Yacyretá Dam
Encyclopedia
The Yacyretá Dam or Hydroelectric Power Station Jasyretâ-Apipé (from Guaraní jasy retã, “land of the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

”) is a dam and hydroelectric
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

 power plant built over the waterfalls of Jasyretâ-Apipé in the Paraná River
Paraná River
The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...

, between the Argentine
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...

 Province of Corrientes
Corrientes Province
Corrientes is a province in northeast Argentina, in the Mesopotamia region. It is surrounded by : Paraguay, the province of Misiones, Brazil, Uruguay, and the provinces of Entre Rios, Santa Fe and Chaco.-History:...

 and the Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...

an City of Ayolas
Ayolas
Ayolas is a city in the department of Misiones, Paraguay. It is also the name of the district that the city is located in.- Toponymy :The city takes its name on behalf of Juan de Ayolas, second of Pedro de Mendoza, who founded Puerto la Candelaria, now Fuerte Olimpo, on the Paraguay River...

. The dam is named for Yacyretâ 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 meters long, and its installed equipment has a maximum power output of 3,100 MW, with an annual maximum power output of 19,080 GWh, 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 of numerous species. The financial management of the project also garnered criticism, as it greatly exceeded its original budget, ultimately costing more than $11 billion, and earning it a reputation as a "monument to corruption
Political corruption
Political corruption is the use of legislated powers by government officials for illegitimate private gain. Misuse of government power for other purposes, such as repression of political opponents and general police brutality, is not considered political corruption. Neither are illegal acts by...

".

Geography

Yacyreta is located 260 kilometers southeast of Asunción
Asunción
Asunción is the capital and largest city of Paraguay.The "Ciudad de Asunción" is an autonomous capital district not part of any department. The metropolitan area, called Gran Asunción, includes the cities of San Lorenzo, Fernando de la Mora, Lambaré, Luque, Mariano Roque Alonso, Ñemby, San...

. It is located in the region of a city called Ayolas, 100 kilometer downstream from Encarnación
Encarnación, Paraguay
Encarnación is the capital city of the Paraguayan department of Itapúa, located at the south of the department, on the right-hand shore of the Paraná River, opposite Posadas, Argentina...

 and 2 kilometers away from the rapids of Apipé. The main dam is near the islands Jasyretâ and Talavera.

Chronology

The initial protocol to determine the use of the waterfalls was signed on February 1, 1925 in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. However, it was not until January 1958 that the Technical Argentine-Paraguayan Commission was created to undertake technical studies of 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 turbine began operation. The 20 programmed units functioned for the first time together on July 7, 1998.

Construction

In addition to the dam, which is 808 meters long, a barrage of materials 65 kilometers 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
San Cosme y Damián
San Cosme y Damián is a town in the Itapúa department of Paraguay.- Sources :* – World-Gazetteer.com...

. The artificial lake formed by the dam rises 21 meters above the original level and covers 1600 square kilometers.

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
Draft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...

 up to 12 feet (3.6 m). A fish ladder
Fish ladder
A fish ladder, also known as a fishway, fish pass or fish steps, is a structure on or around artificial barriers to facilitate diadromous fishes' natural migration. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps into the waters on...

, designed after the ecological studies proved that the presence of the dam inhibited the reproduction of certain migratory species of the Paraná River
Paraná River
The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...

, especially the dorado
Dorado
Dorado is a constellation in the southern sky. It was created in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish , which is known as dorado in Spanish, although it has also been depicted as a swordfish...

 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 produce energy continuously. For comparison, the falls of Iguazú are 70 meters high, with a volume of 1,750 cubic meters per second.

Population and Ecologic Impact

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. Besides, the alteration of the streams of water affected the dynamics of the floating vegetation that in the system Iberá is the habitat of many endemic species. The more calm water behind the dam has also allowed the spread of waterborne diseases and disease vectors, such as schistosomiasis
Schistosomiasis
Schistosomiasis is a parasitic disease caused by several species of trematodes , a parasitic worm of the genus Schistosoma. Snails often act as an intermediary agent for the infectious diseases until a new human host is found...

, dengue fever
Dengue fever
Dengue fever , also known as breakbone fever, is an infectious tropical disease caused by the dengue virus. Symptoms include fever, headache, muscle and joint pains, and a characteristic skin rash that is similar to measles...

 and malaria
Malaria
Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

.

The structure and composition of the productive activities of the primary sector, that in addition to the direct flooding also modifies the level of humidity of thousand of hectares destined to agriculture and the exploit of wood, thousand of cattle were lost in the process of formation of the lake.

Destruction of the habitat submerged by the dam could cause great loss of biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

. Numerous protected species have been affected in one the few spaces in which they survive in Argentina and Paraguay, including deer, pampas, capybara
Capybara
The capybara , also known as capivara in Portuguese, and capibara, chigüire in Venezuela, Colombia, and Ecuador ronsoco in Peru, chigüiro, and carpincho in Spanish, is the largest living rodent in the world. Its closest relatives are agouti, chinchillas, coyphillas, and guinea pigs...

, herons, bogies and yacaré.
The consequences over the fish population of Paraná have been very severe, causing a large drop in the volume of some species, especially when the dam was first constructed. The construction of the system of elevators helped reduce this effect .

Current State

Before February 2011, the water level wass 76 m (249 ft) above sea level, 7 m (23 ft) less than planned. This caused the hydroelectric component of the dam to operate at only 60% of its capacity. The water level was raised, bringing it to 83 m (272 ft) above sea level and covering another 1650 square kilometre of land surface, affecting more than 50,000 people. This brought the installed capacity to its final design of 3,100 MW and the annual generation to about 20,000 GWh.

The plan to finish the Yasyreta project included:
  • Freeing the flooded areas, taking into consideration the expropriation of properties, the safety of the freed areas, the relocation of the population and the rehabilitation of the economy.
  • Doing all the necessary work to reduce negative effects on the natural environment.
  • Repairing the infrastructure, routes, bridges, ports, airports, electric supply lines, etc.
  • Repairing the damage to the urban areas of Encarnación, Posadas and other cities.

Navigation

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
Draft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...

 boats.

Tourism

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 archeological objects, minerals and examples of specimens of the native fauna.
  • The Animal Refuge of Atinguy is located 18 kilometers 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 center 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.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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