Evaluation of Inter-basin Water Transfer Project Scenarios to Central Plateau of Iran Employing COPRAS Multi-criteria Decision Making Method

 Inter-basin water transfer projects include essential, various, complex parameters where mostly have a qualitative inherent. Making an appropriate decision on these projects have not been convenient due to diverse impacts and effectiveness of the parameters as well as irregular and qualitative intrinsic of the criteria. The main objective of this study is the evaluating and prioritizing of the practical inter-basin water transfer scenarios to Central Plateau of Iran employing three approaches of the analytic hierarchy process (AHP), DEMATEL and Shannon Entropy, and proposing this approach for decision making in water resources.

 In this study to supply municipal water consumption deficit of 580 Million cubic meters for three provinces of Esfahan, Yazd, and Kerman, eight practical inter-basin water transfer scenarios were selected. The scenarios transfer water from the great Karun watersheds, including Behesht-Abad, Bazoft, Khersan, and Gukan basins, to the mentioned provinces located in the Central Plateau of Iran. Four criteria, considering the proposed UNESCO criteria for the qualitative and quantitative evaluation of these projects, were assigned including technical risks and performance difficulty (C1); political and social obstacles (C2); environmental difficulties (C3); and prime cost of a cubic meter of water (C4). Upon employing three approaches of the AHP, Shannon Entropy, and DEMATEL, the criteria weights for decision making were determined. Finally, the selected eight scenarios of the study were prioritized, considering the positive and negative measures within the multi-criteria decision making, by using the COPRAS technique.

 Regarding the results of the AHP method, criteria with the highest and the lowest importance were obtained as the technical risks and performance difficulty and the environmental challenges respectively. In the following, results of the DEMATEL method, considering cause and effect graphs, as well as the impact and influence ​​of the criteria, revealed that criteria of C1, C2, and C3, got the second, fourth, and the third ranks respectively, while the C4 criterion was placed in the first rank. Also, the results showed that the former criteria, C1 to C3, were considered as cause criteria, and the latter one, C4, was an effect criterion. In the following, the weight of the criteria was computed using the Shannon Entropy method. Accordingly, the C4 criterion, including the lowest weight (Wj ) and the highest Ej value, had a common impact on the scenarios. While, the C1, with the highest weight and the lowest Ej value, was selected as the most influential and essential criterion. Then, the COPRAS technique was employed to find out the best scenario. The obtained results revealed that the 8th scenario was selected as the best scenario and the most suitable one was based on the assigned criteria. Moreover, the results showed that, except the scenarios 5 to 8 and the second one, other scenarios had various weights by using the different weighting method.

 In this study, eight inter-basin water transfer scenarios were evaluated upon four criteria, including technical risks and performance difficulty; political and social obstacles; environmental challenges; and prime cost of a cubic meter of water. In the following, weights of the mentioned criteria were determined to employ three approaches of the AHP, Shannon Entropy, and DEMATEL, and COPRAS technique was used to prioritizing of the criteria. The obtained results revealed that 8th scenario, including water transfer from the base flow of the Behesht-Abad basin to Esfahan province, through the pumping and short water conveyance tunnel, and from the Kheran-Kersan Dam 3 to Yazd and Kerman provinces was selected as the best scenario for water transfer to central plateau of Iran. Application of the approach is recommended in complex decision making in water resources management, mostly incorporated with conflicts and inhomogeneous qualitative and quantitative criteria, due to practical utilization of this method in the evaluation and prioritizing of scenarios. It is worth noting that the proposed method was conducted in forms of fuzzy and crisp configurations.