Just water reallocation for the environment and agriculture: a translation of Rawls theory of justice

One primary purpose of Water Reallocation (WRA) policies is to fairly redistribute water to different demands. However, these policies create a dilemma for policy-makers, as no exclusive method for measuring justice in water management exists. Rawls’ theory of justice is a pivotal philosophy due to its more precise definition of distributive justice in its modern status and its compatibility with the current justice definition in Iranian laws. A new method is developed by conceptualizing and translating Rawls’ principles, including basic liberties, equality of opportunities, and different principles, into WRA rules. Using the Karkheh River Basin (KRB) to validate the application of the methodology, impacts of just rules were evaluated based on the simulated results of the Soil and Water Assessment Tool (SWAT) model for 31 years (1985–2015), the indicators of Water Footprint (WF) sustainability coupling with economic and food security of KRB’s main agricultural productions. Allocating water to five provinces as players showed that the Basin is currently unsustainable regarding the unsatisfied environmental flows (E-flows) to the Hour-Al-Azim wetland, aquifer overexploitation and high blue water usage. A 9–37% reduction in irrigation water allocation by the just WRA rule can improve 6–29% surface and groundwater resource (blue water) footprint sustainability (BWS) and satisfy the E-flow. The rule also results in a 2.5–12% reduction in agricultural production yields and adversely reduces farmers’ economic income and food production, but these reductions would not significantly endanger food security. Consequently, based on philosophical principles of justice, the proposed methodological framework could enhance the WF sustainability of basin by ensuring everyone’s access to a healthy environment, and Human Right to Water (HRW) and food security.