Environmental Risk Assessment of Dams in Construction Phase Using a Multi-Criteria Decision-Making (MCDM) Method

This study was conducted to identify environmental and human health risks caused by Balarood Dam, in construction phrase. The first step, all risk-generating factors were identified using a Delphi Questionnaire. Afterwards, the identified criteria were prioritized once using the Analytical Hierarchy Process (AHP) method and then by the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Due to the complex and uncertain nature of decision-making in times of risk, it was necessary to use more than one weighting method to ensure accuracy of weights. The results from AHP and TOPSIS revealed a mismatch in priorities; therefore, an integration method was presented blending Mean-Rank, Borda, and Copeland methods. According to the TOPSIS results, factors including cut and fill, explosion, and transportation, were first to third highest-priority risk-generating factors, respectively. Considering the results from the AHP method, factors cut and fill, drilling, and explosion were identified as first to third top-priority risk-generating factors, respectively. The results obtained from the integration method suggested that cut and fill, explosion, and drilling are the most important environmental risks at construction phase. As a general conclusion, different weighting methods can lead to different results by which the fate of a decision may be changed and it is essential to control final scores by applying more than one weighting method.