Water Resources Management in Qarehsou River Basin of Golestan Province under Drought Condition and Environmental Protection: A Cooperative Game Theory Approach

Given the climate change and the need to protect the environment, especially in arid and semi-arid regions, it is necessary to adopt a new mechanism for the equitable allocation of scarce water resources and the resulting benefits among stakeholders. This study used a Cooperative Game Theory (CGT) framework in order to analyze water management under water scarcity and drought conditions in Qarehsou River Basin of Golestan province of Iran. The required data were collected through a survey research and completing the questionnaires in the cropping year of 2017-2018. Loehman stability index was used to investigate the willingness of stakeholders to participate in coalition and the determination of stability. The results showed achieving full cooperation would increase the total benefit of basin. The study of the stability index showed that in general, the grand coalition based on Nash-Harsanyi was more stable than the Shapley value and Nucleolus in drought scenarios. As a result, the cooperation between stakeholders should be increased in the form of basin coordination councils to protect the ecosystem and preserve the economic interests of basin in conditions of water scarcity. The CGT solutions and power index examined demonstrate the importance of combining the strategic behavior of stakeholders in designing acceptable and sustainable policies to reduce the effects of drought in the basin. Therefore, it is recommended to apply Nash-Harsanyi solution to redistribute the benefits of cooperation between stakeholders in the basin; in other words, the distribution of cooperative benefits between stakeholders is based on relative weights, which is calculated based on the maximum demand of water users in the non-cooperative model within a cooperative theory.