Well depth is an indicator that determines the quality of water and the price of drilling work. Every extra meter of water intake arrangement is invested funds and effort. At the same time, small wells are suitable only for technical needs. Therefore, it is so important to determine the optimal depth criterion in order to obtain the most favorable ratio between investment and water quality.
Factors Affecting Depth
Before designing a well, it is necessary to determine the depth. There are several criteria to consider:
- The level at which aquifers are located. For determination, test drilling or analysis of the terrain, taking into account the geological structure, is carried out.
- Terrain relief. In places without drops, the water layer can be close to the surface, on a hilly area, drilling is best done in a lowland.
- Purpose of water intake. How many meters there should be a water well is determined depending on what the liquid will be used for. The deeper the source, the cleaner the water.
To determine the minimum depth of a well for water, it is imperative to take into account the terrain features - geological and climatic. In areas with large forests and high humidity, reserves in underground sources are usually large, located relatively close, and in some places come to the surface in the form of springs. In an arid steppe region, the aquifer may be at a considerable depth or completely absent.
In addition to these factors, the location of the water intake structure must be taken into account. After all, even a zone potentially potentially convenient in depth indicators may turn out to be inappropriate.
Punching wells is prohibited near such places:
- cemeteries;
- landfill sites;
- agricultural fields that are treated with herbicides and nitrate fertilizers;
- industrial facilities.
If there is a hill in the area, drilling at its top is impractical, it will be very far from the water.
Types of wells
To determine the type of hydraulic device, you need to decide to which layer the mine will be drilled. The use of the well directly depends on the water horizon to which it is broken. If there is enough liquid for use in technical needs, it is possible to reach only subsoil water - the overhead water. The smallest depth of a well shaft for such water is four meters, and the maximum is 15 meters.
Groundwater accumulates above the first water-resistant layer at a depth of more than 15 m. Since they do not overlap with the water-resistance above, they rarely meet drinking standards and are subject to seasonal fluctuations.
Mines break through to a loose moisture-saturated layer of the earth. In areas where rainfall is low, there may not be such underground sources.
Aquiferous interstratal layers are located between two water horizons, there may be several. Water quality is high. Very rarely located near the surface, but not higher than 20 m. Most often located at a depth of over 60 m.
Depending on the water horizon in the territory, the following types of water intakes can be created:
- an ordinary well of about 5 m, fed from a water tower;
- a well that makes its way to the sand layers to a depth of 10 to 30 meters;
- Abyssinian well, fed from the same strata as the sand well;
- artesian source.
In the latter embodiment, fluid flows between the calcareous layers, that is, an aquifer breaks through during drilling.The depth of drilling an artesian well for drinking water is more than 50 m.
The type of water intake determines the quality of the water, the difficulty of creating and the productivity of the well. In accordance with the Russian law “On Subsoil”, it is possible to break through a well shaft and use a source from the first water reservoir without special registration. In this category are water intakes, a well on sand, an Abyssinian well.
Water from an artesian spring is much cleaner, but such a hydrological structure requires a license, which is very expensive.
It is also necessary to calculate the required flow rate. In addition to quality, the volume of liquid that they receive for a certain time interval is also important for water consumers. In Abyssinian wells this value is equal to half a cube per hour, in a well on sand the volume rises to one and a half cubic meters per hour, the maximum productivity of an artesian well - up to 3-4 cubic meters per hour.
Optimum depth indicators
It is rational to drill the barrel to the depth that is allowed without additional documents and fees. In some areas, this figure reaches 35 meters, which depends on the hydrogeology of the earth. You can drink such a liquid only by installing filters that clean it of iron, salts of heavy metals and lime.
To select a suitable filtering device after creating a hydraulic structure, it is necessary to take a water sample and send it for laboratory analysis. Then it will be clear what contaminants prevail in the liquid and what should be protected.
When choosing the optimal depth, indirect signs can be used - for example, to clarify the size of water intakes from neighbors. But to equip your well, relying solely on their characteristics, is wrong. Aquifers do not occur evenly, and there is no guarantee that they will be located on your site in the same way as on the adjacent one.
It is also worth studying the data of geological studies that can be requested at the district administration. There are plans for the area, created on the basis of engineering and intelligence activities. They contain information about the specifics of the soil and the occurrence of water horizons.
Drilling exploration will provide the most accurate answer. With its help you can:
- find out the potentially beneficial depth of the mine;
- identify the composition of soil layers;
- to draw water for laboratory research.
If you need to analyze water from the upper reservoir, exploratory drilling can be done with your own hands. To do this, you will need a regular hand drill and extension rods.
How to determine the depth of water intake
If the completion of the well is entrusted to professionals, upon completion of work, they must issue a passport to the well, where the results of the calculation of the static and dynamic fluid levels, as well as the flow rate, are prescribed. In addition to these values, the document contains information on the size and material of the casing and recommendations on the characteristics of equipment suitable for safe operation.
If there is a well that is not documented, all this data will have to be obtained by the owner of the source.
To find out the depth, you need a long cord, a weight on the cable, tape measure. You just need to lower the cable into the shaft and find out its length. But, to determine the static and dynamic levels, and to calculate the flow rate, you will need special devices - level gauges.
The most suitable time for taking measurements is arid weather at the end of the summer season or late spring, when watering the gardens has already begun. During this period, the water level is at a minimum
Stages of arrangement of a hydraulic structure
First you need to determine the type of well and drilling technology. The following steps are standard and do not depend on whether the water intake is installed independently or by professionals:
- The choice of equipment for drilling, tools, consumables, equipment.
- Arrangement of the caisson, if it is provided for by the design.
- Drilling the first section of the hydraulic structure with the installation of casing.
- Drilling the second section, fixing it with pipes.
- Cleaning the drill column when passing through a sand or clay layer.
- Reaching the desired water horizon.
- Installation of the bottom filter of a hydraulic structure.
Work is completed by fixing the casing, installing pressure equipment and the cover.
The creation of the Abyssinian well is slightly different. This is the simplest and most inexpensive type of water intake, also referred to as “needle-hole”. Structurally, it looks like a long inch pipe with a needle-shaped tip and a filter element. They deepen the “needle” by drilling or simply hammer it into the ground for 8-30 meters. The fluid is supplied using pumping equipment, but from a depth of not more than 8 meters. Such wells can be equipped in areas with light, non-rocky soils.
The quality of water and the uninterrupted supply of water depend on the correctly calculated depth of water intake. In order to identify the optimal indicator, when creating, you need to build on your own needs, on the underground water map and on the technical capabilities of drilling.
