Los Caracoles Dam, Concrete-face rock-fill dam and hydroelectric power station in San Juan Province, Argentina

Los Caracoles Dam is a concrete-face rock-fill dam on the San Juan River, 44 km west of San Juan city. Its 136 m-high, 620 m-long embankment holds 10,326,000 m³ of compacted gravel, faced with a reinforced concrete slab. Two Francis turbines of 62.5 MW each sit in a powerhouse fed by a 1,500 m headrace tunnel.

Construction began in 2004 and finished in 2009, marking an important step forward in regional energy infrastructure. The project was part of broader efforts to modernize hydroelectric power in Argentina.

The dam's name comes from the Quebrada de Los Caracoles, the gorge where the San Juan River is impounded. Its reservoir stores water for irrigating 17,000 hectares, and the water reaches the Francis turbines through a 1,500-metre tunnel bored into the right bank. The province, through its state company EPSE, operates the reservoir.

The structure sits along a mountain slope and is accessible from a nearby road. The best view of the installation comes from surrounding heights where you can see the entire system and its impact on the river.

The dam's concrete face is a slab of reinforced concrete with sealed vertical joints, placed on the upstream side of the gravel fill; it used 93,000 m³ of concrete and 8,000 tonnes of steel over 14 months. The 1,500 m headrace tunnel on the right bank, 5.5 m in diameter, feeds the two Francis turbines.