The average global temperature on Earth has increased by about 0.85℃ since 1880 due to the global warming. The
temperature increase affects hydrologic phenomenon and so the world has been suffered from natural disasters such as
floods and droughts. Therefore, especially, in the aspect of water deficit, we may require the accurate prediction of water
demand considering the uncertainty of climate in order to establish water resources planning and to ensure safe water
supply for the future. To do this, the study evaluated future water balance and water deficit under the climate change for
Anseong river basin in Korea. The future rainfall was simulated using RCP 8.5 climate change scenario and the runoff was
estimated through the SLURP model which is a semi-distributed rainfall-runoff model for the basin. Scenario and network
for the water balance analysis in sub-basins of Anseong river basin were established through K-WEAP model. And the
water demand for the future was estimated by the linear regression equation using amounts of water uses(domestic water
use, industrial water use, and agricultural water use) calculated by historical data (1965 to 2011). As the result of water
balance analysis, we confirmed that the domestic and industrial water uses will be increased in the future because of
population growth, rapid urbanization, and climate change due to global warming. However, the agricultural water use will
be gradually decreased. Totally, we had shown that the water deficit problem will be critical in the future in Anseong river
basin. Therefore, as the case study, we suggested two alternatives of pumping station construction and restriction of water
use for solving the water deficit problem in the basin.