Flooding is one of the most common natural hazards worldwide, : Consequently, identifying flood prone areas and assessing flood hazard levels are fundamental steps in disaster management, spatial planning, and the mitigation of flood related impacts. The Kaleybar Chai Watershed is located in northwestern Iran, within East Azerbaijan Province. The present study aims to assess and map flood hazard potential in this watershed using the SIWEC model. In this research, a set of conditioning factors was employed, including slope, distance from drainage networks, drainage density, elevation, precipitation, lithology, soil type, land use, vegetation cover index, topographic wetness index (TWI), slope curvature, and stream power index (SPI). The weighting of these factors was performed using the SIWEC model. The weighting results indicate that distance from rivers (0.18), drainage density (0.15), and slope (0.13) have the greatest influence on flood hazard formation in the Kaleybar Chai Watershed. In contrast, stream power index, topographic wetness index, and slope curvature received the lowest weights, suggesting their relatively limited role in controlling flood occurrence compared to other variables in the study area. The final flood hazard potential zonation map was generated by integrating all thematic layers within a Geographic Information System (GIS) environment. The results show that 174.47, 295.42, 338.78, 266.17, and 119.1 km² of the watershed fall within the very low, low, moderate, high, and very high flood hazard classes, respectively. This spatial distribution indicates that a substantial portion of the watershed is exposed to varying degrees of flood hazard, highlighting the necessity for integrated watershed management and land use planning. Model performance evaluation demonstrates that the SIWEC model exhibits strong accuracy and reliability in flood hazard mapping, achieving c for the validation dataset. These results confirm the effectiveness of the SIWEC model its potential in flood risk management and spatial planning initiatives.