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Abstract

Nagavali is one of the important east flowing river basins, providing a water source for more than 5 million people for various applications in two south Indian states namely Orissa and Andhra Pradesh. During the last two decades, the expansion and intensification of agriculture have increased through the development of various surface water storage projects to support agriculture development. In this scenario, understanding the complete water balance under different land use and climate is required for the sustainable management of water resources and agriculture development. The present study attempted to quantify integrated hydrological processes under changing land use and climate over three decades from 1985 to 2018 with the help of coupled SWAT-MODFLOW. The study quantified the river-aquifer interactions and dynamic groundwater recharge by implementing dynamic land use and climate in the coupled hydrological model for three decades. The integrated model has revealed that the combined impact of land use change and climate has increased runoff by 26%, percolation by 16%, irrigation water requirement by 48%, and groundwater storage has declined by 20%, by the end of 2018 when compared to 1991. The present study emphasized the need of modelling surface–groundwater in an integrated manner for better understating hydrological processes to support sustainable water resource management.