ASSESMENT OF CLIMATE CHANGE IMPACT ON STREAMFLOW VARIABILITY IN UPPER NARMADA RIVER BASIN USING SWAT MODEL

Abstract

A wide range of hydrological processes in different spatiotemporal dimensions can be simulated using SWAT being a physical model. This study uses the Soil Water Assessment Tool (SWAT)model to analyse the possible effect of climate change on the future streamflow of the Narmada River watershed, a sub basin of the Narmada River, India. The model was calibrated for 1988-2007 and validated for 2008-2015 using monthly discharge data at the watershed outlet. Calibration and validation of the SWAT model were carried out in SWAT CUP using the SUFI-2 algorithm. The coefficient of determination (R2) and Nash Sutcliffe efficiency (NSE) were 0.87 in calibration, whereas in validation was 0.85 each. The outcome indicates that the simulated and observed flow have a good match. The calibrated model was then run for the future (2025-52) using climate model output. The study of climate change is completed using the Representative Concentration Pathway RCP4.5 and 8.5 scenarios from three different GCM. The downscaled output of these GCM from CORDEX has been used in this study after bias correction. The study aims to provide an understanding of applicable methodologies, for future streamflow implications from climate change, and worldwide strategies to reduce prediction uncertainty. Future research directions in SWAT modelling are also discussed.