Yacyretá Dam

The Hydroelectric Power Station Jasyretâ-Apipé (from Guaraní language jasy retâ that means “country of the moon”) is the hydroelectric central built over the waterfalls of Jasyretâ-Apipé in the Paraná River, between the Argentine Province of Corrientes and the Paraguayan department of Misiones.

Clarification: The word “Yacyreta” is a misspelling of the original word, the true Guaraní term Jasyretâ. The term “Yacyreta” was used by the Argentine that didn’t know too well the pronunciation and the writing of the words. At the same time, they made the most with the name and used it to create a logo mixing the words “PARAGUA – YACYRETA – RGENTINA”.

The equipment of the central has a installed power of 3200 MW, existing an expansion project that would allow upgrade the capacity to the double. The energy that produces provides the 15% of the total energy demand in Argentina.

Through every turbine can pass 2630 millions of liters of water per hour, meaning that by the 20 turbines of Yacyreta can pass, every hour the equivalent to the usage of 13 days of running water in Asunción (capital of Paraguay) o 2 days in Buenos Aires (Argentina). The energy that can produce in a year is 19,000 Gwh.

In spite of the services offered, the project was object of constants critics during it planning and construction, because of the consequences it had on the ecology – among them, the flooding of a unique environment that caused the extinction of numerous species – as well as the financial management of the project, which had an original budget that was greatly exceeded and reached 11,500 million American Dollars and started many denounces of corruption.

Geography

Yasyreta is located 320 kilometers to the South-East of Asunción. It is located in the region of a city called Ayolas, 100 kilometer downstream from Encarnación 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 singed on February 1, 1925 in the United States. However it will be in January of 1958 that the Technical Argentine-Paraguayan Commission would be created, and would be in charge of the technical studies of uses of the river. The studies were presented on December 3, 1973 in Asunción and the Treaty of Yasyreta was subscribed; both countries compromised to embark together in the construction. For that the Bi-National Organization Yasyreta was founded: in equal condition both parts, each would have juridical ability and technical responsibility to do the studies and projects, as well as the execution of them.

The construction started on December 3, 1983; on April 26, 1989 were signed the notes 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 in May 19, the other branch too, Aña Kuá. On June 1, 1993 it was accessible the navigation floodgate to save the difference of height and on September 2, 1994 the first unit of the hydroelectric central. The 20 programmed units functioned for the first time together on July 7, 1998.

The construction work

In addition to the dam, which is about 808 meters long, it has barrage of materials of about 65 kilometers that closes both arms of the river divided by the island Jasyretâ; the hydroelectric central is in part settled over this. The both extremes are settled in the Argentine coast, in the locality of Rincón Santa María and in the Paraguayn coast, near the city of San Cosme y Damián. The artificial lake formed by the dyke rises 21 meters above the original level and covers 1600 square kilometers.

In each branch there is a slope, the turbines are settled in the main branch, in a slope with 18 gates that allow a maximum flow of 55,000 cubic meters per second. The other branch of the river has 16 more gates with a capacity for another 40,000 cubic meters per second.

A floodgate excavated in the basaltic layer allows the circulation of the boats until 12 feet. A system of elevation – designed after the ecological studies proved that the presence of the dyke inhibit the reproduction of certain migratory species of the Paraná River, specially the dorado and surubí – allows the fish that swim upstream to cover the 25 meters of difference to spawn in the Alto Paraná.

The machine house is 70 meters high, from the foundations to the roof. The waterfall (of 15 meters currently) has an average volume of 8,000 cubic meters per second that pass for the turbines and produce energy continuously. To compare dimensions, the waterfalls of Iguazú are 70 meters high and a volume of 1,750 cubic meters per second.

Population and Ecologic Impact

The area that is today covered by the lake used to be home of 40,000 people that had to move to other places. The elevation of the water level affected also the road infrastructure and sewage of the region in a way that many studies previous to the execution of the project, financed and availed by the World Bank did not have in account; the independent researches confirmed, years later, 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.

In the ecology, the construction of the dam affected mostly in three aspects the regional environment:

The structure of the aquatic habitats, with the elevation of the water level and the flooding of previously dry areas produced a chemical alteration in the water. Besides, the alteration of the streams of water affected the dynamic of the floating vegetation that in the system Iberá is the habitat of many endemic species. Plus, the calmness of the water has made possible the proliferation of species transmitter of diseases, such as esquitosomiais, dengue fever and malaria.

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.

The diversity and stability of the land habitat that could cause great lost of biodiversity. Numerous protected species resulted affected in one the few spaces in which they survive in Argentina and Paraguay, among them are: The deer of the swaps, pampas, capybara, herons, bogies and vacarés.

The consequences over the fish population of Paraná were very severe too, causing an important diminishment of the volume of some species; the construction of the system of elevators helped reduce this effects.

Current State

The plan to finish the project of Yasyreta is:

* To free the flooded areas, taking in consideration the expropriation of properties, the safety of the freed areas, the relocation of the population and the economic-productive activity and the rehabilitation of the economy of the population.
* To do all the necessary work to reduce the effects over the natural environment.
* To repair the infrastructure, routes, bridges, ports, airports, electric supply lines, etc.
* To repair the damages to the urban areas of Encarnación, Posadas and other cities.

In July of 2007 the level of water reached the 76 meters above sea level, 7 meter under the wanted numbers. This difference in the height of the water level is responsible for the hydroelectric center to work with only 60% of its capacity, with a power of 2,100 MW instead of the 3,100 MV that were originally planned. The reason for which is not possible the water to reach 83 meters above sea level is that it would cover another 500 square kilometers of land surface affecting more than 80,000 people.

The presidents of Argentina and Paraguay signed a document to finish the works in December of 2008.

Navigation

To make easier the navigation it was built a floodgate in the locality of Santa María in the Argentine side. This has a longitude of 270 meters, and width of 27 meters and a depth of 5 meters, which allows the passage of 12 foot boats.

Tourism

The area has an abundant fauna and there are areas destined to fishing. With the idea of maintain and protect the native fish, the fishing is regulated, requiring even a special identification for fishing 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 of about 100 hectares, where can be found a great variety of flora and fauna of the region.
* The refuge provides the optimum conditions for the animals to live in a natural environment.

Even though the hydroelectric power station produces relatively low amount of contaminants, the Bi-National Organization has destined areas to the preservation and recuperation of the local flora and fauna, trying to reduce the consequences of the construction. With the flooding, they found and relocated 11,000 animals from 110 different species. Currently, the Organization has a protected area of about 58,000 hectares and pretends to increase it to 187,000 hectares eventually. 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. The Tourism Secretary provides with all the information and details about it.

Reference

* EVP - Wikipedia
* [http://www.evp.edu.py/index.php?title=Portada Enciclopedia Virtual Paraguaya - Portal]

External links

* [http://www.eby.org.ar/ Official Argentine site]
* [http://www.eby.gov.py/ Official Paraguayan site]
* [http://www.oni.escuelas.edu.ar/2002/corrientes/energia/ Yacyretá, Energy of the future]
* [http://www.clarin.com/diario/2005/04/22/sociedad/s-05001.htm Yacyretá and Esteros de Iberá] (Clarín Newspaper)
* [http://maps.google.com/maps?ll=-27.3832,-56.622849&spn=0.111226,0.240704&t=k&hl=en Google Maps Satellite Image of Dam]