The value of cooperation in coastal aquifer management: Lessons for Oman

Groundwater over-abstraction and the resulting decline in groundwater level and quality have limited agricultural activities in many parts of the world. The desire for maximizing the short-term benefits and the fear of free riding by other uses discourage farmers from reducing the current water levels. This results in a classis tragedy of the commons in which groundwater beneficiaries will experience long-term profit losses due to their unsustainable use of groundwater. This paper develops a mathematical modeling framework for understanding the long-term value of cooperation in groundwater use. A numerical example is developed based on the current status of groundwater in a coastal region of Oman, where groundwater over-abstraction has resulted in increases salinity due to seawater intrusion. Using an agent-based model, the long-term changes in groundwater level and salinity as well the long-term benefits of the farmers are first examined. Next, the optimal cropping and groundwater withdrawal strategies are found for a cooperative mechanism based on which parties try to maximize their longterm benefits through coordination. Value of coordination is then calculated by comparison of the total obtainable profit under the non-cooperative and cooperative cases. Knowledge of this value would be necessary to promote policy reforms that enforce immediate reduction of groundwater withdrawals would for increasing the long-term benefits through sustainable use of the system.