Comparison of two calibration-uncertainty methods for Soil and Water Assessment Tool in stream flow modelling

Abstract

Calibration and validation of a hydrological model is necessary before applying it for watershed management. This study addresses the application and comparison of two calibration-uncertainty methods for a distributed model. The Generalized Likelihood Uncertainty Equation and Sequential Uncertainty Fitting version 2 were used in this study to calibrate the Soil and Water Assessment Tool. Performance of
the Generalized Likelihood Uncertainty Equation and Sequential Uncertainty Fitting version 2 was evaluated using three objective functions, namely coefficient of determination, Nash–Sutcliffe Efficiency and coefficient of determination divided by coefficient of regression. Uncertainty statistics used were the P-factor and R-factor. The study established the best method for calibration and uncertainty analysis is Sequential Uncertainty Fitting version 2.