ABSTRACT:

In assessing the removal of dams, it is important to consider the degree to which these efforts could affect channel evolution. A number of previous studies have analyzed the problem of channel evolution using frameworks based on the diffusion equation. In this study, we adopted a similar analytic framework to examine one-dimensional channel evolution within an infinite channel following dam removal. The Fourier transform is used to obtain an analytic solution by which to determine the volume of sediment and position of knickpoints. Analytic results obtained using the proposed models were compared with experiment results reported by Cantelli et al. (2004) and in-situ data related to the Balin dam break in Taiwan. We determined that the rate of sediment volume change is proportional to t^(-1/2) in the early period and t^(-3/2) in the intermediate period, before eventually decreasing to nearly zero. The proposed solution also makes it possible to derive qualitative and quantitative predictions pertaining to bed elevation, sediment volume, and knickpoint positions.