Abstract
Recently, there has been considerable interest to improve the flood control function of the dams by prior releasing. Carrying out prior releasing has the risk in terms of water utilization. Therefore, it should be taken into consideration that releasing larger amount of water than rain gives water shortage. In this study, we examined the possibility of prior releasing using accumulated rainfall forecasted by Japan Meteorological Agency. Concretely, we investigated that it could estimate the accuracy of forecasted accumulated rainfall based on Global Spectral Model (GSM) by adding the information of spreads calculated by One-week Ensemble Prediction System (WEPS). As a result, we found that the accuracy of forecasted accumulated rainfall based on GSM relates to the spreads calculated by WEPS in case of typhoon. The study results further suggest that it will be possible to improve the flood control function of the dams by prior releasing using forecasted accumulated rainfall.
