Four Nations Guard Giant South American Aquifer

By André Muggiati

MONTEVIDEO, Uruguay, May 29, 2003 (ENS) - The Mercosul countries - Brazil, Argentina, Uruguay, and Paraguay - launched this week in Montevideo a project for the preservation of the Guarani Aquifer, one of the largest underground water reserves in the world. Uruguay President Jorge Battle and government officials from the three other countries involved attended the launch ceremony.

Located mainly in Brazil, the Guarani Aquifer covers around 1.2 million square kilometers (463,323 square miles). The aquifer, named in honor of the Guarani Indian Nation extends over a total area greater than that of Great Britain, France and Spain together.


Water from the Guarani Aquifer flows cleanly from deep underground. (Photo courtesy Via Ecologica)
The underground aquifer could be a sustainable the source of water for more than 20 million people. It contains around 37 trillion liters of water and its depth varies from 50 to 1,500 meters (164 to 4,921 feet).

The new project, called the Guarani Aquifer Environmental Protection and Sustainable Development Plan, will cost US$26.7 million. It will be financed by the World Bank, the Dutch and German governments, the International Body for Atomic Energy and the Organization of American States.

The project will unfold in three stages. During the first stage, a basic map of the Guarani Aquifer System use and recovery will be constructed.

In the second stage, implementation of an information system of the aquifer will take place, and finally managers will receive training and institutional reinforcement, including those in the pilot project areas.

The project aims to avoid overexploitation of the reserve, which can be a crucial source of drinking water in the near future. Currently, the waters of the Guarani Aquifer are being used, although there is no control on this usage nor do officials have an idea of how much water is being withdrawn.

The annual recovery of the Guarani Aquifer by the infiltration of rain water is some 160 billion liters, and the amount that can be consumed is about 40 billion liters.

The process of infiltration takes decades, and during this process the soil filters the water, making it clean. This water is considered of excellent quality for public drinking water supply, and wells around 1,500 kilometers (932 miles) deep can provide 700,000 liters per hour.

The project will also work on answering some important questions regarding the future of the aquifer such as determining if there is a need to restrain agricultural and industrial activities in adjacent areas. Contamination by fertilizers and pesticides may ompromise the quality of the underground waters.


A stream originating in the Guarani Aquifer runs past a Brazilian town. Some 500 cities and towns across Brazil draw their water from the Guarani. (Photo courtesy IAEA)
Other activities, like garbage dumping, gasoline stations or construction of cemeteries in these areas can also contaminate the aquifer and may have to be restricted.

With the data resulting from these investigations, the project staffers will map areas where these activities are dangerous to the aquifer and should not be permitted.

Another question concerns the fact that the aquifer's water is considered of excellent quality. Some researchers believe that such a good water should not be used by agriculture and industry. Project officials may forbid access by agriculture and industry to the underground water. They would then have to use only surface waters from the river basins for their activities.

In the other hand, in some parts of Brazil which are subject to a desertification process, the use of the underground water may be authorized for the irrigation of crops. Another possible agricultural use is to warm the surface of land with the deeper, hot water, to avoid the loss of crops due to winter frosts.

These hotter waters, which can be as hot as 50 degrees Celsius (122 degrees Fahrenheit) may be approved for use in the tourism industry, which has been growing in recent years.

The building of an aqueduct to provide water for the São Paulo metropolitan area, which is not on the aquifer area, is also being considered, in spite of the fact that such a system could be wasteful due to leakages.

The city of over 18 million inhabitants is facing a severe water shortage in the near future, as its main water reserves are threatened by pollution and constant growth of settlements without wastewater treatment.

Other metropolitan areas of Mercosul, such as Buenos Aires, Argentina, may also be authorized to use water from the aquifer.