BEDLOAD TRANSPORT RATE MEASUREMENT WITH IMPACT PLATE AT KOSHIBU SEDIMENT BYPASS TUNNEL

Sediment Bypass Tunnel (SBT) is one of the most leading countermeasures against sedimentation problem in reservoirs. However, SBT is prone to severe invert abrasion due to the combination of high sediment density and high flow velocity Therefore sediment transport observation in SBT hould be conducted for predicting abrasion amount and distribution to operate them appropriately. For the sediment monitoring in SBT, where the flow condition is intensive, an impact plate has been developed by strengthening a surrogate sediment monitoring system used in Japan. In this study, the impact plates are installed at Koshibu SBT and calibrated by flushing artificialy posed sediment in the tunnel. The results show the good correlation between the flushed sediment volume and the impact plate out put. Additionaly, the time series and cross sectional property of sediment movement have been revealed.