Until the 2000s, water resources in Tunisia were managed solely by government bodies without any consultation with water users. At the local level, Commissariats Régionaux de Développement Agricole [Regional Agricultural Development Committees (CRDAs)], which represented the government bodies, managed water resources. The Tunisian Government then decided to involve farmers in the local management of water resources by creating Agricultural Development Associations (GDAs). Water resource management by CRDAs must now take into account water demand from farmers belonging to GDAs and, in return, farmers must acknowledge water scarcity and accept the need for resource-sharing. How can CRDAs and GDAs work towards cooperative water management? In this paper, we present a simulation game requested by officials at the Kairouan CRDA in order to develop cooperative management of the water resources in a typical small watershed in central Tunisia. Our aim was to use the game to increase both farmers' awareness of water resource-sharing, scarcity, and the impact of overexploitation, and CRDA officials' awareness of different uses that determine water demands. The game is based on a hydrological model of the watershed and an agro-economic model of farming systems that use water resources for irrigation.