PARAMETER REGIONALIZATION BASED ON LAND-USE TYPES FOR A DISTRIBUTED RAINFALL-RUNOFF MODEL

Abstract

 This study developed a land use-based parameter identification method for a distributed rainfall-runoff model 1K-DHM, by calibrating the soil parameters of all land use types to multi-event and multi-site discharge observations simultaneously. The developed method was applied to the Kikuchi River basin, indicating that the identified parameter sets with the 10 highest Nash coefficient shared the similar value within the same land use type, while they differed among land-use categories. The parameter set with the highest Nash coefficient was validated in 15 basins including Kikuchi River, showing overall high performance with the Nash coefficient between 0.5 to 0.8 at 43 stations and over 0.8 at 44 stations, especially at river basins more than 500 km². Throughout the calibration and validation, this study realized the identification of robust model parameter values that reflect the physical properties of catchment surfaces based on land use types.