Application of 1D Hydrodynamic Model to Assess Optimal Sediment Control in Watershed—A case of Nan-Hwa Reservoir in Southern Taiwan

In the upstreams and tributaries where are prone to collapse are easy to cause collapse and landslide once hitting by typhoons or heavy rains. Therefore, in the treatment of collapse and landslide, it is often solved by constructing a dam to control the sediment.

However, the previous dams usually only consider of the local area near the dams, but the sediment is continuous in the river channel. In order to control the sediment to dynamic equilibrium, it should not only consider of the local area near the dams, but also be necessary to make a comprehensive consideration in the whole watershed. At the same time, it must also consider of dam height, the selection of dam sites and the order of construction.

Therefore, this study takes the Nan-Hwa Reservoir watershed as the research area, and uses CCHE1D to simulate the sediment transport in the channel in the Nan-Hwa Reservoir watershed, and then discusses the influence on sediment transport in the whole watershed and dynamic simulation in different dam configurations. Finally, make an overall benefit assessment for each different dam configurations, and then select a dam configuration that meets benefits to provide a basis for reference with the design for the planning of subsequent watershed management.