ANALYSIS ON THE EFFECT OF PARAMETER CHARACTERISTICS OF RAINFALL-RUNOFF MODEL AND RUNOFF CALCULATION ACCORDING TO THE SCALE OF FLOOD ~A CASE STUDY OF DAMS IN UPPER TONE RIVER BASIN ~

Abstract

 To manage intensification of flood risk accompanied with climate change, it is necessary to predict flood discharge with high accuracy. In this research, we aimed to apply rainfall-runoff model considering vertical infiltration into the large-scale flood which we have not experienced in the past. Therefore, parameter estimations of this rainfall-runoff model are conducted for dam basins in upper Tone river basin, and parameter characteristics are analyzed in the perspective of flood scale. Considering results of this analysis, reproduction calculations of targeted flood events are conducted using estimated parameters. As a result, high reproductivity of runoff analysis which gives Nash coefficient exceeding 0.7 is shown by comparison of runoff calculations using average value of parameters with small scale and medium scale flood events respectively. Also, the tendency of underestimation of calculated discharge near peaks is improved in the case of using parameters derived from medium scale and large scale flood events.