Regional calibration of a water balance model for estimating stream flow in ungauged areas of the Yellow River Basin

Prediction in ungauged basins remains a major challenge in hydrology. A key issue in the application of hydrological models to ungauged areas is regional parameterization. This paper presents a regional calibration approach to constructing regional relationships between the parameters of the Snowmelt-based Water Balance Model (SWBM) and catchment characteristics. Data from 38 well-gauged catchments were used to establish regional regression equations of model parameters, and data from an additional four independent catchments were used to test and validate the proposed regional calibration approach. The results indicated that the SWBM performed well in monthly discharge simulations for the 38 well-gauged catchments. The regional relationships of the SWBM parameters derived from the regional calibration approach were found to be highly correlated to catchment characteristics. In addition, the SWBM performed well in discharge simulations for the additional four test sites using only the constructed regional equations to estimate model parameters.