Abstract
Irrigation water is a crucial resource for economic and social development in Tunisia. In a context of decentralization and State devolution, the local associations for agricultural development or 'Groupements de Développement Agricole (GDA)' manage today a large share of irrigation water in the country. However, these institutions are experiencing a lack of acknowledgment by water users, resulting in a low willingness to pay (WTP) for water. In this article we study to what extent information provided to users on the functioning of the system (« institutional » information) and/or on the decisions taken by other users (« social » information) can affect their WTP. Our analysis is twofold. A field survey first revealed the farmers' demand for better information provision. A laboratory experiment allowed then to isolate the impact of the two types of information on subjects' decisions through a game with similar properties to those observed in the field. Data collected in the lab confirm the existence of a causality relation between information provided to users and their WTP for a common resource such as irrigation water.