respond by altering the routing of material in time and constructing new features in space. The effect of sediment supply variation, in particular, is evident even at the scale of an individual particle being transported. The synthesis of my analysis demonstrates how the response of local processes to global boundary conditions results in the observed channel form in alluvial rivers.

Original Citation

Erikson, C. M., Renshaw, C. E., Dethier, E. N., & Magilligan, F. J. (2025). Watershed- Scale Runoff Efficiency Response to Climate Variability [ eprint: https://onlinelibrary.wiley.co Hydrological Processes, 39 (2), e70086. https://doi.org/10.1002/hyp.70086

Erikson, C. M., Renshaw, C. E., & Magilligan, F. J. (2024). Spatial variation in drainage area — Runoff relationships and implications for bankfull geometry scaling. Geomorphology, 446, 108998. https://doi.org/10.1016/j.geomorph. 2023.108998

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