Climate change will affect the hydrologic cycle, thereby creating new challenges in water management. The study was conducted to examine the effects of climate change on the catchment area of Bengawan Solo Watershed. The goal of this research is to know and predict the climate change impact on water resources based on CCAM (Conformal Cubic Atmosphere Model) with downscaling baseline (historical) model data from 1949 to 2005 and RCP 4.5 from 2006 to 2069. The modeling data was validated with in-situ data (measurement data). To analyze the water availability condition in Bengawan Solo Watershed, the simulation of river flow and water balance condition were done in Bengawan Solo River. Simulation of river flow and water balance conditions were done with ArcSWAT model using climate data from CCAM, DEM SRTM 90 meter, soil type, and land use data. The results of this simulation indicate there is (i) A decrease in rainfall of 0.137 mm/yr and an increase in temperature of 0.002 degrees Celsius per year (ii) River flows measurements shows correlation coefficient reach 0.71 between CCAM data and measurement data and this indicate the CCAM data can represent enough the atmospheric condition in Bengawan Solo River. (iii) The river flow and water balance simulation show that the water resources in Bengawan Solo River did not change significantly. This event occurred because the rainfall also didn’t  change greatly and just decrease around 0.137 mm/yr.

Keywords :   Climate change, CCAM, water resources, Bengawan Solo Watershed