Application of Swat Model to Assess the Impact of Climate Change on the Hydrology of Bharathapuzha River Basin

Abstract

The hydrological cycle will be seriously affected due to the change in climate as the human development and anthropogenic activities are increasing with no proper planning. Unplanned development will surely increase the concentration of greenhouse gas emission and hence the change in climate will be drastic. Foreseeing the effect of climate change on the hydrological cycle will help to take cautious measures. This study mainly concentrates on the effect of climate change on the hydrology of the Bharathapuzha river basin and to predict the streamflow due to climate change in future. To incorporate the climate change, statistically downscaled and bias- corrected data from the recent model i.e. CMIP 6 was utilized for two scenarios; they are SSP370 and SSP585.The GCMs considered here are EC-EARTH 3, ACCESS CM2 and MPI-ESM1-2-HR which are suitable for Indian condition. The future runoff is simulated using a semi distributed deterministic model called Soil and Water Assessment Tool (SWAT) .The model was calibrated and validated using SWAT CUP. The observed stream flow series for a period 1987 to 2012 was utilized to calibrate and validate the model. The coefficient of determination for calibration and validation is 0.84 and 0.81 respectively. Study revealed that the future runoff will be increased in future due to climate change and there is a high probability for flood occurrence.

Keywords: Hydrological modeling, Climate Change, SWAT, CMIP 6, SSP