The complexity of environmental problems demands the involvement of society to build solutions. Particularly, water management recognises participatory processes in its regulations, which present implementation limitations. The participatory elaboration of a timeline of milestones in the Santa Lucía River Basin, source of drinking water for 60% of Uruguay's population, is presented. The strategy articulates academia, a local social organisation and inhabitants of Santa Lucía. The timeline makes visible the strength of social movements to guide state action in territorial management; and that the development of these actions is associated with `crisis´ events. Making the role of social organisation in environmental management visible is relevant in a context of weakening participatory spaces. The importance of strengthening participatory processes for long-term territorial management that considers global change is highlyghted.