Aquifer horizon. Depth of aquifer

The aquifer or horizon are several layers of rocks that have high water permeability. Their pores, cracks or other voids are filled with groundwater.

General concepts

Several aquifers can form an aquifer if they are connected hydraulically. Water is used for water supply in forestry, for irrigation of forest nurseries, in human economic activities. When entering the surface, they can become a source of waterlogging of the territory. This can contribute to the formation of lowland and transitional bogs.

Water permeability

The aquifer is characterized by water permeability of rocks. Water permeability depends on the size and quantity of cracks, pores, and also on the sorting of rock granules. The depth of occurrence of the aquifer can be different: from 2-4 m ("perchage") and up to 30-50 m (artesian water).

Good permeable rocks include:

• gravel;
• Pebbles;
• Coarse-grained sands;
• Fractured and intensely karstic rocks.

Movement of water

The reasons for the movement of water in the pores can be several:

• gravity;
• Hydraulic head;
• Capillary forces;
• Capillary-osmotic forces;
• Adsorption forces;
• Temperature gradient.

Depending on the geological structure, the rocks of the aquifer may be isotropic in the filtration ratio, that is, the water permeability in any direction is the same. The rocks can also be anisotropic, in which case they are characterized by a uniform change in water permeability in all directions.

Depth of occurrence of aquifers in the Moscow Region

Throughout the territory of the Moscow Region the depth of groundwater is not the same, therefore, for the convenience of studying, it was divided into hydrological regions. There are several aquifers:

• Southern region. The water level can be in the range of 10-70 m. The depth of the wells in this area varies from 40 m to 120 m.
• South-western region . The horizon of water is not abundant. The average depth of the wells is 50 m.
• Central District. This is the largest area in the area. He, in turn, is divided into Big and Small. The average thickness of the horizons is 30 m. The waters here are carbonate, carbonate-sulfate.
• East district. The depth of occurrence of the aquifer in this area is 20-50 meters. The waters are mostly highly mineralized, so they are not suitable for water supply.
• Klin-Dmitrov district. It consists of two horizons of the upper carbonate: Gzhel and Kasimov.
• Privolzhsky district. The average depth of the aquifer is 25 meters.

This is a general description of the areas. With a detailed study of aquifers, consider the composition of the bed water , its thickness, specific production rate, sediment density, etc.

It is worth noting that the hydrogeology of the Moscow Region identifies one aquifer complex, which is divided into several horizons of Paleozoic coal deposits:

• Podolsko-Ballakovskaya layer of the Middle Carboniferous;
• Serpukhov aquifer and the Oka suite of the Lower Carboniferous;
• Kashira aquifer of medium carbon;
• Kasimov layer of the upper carbon;
• Gzhel aquifer of Upper Carboniferous.

Some aquifers have a small water saturation and high mineralization, so they are unsuitable for human economic activities.

The aquifer layer of the Serpukhov and Oka suites of the Lower Carboniferous has the maximum thickness relative to other aquifers - 60-70 meters.

The Moscow-Podolsky aquifer can reach a maximum of 45 meters in depth, its average thickness is 25 meters.

How to determine the depth of the aquifer

Sandy aquifer - the name is conditional, since this horizon can consist of a gravel, a mixture of sand and gravel. Sandy aquifers have different thicknesses, their depths also differ.

If we consider the hydrogeology of the Moscow region and the adjacent areas, it can be said with certainty that it is possible to find underground waters at a depth of 3-5 meters, depending on the relative height of the area under study. The depth of occurrence of the aquifer also depends on nearby hydrological objects: a river, a lake, a swamp.

The layer closest to the surface is called "perch". Its water is not recommended for food, since the supply of this layer is due to precipitation, melting of snow, etc., therefore harmful impurities can easily enter here. However, often the waters of "vadose" are used in the farm, and they call it "technical water".

Good filtered water is at a depth of 8-10 meters. At a depth of 30 meters there are so-called "mineral waters", for the extraction of which artesian wells are being built.

It is relatively easy to determine the presence and depth of the upper aquifer. There are many folk ways: using a vine or a metal frame, with the help of a clay pot, by observing plants growing on the territory.