Line watershed falls within the scope of the watershed of the Loire, the source of the Vienna Convention on the Millevaches to the estuary. Watershed, not the Loire river! That is to say the inclined to the sea level, all of the irrigated area, not only the stroke of the river. That is to say, the business areas and wetlands, ditches and highways, meeting rooms and yards. Because water is everywhere, in soil, ground, air, flowing, seeping, evaporating and everywhere connecting the territories between them, indicating their interdependence, making us dream of solidarity. The line of the watershed is not only the geographical dividing line between watersheds but it is also the policy line that connects individuals and groups who have something shared: water, territory, landscape.