The seepage flow rate of conventional earth-rock dams can be monitored using the water-measuring weir method behind the dam. However, earth-rock dams located on deep permeable layer foundations require the construction of impermeable walls to concentrate the seepage of the dam foundation behind the dam for monitoring. This not only incurs high costs and long construction periods but also makes it difficult to ensure that all seepage of the dam foundation can be concentrated. This paper introduces a real-time equivalent monitoring method that combines data from piezometer pipe arrays with finite element simulation calculations. This approach effectively calculates the seepage volume at the dam foundation and overcomes the limitations of traditional interception and water measurement techniques in such geological conditions. The method can accurately simulate the seepage field in the bedrock beneath earth-rock dams, visually displaying the paths and magnitude of seepage throughout the flow field, facilitating the timely detection of any anomalies.