Adequacy of a Multi-objective Regional Calibration Method Incorporating a Sequential Regionalisation

A multi-objective regional calibration technique that incorporates a sequential regionalisation procedure was introduced and evaluated based on 12 catchments in Korea. This study was focused on investigating the impacts of the predictive capacity of a rainfall-runoff model for multiple objectives on the adequacy of regional relationships during the regional calibration. The effectiveness of the regional calibration using a multi-objective approach was evaluated by comparing the predictive performance of the regional calibration using a single-objective approach. The comparative assessment of the regional calibration approaches in the regionalisation suggests that the predictability of the regional models derived from the multi-objective regional calibration approach is generally good and reasonable with respect to the simultaneous catchment response to high and low flows and water balance. However, the multi-objective regional calibration approach displayed weaknesses associated with matching the water balance in the hydrograph, which was primarily caused by the reduced variation of the regional parameters. A more extensive study with a larger number of catchments is needed to develop more accurate regional relationships from the multi-objective regional calibration approach.