An aquifer is a water reservoir located in regions that have permeable soils and rocks. sufficient to allow the penetration, storage and internal circulation of water from the surface. The water is filtered while passing through the pores existing in the relief, which allows the formation of springs, groundwater, rivers and water resources with a large amount of drinking water. Therefore, aquifers have great environmental relevance.
O Alter do Chão aquifer is an example of that kind of natural way. It is located in a part of the Amazon region, more precisely in parts of Pará, Amazonas and also in a small stretch of Amapá, as we can see in the map below:
Location map of the Alter do Chão Aquifer, in Northern Brazil
The existence of an aquifer in the Amazon has always been known to scholars in Earth Sciences, but in 2010, it was discovered that its reserves could be much larger than imagined previously. Its estimated volume is 86,400 km³ of water, enough to guarantee the world leadership in water reserves, surpassing with more than double the amount the
Guarani Aquifer, the second place, with 37 thousand km³, although the area of occupation of the latter is much higher.The Amazon aquifer is of the mixed type, that is, with characteristics of two different types: an upper part of the aquifer free from 50 meters deep and a lower part of the aquifer confined to 430 meters, according to CPRM (Geological Survey) data National). The rocks in the region are of the sedimentary type, predominantly composed of clay and sandstone, which allows greater accessibility to water wells, given that such formations do not hinder the drilling.
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In all, the Alter do Chão aquifer occupies an area of 437,500 km². Several cities in the North region use the available water reserves, including Manaus, which has 40% of its supply coming from this aquifer. It is in Manaus, however, that most of the contamination of the soils of this reserve also takes place, thanks to problems with regard to water treatment and environmental sanitation. The growth of agricultural activity in the North region could also represent a threat, if large amounts of pesticides are used.
The maintenance and sustainability of the Alter do Chão aquifer in the Amazon also involves forest conservation. This is because much of its supply comes from the large amount of rainfall in the region, which helps explain the large volume of water even in an area smaller than the Guarani Aquifer. This high rainfall is generated by the intense humidity produced by the Amazon Forest itself, which, in turn, uses the water resources to carry out evapotranspiration, with the "pumping" of water from the soil to the atmosphere, which is also related with flying rivers.
For this reason, it is understood that there is a need for actions by all spheres of public power towards to ensure the maintenance of natural spaces in the Amazon Forest regions, especially in the area of the aforementioned aquifer. After all, an expansion of deforestation would put at risk the availability of an extremely important water resource, which, if properly exploited, could be perpetuated for generations to come.
By Me. Rodolfo Alves Pena
Would you like to reference this text in a school or academic work? Look:
PENA, Rodolfo F. Alves. "Alter do Chão Aquifer"; Brazil School. Available in: https://brasilescola.uol.com.br/brasil/aquifero-alter-chao.htm. Accessed on June 28, 2021.
