How to deal with irrigation demand in a context of water scarcity and water uncertainty: an example of combining tools in the Charente river basin in France

In period of low water level, some river basins face an imbalance between the available water resource and the uses. In France, the development of the irrigation since the years 1970 is an important cause of this imbalance. The water needs can exceed the natural water supply. Favoured by the 1992 French water act, rending the metering progressively obligatory and that recommend dialogue among water actors, a volumetric management (VM) mechanism has progressively been implemented. A VM consists in finding a equitable distribution of the water in defining, according to its state, some access rules among users. VM already exists in systems where the water supply is foreseeable with a good probability (tablecloth or dam). The Upstream Charente river basin in France face an important imbalance added to high sensitivity of the resource to the climatic conditions. However, a VM is implemented in this basin since the creation of Mas-Chaban dam in year 2000, which allow to resupply the river. This article presents the VM instruments implemented in this basin and discusses their effectiveness and their social acceptability.