Modified calibration strategies and parameter regionalization potential for streamflow estimation using a hydrological model

Calibration and regionalization are two key tasks in hydrological modelling, and the availability of increased data and computing resources has enhanced our ability to complete these tasks. This paper addresses both the tasks, i.e., (i) it proposes novel, model structure based calibration strategies with a goal to improve estimation of high streamflows, and (ii) it explores soil hydraulic properties' association with optimal parameters to estimate streamflows in ungauged catchments. Both the tasks are demonstrated employing a conceptual hydrological model, SAC-SMA, on multiple catchments in the Narmada River Basin. The initial calibrated model exhibited good model performance with high flows being underestimated. Seven calibration strategies by revising parameter space are explored, and improvement in high flows performance is observed at nine out of the 12 catchments. Estimated streamflows based on soil hydraulic parameters demonstrate regionalization potential. The results indicated successful application of proposed methods which are transferable to other basins.