The water resources planning, development and management requires assessment of different components of hydrological cycle, like rainfall, runoff, ground water recharge and evapotranspiration. Each of these components should be quantified and water balance should be made on basin scale. The study was planned for estimating the runoff, evapotranspiration and groundwater recharge by SWAT model and assessing the impacts of climate change on potential surface and ground water resources of basin. The overall scenarios of 1961--2100 shows that the monsoon seasonal rainfall, runoff and crop evapotranspiration are increasing at 24.12mm/decade, 11.55 mm/decade and 2.52 mm/decade while annual and monsoon seasonal potential evapotranspiration are decreasing at 14.20mm/decade and 5.46mm/decade respectively. The groundwater recharge by SWAT model indicated stable trend in Aji basin.