A Study of Riverbed Morphology due to Barlin Dam Break
Date Issued
2011
Date
2011
Author(s)
Lee, Sheng-Wen
Abstract
On September 18, 2007, Barlin Dam, a 38-meter-high dam built in 1977 in Shihmen reservoir collapsed, due to foundation damage and flood impact. After Barlin dam broke, sediment stored in the reservoir was flushed down to the river channel, and the downstream channel was expected to undergo major change in morphology. This event provided a rare chance to investigate and to understand riverbed adjustment after the dam collapsed. In this paper, we will focus on simulating stream profile evolution, discussing the head-cutting and deposition behavior. The quasi-two-dimensional model (NETSTARS) was employed to simulate reservoir and river channel responses after Barlin dam collapsed. Due to the fact that the variation of flow situation and landform was very severe, the output of the model would be shaken. In order to make the output more meaningful, we chose a stability index to evaluate the output and observe riverbed stability. In addition, numerical solution from advection diffusion equation was developed to model the river profile evolution hourly after Barlin dam broke. For the purpose of evaluating the head-cutting behavior and downstream deposition transportation behavior, it is an adopted way to observe the motion of knickpoint (or erosion threshold position) and deposition threshold position. Simulated longitudinal profiles of the thalweg after Barlin dam collapsed finally suggested that head-cutting and deposition behavior is a power law distribution.
Subjects
Dam break
Advection diffusion equation
Finite difference method
head-cutting
stability index
Type
thesis
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