Abstarct: Abstract The Snowmelt Runoff Model (SRM) is designed to simulate streamflow in mountainous catchments, with a particular focus on snowmelt-driven runoff. The model can evaluate the effects of seasonal snow cover and hydrological conditions on daily streamflow patterns in snow-dominated regions. SRM has been widely applied for predicting snowmelt runoff and managing water resources in mountainous areas and can be integrated with satellite data to improve simulation accuracy. In this study, SRM was applied to simulate streamflow in the Taleghan watershed in Alborz Province, covering an area of 940 km² with an elevation range of 1,687 to 4,367 m. Precipitation, temperature, and discharge data were obtained from the regional water authority, and Sentinel-2 satellite imagery was used to extract snow cover. The NDSI, SWI, S3, NDWI, NDSII-1, and NDVI indices were calculated in ENVI and classified using the SVM method, with a kappa coefficient of 0. 98 indicating high classification accuracy. The model successfully simulated the seasonal streamflow pattern, particularly the spring peak, with a coefficient of determination (R²) of 0. 8513 for the 1397 water year (September 2017 to September 2018). The model was also tested for the 1395 and 1396 water years (September 2015 to September 2016 and September 2016 to September 2017), yielding R² values of 0. 4052 and 0. 7167, respectively, demonstrating acceptable performance. Model parameters were determined using a trial-and-error approach baxsed on 60 years of discharge and 30 years of precipitation data. Additionally, automated calibration models such as AWBM were applied using ten years of data and compared with SRM; the results indicated that SRM outperformed AWBM in representing spring runoff peaks. This study demonstrates the high capability of SRM in managing snow-dominated mountainous water resources.