Water is the only substance that exists in nature in liquid, solid and gaseous states. The meaning of liquid water varies significantly depending on location and application. Fresh water is more widely used than salt water. Over 97% of all water is concentrated in the oceans and inland seas. Still ok. 2% comes from fresh water contained in cover and mountain glaciers, and only less than 1% comes from fresh water in lakes and rivers, underground and groundwater.

Water, the most abundant compound on Earth, has unique chemical and physical properties. Since it easily dissolves mineral salts, living organisms absorb nutrients together with it without any significant changes in their own chemical composition. Thus, water is necessary for the normal functioning of all living organisms. A water molecule consists of two hydrogen atoms and one oxygen atom. Its molecular weight is only 18, and its boiling point reaches 100

Water also has unique thermal properties. When her temperature drops to

Water molecules are held together by “hydrogen (or intermolecular) bonds” when the oxygen of one water molecule combines with the hydrogen of another molecule. Water is also attracted to other hydrogen and oxygen containing compounds (called molecular attraction). The unique properties of water are determined by the strength of hydrogen bonds. The forces of adhesion and molecular attraction allow it to overcome gravity and, due to capillarity, to rise up through small pores (for example, in dry soil).

The main source of fresh water is precipitation, but two other sources can also be used for consumer needs: groundwater and surface water.Underground springs. Approximately 37.5 million km 3 , or 98% of all fresh water in liquid form is groundwater, with approx. 50% of them lie at depths of no more than 800 m. However, the volume of available groundwater is determined by the properties of the aquifers and the power of the pumps pumping out the water. Groundwater reserves in the Sahara are estimated at approximately 625 thousand km 3 . Under modern conditions, they are not replenished by surface fresh waters, but are depleted when pumped out. Some of the deepest groundwater is never included in the general water cycle, and only in areas of active volcanism does such water erupt in the form of steam. However, a significant mass of groundwater still penetrates the earth's surface: under the influence of gravity, these waters, moving along waterproof, inclined rock layers, emerge at the foot of the slopes in the form of springs and streams. In addition, they are pumped out by pumps, and also extracted by plant roots and then enter the atmosphere through the process of transpiration.

The water table represents the upper limit of available groundwater. If there are slopes, the groundwater table intersects with the earth's surface, and a source is formed. If groundwater is under high hydrostatic pressure, then artesian springs are formed at the places where they reach the surface. With the advent of powerful pumps and the development of modern drilling technology, the extraction of groundwater has become easier. Pumps are used to supply water to shallow wells installed on aquifers. However, in wells drilled in b

In some parts of the world, increasing consumption of groundwater is having serious consequences. Pumping out a large volume of groundwater, which incomparably exceeds its natural replenishment, leads to a lack of moisture, and lowering the level of these waters requires

In coastal areas, excessive groundwater withdrawal leads to the replacement of fresh water in the aquifer with seawater and saline water, thereby degrading local freshwater sources.

The gradual deterioration of groundwater quality as a result of salt accumulation can have even more dangerous consequences. Sources of salts can be both natural (for example, the dissolution and removal of minerals from soils) and anthropogenic (fertilization or excessive watering with water with a high salt content). Rivers fed by mountain glaciers usually contain less than 1 g/l of dissolved salts, but the mineralization of water in other rivers reaches 9 g/l due to the fact that they drain areas composed of salt-bearing rocks over a long distance.

Indiscriminate release or disposal of toxic chemicals causes them to leak into aquifers that provide drinking or irrigation water. In some cases, just a few years or decades are enough for harmful chemicals to enter groundwater and accumulate there in noticeable quantities. However, once the aquifer has been contaminated, it will take between 200 and 10,000 years to naturally cleanse itself.

When water consumption exceeds water supply, the difference is usually compensated by its reserves in reservoirs, since usually both demand and water supply vary by season. A negative water balance is formed when evaporation exceeds precipitation, so a moderate decrease in water reserves is a common occurrence. Acute shortage occurs when water flow is insufficient due to prolonged drought or when, due to poor planning, water consumption continually increases at a faster rate than expected. Throughout history, humanity has suffered from water shortages from time to time. In order not to experience a shortage of water even during droughts, many cities and regions try to store it in reservoirs and underground collectors, but at times additional water-saving measures are necessary, as well as its normalized consumption. OVERCOMING WATER SCARCITY

Flow redistribution is aimed at providing water to those areas where it is scarce, and water resource protection is aimed at reducing irreplaceable water losses and reducing local demand for it.Redistribution of runoff. Although traditionally many large settlements arose near permanent water sources, nowadays some settlements are also created in areas that receive water from afar. Even when the source of the supplementary water supply is within the same state or country as the destination, technical, environmental or economic problems arise, but if the imported water crosses state borders, the potential complications increase. For example, spraying silver iodide into clouds causes an increase in precipitation in one area, but it may cause a decrease in precipitation in other areas.

One of the large-scale flow transfer projects proposed in North America involves diverting 20% ​​of excess water from the northwestern regions to arid regions. At the same time, up to 310 million m would be redistributed annually

The project of towing icebergs from Antarctica to arid regions, for example, to the Arabian Peninsula, is attracting much attention, which will annually provide fresh water to 4 to 6 billion people or irrigate approx. 80 million hectares of land.

One of the alternative methods of water supply is the desalination of salt water, mainly ocean water, and its transportation to places of consumption, which is technically feasible through the use of electrodialysis, freezing and various distillation systems. The larger the desalination plant, the cheaper it is to obtain fresh water. But as the cost of electricity increases, desalination becomes economically unviable. It is used only in cases where energy is readily available and other methods of obtaining fresh water are impractical. Commercial desalination plants operate on the islands of Curacao and Aruba (in the Caribbean), Kuwait, Bahrain, Israel, Gibraltar, Guernsey and the USA. Numerous smaller demonstration plants have been built in other countries.

However, each of these methods of conserving water resources has one or another impact on the environment. For example, dams spoil the natural beauty of unregulated rivers and prevent the accumulation of fertile silt deposits on floodplains. Preventing water loss as a result of filtration in canals can disrupt the water supply of wetlands and thereby adversely affect the state of their ecosystems. It may also prevent groundwater recharge, thereby affecting water supplies to other consumers. And to reduce the volume of evaporation and transpiration by agricultural crops, it is necessary to reduce the area under cultivation. The latter measure is justified in areas suffering from water shortages, where savings are being made by reducing irrigation costs due to the high cost of energy required to supply water.

For sprinkling or drip irrigation, which has been practiced recently, low-power pumps are used. In addition, there are giant center-pivot irrigation systems that pump water from wells in the middle of the field directly into a pipe equipped with sprinklers and rotating in a circle. The fields irrigated in this way appear from the air as giant green circles, some of them reaching a diameter of 1.5 km. Such installations are common in the US Midwest. They are also used in the Libyan part of the Sahara, where more than 3,785 liters of water per minute are pumped from the deep Nubian aquifer.

The most important component of Russia’s water resources is rivers. The center of the state territory of Russia was determined by the headwaters of the rivers, the area of ​​the territory. – their mouths, settlement – ​​the direction of river basins. Rivers have influenced our history in many ways. On the river, the Russian man came to life. During the migration, the river showed him the way. For a significant part of the year she fed. For a merchant it is a summer and winter road.

The Dnieper and Volkhov, Klyazma, Oka, Volga, Neva, and many other rivers went down in Russian history as places of the most important events in the life of the country. It is no coincidence that rivers occupy a prominent place in Russian epic.

On the geographical map of Russia, the extensive river network attracts attention.
There are 120 thousand rivers in Russia over 10 km long, including more than 3 thousand medium (200-500 km) and large (more than 500 km). The annual river flow is 4270 km3 (including in the Yenisei basin - 630, Lena - 532, Ob - 404, Amur - 344, Volga River - 254). The generic river flow is taken as the initial value when assessing the water supply of the country.

Reservoirs have been created on many rivers, some of which are larger in area than large lakes.

Russia's huge hydropower resources (320 million kW) are also unevenly distributed. More than 80% of the hydropower potential is located in the Asian part of the country.

In addition to the function of storing water for the operation of hydroelectric power stations, reservoirs are used for watering land, water supply to the population and industrial enterprises, shipping, timber rafting, flood control, and recreation. Large reservoirs change natural conditions: they regulate river flow, influence climate, fish spawning conditions, etc.

Russian lakes, of which there are more than 2 million, contain over half of the country's total fresh water. At the same time, Baikal contains about 95% of Russia’s lake water. There are relatively few large lakes in the country, only 9 of them (excluding the Caspian) have an area of ​​more than 1 thousand km2 - Baikal, Ladoga, Onega, Taimyr, Khanka, Chudsko-Pskovskoye, Chany, Ilmen, Beloe. Navigation is established on large lakes, their water is used for water supply and irrigation. Some of the lakes are rich in fish, have reserves of salts and healing mud, and are used for recreation.

Swamps are common on plains in areas of excess moisture and permafrost. In the tundra zone, for example, the swampiness of the territory reaches 50%. Severe swampiness is characteristic of the taiga. The swamps of the forest zone are rich in peat. The best quality peat, low-ash and high-calorie, is produced by raised bogs located on watersheds. Swamps are the source of food for many rivers and lakes. The most swampy region in the world is Western Siberia. Here, swamps occupy almost 3 million km2, and more than 1/4 of the world's peat reserves are concentrated in them.

Groundwater is of great economic importance. It is an important source of nutrition for rivers, lakes and swamps. The groundwater of the first aquifer from the surface is called groundwater. The soil formation processes and the associated development of vegetation cover depend on the depth, abundance and quality of groundwater. When moving from north to south, the depth of groundwater increases, its temperature rises, and mineralization increases.

Groundwater- a source of clean water. They are much better protected from pollution than surface waters. An increase in the content of a number of chemical elements and compounds in groundwater leads to the formation of mineral waters. About 300 springs are known in Russia, 3/4 of which are located in the European part of the country (Mineralnye Vody, Sochi, North Ossetia, Pskov region, Udmurtia, etc.).

Almost 1/4 of Russia's fresh water reserves located in glaciers occupying about 60 thousand km2. These are mainly cover glaciers of the Arctic islands (55.5 thousand km2, water reserves 16.3 thousand km3).

Large areas in our country are occupied by permafrost - rock strata containing ice that does not thaw for a long time - about 11 million km2. These are the territories east of the Yenisei, the north of the East European Plain and the West Siberian Lowland. The maximum thickness of permafrost is in the north of Central Siberia and in the lowlands of the Yana, Indigirka and Kolyma river basins. Permafrost has a significant impact on economic life. The shallow occurrence of the frozen layer impairs the formation of the root system of plants and reduces the productivity of meadows and forests. The laying of roads and the construction of buildings change the thermal regime of permafrost and can lead to subsidence, sloughing, swelling of soil, distortions of buildings, etc.

The territory of Russia is washed by the waters of 12 seas: 3 seas of the Atlantic Ocean, 6 seas of the Arctic Ocean, 3 seas of the Pacific Ocean.

The Atlantic Ocean approaches the territory of Russia with its inland seas - the Baltic, Black and Azov. They are highly desalinated and quite warm. These are important transport routes from Russia to Western Europe and other parts of the world. A significant part of the coast of these seas is a recreational zone. Fishing value is low.

The seas of the Arctic Ocean seem to “overlap” the Arctic coast of Russia over a vast area - 10 thousand km. They are shallow and covered with ice most of the year (except for the southwestern part of the Barents Sea). The main transport routes pass through the White and Barents Seas. The Northern Sea Route is important.

Oil and gas deposits on the shelf are promising. The Barents Sea is of greatest commercial importance.

Pacific Seas- the largest and deepest of those washing Russia. The southernmost of them, Japan, is the richest in biological resources and is widely used for international shipping.

The aquatic environment includes surface and groundwater. Surface water is mainly concentrated in the ocean, containing 1 billion 375 million km3 - about 98% of all water on Earth. The ocean surface (water area) is 361 million km2. It is approximately 2.4 times larger than the land area of ​​the territory, occupying 149 million km2. The water in the ocean is salty, and most of it (more than 1 billion km3) maintains a constant salinity of about 3.5% and a temperature of approximately 3.7 ° C. Noticeable differences in salinity and temperature are observed almost exclusively in the surface layer of water, as well as in the marginal and especially in the Mediterranean seas. The content of dissolved oxygen in water decreases significantly at a depth of 50-60 meters.

Groundwater can be salty, brackish (less salinity) and fresh; existing geothermal waters have an elevated temperature (more than 30°C). For the production activities of mankind and its household needs, fresh water is required, the amount of which is only 2.7% of the total volume of water on Earth, and a very small share of it (only 0.36%) is available in places that are easily accessible for extraction. Most of the fresh water is contained in snow and freshwater icebergs found in areas mainly in the Antarctic Circle. The annual global river flow of fresh water is 37.3 thousand km3. In addition, a part of groundwater equal to 13 thousand km3 can be used. Unfortunately, most of the river flow in Russia, amounting to about 5000 km3, occurs in the infertile and sparsely populated northern territories. In the absence of fresh water, salty surface or underground water is used, desalinating it or hyperfiltrating it: passing it under a high pressure difference through polymer membranes with microscopic holes that trap salt molecules. Both of these processes are very energy-intensive, so an interesting proposal is to use freshwater icebergs (or parts thereof) as a source of fresh water, which for this purpose are towed through the water to shores that do not have fresh water, where they are organized to melt. According to preliminary calculations by the developers of this proposal, obtaining fresh water will be approximately half as energy intensive as desalination and hyperfiltration. An important circumstance inherent in the aquatic environment is that infectious diseases are mainly transmitted through it (approximately 80% of all diseases). However, some of them, for example, whooping cough, chickenpox, tuberculosis, are transmitted through the air. To combat the spread of diseases through water, the World Health Organization (WHO) has declared this decade the Decade of Drinking Water.