Cottages and household plots, characterized by a lowland location and high standing groundwater, can cause a lot of inconvenience to the owners. How to deal with groundwater and how to determine the level of their occurrence, as well as the nature of the damage resulting from the close occurrence of groundwater will all be the subject of this article.

Content

1. Groundwater. Groundwater occurrence level and their harm
2. How to determine the level of groundwater?
3. Groundwater level reduction. Main methods
4. Open and closed drainage systems. What to choose?
5. Artificial reduction of groundwater. Drainage or dewatering?  video

Groundwater. Groundwater occurrence level and their harm

First you need to determine the terminology. Ground waters are called gravity-free gravity waters that are located not deep from the earth’s surface on the first water-resistant horizon and are the waters of the first aquifer.

Speaking about the level of groundwater, it should be noted that the shallow depth of their occurrence contributes to its constant fluctuations depending on the season. So, the period of precipitation can be marked by a sharp increase in the level of groundwater in the area, and heat and drought, respectively, decrease. This is due to natural sources of groundwater supply, among which atmospheric precipitation, melt snow water, nearby rivers and lakes can be distinguished.

The construction of facilities of any nature, whether for residential or household purposes, must necessarily be associated with measuring the level of groundwater, since damage to the owners because groundwater is close to the site can significantly increase the operational cost of the site. Firstly, they can contribute to leaching of the soil, due to which the foundation sags, and then there is a significant deformation of the building and cracks appear. The first signs of deformation of residential buildings are shedding of plaster, the appearance of cracks in glass without any external influences and causeless jamming of doors and windows.

Gardeners, in the area of \u200b\u200bwhich the groundwater is located close, will also have a hard time: trees growing in such a terrain do not tolerate the undesirable neighborhood, and their root system, reaching groundwater, is in a state of oxygen starvation, which causes premature death of trees.

How to determine the level of groundwater?

That is why it is important to have a rough idea of \u200b\u200bthe methods for the initial determination of groundwater in order to then take timely measures to combat them. It is recommended to determine the level of their occurrence in the off-season, in autumn or spring, when the amount of precipitation reaches a maximum. For this purpose, several methods have been developed, a little more common of which are recognized:

1. Geobotanical. The essence of the method is to determine the compliance of growing plants with soil and hydrogeological features of the area. To do this, you need to use specialized tables that indicate plants that are common on soils with certain qualitative characteristics, as well as the main signs of soil overmoistening;

2. The level of groundwater occurrence can also be determined by paying attention to the water level in nearby wells or located directly on the site. To do this, on the walls of the well, it is necessary to find the highest position of water, compare it with the level indicators of groundwater and measure from the surface of the earth;

3. Another well-known method requires drilling a well in a garden plot, the depth of which is at least two meters. Having created a well, you need to observe it for some time: if water appears in the well, this indicates a high level of groundwater occurrence, and if the bottom of the well after a while remains dry, you have no reason to worry, the groundwater is far away.

Groundwater level reduction. Main methods

If, after ascertaining the level of occurrence of groundwater, you came to disappointing conclusions, then the time has come to think about reducing it. Lowering the groundwater level at the dacha is a necessary measure to prevent the above-mentioned undesirable consequences and can be carried out both at the stage of construction activities and in the midst of the operation of buildings and structures for various purposes. It is carried out as follows:

1. One of the most common ways to reduce the groundwater level in the garden, known since ancient times, is the arrangement of the pond. For these purposes, it is recommended to equip it in the very center of the estate, after which you can safely enjoy the results of the work done: the pond not only effectively reduces the level of groundwater, helps protect the basement, cellar and garden from flooding, but also has a lot of decorative advantages;

2. If the construction of residential buildings has already been completed, and water still continues to stagnate on the site, the situation will have to be corrected in a different way. The installation of a drainage system of closed or open types is the only optimal way out of this situation.

Open and closed drainage systems. What to choose?

- an open drainage system contributes to a slight decrease in the level of groundwater (30-50 cm) and is a ditch, the depth of which reaches 70 cm, covered with gravel, gravel, and coarse sand. In this case, the thickness of the drainage layer should be at least 10-15 cm;

- a closed drainage system, from a structural point of view, is a trench located with a slope towards the drain and drainage filled with drainage components. For greater efficiency, a perforated pipe is laid at the bottom of such drainage. Specialists recommend equipping indoor drainage around the perimeter of buildings or the site as a whole. Placement of drainage pipes should be carried out in the territory where vehicles and other specialized equipment are excluded in order to avoid damage to the drainage network.

Artificial reduction of groundwater. Drainage or dewatering?

If at the construction stage there is a need to organize pits and trenches, care must be taken in advance to prevent the entry of groundwater into them. This is also done in several ways:

1. An open drainage method aimed at pumping groundwater using pumps from pits or trenches, the lower part of which is equipped with sumps or so-called drainage pits. The essence of the method is that water seeping through the bottom and slopes of the trench is collected in sumps and pumped out through the operation of diaphragm pumps.

2. If the installation of an open drainage system is a deliberately inappropriate solution, often resort to artificially lowering the groundwater level or lowering the groundwater at the cottage, which helps to lower the groundwater below the bottom of the designed pit. Its essence lies in the pumping of groundwater through deep pumps, which are made from boreholes designed to reduce water, or mine wells, which are located in the immediate vicinity of the work. When using this method, the groundwater level drops sharply, which leads to the necessary dehydration of the soil necessary at this stage of construction. In the process of applying this technique, not only the integrity of the slopes of the trench is maintained, but the weakening of the foundations of nearby structures is also prevented.

For familiarization, we offer several methods of water reduction, less common in personal plots. The main ones are:

1. Electroosmosis method;

2. Needle filter;

3. Vacuum.

Important! Intensive and simultaneous groundwater pumping, regardless of the methodology used, requires careful analysis and environmental protection, as it can lead to a violation of the integrity and relationships of underground and surface water sources, which cause the springs to dry out and subside on the earth's surface.

Author: Sergey and Svetlana Khuentsov

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