Dams

Advantages	Disadvantages
water supplies assured prevent floods	people are forced to move ecosystems destroyed expensive water related diseases

A dam in Argentina

Yacyretá Dam

   The Yacyretá Dam is a dam and hydroelectric power plant built over the waterfalls of Jasyretâ-Apipé in the Paraná River, between the Argentine Province of Corrientes and the Paraguayan City of Ayolas.

   The construction of the dam affected the environment of the region in three ways. Firstly, it altered aquatic habitats because of the elevation of the water level and the flooding of 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 floating vegetation that in the system Iberá is the habitat of many species. The more calm water behind the dam has also allowed the spread of waterborne diseases, such as schistosomiasis, dengue fever and malaria. Destruction of the habitat submerged by the dam caused great loss of biodiversity. Numerous protected species have been affected in one of the few spaces in which they survive in Argentina and Paraguay, 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. Moreover, the lake created by the dam displaced 40,000 people.