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

An 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 efficacy of model with high R² and NSE. For future scenarios, the NESM3 model showed the least variation of quartiles based on R², RMSE, MAE and HSS, depicting more accuracy for present-day conditions than other models. Both the northern and the southern areas of the sub-basin experienced higher runoff under SSP585, whereas central areas along with the northwestern 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 to be an important method in simulating the SW-GW dynamics under climate change scenarios.