Krishna S, Surajit Deb Barma, Mahesha Amai

The present work considers the application of Variogram Analysis of Response Surfaces Toolbox (VARS-TOOL) to identify the sensitive parameters of a rainfall-runoff model in the Netravati river basin of Karnataka, India using the global sensitivity analysis method. The statistical bootstrapping method is used to obtain the confidence intervals around each of the sensitivity indices. The VARS-TOOL generates results based on the different approaches considering the desired sampling technique and the rankings and reliability estimates of the rankings of the different parameters can be obtained. The sensitive parameters from most influential to least influential parameters are grouped and represented in the form of a dendrogram. The precipitation multiplier, fraction of soil entering fast reservoir and slow reservoir coefficients were found to be most influential parameters for the basin. The air temperature threshold for melting/freezing and base melt factor was least influential. The results of the present study can prove to be helpful in further understanding of the application of VARS-TOOL and can be used for further development of the toolbox for sensitivity analysis.