Guaraní Aquifer
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The Guaraní Aquifer, located beneath the surface of Argentina, Brazil, Paraguay and Uruguay, is one of the world's largest aquifer systems and is an important source of fresh water.[1] Named after the Guaraní tribe, it covers 1,200,000 km², with a volume of about 40,000 km³, a thickness of between 50 m and 800 m and a maximum depth of about 1,800 m. It is estimated to contain about 37,000 km³ of water (arguably the largest single body of groundwater in the world, although the overall volume of the constituent parts of the Great Artesian Basin is much larger), with a total recharge rate of about 166 km³/year from precipitation. It is said that this vast underground reservoir could supply fresh drinking water to the world for 200 years. Due to an expected shortage of fresh water on a global scale, which environmentalists suggest will become critical in under 20 years, this important natural resource is rapidly becoming politicized, and the control of the resource becomes ever more controversial.
[edit] Geology of the aquifer
The Guaraní Aquifer consists primarily of sedimented sandstones deposited by fluvial and eolian processes during the Triassic and Jurassic periods (between 200 and 130 million years ago), with over 90% of the total area overlaid with igneous basalt of a low-permeability, deposited during the Cretacous period, acting as an aquitard and providing a high degree of containment. This greatly reduces the rate of infiltration and subsequent recharge, but also isolates the aquifer from the Vadose zone and subsequent surface-associated losses due to evaporation and evapotranspiration.
Research and monitoring of the aquifer in order to better manage it as a resource is considered important, as the population growth rate within its area is relatively high — resulting in higher consumption and pollution risks.
The countries over the aquifer are also the original four Mercosur countries.
[edit] References
[edit] External links
- Official Site for the book about the Aquifer, by Nadia Rita Boscardin Borghetti, José Roberto Borghetti and Ernani Francisco da Rosa Filho (in Brazilian Portuguese)
