There are various environmental risks in both the construction and operation phases of huge civil projects such as dam construction. As a result, it is critical to implement appropriate risk control and risk mitigation measures before the initiation of the activities posed by these schemes. The goal of this research is to identify and categorize the environmental risks posed by the Amirkabir Dam during its construction and operation phases. After identifying the risks, the risk factors were prioritized using the FMEA method, with the risks being ranked according to their severity, probability of occurrence, and ability to detect. The study’s findings revealed that the highest risk in the dam construction stage is associated with road construction and vehicle exhaust gases (RPNs of 280 and 252, respectively), and the highest risk in the operation phase is associated with borrow area overuse (erosion and sediment downstream of the dam) (RPN of 280).