The Environmental risk assessment of dams applying SIR and VIKOR methods through post- assessment approach of environmental impact (Case study: Balarood dam of Khuzestan)

vast projects such as dam building hold a wide range of potential risks on their surrounding environments in the process of construction or operation. Thus environmental risk assessment studies on dams is identified to be the most appropriate tool for specifying analyzing and evaluating these risks. This study was conducted to assess the environmental risks of dams by using SIR and VIKOR methods with the approach of post- assessment of environmental impact studies. The construction phase of the Balarood Dam in Khuzestan has been selected as the case study, and After examining the scope of studies and activities during the construction phase, the actual effects on the environment were identified. The evaluation and prioritorising of the actual effects has been identified in the while the the implementation of the project took place, using the SIR method, which is a multi-criteria decision-making method. The results show that by applying this method the effects on surface water quality, quantity, the ecosystems and natural habitats with 13.5, 7.198, and 5.757 scores, were identified as the most important environmental effects in post-assessment studies of the Balarood Dam. Based on the identified factors and effects, environmental risks were identified during the construction phase and then assessment and prioritized using the VIKOR method. Based on this method, the risk of water pollution in terms of high, low and moderate terms (0.2, 0.5, 0.8 = (v), respectively, with weights of (0.700, 1.000, 1.300) was identified as the most important risk. The most important proposed corrective action to reduce Environmental impacts and risks are the creation of an industrial wastewater treatment system.