Ясирета: Плотина на реке Парана и её история

Dam on the Paraná River on the border of Argentina and Paraguay
The Yacyreta Dam is managed by the Yacyreta Bi National Entity, established by treaty between the two countries.

Yacyreta is located southeast of Asunción. It is located in the region of a city called Ayolas, downstream from Encarnación and away from the rapids of Apipé. The main dam is near the islands of Jasyretâ and Talavera.

The initial protocol to determine the use of the waterfalls was signed on February 1, 1925, in the United States. However, it was not until January 1958 that the Technical Argentine Paraguayan Commission was created to undertake technical studies of the uses of the river. The studies were presented on December 3, 1973, in Asunción and the Treaty of Yasyreta was signed; both countries compromised to embark together in the construction. For that, the Bi National Organization Yasyreta was founded. Each state would share jurisdiction and responsibility for executing studies and projects related to the dam. The construction started on December 3, 1983; on April 26, 1989, agreements were signed that defined the definitive plans for the protection of the valleys and streams to the right side of the river (Paraguay). In June of the same year the main branch of the river was closed and on May 19, the other branch, Aña Kuá, was also closed. On June 1, 1993, the navigational ship lock was opened, and on September 2, 1994, the first hydroelectric Kaplan turbine began operation. The 20 programmed units functioned for the first time together on July 7, 1998.

In addition to the dam, a barrage of materials long closes both arms of the river divided by the island Jasyretâ; the hydroelectric dam is in part located over this. Both extremes are settled in the Argentine coast, in the locality of Rincón Santa María and in the Paraguayan coast, near the city of San Cosme y Damián. The artificial lake formed by the dam rises above the original level and covers
Each branch has a slope. The turbines are in the main branch, in a slope with eighteen gates that allow a maximum flow of 55,000 cubic meters per second. The other branch of the river has sixteen more gates with a capacity for another 40,000 cubic meters per second. A ship lock excavated in the basaltic layer allows passage of boats with draft up to 12 feet (3.6 m). A fish ladder, designed after the ecological studies proved that the presence of the dam inhibited the reproduction of certain migratory species of the Paraná River, especially the dorado and surubí, allows fish that swim upstream to cover the 25 meter difference to spawn in the Alto Paraná. The machine house is 70 meters high. The waterfall, currently 15 meters high, has an average volume of 8,000 cubic meters per second that pass through the turbines and produces energy continuously. For comparison, the falls of Iguazú are 70 meters high, with a volume of 1,750 cubic meters per second.

The lake created by the dam displaced 40,000 people. The elevation of the water level also affected the road infrastructure and sewage of the region in a way that many studies undertaken prior to construction of the dam did not take into account ; independent research later confirmed that the census of INDEC in 1990 was altered to reduce the amount of money the Yacyreta Organization would have to pay to compensate the people displaced. Ecologically, the construction of the dam most greatly affected the environment of the region in three ways. Firstly, it altered aquatic habitats via the elevation of the water level and the flooding of previously dry areas, which produced chemical changes in the water, including a drop in water oxygen levels. The construction of the system of elevators helped reduce this effect .

To ease navigation a ship lock was built in the locality of Santa María in the Argentine side. This has a length of 270 meters, and width of 27 meters and a depth of 5 meters, which allows the passage of 12 foot draft boats.

The area has an abundant fauna and there are areas for fishing. Fishing is regulated to protect and maintain fish populations, requiring fishing permits that can be obtained in the regional Office of Fishing. The Yacyreta Regional Museum is located in Ayolas. It exhibits archaeological objects, minerals and examples of specimens of the native fauna. The Animal Refuge of Atinguy is located 18 kilometres from Ayolas; its territory is roughly 100 hectares, where a great variety of flora and fauna of the region can be found. The refuge provides conditions for the animals to live in a natural environment. Even though the hydroelectric power station produces a relatively low amount of contaminants, the Bi National Organization has set aside areas for the preservation and recuperation of the local flora and fauna, trying to reduce the consequences of the construction. From flooding, 11,000 animals from 110 different species were relocated. Currently, the Organization has a protected area of about 58,000 hectares, with plans for an eventual increase to 187,000 hectares There is a centre for visitors and a track of 2,500 meters called "Akuti po’i" that serves to take guided tours. There are several hotels to stay in when visiting the place, such as the Hotel Nacional de Turismo and the Jasyretâ Apart Hotel.