Model parameterization scheme for a distributed hydrological model, BTOPMC

A distributed hydrological model (BTOPMC) provides a distributed estimation of water balance components imperative for sustainable water resource management. The model employs numerous calibration parameters to represent the complex river system. The model uses a transfer function relating the basin scale parameters to estimate grid scale parameters. However, in large and heterogeneous river basin systems, more hydrological response units and subsequently more calibration parameters are required. The study developed the functional relationship between model parameters and catchment attributes at multiple scales to reduce the calibration parameters. The functional relationship developed from one of the test basins from Nepal with extant observations is analyzed by endogenizing the relationship and calibrating its coefficient rather than directly calibrating parameters. The results show that calibration of the regional relationship coefficient rather than the model parameters resulted in comparable model performance to direct calibration, but with more identifiable model parameters. • Developed model parameterization scheme for BTOPMC hydrological models. • Reduced calibration parameters, enhancing model use in data-scarce regions. • Downscaling basin scale parameters to subbasin scale parameters.