Case analysis of sediment bypass tunnels (Switzerland, Taiwan, Japan)

Abstract

This research collected and analyzed the specifications of 15 sediment bypass tunnels in order to assist in the systematizing of planning and design methods for sediment bypass tunnels. First we classified the sediment bypass tunnels by the purpose of the dam and the main purpose of the sediment bypass tunnel, and then we analyzed each for design discharge, tunnel structure, and target grain size of sedimentation. We found that the approach to setting of the design discharge changed according to the classification of the sediment bypass tunnels and that the efficiency of the design discharge may be impacted by regional characteristics. Based on the analysis results for factors such as tunnel structure and target grain size of sedimentation, we have listed points to consider in the planning and design of sediment bypass tunnels in the future.