A largest-class flood caused by a typhoon under a climate change condition at the Yodo River basin is examined by using rainfall data developed by a physically-based course ensemble typhoon experiment for the Isewan Typhoon in 1959 and a distributed rainfall-runoff model including flood regulation with dam reservoir operation. Simulated flood discharge at the Hirakata station under a pseudo global warming condition is analyzed, and it is found that the peak flood discharge at the Typhoon 18 in 2013 is larger than the largest peak discharge estimated by the Isewan Typhoon course ensemble simulation under a pseudo global warming condition. Magnitudes of floods with different return periods of rainfall patterns for the Isewan Typhoon and the Typhoon 18 in 2013 are also examined for evaluating the effect of flood control by dam reservoirs in the basin.
