The Bakhtiari Dam, as one of the tallest concrete arch dams under construction in the Middle East, possesses significant geotechnical and structural importance. Given the complex geological setting of the region, foundation seepage has emerged as one of the major challenges in evaluating the safety and stability of the dam. If left uncontrolled, seepage can lead to increased pore water pressure, reduced stability, differential settlements, and even structural failure over time. Therefore, accurate identification and analysis of the hydraulic and structural behavior induced by seepage is essential during both the design and operational phases. This study aims to assess the impact of foundation seepage on the architectural stability and structural design of the Bakhtiari Dam using numerical modeling based on the Finite Difference Method (FDM) to simulate the coupled hydraulic–mechanical behavior of the structure. Initially, a 3D numerical model of the dam and its foundation was developed using regional geological and geotechnical data. Subsequently, hydrostatic loads and various permeability conditions were applied to analyze seepage paths, pore pressures, and the resulting stresses in the foundation and dam body. The results indicate that foundation seepage can alter the stress–strain distribution in the dam body, increase horizontal displacements at the crest, and reduce structural safety in specific zones. Key findings include the identification of high-risk seepage zones, the effectiveness of drainage systems in controlling pore pressure, and the recognition of design weaknesses at the foundation–abutment interface. Accordingly, solutions such as deep grout curtain enhancement, reinforcement of the dam body with special materials, and the implementation of real-time monitoring systems are proposed. The innovation of this research lies in the integrated use of numerical modeling, architectural–structural approaches, and seepage risk analysis within a unified framework tailored for high arch dams. The outcomes of this study can serve as a scientific and practical reference for enhancing the safety of similar dams located in highly permeable regions