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.

[3] 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[3] causing the extinction in the wild of several species.

[4] The financial management of the project also garnered criticism, as it greatly exceeded its original budget, ultimately costing more than $11 billion.

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).

On June 1, 1993, the navigational ship lock was opened, and on September 2, 1994, the first hydroelectric Kaplan turbine began operation.

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).

A ship lock excavated in the basaltic layer[clarification needed] allows passage of boats with draft up to 12 feet (3.6 m).

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 [citation needed]; 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.

[3] 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.

Numerous protected species have been affected in one of the few spaces in which they survive in Paraguay and Argentina, including pampas deer, capybara, certain water birds and yacare caiman.

The consequences for 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.

Even though the hydroelectric power station produces a relatively low amount of contaminants[citation needed], 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.