Hydroelectric power station



The fourth dike of the Integral Use of the Rio San Juan will have the largest reservoir volume (605 hm3), expanding irrigation capacity in the region and regulating the water levels and the flow of the river, which is the motor of the local economy. Its annual energy production will reach 343 GWh.

A project that guarantees vital resources for San Juan: water and energy

187.550 m3


16.900.000 m3


70 MW

installed capacity

3,8 km



Hydroelectric power plant El Tambolar


Energía Provincial Sociedad del Estado (E.P.S.E.) , Provincia de San Juan


The El Tambolar Hydropower plant, is to be built on the San Juan River near the town of Pachaco, 145 km from the city of San Juan and 20 km upstream of the Los Caracoles dam.

The works involve an access road from the Los Caracoles power plant, the diversion channels for the San Juan River, a gravel concrete-faced dam with flood spillway and an open-air channel.  Generation is pressure-driven and there is an external power plant.

The diversion of the river for the construction of the dam was undertaken by building two parallel tunnels lined with a reinforced concrete trunk section on the right bank of the river. Both tunnels are 6 meters in diameter and have a length of 492 meters. One of the two tunnels will later function as a bottom outlet, so a sluice gate will be built inside it with an access tunnel leading to it.

The dam will have a height of 88 m above the river and 113 m from its foundation on the rock. The crown is 450 m long with a filling of a volume of 5,100,000 cubic meters of alluvial materials. The concrete face will be 76,000 m2, while the spillway located on the right bank will be free with a weir of 250 m in length able to take as much as 3,200 m³/s.

Tunnels take the water to the powerhouse through the rock mass with a circular section of 5.70 meters in diameter and 2,600 meters in length, with a surge chamber and pressure steel pipe in the final stretch before reaching the powerhouse.