The world faces major problems related to water scarcity. In this century, according to several researchers, the lack of water will be one of the biggest problems that humanity will have to face.
Most of planet Earth is composed of water, however, the percentage that offers conditions for consumption, considering that a huge part is salt water, others are polluted, in addition to glaciers, subsoil, soil and atmosphere.
A large part of the water contained in emerged lands is found in the subsoil, that is, underground water, besides, of course, the rivers, which respectively offer water to humans and other living beings.
Groundwater is identified in two ways, the first called the unsaturated zone where water is spread between air, soil and rocks. The second is called the saturated zone, in which case the water is stored in large quantities, forming a kind of underground river.
In addition to this classification, there are two types of groundwater, groundwater and artesian. The first is located in the unsaturated zone, it is close to the surface, so the waters are prone to contamination. The second is located in the saturated zone, a little away from the surface. Due to these characteristics, it is necessary to build artesian wells to draw water from these places.
By Eduardo de Freitas
Graduated in Geography
Source: Brazil School - https://brasilescola.uol.com.br/geografia/aguas-subterraneas.htm