What is a perch in a well. Water sources for wells, ground and underground waters. Aquifers and their occurrence

Verkhovodka and groundwater.

Verkhovodka is a temporary accumulation of groundwater in the aeration zone. This zone is located at a shallow depth from the surface, above the groundwater horizon, where part of the rock pores is occupied by bound water, and the other part by air.

The perch is formed over random aquicludes (or semi-aquicludes), in the role of which may be lenses of clays and loams in the sand, interlayers of denser rocks. During infiltration, water temporarily lingers and forms a kind of aquifer. Most often this is associated with a period of heavy snowmelt, a period of rain. The rest of the time, the perched water evaporates and seeps into the underlying groundwater.

Another feature of perched water is the possibility of its formation even in the absence of any water-resistant interlayers in the aeration zone. For example, water flows abundantly into the loamy strata, but due to low water permeability, seepage occurs slowly, and perched water forms in the upper part of the stratum. After a while, this water will be absorbed.

In general, perched water is characterized by: temporary, often seasonal in nature, a small distribution area, low power and non-pressure. In easily permeable rocks, for example, in sands, perched water occurs relatively rarely. It is most typical of various loams and loess rocks.

Verkhovodka poses a significant danger to construction. Lying within the underground parts of buildings and structures (basements of boiler rooms), it can cause their flooding, if drainage or waterproofing measures were not provided in advance. Recently, as a result of significant water leaks (water supply, pools), the appearance of perched water horizons on the territory of industrial facilities and new residential areas located in the zone of loess rocks has been noted. This poses a serious danger, since the foundation soils reduce their stability, and the operation of buildings and structures becomes more difficult.

During engineering and geological surveys carried out in the dry season, perched water is not always found. Therefore, its appearance for builders may be unexpected.

Ground water.

Groundwater horizons are called groundwater horizons that are constant in time and significant in terms of distribution area, lying on the first aquiclude from the surface.

From above, groundwater is usually not blocked by impermeable rocks, and they do not fill the permeable layer at full capacity, so the groundwater surface is free, non-pressure. In some areas, where there is still a local water-resistant cover, groundwater acquires a local pressure (the value of the latter is determined by the position of the groundwater level in adjacent areas that do not have a water-resistant cover). When a borehole or dug well reaches groundwater, their level (the so-called groundwater mirror) is set at the depth where they were encountered. The areas of supply and distribution of groundwater coincide. As a result, the conditions of formation and the regime of groundwater have characteristic features that distinguish them from deeper artesian waters: groundwater is sensitive to all atmospheric changes. Depending on the amount of atmospheric precipitation, the surface of groundwater experiences seasonal fluctuations: in the dry season it decreases, in the wet it rises, the flow rate, chemical composition and temperature of groundwater also change. Near rivers and reservoirs, changes in the level, discharge, and chemical composition of groundwater are determined by the nature of their hydraulic connection with surface water and the regime of the latter. The amount of groundwater runoff over a long period is approximately equal to the amount of water received by infiltration. In a humid climate, intensive processes of infiltration and underground runoff develop, accompanied by leaching of soils and rocks. At the same time, easily soluble salts - chlorides and sulfates - are removed from rocks and soils; as a result of long-term water exchange, fresh groundwater is formed, mineralized only due to relatively poorly soluble salts (mainly calcium bicarbonates). In a dry warm climate (in dry steppes, semi-deserts and deserts), due to the short duration of precipitation and low precipitation, as well as poor drainage of the area, underground runoff of groundwater does not develop; in the expenditure part of the groundwater balance, evaporation prevails and their salinization occurs.

Differences in the conditions for the formation of groundwater determine the zonality of their geographical distribution, which is closely related to the zonality of the climate, soil and vegetation cover. In the forest, forest-steppe, and steppe regions, fresh (or low-mineralized) groundwater is common; within the dry steppes, semi-deserts and deserts on the plains, saline groundwater prevails, among which fresh water is found only in some areas.

The most significant reserves of groundwater are concentrated in alluvial deposits of river valleys, in alluvial fans of foothill areas, as well as in shallow massifs of fractured and karst limestones (less often in fractured igneous rocks).

In lowlands, ravines, valleys, and other negative areas of relief below the groundwater level, they flow to the surface in the form of springs. They largely feed ponds, lakes and rivers.

Artesian water.

Artesian water - underground water enclosed between water-resistant layers and under hydraulic pressure. They occur mainly in pre-anthropogenic deposits, within large geological structures, forming artesian basins.

Opened artificially rise above the roof of the aquifer. With sufficient pressure, they pour out onto the surface of the earth, and sometimes even gush. The line connecting the marks of the steady pressure level in the wells forms a piezometric level.

Unlike groundwater, which is involved in modern water exchange with the earth's surface, many are ancient, and their chemical composition usually reflects the conditions of formation.

Originally associated with trough structures. However, the conditions under which these waters are formed are very diverse; can often be found in flexure-like asymmetric monoclinal bedding. In many areas they are confined to a complex system of cracks and faults.

Within the artesian basin, three areas are distinguished: supply, pressure and discharge. In the recharge area, the aquifer is usually elevated and drained, so the waters here have a free surface; in the pressure area, the level to which water can rise is located above the top of the aquifer. The vertical distance from the top of the aquifer to this level is called the head.

In contrast to the recharge area, where the thickness of the aquifer varies depending on meteorological factors, in the pressure area, the thickness of the artesian horizon is constant in time. At the boundary between the supply area and the pressure area, due to the amount of incoming atmospheric water, in different seasons, a temporary transition of water with a free surface into pressure water can occur. In the area of discharge, waters come to the earth's surface in the form of ascending springs. If there are several aquifers, each of them can have its own level, determined by the conditions of nutrition and water runoff. When the synclinal occurrence of the layers corresponds to relief depressions, the pressures in the lower horizons increase; when the relief rises, the piezometric levels of the lower horizons are located at lower elevations. If, thanks to a well or well, two aquifers are connected, then with an inverted relief, it flows from the upper horizon to the lower one.

Distinguish artesian basin and artesian slope. In an artesian basin, the supply area is located next to the pressure area; further in the direction of the underground runoff, there is an area of unloading of the pressure horizon. In the artesian slope, the latter is located next to the feeding area.

Each large artesian basin contains waters of different chemical composition: from highly mineralized brines of the chloride type to fresh low-mineralized waters of the hydrocarbonate type. The first usually occur in the deep parts of the basin, the second - in the upper layers (in various artesian basins of Russia at a depth of 100 to 1000 m).

The fresh waters of the upper aquifers are formed as a result of precipitation infiltration and rock leaching processes. Deep, highly mineralized waters are associated with the altered waters of ancient marine basins that were located in various geological epochs on the territory of the modern artesian basin.

In Russia, due to the wide variety of hydrogeological conditions, artesian basins are sometimes called water-pressure systems. The largest water supply system in Russia is the West Siberian artesian basin with an area of 3 million km2. There are large basins of pressure waters abroad in North Africa, as well as in the eastern part of Australia.

The Moscow region, unlike neighboring regions, can rightfully be proud of the diversity of its natural landscape. This is due to the fact that several large landforms are found on its territory - the Upper Volga Lowland (Taldomsky, part of the Klinsky and Dmitrovsky districts) in the northern part of the region. The famous Meshcherskaya lowland (Noginsky, Pavlovo-Posadsky, Ramensky, Egorevsky, Orekhovo-Zuevsky, Shatursky, part of the Kolomensky and Lukhovitsky districts), described by K. G. Paustovsky in a number of stories. The Smolensk-Moscow upland with a spur in the form of the Klin-Dmitrovsky ridge (Shakhovskiy, Volokolamskiy, Mozhaiskiy, Ruzskiy, Istra, Krasnogorskiy, Solnechnogorskiy, Dmitrovskiy, Sergiev Posadskiy, etc.) East. Moskvoretsko-Oka Plain, located on the right bank of the Moscow River, south of the Smolensk-Moscow Upland. In the south of the Moscow region, a small part is occupied by the Zaokskoe erosion plateau (Kashirsky, Zaraisky and Serebryano-Prudsky districts), which, as the name implies, is characterized by strong indentation with ravines, gullies and river valleys.

Such a variety of relief forms determines, first of all, the variation of the water regimes of the territories. We are primarily interested in wetlands. If you open the topographic map of the Moscow region, you can see the shaded zones gravitating towards the Upper Volga and Meshcherskaya lowlands. In the cartography of the Non-Chernozem Region, shading denotes wetlands and swamps. The study of the map can provide significant assistance at the first stage of choosing the area in which the land for development is acquired. Unfortunately, even in areas with favorable water regime - Sergiev Posad, Istra, Volokolamsk, Ruzsky, Podolsky, Chekhov, there are territories that are not marked on the map and are subject to periodic or constant waterlogging. Therefore, when choosing a site for development, one should also be based on visual signs of waterlogging and common sense.

Before proceeding to a brief description of the water regime of the lands of the Moscow region, it is necessary to consider the causes of waterlogging of soils. The most common in the Moscow region are atmospheric and alluvial slope (sedimentary), ground and alluvial riverbed waters.

Causes of waterlogging of soils according to F.R. Zaidelman "Soil Reclamation", 2003.

Atmospheric and alluvial slope waters enter directly into the territory of the site or pass a short way along the slope surface. It is the sedimentary waters that are responsible for the appearance of the so-called perched water (autochthonous, “local” waters). Verkhovodka occurs when there is a horizon with low water permeability in the soil profile, for example, a parent rock, and is typical for soils with a heavy mechanical composition (clay and loam). Waterlogging of such areas is periodic and is characterized by sharp fluctuations in the level of perched water during the year. Strong watering of the site after spring snowmelt or prolonged precipitation may be replaced by a sharp drop in the perched water level during the dry period. It is this cause of soil waterlogging that is most difficult to diagnose, since the acquirer of the territory often has only a few days at his disposal to make a decision on the purchase. For this reason, it is recommended to transfer the acquisition of plots to spring after the soil horizon has completely thawed. During this period, the presence and level of perched water can be easily determined by a device on the territory of the site of the pits with a drill or a shovel. It is optimal if the top water is not diagnosed or if its level is below 1.2-1.4 m, which creates favorable conditions for the cultivation of most fruit and berry and ornamental crops. If this is not possible, then it makes sense to pay attention to the nature of the terrain. As a rule, areas at the lowest point of the territory - a catchment area, in the lower third of a slope, on subslope territories or located on a slope and having natural barriers to subsoil water flow in the lower part in the form of a roadbed, a concrete retaining wall will experience significant fluctuations in the level of perched water. I would like to point out that the diagnosis of the water regime of the territory with this type of waterlogging should be carried out taking into account all factors, since the level of perched water is strongly influenced by weather conditions (rapid snowmelt, thin snow cover, dry spring, etc.).

Groundwater (allochthonous water, “coming from outside”) is formed in a permeable aquifer and is located on a water-resistant layer. Groundwater is characterized by slight level fluctuations and a relatively stable flow throughout the year. This groundwater differs from perched water. The presence and level of groundwater in this massif is easy to identify by examining drinking wells in adjacent areas or by drilling pits. As mentioned earlier, the optimal depth of groundwater is not higher than 1.2-1.4 m from the soil level. When determining the groundwater level, one should pay attention to the presence of perched water, which can change the level of allochthonous waters during periods with high precipitation. As in the case of perched water, the level of groundwater is closely related to the nature of the terrain. A high level of groundwater is typical for low-lying landscape elements, floodplain terraces of rivers (part of the territory along the river bed, periodically flooded by hollow or flood waters) or near-water areas of large reservoirs.

Swamping of private territories with alluvial channel waters in the conditions of the Moscow Region is rare, since the floodplain lands of large rivers are classified as nature conservation lands. Outwardly, the signs of swamping are similar to those in swamping by atmospheric and groundwater due to the periodic increase in the level of perched water during spring or flood floods. These lands are confined to river floodplains, but can also be found in areas around large lakes and reservoirs in the absence of excess water runoff from reservoirs during snowmelt or prolonged rains.

Thus, knowing the features of the relief of territories located in certain areas of the Moscow region, it is possible to predict the water regime of the lands. Thus, the territories located in the Upper Volga and Meshcherskaya lowlands are characterized by high moisture content (up to 65% of the area for the Meshcherskaya lowland) due to swamping by ground and atmospheric waters. Drainage activities in these areas are often hampered by the lack of suitable intakes for groundwater discharge.

The territory of the Smolensk-Moscow Upland as a whole is characterized by a favorable water regime and land drainage. Here, local waterlogging of soils caused by alluvial slope waters is most often observed. The actual drainage measures do not cause any particular difficulties. In contrast to the Smolensk-Moscow Upland, the territory of the Moskvoretsko-Oka Plain is characterized by less hilliness and, accordingly, a lesser influence of slope waters on swamping, and flooding of lands by atmospheric waters is more common here. In some areas, bogging with groundwater occurs. In general, the territory is characterized by good drainage. The Zaokskoye Plateau is unique in the sense that the territory is a relatively narrow watershed (lines dividing the watersheds of rivers), dissected by deep river valleys, gullies and ravines. There are practically no wetlands here.

In conclusion, it should be noted that territories with a high standing of groundwater are characteristic of six hundred plots, which in Soviet times were allocated on lands unsuitable for agricultural use. At the present time, buyers are offered land withdrawn from the funds of collective farms and state farms. Such lands are characterized by a favorable water regime. For the same reason, it is most often necessary to consider the situation of periodic flooding of lands caused by a change in the level of perched water during the season. This is expressed in particular in the appearance of water in the basement during active snowmelt or prolonged rains. The damage from periodic flooding in its destructive scale is commensurate with the constant flooding of groundwater, since the owner of the site often does not suspect the presence of perched water and improves the territory based on technologies designed for a favorable water regime.

In a broad sense, groundwater refers to any type of water that occurs underground.

But in the drilling industry, underground aquifers are classified by depth.

The options for using the underlying fluid can be completely different. From human drinking to water supply for livestock farms and industrial production.

Layer classification

Verkhovodka.

A low-volume and unstable layer of water, located at a depth of up to 3 m below the soil level.

The volume of perch water is not enough to provide technical water supply for production or a private house.

As a source of water, it is also not suitable due to heavy pollution.

Directly, groundwater. This is the first permanent layer of the aquifer, located above the water-resistant clay soil.

It has a free surface, there is no “roof” of waterproof rocks above it.

interstratal waters. They are located below the first water-resistant layer at a depth of 100 m.

They are divided into pressure and artesian.

Types of groundwater

The sources of groundwater formation can be nearby fresh water bodies (rivers, lakes) and any atmospheric precipitation, incl. melting snow.

From perched water, groundwater differs in constancy, i.e. they are always present in places of occurrence, but their volume varies depending on the season.

In spring, during floods, the groundwater layer reaches its peak, and dries up in the hottest months of summer.

But the lowest groundwater does not fall in summer., and in winter - then the aquifer goes deep into the ground.

The difference between groundwater and artesian water is the lack of pressure. To bring them to the surface, special systems called capturing are required.

The most common type of capping systems- wells with a lifting drum. Borehole wells with a submersible pump powered by an electrical network are considered a more progressive type of capturing.

They allow you to raise large volumes of groundwater to the surface.

Depending on the depth of location, high and low groundwater levels are distinguished.

This criterion is important during construction - if you build a house on a site with a high level of groundwater, they will quickly flood the foundation.

The bearing properties of the soil also depend on the level of groundwater, so buildings built on marshy soils and in lowlands risk going underground over time.

High groundwater level is considered to be up to 2 m below the ground surface or less. Accordingly, the upper aquifer located below 2 m will be considered low.

The level of the aquifer must be taken into account when pouring the foundation:

according to all technologies, it is laid at least half a meter above groundwater.

If the point of occurrence of groundwater is less than the depth of the foundation, they are pumped out, followed by waterproofing the bottom of the pit.

But even with such measures, there is a danger of flooding basements and basements, therefore, for the construction of apartment buildings and other high-rise buildings, sites with a low level of occurrence are chosen.

Influence on the strength of structures

Fluctuations in the level of groundwater, under already erected buildings, can cause deformations not only of the foundation, but also of the walls. This may be due to the following factors:

saturation of the soil with easily soluble minerals in water.
Over time, the soil changes its structure, substances dissolved in groundwater disappear from it.
Under the pressure of the walls, the soil that has lost its density sags, and the structure falls.
To avoid this, before the start of construction, a chemical analysis of the soil is carried out for the concentration of easily soluble substances;
the location of the building on the so-called. quicksand- fine sandy soils, which, when flooded by groundwater, begin to slide.
If there are groundwater outlets on the construction site, the risk that the building will “float” along with the soil increases significantly.
To prevent this phenomenon, when designing buildings on quicksand, the direction and speed of groundwater movement, the nature of the relief, etc. are taken into account;
location of the building on clay soils.
As in the case of quicksand, when flooded with groundwater, such soils greatly lose their stability.
Given the spread of clay soils in our country, the construction of high-rise buildings on them is possible if measures are taken to divert the aquifer before starting work.

There are also so-called. aggressive ground water, characterized by a high concentration of alkalis and acids dissolved in them.

Such waters destroy the concrete foundations of buildings much faster than ordinary ones.

Sources of water supply in industry and agriculture

Despite the fact that groundwater is much cleaner than perch, it contains enough mineral impurities to make it undrinkable.

The underground source of drinking water is the lower, interwater layer.

Groundwater is used for technical purposes for irrigation of plots or to meet the needs of the production cycle.

They can be used for drinking (read how to find water in a garden plot) only after several stages of filtration.

How to determine the level of occurrence

In ancient times, underground water sources were searched for by characteristic external signs. Even if the land does not look swampy, but moisture-loving plants grow on it:

digitalis,
hemlock,
reeds, etc.
- this indicates the proximity of water to the level of the soil.

In addition, the nature of the green "carpet" can also tell about the depth of groundwater - if the plants are tall, green and succulent, this means that the roots receive moisture from the ground in abundance.

Insects also help to determine the places where groundwater is close to the surface of the earth.

If midges constantly hover over the site, which are attracted to places with high humidity, or there are a lot of anthills, then the groundwater is high.

Now there are more accurate methods for determining the level of the aquifer.

Inspection of nearby wells

Within a radius of 3-5 km, the groundwater level will not differ much, therefore, to determine it in a selected area, it is enough to look into the nearest wells.

They are filled only from the aquifer, respectively, you can find out its depth by measuring the distance from the surface of the earth to the water using a tape measure.

Drilling test wells

If there are no wells in the immediate vicinity of the site, the drilling method is used.

With the help of a garden drill along the perimeter of the site, several pits are punched in the ground, 2.5 m deep, and they are observed for 3 days.

If during this time they were not filled with water, it means that in the given area the level of groundwater is low and construction can be safely started.

Only a geomorphologist can do this with accuracy.- A specialist in the relief of the earth's surface.

There is another method of searching for groundwater - psychic.

A person who has the ability to feel subtle matters walks around the site with two iron rods bent in the shape of the letter "L".

It is believed that in places where the ends of the rods diverge to the sides, groundwater is low.

This method is rather controversial, and, of course, is not used for soil analysis during construction.

Conclusion

In conclusion, I would like to remind you that water brings not only life, but also destruction.

Our publication aims to acquaint the reader with which aquifers are beneficial, and which are best removed from the site in order to save the foundations of capital buildings from destruction.

See in the proposed video how test drilling of pits is carried out to determine the height of the aquifer outlet to the earth's surface.

Verkhovodka

non-pressure groundwater, lying closest to the earth's surface and not having a continuous distribution. They are formed due to the infiltration of atmospheric and surface waters, retained by impermeable or slightly permeable wedged out layers and lenses, as well as as a result of condensation of water vapor in rocks. They are characterized by seasonality of existence: in dry times, they often disappear, and during periods of rain and intense snowmelt, they reappear. They are subject to sharp fluctuations depending on hydrometeorological conditions (the amount of precipitation, air humidity, temperature, etc.). V. also includes waters that temporarily appear in bog formations as a result of excess feeding of bogs. V. often occurs as a result of water leaks from the water supply system, sewerage, pools, and other water-carrying devices, which can result in swamping of the area, flooding of foundations and basements. In the area of distribution of permafrost rocks, water is classified as supra-permafrost water. V.'s waters are usually fresh, slightly mineralized, but often polluted with organic matter and contain elevated amounts of iron and silicic acid. V., as a rule, cannot serve as a good source of water supply. However, if necessary, measures are taken to artificially preserve V.: arrangement of ponds; diversions from rivers that provide constant power to operated wells; planting vegetation that delays snowmelt; creation of waterproof jumpers, etc. In desert regions, by making grooves in clayey areas—takyrs—atmospheric water is diverted to an adjacent area of sand, where a wind lens is created, which is a certain supply of fresh water.

Lit.: Lebedev A.F., Soil to groundwater, 4th ed., M., 1936.

A. M. Ovchinnikov.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

Synonyms:

See what "Verkhovodka" is in other dictionaries:

perch- Non-pressure groundwater, lying closest to the earth's surface (in the aeration zone) and located above the groundwater horizon. [Terminological dictionary for construction in 12 languages \u200b\u200b(VNIIIS Gosstroy of the USSR)] top water Temporary, ... ... Technical Translator's Handbook

Verkhovodchitsa, commander, leader, horseman, leader, atamansha Dictionary of Russian synonyms. verkhovodka n., number of synonyms: 11 atamansha (2) ... Synonym dictionary

Non-pressure underground waters closest to the earth's surface that do not have a continuous distribution; periodically accumulate and then disappear due to evaporation or overflow into deeper horizons ... Big Encyclopedic Dictionary

Temporary accumulation of groundwater in the aeration zone on impermeable or poorly permeable rocks occurring in the form of small lenses and interlayers ... Geological terms

Verkhovodka, svetlukha, sorovitsa, turpentine (Tversk.), Posmolny indigenous water (Shenk. near Arkhang. province), tar water, water collected during tar smoking, dark brown in color, with a sharp, burnt sour smell; mainly used on... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

- (a. leakage water, vadose or temporary water; n. oberirdisches Wasser, vadoses Wasser; f. eau a ciel ouvert, nappe suspendue temporaire; i. aguas a cielo abierto) temporary accumulation of gravitational. groundwater in the aeration zone in the rocks ... ... Geological Encyclopedia

SUPERVOD, a, m. (colloquial). The one who rules. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

Ground water located in the surface layers of the earth and the roadway. V. can adversely affect the stability of earthworks and cause sliding and dumping of the excavation slope, the formation of abysses, etc. Due to the shallow location of V. ... ... Technical railway dictionary

Temporary or seasonal accumulation of groundwater in the aeration zone, in settlements (soils) lying close to the surface and underlain by lenses or wedged out interlayers of waterproof or poorly permeable settlements (soils). V. disappears ... ... Geological Encyclopedia

perch- leakage water, vadose or temporary water *oberirdisches Wasser, vadoses Wasser underground water, which lies close to the surface (higher than the groundwater horizon), slopes to sharp kolivany, easily wanders. V. Timchasov is not seasonally stingy ... ... Girnichiy encyclopedic dictionary