An evolutionary bargaining framework for allocating water and reclaimed wastewater in agricultural regions

This paper presents a new framework for modeling the bargaining process among stakeholders by coupling social choice and bargaining methods. Based on this framework, two methods of evolutionary bargaining coupled with Borda count (BBC) and evolutionary bargaining coupled with pairwise voting (BPV) are proposed, and the results of applying them as challenging problems of allocating water and reclaimed wastewater in agricultural regions are analyzed. After proposing some candidate scenarios of allocating water and reclaimed wastewater, non-dominated scenarios are determined. Then, in the first level of bargaining, using a social choice technique, each stakeholder chooses the most desirable scenario out of the non-dominated ones, regardless of the utilities of other stakeholders. The selected scenarios by all stakeholders can provide them an estimate of other stakeholders' expected utilities. This enables each stakeholder in the next step of bargaining to suggest a scenario that improves their own utility and gives the minimum acceptable utility of other stakeholders. If the bargaining process provides more than one scenario, a social choice method is applied to find the most preferred scenario. The applicability and performance of the proposed framework are evaluated by applying it to the Varamin plain, in the south-east of Tehran, Iran.