EVALUATION OF SEDIMENT BYPASS EFFICIENCY BY FLOW FIELD AND SEDIMENT CONCENTRATION MONITORING TECHNIQUES

Abstract

This paper evaluates the performance of the sediment bypass tunnel that diverts the suspended sediment from Lake Miwa to downstream reaches below Miwa dam. In such a complex processes during bypassing, it is difficult to predict the sediment bypassed efficiency numerically. Therefore, the digital image techniques were developed and implemented to measure the flow pattern and suspended sediment concentration SSC for the first time in Miwa dam. Where, field measurements were conducted during flood seasons in June and July 2010. Surface flow velocity and SSC were analyzed to clarify the performance before and after the commencement bypassing operation mode. The measured sediment bypassed efficiency assists the decision making on optimization of bypassing performance and validates numerical prediction. The facility proved its effectiveness in mitigating reservoir sedimentation in Miwa dam and turbidity of river water contributing towards restoration of downstream environment.