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Title:Laboratory experiments on alluvial cover in mixed bedrock-alluvial meandering channels and on the formation and evolution of supraglacial meltwater meandering streams
Author(s):Fernandez Arrieta, Roberto
Director of Research:Parker, Gary
Doctoral Committee Chair(s):Parker, Gary
Doctoral Committee Member(s):Garcia, Marcelo H.; Rhoads, Bruce; Venditti, Jeremy
Department / Program:Civil & Environmental Eng
Discipline:Civil Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Abstract:Rivers and other channels containing liquid flow develop meandering patterns over different media and across a broad range of scales. For example, alluvial rivers form and evolve by erosion and deposition of sediment, and by interactions with riparian vegetation. Meandering channels also form in bedrock where the driving processes include dissolution, abrasion by sediment particles, plucking of bedrock, and weathering. Rivulets on a plane can also meander due to an instability associated with surface tension, and channelized flows over ice surfaces also develop meandering patterns due to differential melting. In spite of the differences in size and underlying mechanisms, similarities in planform and channel morphology exist across media and scale, suggesting that there is a common underlying framework of river meandering. This dissertation focuses in two types of meandering channels, namely, mixed bedrock-alluvial meandering channels, and meltwater meandering channels. Experimental work was conducted to advance the current understanding of the processes and characteristics of these two types of meandering rivers. Specifically, this dissertation answers the following questions: 1. How does alluvial cover, as it relates to sediment supply and channel curvature, affect the zones of potential erosion in mixed bedrock-alluvial meandering rivers? 2. What is the role of alluvial cover fluctuations in erosion in mixed bedrock-alluvial meandering channels? 3. How does hydraulic roughness in a bedrock river change under different sediment supply scenarios and how do these changes relate to the ratio of areal alluvial cover to total bed area averaged over a reach? 4. How can the composite roughness, including the effect of bedrock and alluvium in a channel of complex shape, be better described and quantified so as to inform numerical models? 5. How do meltwater meandering channels form and evolve? 6. What are the characteristics of meltwater meandering channels and what is the degree of similarity between them and meandering channels in other media?
Issue Date:2018-06-20
Rights Information:Copyright 2018 Roberto Fernandez Arrieta
Date Available in IDEALS:2018-09-27
Date Deposited:2018-08

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