After more than two years of work, the modernization of the Quebrada de Ullum Hydroelectric Plant concluded with a historic event: the release of a large volume of water into the course of the San Juan River. It was an unusual spectacle that reminded of the river’s natural power, becoming the protagonist after years of drought.
The project was carried out by the Provincial Energy State Company (EPSE) and involved the replacement of essential components such as the turbine and generator, as well as new security systems. These improvements will extend the lifespan of the plant by at least two decades, making it one of the most important in the province.
To test the functionality of the renovated machinery, tests were carried out for three days that required releasing peaks of up to 116 cubic meters per second from the dam. This extraordinary release, which had not occurred since 2016, was carefully planned to ensure safety and avoid negative impacts on the population.
The additional flow did not reach the full length of the river, but it transformed the landscape downstream of the dam for hours, offering residents and visitors an unusual sight. Beyond the visual impact, this operation played a key environmental role by contributing to the recharge of the province’s underground aquifers.

Clean Energy and Sustainable Modernization
With a capacity of 45 MW, the Quebrada de Ullum Hydroelectric Plant is now positioned as the most modern in the province thanks to the incorporation of automated technology. Its upgrade ensures a more stable and secure electrical supply, providing renewable energy to the national grid.
These types of projects reinforce San Juan’s role as a leader in hydroelectric generation. In a context of recurring droughts, efficient management of dams and power plants is essential to sustain energy production and agriculture without compromising natural resources.
The modernization also paves the way for new water replenishment strategies, integrating energy production with environmental preservation. By releasing water into the natural course of the San Juan River, the positive impact is multiplied: clean energy, aquifer recharge, and revitalization of an ecosystem that is essential for the province’s future.

The Value of the San Juan River in Environmental and Social Life
The San Juan River is the backbone of the provincial ecosystem. Its course, fed by the mountain thaws, sustains a vast network of irrigation channels that support local agriculture. From vineyards to vegetable crops, they depend on its flow to thrive in an arid climate region.
In addition to its productive importance, the river acts as a natural reservoir of groundwater. Much of the population and industry in San Juan is supplied by aquifers that recharge precisely due to these filtrations. Each controlled flow release, like the one carried out in Ullum, reinforces that delicate water balance.
The river also holds strong cultural and recreational value. Its banks have historically been spaces of gathering and identity for the local population. Keeping its course alive not only preserves an ecosystem but also a natural heritage linked to the history and daily life of the people of San Juan.



