Few people know the answer to the question, what is hydrogeology? Only a few, unfortunately, are generally aware of what a word is, such a concept exists. But, of course, you need to know that hydrogeology is not just a science of nature or something else generalized, but the science of groundwater ("hydro" - water, "geo" - earth, "logos" - a word).
Definition and general information
Hydrogeology is a science that studies groundwater: its movement, origin, composition (chemical), bedding conditions, patterns of interaction with the atmosphere, surface waters and rocks (mountain). This science consists of several sections, among which are the dynamics of groundwater, hydrogeochemistry, and the study of mineral, thermal, and industrial waters. Hydrogeology is interconnected with geology (in particular, with engineering geology), geography, hydrology and other sciences that study the Earth.
To carry out the necessary calculations, not only mathematical, but also chemical, physical, geological research methods are used. Without hydrogeology, it is problematic to forecast water inflows, eliminate the environmental consequences of the hydraulic structure (such structures include reservoirs, dams, hydroelectric power stations, shipping locks, etc.), design the use of water deposits for various purposes and quality (drinking, technical, mineral, industrial, thermal) .
What is groundwater?
Underground water is understood to be below the earth's surface, the upper part of the earth's crust, in rocks of water (both in liquid, and in gaseous, and in solid state). They are a type of mineral. Groundwater is divided into soil, ground, interstratal, artesian, mineral. During familiarization with the concept of "hydrogeology", groundwater is the subject of study, therefore, a general idea of what groundwater is needed.
History tour
There are sources from which it can be concluded that humanity has known about groundwater since ancient times. It is known for certain that in the II-III millennium BC, in China, Egypt and several other countries (civilizations) there were wells, the depth of which was more than a dozen meters. Already in the 1st millennium BC, Aristotle, Thales, Lucretius, Vitruvius (ancient Greek and Roman scientists) described the properties, origin, water cycle in nature, including underground. In 312 BC, a tunnel was built underground in the city of Affliano, in which water flowed by gravity.
The Arab philosopher Al-Biruni in the 1st millennium AD first speculated that there should be underground reservoirs (storages) of water above the springs so that it could beat up with the key. A researcher from Persia (now Iran) Karadi gave a formal idea of the water cycle in nature, its search, including drilling as a search method. These and many other historical facts indicate that hydrogeology is a science whose information arose in ancient times. Information from ancient studies has been largely confirmed by modern scholars.
Hydrogeology of the USSR
Only after the October Revolution of 1917 in our country such a science as hydrogeology began to develop intensively. Since 1922, Russia became the Union of Soviet Socialist Republics. It was at this time that the formation of the first hydrogeological centers took place. In about fifty years, a general hydrogeology was formed, which included a great deal of knowledge. It has become a large informative and significant area of geological knowledge. The fruitful period for geology and hydrogeology of pre-revolutionary Russia helped in many respects to such an intensive development.
Lomonosov, Krasheninnikov, Zuev, Lepekhin, Falk and many others made their invaluable contribution to science (and not only in relation to hydrogeology). In Soviet Russia, the successors of pre-Soviet experience were such outstanding scientists as Lvov, Lebedev, Khimenkov, Vasilevsky, Butov, Obruchev and many other scientific servants who organized hydrogeological research in the USSR and compiled catalogs of boreholes. Gradually, hydrogeology emerged from other geological sciences. It was during this period that the foundations of hydrogeology were formed in the USSR, in Russia.
Directions of hydrogeology
Due to the fact that hydrogeology covers a large amount of knowledge, research methods, targeted research questions, as well as indirect problems in such areas as groundwater, there are several areas of this science:
- Regional This direction is devoted to the study of regional (various countries of the world and geostructure) new underground water basins.
- Genetic. Salt, thermal, and brine waters (from shorter to deeper horizons) were studied in a scientific analysis of this direction.
- Hydrodynamic. The direction that deals with the calculation part regarding the movement of water and the laws of this movement, the compilation of models using mathematical modeling.
- Hydrogeochemical. Consideration of the composition of water, the conditions of its formation, the formulation and solution of various tasks, including in the field of mineral exploration, are objects of study.
- Paleohydrogeological. The historical foundations of the formation of science, its role are studied.
- Ecological. Engaged in the protection of groundwater.
Water in the Earth's crust: distribution, zones
Groundwater has a special distribution in the earth's crust - they form, as it were, two floors. The first floor, lower, is formed by dense rocks (igneous and metamorphic), as a result of which it contains a fairly limited amount of water. The second floor, containing the main amount of groundwater, consists of sedimentary rocks. Due to the large volume of water in the top floor, it is divided into several zones:
- Upper - fresh water. They are used as drinking, household and technical.
- Medium - mineral water. These waters contain various kinds of salts, trace elements and even biologically active substances. A lot of articles have been written about the beneficial properties of mineral waters, they are advertised on every corner and are recommended as an aid to the body in the fight against ailments. However, do not forget that mineral water, like any other substance with medicinal properties, has contraindications.
- Lower - highly saline brines. These waters contain a large amount of dissolved minerals (mainly chlorides and sulfates), in connection with which they produce salt, bromine, iodine and other substances.
Permeability groups
The water permeability of the soil is its ability to pass water through itself. Depending on this indicator, soils are:
- Permeable - soils through which water passes quite easily, being filtered at the same time. Sand, gravel belong to such rocks.
- Waterproof - soils that have minimal ability to absorb water. Clays belong to such a group - after being soaked with water, they cease to let water through. Marble, granite are the most famous examples of waterproof rocks.
- Semi-permeable - soils that allow limited water passage: clay sands, loose sandstones.
Hydrogeological pools
Groundwater pools are called hydrogeological. This means that in the underground hydrosphere a water system is distinguished, which is characterized by a commonality not only of the occurrence conditions, but also of the geological and structural boundaries. Hydrogeological pools can be divided into several groups.
- Artesian - a group of basins, which are a negative element in the series of hydrogeological basins, which are an accumulation of water (of course underground) and containing pressure head formation water.
- Groundwater - pools, representing a whole system of groundwater flows, which is distinguished by the position of the hydrodynamic boundaries.
- Fractured waters - basins, which are a hydrogeological massif of distribution of karst, fissure and fissure-vein waters.
- Underground runoff - as in the case of groundwater basins, is a system of water flows (naturally, underground) with a common direction.
Hydrogeological systems
There is such a thing as a hydrogeological system. This system is an association of bodies called "geological bodies", in them the waters are not only interconnected, but also have common laws of motion. It is, of course, about groundwater. Connections and interactions between system components can be of three types:
- Direct - interaction across a common border.
- Indirect - through other elements of the same system or system that borders on the studied one.
- Indirect - through another system, elements from outside come into the analyzed one.
The systems themselves can be divided into natural and natural-technogenic. Natural and technogenic include engineering structures.
Hydrogeology today
The current state of groundwater, its changes as a result of human activities in the field of economic activity, is studied by engineering hydrogeology. Of course, this is not a separate science, but a section of hydrogeology as a whole.
Hydrogeology and engineering geology are studying the influence of engineering activities on groundwater, their chemical properties, interaction with rocks, processes in rock formations. To date, the most pressing issue that experts are addressing is the rational use of groundwater.
It is necessary not only to deal with water consumption, but also to ensure that there is no depletion and pollution at minimal cost. At the same time, the issue of the need to manage groundwater during economic activities remains relevant.