Multi-criteria Decision-making Approach for Environmental Impact Assessment to Reduce the Adverse Effects Of Dams

Environmental Impact Assessments (EIAs) of development projects are necessary to minimize negative impacts and maximize benefits. The objective of this paper is to determine the best strategy to mitigate the adverse effects of dam construction with Multi-Criteria Decision-Making (MCDM) method based on results of EIAs. For this purpose, a group of experts in various pertinent fields was formed, and according to field observations, the main criteria set for evaluating dam construction effects and improvement strategies were proposed by experts group. The main evaluation criteria are defined in terms of impacts on (1) natural resources, (2) ecosystems, (3) socio-cultural institutions, and (4) economics and their sub-criteria. The improvement alternatives are: (1) relocation of city waste disposal, (2) forestry and watershed management, (3) construction of a sewage collection network and treatment plant, and (4) controlling the use of pesticide and fertilizer in agricultural lands and optimizing their type and method of use. Each of sub-criteria were weighted with Integrated Determination of Objective Criteria Weights (IDOCRIW) and the improvement strategies are ranked using the Combined Compromise Solution (COCOSO) method. This paper's methodology is evaluated with the Nohob Earth Dam in Qazvin province, Iran. Results show that socio-cultural criterion has the largest weight. Results of COCOSO demonstrate the alternative of relocation of city waste disposal ranks as the first priority.