The Yacyretá Dam or Jasyretâ-Apipé Hydroelectric Power Station (from Guaraní jasy retã, "land of the moon") is a dam and hydroelectric power plant built over the waterfalls of Jasyretâ-Apipé in the Paraná River, between the Paraguayan City of Ayolas and the Argentine Province of Corrientes. The dam is named for Yacyretá Island just upstream, much of which the dam submerged. The word "Yacyreta" is the Hispanicized spelling of the original Guaraní term Jasyretâ. The dam is 808 metres (2,651 ft) long, and its installed equipment has a maximum power output of 3,100 megawatts (4,200,000 hp), with a record maximum annual power output of 20.091 TWh (72.33 PJ) achieved in year 2012, and a maximum water flow rate of 55,000 cubic meters per second. Until February 2011, its reservoir was seven meters below its planned water level, only allowing it to operate at 60% capacity. The project generated controversy and criticism during its planning and construction because of the effects it had on local ecology, particularly the flooding of a unique environment causing the extinction in the wild of several species. The financial management of the project also garnered criticism, as it greatly exceeded its original budget, ultimately costing more than $11 billion. On 18 September 2006 Paraguay agreed to settling its part of the overall debt of $11,000,000,000 owed to Argentina for the construction of Yaciretá by paying in electricity, at the rate of 8,000 GWh per year for 40 years. In 2014 Paraguay consumed almost 5 percent of its share of Yacyreta's production, exporting the rest to Argentina. The Yacyreta Dam is managed by the Yacyreta Bi-National Entity, established by treaty between the two countries.
Geography
Yacyretá is located 260 kilometres (160 mi) southeast of Asunción. It is located in the region of a city called Ayolas, 100 kilometres (62 mi) downstream from Encarnación and 2 kilometres (1.2 mi) away from the rapids of Apipé. The main dam is near the islands of Jasyretâ and Talavera.
Chronology
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.
Construction In addition to the dam, a barrage of materials 65 kilometres (40 mi) 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 21 metres (69 ft) above the original level and covers 1,600 square kilometres (620 sq mi). 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 bedrock 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.
Population and ecological impact
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