The purpose of this study is to examine the influence of migration process of main channel along the sand-bed river on flood-control structure, through the understanding on the behavior with compound cross section by means of characteristics analysis and field investigation. The outcome from the theoretical analysis and application is expected to provide the engineers as a guideline for their design and planning needs.
From analyses of river morphology of main channel in Toucian River, Jhuoshuei River, Bajhang river, Gaoping River, and Beinan River, no common migration patterns can be summarized. To carry out the improvement planning, the reconnaissance, field data collection and numerical modeling are sufficiently required. In particular, for the planning purposes, numerical model is an efficient and necessitated tool to provide the morphology tendency. However, no suitable model has been developed yet for the channel migration behavior. This study will extend the RESED2D model, which is a 2D depth-averaged mobile-bed model, to couple with capabilities of simulation of bed-evolution and river bank erosion/sliding. For this study the two mechanisms including bed evolution and river bank sliding are couply computed and applied to specific reach with sand-material bed in Jhuoshuei River. The simulation results show that the model developed has the practical-case potential. The application study on Jhuoshuei River draws out some valuable information for future engineering improvement planned.