How to determine the depth of an aquifer. Identifying and searching for aquifers

Water on our planet is found in 3 main places: oceans, groundwater, fresh lakes and rivers.

Groundwater is located in aquifers. An aquifer is a section of the subsoil, most often horizontal, with a high water content. Underground water can be limited by layers of soil that do not allow water to pass through (aquitard) or rock that partially allows water to pass through.

Groundwater is located in one of 3 aquifers:

• − 1 aquifer (upper water), usually located at a depth of up to 25 meters, the exact depth depends on the hydrogeological features of the area;
• − 2 aquifer, can be pressure or non-pressure and is located at a depth of 40 - 90 meters;
• − artesian water or aquifer 3 is characterized by occurrence at a depth of 110 to 200 meters.

Main characteristics of the aquifer:

• − the amount of water that can be pumped out per unit of time, usually measured in liters/second or cubic meters/hour;
• − seasonal amplitude of water level, the indicator describes the depth of water in different time of the year;
• − depth of location of the base and roof of the aquifer;
• − thickness of the aquifer, that is, the thickness of the soil layer containing water.

First aquifer

The most accessible water is located close to the surface, at a depth of 3 to 25 meters. Such water is usually obtained using a well, which can be dug without the use of special equipment. The source of water for “overwater” is surface water: rain, snow. Surface water seeps through the soil and accumulates above the first impermeable layer.

Characteristic disadvantages of water from 1 aquifer: water accumulates impurities from the surface of the earth (fertilizers, organic impurities from the surface of the earth); water accumulates impurities as it seeps through loose rocks; The amount of water in the first aquifer is limited and unstable, highly dependent on rainfall, time of year and temperature.

The main disadvantage of 1 aquifer as a long-term source of water is its short service life, a maximum of several years.

Water from aquifer 1 does not meet the requirements for drinking water and its filtration is expensive, so such water is used only for domestic needs.

Second aquifer

2, the aquifer is protected from external influence by the upper waterproof layer of soil, so atmospheric water and external pollution do not enter this horizon. Water from the second aquifer is much better than from the perched water and after minor purification it can be used for food.

Another great advantage of the second aquifer over the first is a large supply of water and a long period of non-stop operation.

Third aquifer

Modern homeowners prefer to drill wells on their property instead of building wells. However, both sources of water supply must be built in areas where there are underground aquifers, so before you start drilling, you need to find this place.

Location of aquifers in soils

In most cases, the very first aquifer is located at a depth not exceeding 5 meters (although there are exceptions). Water obtained from such depths is not used for cooking or as a drinking water, it is suitable for technical purposes. This is due to the low quality of water, the presence of harmful substances and impurities in it.

The second layers, with a depth of up to 20 meters, are more suitable for using water for domestic purposes, although to use it for drinking it is necessary to install filter systems when constructing wells.

The depth of drilling to the third, limestone aquifer is very large, and it is not practical to install this type of source for house wells (although in country cottage towns this solution is practiced for several owners).

In order to accurately and correctly determine the depth of the aquifer, and, accordingly, the type of equipment and the diameter of the casing pipes, drillers most often perform test drilling.

When determining the location of water carriers, it is necessary to take into account that horizons can have not only a horizontal location, they go deep into the soil, rising upward in places. In addition, the volume of water in the layers can vary from 1-2 m³ to tens of cubic meters.

All this suggests that to accurately determine the location for a future well, it is best to use several methods at once.

Basic methods for determining aquifers at sites

Despite the emergence of new methods for determining the occurrence of water carriers, modern instruments and tools, the use of old “folk” methods and ancient recipes for searching for water is quite effective.

Method #1: Natural Phenomena

Good results when searching for water in areas are obtained from observations of natural phenomena By studying the signs, it is easy to recognize and identify the area under which the waters lie.

The soil under which the source is located is most often characterized by high humidity, abundant dew in the morning, and evaporation when the temperature rises. Early in the morning, fog always swirls over such areas, the grass has a more intense green color, and grows much thicker.

When determining the location under which the aquifer is supposed to be located, it is very important to pay attention to the relief features. This is due to the fact that underground horizons with volumes of water follow the line of the ground relief. Thus, water can most likely be found in lowlands, ravines, and depressions. And, on the contrary, it is useless to look for it on hills and slopes, elevations.

Method #2: Determination by plants

Easy to determine burial depth water resources according to the varieties of plants growing in the area.

There are even certain plants that accurately indicate the presence of an aquifer, and accordingly help in the problem of how to determine the aquifer when drilling a well. When searching for water by plant species, you need to take into account that the presence of one or more plants does not indicate the occurrence of aquifers; this may be due to random growth. You need to pay attention only to large groups of plants.

The most “informed” plants that “report” the occurrence of water, as well as the depth of its location, are:

thickets of cattails indicate the occurrence of water at a depth of about a meter;

sandy reed reports the depth of the water carrier in the range of 1.0 - 3.0 meters;

if black poplar grows on the site, then the underwater source is located no deeper than 3 meters;

the sarsazan shrub of the Amaranthaceae family was noticed in areas under which the aquifer lies at a depth of about 5.0 meters;

wormwood often grows in areas with low humidity, which indicates a groundwater depth of 6-7 meters (sandy wormwood indicates an even greater depth - up to 10.0 meters);

alfalfa takes root even on dry soils and is not demanding on moisture, so the source of water under the plantation of these plants can be at a depth of 15 meters.

Among the general signs of the location of water indicated by plants, we can note the characteristics of the root system. Thus, grass with small roots indicates a shallow depth of aquifers, while thickets of bushes and bushes, groves of trees with long roots indicate that the water is deep underground.

Method #3: The Ancient Pottery Method

The ancient "pottery" method has been used for a long time. To determine the location of an underground source, completely dry pottery was placed upside down overnight in areas where an underground aquifer was suspected. A sign of the presence of a source in this place was the appearance of liquid under the dishes.

Modern water seekers have improved this ancient method. To determine an underground source, use well-dried silica gel, which absorbs moisture well, and a clay pot. Silica gel is placed in a pot, the neck is tightly covered with a cloth, and weighed. After this, the container is buried in the ground to a depth of 1.5-2.0 meters and left for a day. After 24 hours, the container is dug out and weighed again. Increased weight indicates the presence of an underground source (the greater the volume of moisture that the silica gel absorbed, the greater the weight, the closer the water carrier is to the surface of the earth).

Sometimes silica gel is replaced with finely crushed ceramic bricks and ceramic dust.

Method #4: Pendulums and Frames

The use of frames and pendulums when searching for water in areas has also not lost its relevance today. This method is based on the principle of dowsing, and only professional “dowsers”, people with developed extrasensory abilities, can search for water using this method.

Aluminum (copper, steel) wire frames with curved edges and a handle made of an elderberry branch are usually 35-40 cm long. Forks of viburnum, willow, and vine branches can also serve as frames.

A small weight made of copper, steel, aluminum, bronze in the form of a ball or cone, suspended on a thread 20-30 cm long, is used as a pendulum.

It is very important to have water for your home and garden. Some lucky people can connect to a centralized water supply, but most have to find their own source. We will talk further about how to find water on the site yourself, with your own hands.

Aquifers and their occurrence

The structure of the rocks is very heterogeneous. Even in one area at a distance of a meter, the “pie” - the composition of the layers and their sizes - can differ significantly. That’s why it can be so difficult to find water on a site; you have to drill several wells to find a normal aquifer. There are three main aquifers:

I must say that it is not difficult to find perched water on the site. Knowing some features of the vegetation and checking some points, you can determine the location of the water carrier with fairly high accuracy.

With an aquiferous sand layer, everything is much more complicated - the depths are serious, you have to rely mainly on the location of your neighbors' wells, and not some indirect signs.

It is possible to find artesian water on the site only through test drilling. Maps of the occurrence of aquifers can help. Since 2011 in Russia they have been publicly available (without payment). To receive a map of your region, you need to send an application to ROSGEOLFOND. You can do this on their official website, or you can download the forms of the required documents, fill them out and send them by mail (with acknowledgment of delivery).

How to find water on a site using traditional methods

There are quite a few folk ways searching for water in the area. You can believe in them, you can not believe in them, but on average, the hit rate is 70-80%, which is no lower than that of “scientific” methods, so it’s definitely worth a try. These methods require some time and attention, but they are free (if you are looking for water in your area yourself), so they can be combined - test several methods, and dig/drill at the point where their readings converge.

Paying attention to plants

This point makes sense only if the site is not developed, but is “inhabited” with wild plants. Based on where and what plants grow, you can quite accurately determine the depth of the water.

All you need to do is walk around the area, look where it is growing, place markers near the plants found, on which you can indicate the possible depth of water. The table provides a list of plants that can be used to determine the presence of water at a given depth.

Plant - indicator	Depth of perched water
Cattail, wild rosemary, downy birch	0 - 1 m
Sandy reed, buckthorn, wheatgrass,	1 - 3 m
Reed, oleaster, sarsazan, spruce, blackberry, raspberry, black poplar	up to 5 m
Artemisia paniculata, glossy, heather, Scots pine, bird cherry, pedunculate oak,	up to 7-8 meters
Licorice, sand wormwood, yellow alfalfa (up to 15 m), juniper, hazel, cornflower, bearberry, beech	from 3-5 to 10 meters

There are several types of trees in the table. It's about not about arrays, but about single plants, maybe a small group of plants that “clump” in one place. In case of herbaceous plants the opposite is true - these are not single specimens, but clearings occupying a certain area of ​​soil.

Using Frames

In a long-developed area, it will not be possible to determine by the plants where the water is. Here you will have to use other methods. One of the most common and highly probable is searching using frames - aluminum wires bent at an angle of 90°. This method is also called dowsing. Take two pieces of wire 30-40 cm long. A piece 10 cm long is bent at a right angle.

To make the “readings” more accurate, the short parts are inserted into tubes made from thin branches of the tree-like elderberry. The core of the cut elderberry branches is removed and a bent wire is inserted inside. The ends of the wire should move freely.

Searching for water in the area using dowsing - frames

Taking the frames in both hands, the ends of the wires are pulled apart in opposite directions (180°) and walked around the area with them, observing their condition. Somewhere the frames will come together, somewhere they will turn in one direction (to the right or left - along the flow of the water). It is by these movements that they determine where the water is.

If the frames come together (their ends move at some angle), there is water in this place. Moving further, you will see that the frames have separated again - the aquifer has ended. You can repeat the maneuver from different directions and points, this way you can localize the location of the water carrier. If during the reverse pass both frames come together, you have determined the place where you need or. If the frames deviate to the right or left, you need to go in that direction and look for a place where they will converge again.

If the frames are motionless, there is no water in the area or the water carriers are located very deep.

Using a rod (wooden slingshot)

You can find water in the area using a wooden slingshot. You need to find two branches that grow from the same point. The branches must be thick, at least 1 cm, and even. Try to find them of the same thickness. They must be cut off with a piece of the trunk (15-20 cm) on which they grew. It should look like a big slingshot.

The leaves are cleaned, the thin ends of the rods are cut off, leaving at least 40 cm on each side of the “fork”. The branches are bent to the sides so that the angle is at least 150°, they are secured in this position and left to dry. The wood may not be completely dry, but the angle should be preserved.

How to find water on the site with your own hands - this is how they work with vines

The dried vine is taken by the ends of the fork and held horizontally at shoulder level. In the place where there is water underground, part of the trunk will slope towards the ground. It will be possible to drill a well in this place. If there are no deviations, there is no water in the area at a shallow depth.

Determining the amount of water in an underground source

In addition to finding water, it would be nice to also determine its volume. They can be approximated using clay pots and silica gel. Take clay pots, pour silica gel into them, and tie the neck with cotton cloth. The packaged pots are weighed (the weight can be written on the pot itself). The prepared shells are buried in places where water is expected to be found and left for a day.

A day later, the pots are dug up and weighed again.

The pot that has gained the most weight marks the vein with the most water.

Finding water - watching nature

You can find water in your area simply by observing nature. You've probably noticed that in some places the fog is the thickest. Sometimes it even resembles a river - meandering and stretching in some direction. At such points, groundwater is usually closest. You also need to look at the amount of dew in the morning. If there is more of it in places where the fog was especially thick, then there is definitely water there.

Another thing that can help you find water in your area is observing insects. On a warm, windless evening, midges often gather in clouds or pillars. And they are located in certain places. Under the places where insects accumulate there are usually sources of water. If you look at the ground in that place and don’t find ant nests, then there really is water there - ants don’t make their nests above water.

How to determine the groundwater level

You can roughly estimate at what depth the perched water is located by looking at the plants growing above it. As can be seen from the table above, certain types of plants feel normal if the water is neither above nor below a certain depth. This way you can roughly estimate how deep the water is.

For areas where there is a natural body of water nearby - a river, a lake - the depth of the water can be determined with an accuracy of up to a meter. For this you will need a barometer. With it you go down to the water itself and measure the pressure. Then you go to the suspected water source and measure the pressure there. The difference is usually expressed in tenths and every tenth (0.1) is equivalent to a meter of depth. For example, the difference in measurements is 0.7 mm/Hg. pillar This means that the water is at a depth of 7 meters.

What else can help find water on the site? Communication with neighbors who already have a well or borehole. It is advisable to find out from them where they drilled/digged, how many times, whether there is a lot of water or not, at what depth the water surface is, what quality it is. Based on the location of all the nearest successful and unsuccessful attempts from your neighbors, you can determine with a fairly high degree of probability where your water is.

Water is the source of life on Earth, without it it is difficult to imagine activity modern man. Water is used for various purposes: drinking and household needs, watering livestock. Those who live in the private sector far from the city know that the main sources of drinking water are wells, wells or captages. In one case or another, it is necessary to carry out water on our own. Great importance has a determination of the exact location of the aquifer vein. The location of aquifers varies in depth, and the quality of water largely depends on this.

Each level of water bearer has its own characteristics. Depending on this, several types of underground veins are distinguished: perched water, groundwater and interstratal water. The latter are divided into pressure and non-pressure. They are the cleanest, but at the same time, they are the most difficult to get to. Hydrogeological features are important not only when installing water supply systems, but also in construction. In this case, the groundwater level is of great importance. Let us consider in more detail how perched water, groundwater and interstratal water differ from each other, and what is their depth.

Aquifers of the earth

There are several aquifers in the earth's thickness. Water accumulates in the ground due to the presence of impermeable layers. The latter are formed, to a greater extent, by clay. Clay practically does not allow water to pass through, thereby protecting aquifers from pollution. Less commonly, stones can be found in the impermeable layer. An interesting fact is that between clay layers there are almost always layers formed by sand. It is known that sand retains moisture (water), as a result of which water accumulates and thereby forms the aquiferous subsoil of the earth. You need to know that aquifers can be protected by impermeable layers on both sides or only on one.

The deepest aquifer, which is used in modern times for water consumption, is formed by artesian waters. It can be located at a depth of more than 100 meters. Artesian waters do not lie in the thickness of sand, but in a layer formed by limestone. Thanks to this they have a special chemical composition. There are also more accessible aquifers. These include perched water. It is of great importance that it is not protected on top by a waterproof layer, therefore it is not suitable for drinking purposes. Aquifers may be thin in some areas and very large in others. This is observed as a result of fracture of impermeable layers. Such areas have a high flow rate.

Verkhovodka and its features

The very first aquifer is called perch. This water got its name due to the fact that the layer is located very close to the surface. The depth at which it can be detected ranges from 1 to 4 meters. Verkhodka refers to free-flowing groundwater. Such water is not available everywhere, so it is an unstable aquifer. Verkhodka is formed as a result of the filtration of surface water or precipitation through the soil. Because of this, it has not found wide application for drinking needs. There are several reasons for this:

• low flow rate and its variability;
• the presence of a large number of pollutants;
• inability to fully meet the needs of the population.

Verkhodka is formed periodically. It depends on the presence of precipitation and floods. In the warm season (summer) it is very difficult to find this source of water. Often it is located on the first waterproof layer, so when this layer emerges, a wetland can form. The water of this aquifer is characterized by being fresh and having low mineralization. Moreover, it is contaminated organic substances. In some cases, it contains a lot of iron. It can be suitable for household needs as an additional source of water for watering or irrigating plants.

Characteristics of groundwater

Determining the level of groundwater in private construction is observed very often. They are most often used for water supply to the residential sector. Wells or catchments are built to collect groundwater. Wells are often drilled for interstratal waters. Groundwater forms the first permanent aquifer, which lies on the first impermeable layer of the earth. They are non-pressure. This indicates that they are not protected from above by waterproof soil, and the layer of earth itself remains half filled.

They are distributed almost everywhere, unlike perched water. It is important that groundwater largely depends on precipitation, so its flow may vary depending on the time of year. In spring and autumn it is greater than in summer and winter. The level of this layer follows the configuration of the relief, so the thickness of this layer is different in different areas. The water that accumulates in the alluvial depths is widely used for drinking. Groundwater lies at a level from several meters to tens. The chemical composition and mineralization are determined by the location of the layer. If there are surface sources (rivers, lakes) with fresh water nearby, then the underground layers can be used for drinking, washing and other purposes. But this requires their cleaning (boiling or filtering).

Interstratal aquifers

When choosing an aquifer for a future well or well, you need to know that interstratal water is of higher quality (clean), unlike groundwater.

Interstratal waters are characterized by the fact that they are surrounded above and below by impermeable layers.

The depth at which they can be found ranges from 10 meters or more. There are non-pressure and pressure interstratal waters. The first ones are not so widespread, they are very difficult to find. They are found in layered sediments, at the top of the geological section. In terms of their chemical composition, they are more balanced and pure, therefore they are used for water supply.

The most popular are pressure waters called artesian waters. It has been established that their chemical composition is constant. They are rich in various minerals. This water can be drunk even without pre-treatment. This aquifer is protected from above and below. Their flow rate is always large and constant. Their depth is about 100 meters or more. It is to obtain artesian water that a well is drilled. Artesian waters are among the minerals of great value.

How does water quality depend on the depth of the aquifer?

In the location of aquifers, it is believed that water quality improves as depth increases. This is actually true. During the private construction of wells or boreholes, the first water begins to appear already at a depth of 2-3 meters from the surface. This is the water of the first aquifer. It is contaminated with chemicals and organic matter that comes from the surface. Are of great importance wastewater, which easily penetrate into the first aquifer. When constructing a well, the optimal digging depth is 15-20 meters.

Groundwater and interstratal waters lie here. To find an artesian vein, you need to dig further. In this case, it is better to use drilling. Thus, the occurrence of aquifers is of great importance for the water supply of the population. Many regions are experiencing shortages clean water, which serves as a reason to search for new sources.

If you have become the owner of your own land, on which you intend to build a house, grow various garden and vegetable crops, then you just need to know some information about your personal plot. You should have such knowledge about your land as, a map of the distribution of the main types of soil, the thickness of the fertile layer, the depth of soil freezing in your area, data on the prevailing wind rose and much more. All this information will be very useful for you. You will be able to use the resources of the site as efficiently as possible at the lowest cost.

Figure 1. Groundwater occurrence diagram.

Such information can really save you from many problems. For example, having learned the dominant wind rose in your area, you can take this factor into account and build buildings in such a way as to protect some of them from the effects of wind; as a banal example, you can point to the construction of a brick barbecue. This structure is durable, unlike its metal counterpart, so you can’t just move it. If the dominant winds were not taken into account during construction, then it will constantly smoke the house and yard.

But even more important information is data showing the groundwater level in your area.

The importance of knowledge

A map of the groundwater level in your area, or better yet specifically in your area, is an extremely important document for any land owner. With this knowledge, you can confidently plan the construction of a house or future planting of vegetable and garden crops. Only knowing exactly the depth of groundwater can you choose the right type and depth of foundation for a house, because the slightest errors in calculations can lead to deformation of the foundation and even destruction of the entire house, which will entail not only material losses, but also a risk to the lives of those living in people's house.

Underground water supplies are also important for plants. Aquifers lying too deep will not be able to nourish the soil and give life to plants, but water located too close will not bring joy either. If the roots are in water for a long time, they “suffocate” and the plant may die. Trees are especially sensitive to this, the depth of their roots is much greater than that of shrubs and garden plants.

These 2 factors alone are quite sufficient to understand how important it is to know the hydrological situation in your area.

Return to contents

Groundwater map

Where can you get a map of the location of groundwater in your area and how can you find out at what depth the aquifers lie? There are 2 ways for this. The simplest and most reasonable thing is to contact the appropriate authority in your city or district. This could be a land management committee, an architectural committee, a hydraulic exploration committee, and so on; different organizations may have different organizations in different areas.

But there are situations when such a card does not exist or for some reason it does not suit you. In this case, you will have to do the research yourself. To do this, there are many both strictly scientific and folk ways of studying. Using some of them or combining them, you can quickly and accurately determine at what depth they lie on your site.

Here it is also worth noting such an important point as the type of groundwater. The fact is that there are 3 types of them. Each of them has its own characteristics and requires different efforts for its operation.

1. Ground free-flow water is the moisture that falls with various precipitation and saturates the top layer of soil. Water from natural reservoirs can also get here. To use this type of water resource, it is enough to build a simple well.
2. Ground pressure water is a little more difficult to use, since it lies at great depth and represents a water lens located between 2 waterproof layers (usually clay). Water enters these underground reservoirs from vast areas and can have a volume measured in cubic kilometers and is usually under great pressure. To use this resource it is necessary to drill a deep well.
3. Verkhovodka. This is all the water that has accumulated in the top layer of soil after precipitation. It practically does not accumulate, and its volume is directly dependent on the level of precipitation.

An approximate diagram of the location of all 3 types of groundwater can be seen in Fig. 1.

Return to contents

Technical methods of exploration

The simplest technical intelligence in your case might look like this. If your neighbors live next to you and they already have wells or boreholes, then don’t be lazy to visit them and ask them to look at the water level in these devices. The more wells you can check, the more accurate the picture of groundwater occurrence will appear before you. Look at the terrain; if it is flat, then most likely the level of aquifers on your site is at the same depth as your neighbors. If the area is replete with elevation changes, this will complicate an accurate analysis of the hydrological situation. But in any case, this information will help you at least roughly navigate this issue.

After this, it is worth starting direct exploration of the aquifers and conducting several test drillings in the area using a thin drill. If you stumble upon an aquifer at a depth that suits you, then all search work can be completed and a full-fledged well can be drilled. And if it was not possible to find it, then we need to drill several more wells in other places.

Before starting work, it is very important to take into account the terrain features of your site. For example, on a flat surface it is easier to find water at the same level as your neighbors. While in the lowlands, groundwater, as a rule, comes closer to the surface of the earth than in the hills. And if there is a ravine or stream in the neighborhood or on the site itself, then the well can only be dug on its slope, since in other places there will be no water, it has already found a way out and does not accumulate in thick layers.

As you can see, care is needed even when technically searching for aquifers. But a trained eye is especially important when searching for water using traditional methods.

Return to contents

Folk signs

It is possible, using modern technology, to drill several wells in an area and thus quickly find out whether there is water and at what depth it is. But it is not always possible to use a drilling rig, and even if you have one, you can significantly save time and resources by conducting a preliminary survey of the site using traditional methods. They will help reduce to a minimum the places where the aquifer may lie close. So let's look at them.

The groundwater level significantly affects vegetation. If he comes close enough, this can be noted both by the condition of the plants themselves and by their species diversity. This is especially noticeable during the dry season, when such an island of fresh greenery resembles an oasis in its freshness and brightness. If the plants have enough moisture, they have a richer color and grow thicker. They like such places: sedge, reeds, horsetails, sorrel, coltsfoot and some other plants. If you have a place on your site where such plants prefer to grow and they have a rich and bright color, then you can be sure that the water is close.

Observation will help you find such a place in other ways. For example, in summer, at dusk, in a humid place, you can notice a slight foggy haze when moisture from the air settles in a cooler place. This means that here, too, the water is close to the surface.

You can take a closer look at the behavior of animals, they can also tell you where to look for water. For example, it is common knowledge that cats prefer to rest where it is cool and humid. She will choose just such a place on earth. While the dog, on the contrary, will avoid such a place.

By carefully observing the behavior of your pets, you can learn a lot about your property. Even the behavior of mosquitoes depends on the presence of water. In the evenings, a swarm of mosquitoes hover over the place where the water comes close.

Water that comes close to the surface has a depressing effect on plants; trees, whose roots may die, are especially affected by it. In the same way, water affects animals; no one likes it when their home is flooded with water, so in those places where groundwater lies close to the surface, you cannot find mouse holes or colonies of red ants.