Hydrological Modeling of Groundwater and Surface Water Interactions in Response to Anthropogenic Climate Variability

Abstract

Purpose: This study examines the relationship between groundwater and surface water in the Amaravathi River Basin, India, due to anthropogenic variability in climate factors. Methodology: A coupled SWAT-MODFLOW model has been developed based on publicly available data sets, such as data on meteorological, hydrological, land use, and climate projection data. The simulations of future climate scenarios were carried out using SSP2-4.5 and SSP5-8.5 pathways in the period of 2025-2060. Statistical indicators that were used to perform model calibration and validation include Nash Sutcliffe Efficiency (NSE), Root Mean Square Error (RMSE), and Coefficient of Determination (R²). Results: The results show that under SSP2-4.5 and 17.9% under SSP5-8.5, there is a significant increase in surface runoff compared to the period before the change. On the contrary, the area of groundwater recharge reduces by 8.5% and 16.9%, respectively. Under high-emission conditions, there is a decrease in baseflow contribution, by 42 % to 34 %, which indicates a weakened groundwater-surface water connection. The performance of the models was good with a range of NSE values between 0.72 and 0.85 and high values (greater than 0.75) of R². Conclusion: The research shows that climate variability will result in a transition to hydrological regimes dominated by runoffs, reducing groundwater sustainability and vulnerability of systems. The integrated modeling framework can give essential information on how climate-resilient water management strategies are developed.