The Itaueira River, located in southern Piauí, has always played an essential role for the region's rural communities, providing water, food, and traditional agricultural practices. Currently, its riverbed is dry, leaving only a few active springs, such as the one in the Brejo community, which still quenches the thirst of animals and sustains subsistence farming. The objective of this research was to analyze the importance of the Brejo spring and to record the memories and knowledge of local residents about the environmental transformations that have occurred over time. To this end, a qualitative case study methodology was adopted, based on direct observation, photographic records, and semi-structured interviews. The results revealed profound changes in the river's water regime, related both to decreased rainfall and to human interventions, such as the construction of dams and the spread of wildfires. Despite this, the Brejo spring resists, sustaining agricultural practices, animal survival, andthe preservation of traditional knowledge passed down through generations.