Abstract
In midwinter, in the Motsukisam River basin, flooding was occurred by the sudden high temperature and rainfall. Although consideration of flood damage in winter is rare, it is necessary to investigate the scale, frequency, and factor of such snowmelt during the rain for disaster countermeasures.
In this paper, we extend the model of the past study which examined the long-term water circulation on a daily basis to the hourly basis and tried to reproduce these events which occurred in Motsukisam river basin. As a result, snow melting coincides with rainfall from the previous day and runoff amount increased. In addition, we assumed the scale of these flooding due to snowmelt and rainfall to be the sum of the amount of rainfall and snowmelt runoff, and estimate the scale and return periods of these events.
