Onset and growth of tributary-dammed lakes across alluvial rivers: theory and experiments
Date Issued
2007
Date
2007
Author(s)
Hsu, Pei-Chen
DOI
en-US
Abstract
The response of alluvial rivers to the influence of tributaries is examined in the present thesis using a combination of theory and experiment. The river bed response is described using diffusion theory, and solutions are constructed using analytical methods. The predictions of the theory are then compared quantitatively against small-scale laboratory experiments, and qualitatively against documented river profiles. The theory predicts, and experiments confirm, that the river can respond in two different ways to a concentrated sediment influx from a tributary. When the influx is low to moderate, a cuspate aggradation of the long profile is obtained. When the influx is high, however, the river evolves a backwater region upstream of a tributary dam, interrupting sediment motion. The backwater region then grows into a tributary-dammed lake, maintaining a self-similar shape which co-evolves with upstream and downstream aggradation profiles. During lake growth, the upstream edge of the lake auto-retreats along a line of constant inclination. These results suggest that alluvial diffusion theory may help interpret both small-scale experiments and large-scale river processes.
Subjects
支流堰塞湖
尖岬
填積作用
擴散理論
tributary-dammed lakes
cusp
aggradation
diffusion theory
Type
thesis
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