Examination of players’ strategies in determining the optimal groundwater exploitation by game theory

The growing water demand and decreasing groundwater recharge have made groundwater management one of the most severe challenges in most countries of the world, and Iran is no exception. This study aims to examine the optimal groundwater exploitation in three cropping years (2020–2021, 2021–2022, and 2022–2023) in a study of the Silakhor plain, Iran, by use of game theory. Game theory problems involve multidecision-making to address conflicting objectives. Thus, farmers and environmentalists were considered as game theory ‘players’ and their strategies were examined. Two groups of groundwater exploitation scenarios were considered based on both groundwater recharge and the current exploitation. Optimal groundwater exploitation was determined. The results of determining exploitation scenarios based on the current exploitation show that the optimal groundwater exploitation in the Silakhor plain is 103.9, 101, and 99 million m³ in the next 3 years, respectively; these values decrease by 6.7, 7, and 7.4%, respectively, by determining exploitation scenarios based on groundwater recharge. The second major finding is that the farmers’ net benefit will increase by 18% by applying the optimal cropping pattern. Taken together, the results show that the design of the game structure is very important and the basis of the players’ strategies must be determined before using conflict resolution methods.