AQUIFERO GUARANI E ALTER DO CHÃO (MAIOR AQUÍFERO DO MUNDO/PLANETA) SAGA/SAG RIOSUL POÇOS ARTESIANOS

Water Resources and Aquifers: A Deep Dive

Overview of Earth's Water Distribution

• Approximately 75% of the Earth's surface is covered by water, with the remaining 25% consisting of continents.

• Of all the water on Earth, 97.2% is saltwater, while only 2.8% is freshwater.

Freshwater Accessibility

• If all freshwater were contained in a 20-liter bottle, only about 13.8 liters would be glaciers and ice caps, which are difficult to access.

• Groundwater accounts for approximately 5.9 liters in this analogy, also challenging to access; rivers and lakes contribute merely 52 ml—about one-fifth of a glass of water available for human use.

The Amazonian Aquifer Discovery

• A significant aquifer capable of supplying water for up to 250 years exists beneath the Brazilian Amazon, previously known as Alter do Chão but reclassified as the Grande Amazônia Aquifer System (SAGA) due to new research findings from UFPA in 2013.

• This aquifer spans an area of approximately 1.3 million square kilometers across several Brazilian states and has an estimated reserve of around 162,520 km³ of water, making it the largest known aquifer globally.

Geological History and Formation

• The geological history includes periods when South America was connected to Africa; volcanic activity led to basalt formations that now cover much of the region where these aquifers exist.

• Over millions of years, erosion allowed water to infiltrate into fractured rock layers above basalt deposits, forming significant underground reservoirs like the Guarani Aquifer System located in Brazil, Argentina, Paraguay, and Uruguay.

Characteristics and Importance of Aquifers

• The Guarani Aquifer covers about 1.19 million square kilometers with varying depths across regions; it contains roughly 37 trillion cubic meters of freshwater—equivalent to a lake the size of Uruguay at a depth of about 200 meters.

• It replenishes through rainfall that seeps into rock fissures at an annual recharge rate estimated at around 80 km³ per year—enough for sustainable usage over time without depleting resources significantly.

Interactions Between Surface and Groundwater

• In some areas, there is connectivity between surface waters (rivers/lakes) and groundwater systems; however, certain regions have confined waters that can be accessed via wells without needing pumping due to natural pressure dynamics allowing flow rates up to 300 liters per second from some wells.

• These thermal waters range from temperatures between 33°C and 65°C offering potential applications for geothermal energy or thermal tourism opportunities within these regions rich in natural resources like hot springs or mineral baths.

Conclusion on Water Resource Management

• The majority of these aquifers are protected by impermeable basalt layers preventing evaporation or contamination; thus they represent critical reserves for future potable water supply amidst growing global demands on freshwater resources.

This structured overview provides insights into both historical context and current significance regarding major aquifers such as those found in Brazil's Amazon region while emphasizing their vital role in sustaining human populations long-term amid environmental challenges ahead.

Guarani and the Amazon Aquifer: A Comparative Analysis

Characteristics of the Guarani Aquifer

• The Guarani aquifer, located in southern Brazil, is situated beneath rocky terrain, contrasting with the sandy soil found in the Amazon region.

• Rainwater easily penetrates sandy soil, creating a natural filtration system that results in clean drinking water from underground reservoirs.

• Drilling into sandy ground for wells is both easy and cost-effective; chemical treatment stations are often unnecessary.

The Alter do Chão Aquifer

• The Alter do Chão aquifer is recognized as a strategic global reserve, estimated to have existed for 300 to 400 years.

Discovery of Subterranean Rivers

• Recently, it was revealed that a subterranean river named "Hans," extending 6,000 km beneath the Amazon River at depths of 4,000 meters, rivals the previously known longest river.

• Both rivers flow in the same direction; while surface water follows the riverbed, deeper waters penetrate through soil towards the ocean.

Flow Rate Comparisons

• Researchers estimate that this subterranean river has an impressive flow rate of 3 million liters per second.

• This flow rate surpasses that of Brazil's São Francisco River, which has a flow rate of approximately 2.8 million liters per second.

• The subterranean river was named after Professor Valia, one of its discoverers.