In France, the drought system cuts across two different administrative structures:
- The water management structure, which follows the geographical limits of the watersheds, a homogeneous unit from the point of view of water,
- The alert structure, which follows the administrative boundaries of the state organization: the Departments.
When a water shortage is felt in a watershed, each concerned Department issues a decree to restrict water uses. This decree is issued by the Prefecture, and sent to all the mayors concerned.
Example of an overlap map between the Watershed and the Department