This study investigates the impact of climate change on streamflow dynamics in the Berach-Banas catchment of Rajasthan through climate projections, MIKE Hydro River modeling, and streamflow predictions. The USGS SRTM data was utilized for river network and catchment delineation. Historical meteorological data (precipitation, evapotranspiration) from 14-gauge stations, and streamflow data from Chittorgarh and Bigod (2000–2022) were collected. Climate change projections, based on the RCP4.5 scenario spanning from 1951 to 2100, were obtained from the CORDEX. Ten regional climate models (RCMs) were used to downscale climate data. The hydrological model, employing MIKE Hydro River and the NAM Rainfall-Runoff (RR) module, incorporated ten water storage structures to manage monsoon-season water. Thirteen sub-catchments were integrated into the hydrological system. Calibration (2011–2015) and validation (2017–2022) demonstrated strong model performance at Chittorgarh (R2 0.94, %WBL 0.17%) and Bigod (R2 0.97, %WBL 0.05%) during calibration, and Chittorgarh (R2 0.93, %WBL 1.23%) and Bigod (R2 0.96, %WBL 0.78%) during validation. Sensitivity analysis revealed that CQOF, CK1,2, and Lmax are critical parameters, consistent with prior studies in Indian river basins, highlighting their importance in streamflow prediction. Climate change impact analysis indicated a consistent increase in streamflow rates for 2026, 2056, and 2091 compared to 2022, potentially due to temperature rise and precipitation changes. These findings underscore the significant impact of climate change on regional hydrology, with implications for water resource management and adaptation strategies. By providing valuable insights into future streamflow patterns, this study contributes to the development of sustainable and resilient water management approaches in the context of a changing climate.