Author ORCID Identifier
https://orcid.org/0000-0001-7862-249X
Date of Award
Spring 6-8-2024
Document Type
Thesis (Ph.D.)
Department or Program
Earth Sciences
First Advisor
Carl Renshaw
Second Advisor
Francis Magilligan
Third Advisor
David Dethier
Abstract
Alluvial channels are always amidst cycles of disturbance and response, continually arcing towards, or back to, a dynamic equilibrium where the channel is subtly adjusted so that it is just able to transport the sediment load supplied from reaches above. As the landscape, and now the climate, have been altered by human activity, channels have been subjected to a changing balance of external forcings. Increasingly large and frequent floods, dam construction/removal, land use change, artisanal gold and sand mining all have drastically perturbed river channels’ delicate adjustment – how will they respond? Here, I consider the question from the grain to global scale and present data that suggests that alluvial channels are remarkably resilient, readjusting to dynamic equilibrium conditions post-disturbance in months to years. Yet, my data also suggest that despite their resilience, the magnitude of adjustments that river channels have been, and will be, forced to make may alter their character substantially. Channels overwhelmed with sediment change the ways in which they convey material on the bed to accommodate drastic shifts in the loads delivered to them. While those changes accommodate sediment transport within the channel, the suite of variables which the channel can adjust via the prevailing hydrology are limited. My work demonstrates that the dynamic stability of river systems also relies on extra-channel adjustments to extrinsic factors imposed on the channel, and that changes to those extrinsic factors, including the climate, will ultimately shape rivers of the future.
Original Citation
Fields, Jordan F. The Influence of Sediment-Supply on River Recovery from Reach to Watershed-Scales. Doctoral Dissertation. Dartmouth College, Hanover, NH. 2024.
Recommended Citation
Fields, Jordan, "The Influence of Sediment-Supply on River Recovery from Reach to Watershed-Scales" (2024). Dartmouth College Ph.D Dissertations. 252.
https://digitalcommons.dartmouth.edu/dissertations/252