Application of fuzzy inference system method in selection of appropriate option for inter-basin water transfer system (Case study: Beheshtabad water transfer project)

In recent years, inter-basin water transfer is inevitable due to an increase in population cities and inappropriate spatial water resources distribution and is considering as a way for dealing with water shortage. Regarding the complexity of these projects caused by various factors of getting involved such as environmental issues, right of water and water balance, social conflicts and immigration, decision-making with regard to the effects of inter-basin water transfer is very important. The increasing need for water resources for various purposes, such as agriculture, drinking and industry, has faced many difficulties and limitations in achieving available and usable water. In such circumstances, inter-basin water-transfer plans have become part of the country's management policies to provide new water resources. In these projects, the capacities of the source and destination basins may not be properly evaluated, despite the variety of multi-criteria decision-making methods that determine the best option considering all effective decision-making criteria. These methods have not yet been used appropriately in national executive and infrastructure projects such as inter-basin water transfer in Iran. Based on literature review on various political, security, social, cultural, economic and environmental dimensions, the negative and positive effects of the inter-basins water transfer could be assessed by Fuzzy inference system. Proponents and critics of the water transfer projects mostly focus on the negative environmental consequences. From a social and political viewpoint, the inter-basin water transfer has positive outcomes that could be leading to an increase in social capital and avoid conflicts. Therefore, water transfer could be the origin of many changes in origin and destination basins that should be assessed by different viewpoints and considering technical, economic and environmental aspects and emphasis on the social and political assumptions. Hence, the water transfer project is feasible when technical ability and also environmental evaluation were confirmed. In this research, on the basis of problem’s nature, decision-making criteria were identified. The applied criteria in water resources researches returns to benefit-cost ratio calculation. Employment factor is another key factor that could have an important role in selection of the best project. Also, regrading to people's welcome and their satisfaction from execution of the project, this criterion was also very important. The main decision-making criteria were defined based on investigating different sources. Fourteen studied criteria were assessed independently in decision-making matrix, including: Land acquisition, induction earthquake, migration, water quality depletion and pollution of water resources, springs and wells, dam geology problems, reservoir geology problems, transmission line problems, current costs, capital costs, production energy, consumption energy, ease of use, and duration of project implementation. The decision matrix was formed by determining the values of each criterion for each option. In the second case, the sub-criteria were defined and each criterion was subdivided into several sub-criteria. Then, the model developed by matrix along with the sub-criteria. The following criteria were defined as follows:  (1) Social: Including 3 subgroups of land acquisition, earthquake induction and migration; (2) Environment: Includes 2 subgroups of water quality depletion and contamination of water resources and drying of wells and springs; (3) Geological and Executive Problems: Includes 3 subgroups of dam geology problems, reservoir geology problems, and transmission line implementation problems; (4) Economic: Includes 4 subcategories of the current cost, capital cost, energy consumption and production energy; (5) Ease of operation; (6) Duration of project implementation. Fuzzy inference system method is one of the most widely used multi-criteria decision making methods and in this research, the inter-basin water transfer scheme in Beheshtabad in Chaharmahal-and-Bakhtiari province has been investigated by the fuzzy inference system and hierarchical analysis methods. The purpose of this study is to apply the fuzzy inference system method to evaluate the suitable option of Beheshtabad Basin Water Transmission System considering 14 quantitative and qualitative criteria. Pairwise comparisons were carried out according to experts and then 14 criteria were ranked using hierarchical analysis of multi criteria and the best option for water transfer was selected based on fuzzy inference system method. The results showed that the first option is superior to the others and also the current cost and capital cost were the most important criteria; while, the reservoir geological problems criterion was introduced as the least important one. The second option with a confidence level of 86.9% based on fuzzy decision making was recognized as desirable. The confidence level of the sixth option was 38.9% and the seventh option was 23.9%, based on the fuzzy method. Option seven was chosen as the lowest priority of Beheshtabad water transfer project, because it had a low numerical value according to many criteria.