People are not fish, but water is a necessary condition for human life, as well as any other living creature. And easy access to it, sufficient quantity and proper quality are the main conditions for comfort and a good standard of living.
On average, over the course of 75 years of life, a modern citizen of developed countries, one way or another, consumes from 3.8 to 19 million liters of water as drinking water or for household and hygienic purposes (washing, bathing, toileting, etc.). That is, from 138 to 694 liters per day. Residents of not very civilized areas spend several times less for their own needs - over 75 years, only 380 thousand liters of water, that is, about 13 liters (one bucket) per day.
B O Most of the territory of our country does not suffer from a lack of water, but there are many places in the world where life-giving moisture is, in principle, rare, and the shortage of drinking water does not only exist in science fiction films about doomsday. According to the latest UN report, by 2030 more than half (67%) of the world's population will experience a lack of drinking water.
As they say in the song from the famous Soviet film: “No shave, no drinking, no washing, no swimming, for a man without water - neither here nor there!”
So, let's look at the classification of groundwater. It is worth keeping in mind that, like any classification, it is conditional: there is no clear boundary between aquifers. And the thickness or moisture capacity of a particular layer depends on the geology of the site.
Soil water
Soil water constitute the uppermost level of groundwater: they are located in the root zone - in the fertile layer where the roots of herbaceous plants and the surface root system of trees are located. Soil moisture reserves are replenished by rain and melt water and actively evaporate into the atmosphere, that is, its volume very much depends on the processes evaporation And transpiration.
The lower part of the soil water zone is called suspended (vadose). The zone of suspended water becomes saturated and water begins to seep into the lower layers of the soil under the influence of gravity. This water is called gravitational. If there was a lot of precipitation, for example, in the rainy autumn season or in the spring with active snow melting, the movement of gravitational waters increases. Soil water is of great importance in plant life, but is not used for human water supply.
Groundwater
Permeable rocks beneath the fertile layer form the first permanent aquifer. Usually, first aquifer constitute unconsolidated deposits. The water in this layer fills the pores between the rock particles: this is the level that is called in the professional slang of drillers "on the sand".Its saturation with moisture depends quite strongly on the amount of precipitation and temperature fluctuations - in years with little rain, the groundwater level can drop significantly. In addition, groundwater may become contaminated. This is why it is forbidden to make unsealed containers for sewage in cesspools: in a pit without a bottom, pollution falls directly into the first aquifer.
Groundwater, due to its relatively shallow occurrence, is easily accessible and widely used for the needs of private villages, towns and small enterprises. Although, as mentioned above, on Internet resources where issues of water extraction are discussed, groundwater is often called high water, not intended for use as drinking water.
Groundwater is extracted using small ones. These waters are free-flowing: the level in the well is set at the level of the groundwater table.
Interformational waters
Below the groundwater, separated from it by layers of waterproof or weakly permeable rocks that make up the aquifer layer, there is the next layer of permeable rocks, forming second aquifer. It is composed of denser rocks in which water pours into cracks, forming filled cavities. The second water horizon is fed by percolation (infiltration) of groundwater through layers with weak penetrating ability. This also occurs in places where water-bearing layers of interstratal waters emerge closer to the surface, in breaks in the impermeable layer of the upper water horizon.Their level is much less susceptible to fluctuations from the effects of precipitation or temperatures on the earth's surface. Deep burial protects interstratal waters from contamination. Groundwater located at great depths, under aquitards, may already have hydrostatic pressure. In this case they are called pressure. Interstratal waters are classified as renewable minerals, which means they are state property (RF Law “On Subsoil”).
In addition to household purposes and technical water supply (for industry, land irrigation, pasture watering), groundwater is used for medicinal purposes ( mineral water), in the energy industry ( geothermal waters) and in industry - to extract valuable substances dissolved in them.
Artesian waters
Artesian waters- This is a type of interstratal groundwater. Their difference is that they completely fill the aquifer and are under pressure in it. Pressure waters usually lie within geological structures that have a concave structure - in troughs, flexures, forming artesian basins.
When such an aquifer is opened, the water level rises above the groundwater table, sometimes flowing freely from the well as a fountain. Artesian waters, as a rule, are located at great depths - from 100 to 1000 meters. In some Internet sources, everything with great depth is called artesian, which is not entirely correct. Initially artesian they called it exactly flowing wells, now the term “artesian” refers to all pressure waters.
For water supply, the two upper aquifers are usually used. Water located on b O at greater depths, it most often has increased mineralization, and its extraction involves high financial costs.
Verkhovodka
And finally, about high water. Experts and those interested in the issue of groundwater extraction do not recommend using perched water as a source of drinking water. And they are doing the right thing, because the perched water is not a permanent aquifer. It appears seasonally, during the spring melting of snow or during the period of prolonged autumn rains.Verkhodka is typical for clayey and loamy soils. Its appearance is associated with the accumulation of water over soils that are poorly permeable to water: clayey soils swell from abundant moisture and cease to allow precipitation water to pass into the underlying soil layers.
A pit filled with "overwater"
On the surface of the earth, accumulations of water form in natural depressions; water also appears lower - a meter or one and a half from the surface. In sandy soils, perched water is rarer and forms locally, on temporary aquicludes - layers of clay in the main sandy soil.
It is not worth using the upper waters for the needs of the countryside: they have a pronounced seasonal nature, their quantity is not enough. And most importantly, such waters are polluted. Due to their shallow location, they have not yet had time to purify themselves, passing through a natural filter - the thickness of the earth. Verkhodka can be used for irrigation by artificially deepening natural depressions where it accumulates in the spring, as, for example, in the photo above.
High water can be confused with a high groundwater level. The first aquifer can begin quite shallow from the surface of the earth: in the northern regions - from 50 cm (in the tundra region). As you move south, the depth of the aquifer increases: from 3-5 meters in the middle zone to 15-20 in the southern regions. In rural areas, far from highways and industrial zones, drinking water often has a shallow depth. So, for example, in our village there are only three public rings.
That's all about what aquifers are. For information about what is best for a summer cottage - or what depth to dig or drill, how to determine the groundwater level, as well as about the legal aspect of underground water extraction, read in other materials.
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