Quantification of the surface and groundwater dynamics of Upper Godavari Sub-Basin using SWAT-MODFLOW and CMIP6 climate change scenarios

The integrated surface-groundwater (SW-GW) model effectively captures the spatiotemporal variation of the groundwater dynamics under the impact of climate change and anthropogenic activities. Hence, this study examines the efficacy of SWAT-MODFLOW using CMIP6 climate models in simulating spatio-temporal patterns of groundwater dynamics at Upper Godavari Sub-Basin in India. The models were calibrated and validated using the SUFI-2 algorithm and indicated the efficaciousness of model with high R² and NSE. For future scenarios, NESM3 model showed least variation of quartiles based on R^2, RMSE, MAE and HSS depicting more accuracy for present day condition than other models. The north-southern areas of the sub-basin experienced higher runoff under SSP585, whereas central areas along with north-western region experienced significant soil moisture decline under SSP126 and SSP245. Hence, the findings successfully captured the anomaly of head and SW-GW interaction and proved as an important method in simulating the SW-GW dynamics under climate change scenarios.