K N Loukika ¹ Venkata Reddy Keesara ¹ Eswar Sai Buri ¹ Venkataramana Sridhar ^2*

• ¹ National Institute of Technology Warangal, Warangal, Telangana, India
• ² Virginia Tech, Blacksburg, United States

The behavior of water between the surface and subsurface is a dynamic and intricate process, involving a complex interplay between surface and groundwater. This interaction is vital for supporting ecosystems, however, over-extraction, reduced streamflow, and the impacts of climate change, contribute to water scarcity. Integrated management of surface and groundwater resources is crucial. The spatio-temporal variations of surface and groundwater interactions were analysed using integrated SWAT and MODFLOW model using QSWATMOD plugin in QGIS software. The surface and groundwater interactions were analysed for future periods under climate and Land Use Land Cover (LULC) change scenarios. Pre-Monsoon, Monsoon, Post-Monsoon Kharif, Post-Monsoon Rabi seasons are considered for analysing the surface and groundwater interactions. The future LULC’s are projected using the Dyna-CLUE model for three user defined scenarios such as past trend (scenario 1), drastic change in built-up and barren land (scenario 2) and restricted agricultural land (scenario 3). For projecting the interactions under both changing climate and LULC, LULC scenario 1 was used for near future period, LULC scenario 2 for mid future period and LULC scenario 3 for far future period. Under the climate change scenario, the maximum groundwater recharge under SSP5-8.5 scenario is observed as 20805 m3/day in the near future, and the maximum discharge under SSP2-4.5 scenario is observed as 9035 m3/day in the mid future period. In both climate change and combined scenarios (both climate and user-defined LULC), there was a greater recharge of groundwater during the monsoon season relative to other seasons, while there was a greater discharge of groundwater during the Post-Monsoon Rabi season. In the combined scenarios, the maximum discharge was under SSP5-8.5 with 15009 m3/day in the mid future, and the groundwater recharge was greater in the near future period under SSP3-7.0 with 19556 m3/day. The groundwater surface water interactions were analysed in four seasons out of which monsoon season, has maximum recharge and groundwater discharge was more in the Post-Monsoon Rabi season. The results found in this study's can be used to plan and develop short term and long-term integrated surface and groundwater management strategies of the basin under changing climate and LULC.