INVESTIGATION OF ENSEMBLE DAM INFLOW SIMULATION IN SAI RIVER BASIN

Abstract

 This research conducted ensemble inflow simulations for electric power generation dams in the Sai River in Japan. After developing the Water and Energy Based Distributed Hydrological Model 4 components for Snow (WEB-DHM-4cS), we validated the model by conducting hydrological simulations for three consecutives years from August 2015 to July 2018 and confirmed that the model could properly express peak discharges, snow-melt discharges, and base flows in the basin. Then, we performed ensemble inflow simulations of the flood event at July to September 2018 in the Sai River by inputting an ensemble 39-hour rainfall dataset to WEB-DHM-4cS. As a result, we predicted the flood discharge (800m3/s) at Ikusaka Dam with lead times of 7 to 31 hours and the accumulated inflow volume at Takase Dam with lead times of 6, 12 and 24 hours highly accurately with an error rate being less than 5%.