This study aims to clarify the characteristics of runoff in a paddy field area which is affected by the effect of storage capacity and often troubled by inundation.
First, the method of estimation of unit hydrograph is proposed by adopting the conception of linear reservoir considered the storage capacity and the effect of flooding of the paddy field area in runoff process.
Next, the adaptability of the method is examined for the observed rainfall and runoff data.
As a result, the usefulness of the unit hydrograph method considered the effect of storage and flooding has been shown to the practical estimation of the runoff in the paddy field area by evaluating the optimum decay constant. Moreover, it has been clarified that the decay constant is tend to increase together with the magnitude of rainfall intensity or runoff.