Water resources and their condition. Water resources and people. Features, condition, problems of the country's water resources. What are water resources? Water fees

Water resources- surface and underground waters that are located in water bodies and are used or can be used. In a broader sense - water in liquid, solid and gaseous states and their distribution on Earth. Water resources are all the waters of the hydrosphere, that is, the waters of rivers, lakes, canals, reservoirs, seas and oceans, groundwater, soil moisture, water (ice) of mountain and polar glaciers, atmospheric water vapor.

The total volume (one-time reserve) of water resources is 1390 million cubic km, of which about 1340 million cubic km is the water of the World Ocean. Less than 3% is fresh water, of which only 0.3% is technically available for use. Every year, on April 24, according to the decision of the UN, World Water Day is celebrated. The largest consumer of water is agriculture. Water resources are considered inexhaustible because invented a technology for desalination of salty sea waters.

Use of water resources. Recirculating and closed water systems. Intensive development of industry and agricultural production, an increase in the level of improvement of cities and towns, and significant population growth have led to a shortage and sharp deterioration in the quality of water resources in almost all regions of Russia in recent decades.

One of the main ways to meet society's needs for water is the engineering reproduction of water resources, i.e. their restoration and increase not only quantitatively, but also qualitatively. The prospects for rational reproduction of technological water consumption are associated with the creation of re-sequential, recycling and closed water supply systems at enterprises. They are based on the amazing property of water, which allows it not to change its physical essence after participating in production processes.

Russian industry is characterized by a high level of development of recycling water supply systems, due to which the saving of fresh water spent on production needs averages 78%. The best indicators of using circulating systems are in the gas (97%), oil refining (95%) industries, ferrous metallurgy (94%), chemical and petrochemical (91%) industries, and mechanical engineering (85%).

Maximum water consumption in circulating and re-sequential water supply systems is typical for the Ural, Central, Volga and West Siberian economic regions. In Russia as a whole, the ratio of the volumes of fresh and recycled water use is 35.5 and 64.5%, respectively.

The widespread introduction of advanced water circulation systems (even closed ones) can not only solve the problem of water supply to consumers, but also preserve natural water sources in an environmentally friendly state.

IN last years due to economic destabilization, which led to a drop in industrial output and a decrease in productivity Agriculture and the reduction of irrigated areas, in Russia there has been a decrease in the volume of water consumption (for 1991 -1995, fresh water - by 20.6%, sea water - by 13.4%). The structure of fresh water use has also changed: water consumption for industrial needs decreased by 4% (from 53% in 1991 to 49% in 1995), for irrigation and water supply - by 3% (from 19 to 16%), at the same time the share of domestic drinking water supply increased by 4% (from 16 to 20%).

By 1997, the volume of fresh water use in Russia amounted to 75780.4 million m3/year, sea water - 4975.9 million m3/year.

Communal water supply. The Russian public utilities supply the water needs of the urban population, utilities, transport and other necessities. industrial enterprises, as well as water consumption for the improvement of populated areas, watering streets and extinguishing fires.

Distinctive feature public utilities - constant water consumption and strict requirements for water quality. The main volume (84-86%) of consumed water is used for household and drinking needs of the population; on average in Russia, specific water consumption per city resident is 367-369 l/day.

About 99% of cities, 82% of urban settlements, 19.5% of settlements in rural areas are provided with centralized water supply. The improvement of urban housing stock on average across the country is characterized by the following indicators: provision of central water supply - 83.8%, sewerage - 81.4%, central heating - 84.7%, baths and showers - 76.7%, hot water supply - 70.8% (data for 1996). Industry enterprises discharge about 13 km 3/year of wastewater into surface water bodies; for various reasons, insufficiently purified water predominates in the structure of discharged water. In the whole country, about 70% of all supplied water is pre-passed through treatment systems.

Due to the unfavorable state of drinking water supply sources and the imperfection of the water treatment system, the problem of water quality continues to be acute. Standard treatment facilities, including a two-stage scheme of clarification, decolorization and disinfection, cannot cope with the increasing loads of new pollutants (heavy metals; pesticides, halogen-containing compounds, phenols, formaldehydes). Chlorination of water containing organic matter, accumulating in water sources, leads to secondary pollution and the formation of carcinogenic organochlorine compounds.

About 70% of industrial enterprises discharge wastewater into public sewers, which, in particular, contains salts of heavy metals and toxic substances. The sludge formed during the treatment of such wastewater cannot be used in agriculture, which creates problems with its disposal.

Industrial water supply. Industrial water supply, which ensures the functioning of technological processes, is the leading area of ​​water use. Industrial water supply systems include hydraulic structures for collecting process water and delivering it to enterprises, as well as water treatment systems.

Industrial potential of everyone economic region Russian Federation represented by almost all major industries. There are also areas where very specific industries are predominantly concentrated. For example, 46% of light industry production is concentrated in the Central Economic Region, the Ural Economic Region accounts for about 70% of ferrous and non-ferrous metallurgy products, and the West Siberian Region accounts for 46% of the fuel industry.

The volume of water consumption depends on the structure of industrial enterprises, the level of technology, and the measures taken to save water. The most water-intensive industries are thermal power engineering, ferrous and non-ferrous metallurgy, mechanical engineering, petrochemical and wood processing industries. The most water-intensive industry, the electric power industry, accounts for about 68% of the total consumption of fresh water and 51% of recycled water.

Since most industrial facilities are concentrated in major cities, in Russia, integrated industrial-municipal water supply systems have gained priority, which, in turn, leads to unreasonably high costs for industrial needs of drinking quality water (up to 30-40% of the daily supply of city water supply systems).

Industrial enterprises are the main source of surface water pollution, annually discharging a large amount of waste water (35.5 km in 1996). Wastewater from the chemical, petrochemical, oil refining, pulp and paper and coal industries is especially diverse in its properties and chemical composition. industry, despite the sufficient capacity of treatment facilities, only 83-85% of discharged wastewater meets regulatory requirements. In the structure of discharged water containing pollutants above the standard level, discharge without treatment currently amounts to 23% (in 1991 - 28%). , the remaining water is discharged insufficiently purified.

Agricultural water supply. In rural areas, water supply is carried out mainly through local systems and through individual provision of water users. Local water supply systems are very dependent on the quality of water in the sources and, if necessary, are equipped with special structures. In high density areas rural population group systems are used. For the needs of the industry, about 28% of the total volume of water withdrawn is taken from natural water sources.

Among agricultural sectors, the main consumer of fresh water and a major polluter of surface water bodies, discharging untreated wastewater through the collector and drainage network, is irrigated agriculture. A serious danger to surface water bodies is the removal of fertilizers and pesticides from agricultural fields.

Another large consumer of water and a powerful source of pollution of surface and groundwater are livestock complexes for raising cattle, pigs, and poultry. Purification of livestock wastewater is associated with great difficulties, since it must be long time keep in storage ponds.

Water transport. Water transport is perhaps the most ancient water user. Up to 50 million tons of cargo are transported along Russia's inland waterways (rivers, lakes, reservoirs, canals), with a total length of over 400 thousand km.

When using rivers and other water bodies For navigation, it is necessary to maintain guaranteed depths, flow conditions and other conditions that ensure the uninterrupted operation of water transport during the navigation period. In a number of cases, the interests of water transport conflict with the interests of other water users and water consumers, such as water supply, irrigation, and hydropower. For example, hydraulic construction, on the one hand, makes it possible to increase the depth and width of the waterway, eliminate rapids, and on the other hand, it introduces serious complications into the operation of water transport by reducing the duration of the navigation period, sharp daily and weekly fluctuations in flow rates and water levels in the downstream of hydroelectric power stations. .

Water transport, without placing high demands on water quality, is one of the significant sources of pollution of water bodies with oil products and suspended substances.

Timber rafting has a very adverse effect on the ecological state of water bodies, changing the natural state of riverbeds, clogging water bodies with submerged wood, and destroying spawning areas.

Fisheries. Fisheries are directly related to the use of water resources and place very high demands on their regime, quantity and quality. For successful reproduction and normal development of fish, clean water with a sufficient amount of dissolved oxygen and the absence of harmful impurities, appropriate temperature and food supply are necessary. Water quality standards for fisheries are more stringent than for drinking water supplies.

In Russia, about 30% of catches in inland seas and reservoirs are freshwater fish (pike, bream, pike perch, roach, perch, carp, whitefish, stellate sturgeon, beluga, salmon, chum salmon, pink salmon). In recent years, there has been a decline in catches, which is due to a decrease in the productivity of fisheries as a result of intense anthropogenic impact. The increase in fish reproduction is carried out through artificial fish breeding in fish hatcheries, spawning and nursery farms, and fish hatcheries. A very promising direction is the cultivation of fish in cooling ponds of thermal power plants.

Recreation. Water bodies are a favorite place for recreation, sports, and people's health. Almost all recreational institutions and structures are located either on the banks of water bodies or near them. In recent years, the scale of recreational activities on water bodies has been constantly growing, which is facilitated by an increase in the urban population and improved transport communications. In the Russian Federation, about 60% of all sanatoriums and over 80% of recreational facilities are located on the banks of reservoirs. 60% of tourist centers and 90% of recreational facilities for the largest suburban holiday in the country.

WATER RESOURCES, in ó waters in liquid, solid and gaseous states and their distribution on Earth. They are found in natural bodies of water on the surface (oceans, rivers, lakes and swamps); in the subsoil (groundwater); in all plants and animals; as well as in artificial reservoirs (reservoirs, canals, etc.).

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

° C at atmospheric pressure 760 mmHg Art. On bó At higher altitudes, where the pressure is lower than at sea level, water boils at lower temperatures. When water freezes, its volume increases by more than 11%, and the expanding ice can rupture water pipes and pavements and erode rock into loose soil. Ice is less dense than liquid water, which explains its buoyancy.

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

 0 ° C and it freezes, then 79 calories are released from each gram of water. During night frosts, farmers sometimes spray their gardens with water to protect the buds from frost damage. When water vapor condenses, each gram of it releases 540 calories. This heat can be used in heating systems. Due to its high heat capacity, water absorbs a large amount of heat without changing temperature.

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).

 DISTRIBUTION OF WATER IN NATURE

When the temperature of water changes, the hydrogen bonds between its molecules also change, which in turn leads to a change in its state from liquid to solid and gaseous. see also WATER, ICE AND STEAM.

Since liquid water is an excellent solvent, it is rarely absolutely pure and contains minerals in a dissolved or suspended state. Only 2.8% of 1.36 billion km

3 of all the water available on Earth is fresh, and bó The majority of it (about 2.2%) is in the solid state in mountain and cover glaciers (mainly in Antarctica) and only 0.6% is in the liquid state. Approximately 98% of liquid fresh water is concentrated underground. Salty waters of the oceans and inland seas occupying more than 70% earth's surface, constitute 97.2% of all waters on Earth. see also OCEAN.The water cycle in nature. Although the world's total supply of water is constant, it is constantly being redistributed and is therefore a renewable resource. The water cycle occurs under the influence of solar radiation, which stimulates the evaporation of water. In this case, the minerals dissolved in it precipitate. Water vapor rises into the atmosphere, where it condenses, and thanks to gravity, the water returns to the earth in the form of precipitation rain or snow (see also RAIN). Bó Most precipitation falls over the ocean and only less than 25% falls over land. About 2/3 of this precipitation enters the atmosphere as a result of evaporation and transpiration, and only 1/3 flows into rivers and seeps into the ground. see also HYDROLOGY.

Gravity promotes the redistribution of liquid moisture from higher to lower areas, both on the earth's surface and under it. Water originally set in motion solar energy, in the seas and oceans moves in the form ocean currents, and in the air in the clouds.

Geographic distribution of precipitation. The volume of natural renewal of water reserves due to precipitation varies depending on geographical location and the sizes of parts of the world. For example, South America receives almost three times more rainfall annually than Australia and almost twice as much as North America, Africa, Asia and Europe (listed in order of decreasing annual precipitation). Part of this moisture returns to the atmosphere as a result of evaporation and transpiration by plants: in Australia this value reaches 87%, and in Europe and North America only 60%. The rest of the precipitation flows over the earth's surface and eventually reaches the ocean with river runoff.

Within continents, precipitation also varies greatly from place to place. For example, in Africa, in Sierra Leone, Guinea and Cote d

" Ivoire receives more than 2000 mm of precipitation annually, in most parts central Africa from 1000 to 2000 mm, but in some northern regions (Sahara and Sahel deserts) precipitation is only 500 1000 mm, and in southern Botswana (including the Kalahari Desert) and Namibia less than 500 mm.

Eastern India, Burma and part South-East Asia receive more than 2000 mm of precipitation per year, a b

ó most of the rest of India and China are from 1000 to 2000 mm, with northern China only 500 to 1000 mm. In the territory of northwestern India (including the Thar Desert), Mongolia (including the Gobi Desert), Pakistan, Afghanistan andó Most of the Middle East receives less than 500 mm of rainfall annually.

In South America, annual precipitation in Venezuela, Guyana and Brazil exceeds 2000 mm, b

ó Most of the eastern regions of this continent receive 1000-2000 mm, but Peru and some areas of Bolivia and Argentina receive only 500-1000 mm, and Chile less than 500 mm. In some areas of Central America located to the north, over 2000 mm of precipitation falls per year, in the southeastern regions of the USA - from 1000 to 2000 mm, and in some areas of Mexico, in the northeast and Midwest of the USA, in eastern Canada - 5001000 mm, while in central Canada and the western USA less than 500 mm.

On far north Australia's annual precipitation is 10002000 mm, in some other northern regions it ranges from 500 to 1000 mm, but

ó most of the mainland and especially its central regions receive less than 500 mm.ó most of former USSR it also receives less than 500 mm of precipitation per year.Time cycles of water availability. At any point on the globe, river flow experiences daily and seasonal fluctuations, and also changes at intervals of several years. These variations are often repeated in a certain sequence, i.e. are cyclical. For example, water flows in rivers whose banks are covered with dense vegetation tend to be higher at night. This is because from dawn to dusk vegetation uses groundwater for transpiration, resulting in a gradual reduction in river flow, but its volume increases again at night when transpiration stops.

Seasonal cycles of water availability depend on the distribution of precipitation throughout the year. For example, in the Western United States, snow melts together in the spring. India receives little rainfall in winter, but heavy monsoon rains begin in midsummer. Although the average annual river flow is almost constant over a number of years, it is extremely high or extremely low once every 11-13 years. Perhaps this is due to cyclicality solar activity. Information on the cyclicity of precipitation and river flow is used in forecasting water availability and frequency of droughts, as well as in planning water protection activities.

 WATER SOURCES

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 state accounts for groundwater, and 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 . IN modern conditions they are not replenished by surface fresh waters, but are depleted when pumped. 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

ó greater depth, to the level of pressure artesian waters, the latter rise and saturate the overlying groundwater, and sometimes come to the surface. Groundwater moves slowly, at a speed of several meters per day or even per year. They are usually found in porous pebbly or sandy horizons or relatively impervious shale formations, and only rarely are they concentrated in underground cavities or underground streams. To correctly select the location for drilling a well, information about geological structure territories.

In some parts of the world, increasing consumption of groundwater is having serious consequences. Pumping 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

ó higher costs for expensive electricity used to extract them. In places where the aquifer is depleted, the earth's surface begins to subsidence, and there it becomes more difficult to restore water resources naturally.

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

Gradual deterioration of groundwater quality as a result of salt accumulation may 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 chemical substances got into groundwater and accumulated there in noticeable quantities. However, once the aquifer has been contaminated, it will take 200 to 10,000 years to naturally cleanse itself.

Surface sources. Only 0.01% of the total volume of fresh water in liquid state is concentrated in rivers and streams and 1.47% in lakes. To store water and constantly provide it to consumers, as well as to prevent unwanted floods and generate electricity, dams have been built on many rivers. The Amazon in South America, the Congo (Zaire) in Africa, the Ganges with the Brahmaputra in Africa have the highest average water consumption, and therefore the greatest energy potential. south asia, Yangtze in China, Yenisei in Russia and Mississippi with Missouri in the USA. see also RIVER.Water consumption by different crops. To obtain high yields, a lot of water is required: for example, growing 1 kg of cherries requires 3000 liters of water, rice 2400 liters, corn on the cob and wheat 1000 liters, green beans 800 liters, grapes 590 liters, spinach 510 l, potatoes 200 l and onions 130 l. The estimated amount of water used just to grow (not process or prepare) the food crops consumed daily by one person in Western countries, for breakfast approx. 760 l, for lunch (lunch) 5300 l and for dinner 10,600 l, which is a total of 16,600 l per day.

In agriculture, water is used not only to irrigate crops, but also to replenish groundwater reserves (to prevent the groundwater level from dropping too quickly); for washing out (or leaching) salts accumulated in the soil to a depth below the root zone of cultivated crops; for spraying against pests and diseases; frost protection; fertilization; reducing air and soil temperatures in summer; for caring for livestock; evacuation of treated wastewater used for irrigation (mainly grain crops); and processing of harvested crops.

Food industry. Processing of different food crops requires varying amounts of water depending on the product, production technology and the availability of sufficient quality water. In the USA, from 2000 to 4000 liters of water are consumed to produce 1 ton of bread, and in Europe only 1000 liters and only 600 liters in some other countries. Preserving fruits and vegetables requires from 10,000 to 50,000 liters of water per ton in Canada, but in Israel, where water is a great scarcity, only 40001500. The “champion” in terms of water consumption is lima beans, 70,000 liters of water are consumed in the USA to preserve 1 ton of them. Processing 1 ton of sugar beet requires 1,800 liters of water in Israel, 11,000 liters in France and 15,000 liters in the UK. Processing 1 ton of milk requires from 2000 to 5000 liters of water, and to produce 1000 liters of beer in the UK 6000 liters, and in Canada 20,000 liters.Industrial water consumption. The pulp and paper industry is one of the most water-intensive due to the huge volume of raw materials processed. The production of each ton of pulp and paper requires an average of 150,000 liters of water in France and 236,000 liters in the USA. The newsprint production process in Taiwan and Canada uses approx. 190,000 liters of water per 1 ton of product, while the production of a ton of high-quality paper in Sweden requires 1 million liters of water.Fuel industry. To produce 1000 liters of high-quality aviation gasoline, 25,000 liters of water are needed, and motor gasoline requires two-thirds less.Textile industry requires a lot of water for soaking raw materials, cleaning and washing them, bleaching, dyeing and finishing fabrics and for other technological processes. To produce each ton of cotton fabric, from 10,000 to 250,000 liters of water are needed, and for woolen fabric - up to 400,000 liters. The production of synthetic fabrics requires significantly more water - up to 2 million liters per 1 ton of product.Metallurgical industry. In South Africa, when mining 1 ton of gold ore, 1000 liters of water are consumed, in the USA, when mining 1 ton of iron ore, 4000 liters and 1 ton of bauxite are consumed 12,000 liters. Iron and steel production in the US requires approximately 86,000 liters of water for every ton of production, but up to 4,000 liters of this is deadweight loss (mainly evaporation), and therefore approximately 82,000 liters of water can be reused. Water consumption in the iron and steel industry varies significantly across countries. To produce 1 ton of pig iron in Canada, 130,000 liters of water are spent, to smelt 1 ton of pig iron in a blast furnace in the USA 103,000 liters, steel in electric furnaces in France 40,000 liters, and in Germany 8000 12,000 liters.Electric power industry. To produce electricity, hydroelectric power plants use the energy of falling water to drive hydraulic turbines. In the USA, 10,600 billion liters of water are consumed daily at hydroelectric power stations (see also HYDROPOWER). Wastewater.Water is necessary for the evacuation of domestic, industrial and agricultural wastewater. Although about half of the population, such as the United States, is served by sewer systems, wastewater from many homes is still simply dumped into septic tanks. But everything wouldó Greater awareness of the consequences of water pollution through such outdated sewer systems has stimulated the installation of new systems and the construction of water treatment plants to prevent the infiltration of pollutants into groundwater and the release of untreated wastewater into rivers, lakes and seas (see also WATER POLLUTION). WATER SHORTAGE

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 supply 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 needed, 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 They 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

 3 water, an end-to-end system of reservoirs, canals and rivers would facilitate the development of navigation in the interior regions, the Great Lakes would receive an additional 50 million m annually 3 water (which would compensate for the decrease in their level), and up to 150 million kW of electricity would be generated. Another grand plan for the transfer of flow is associated with the construction of the Grand Canadian Canal, through which water would be directed from the northeastern regions of Canada to the western ones, and from there to the United States and Mexico.

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 systems distillation. 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.

Protection of water resources. There are two widespread ways to conserve water resources: preserving existing supplies of usable water and increasing its reserves by constructing more advanced collectors. The accumulation of water in reservoirs prevents its flow into the ocean, from where it can only be extracted again through the process of the water cycle in nature or through desalination. Reservoirs also make it easier to use water at the right time. Water can be stored in underground cavities. In this case, there is no loss of moisture due to evaporation, and valuable land is saved. The preservation of existing water reserves is facilitated by channels that prevent water from seeping into the ground and ensure its efficient transportation; application more effective methods irrigation using wastewater; reducing the volume of water flowing from fields or filtering below the root zone of crops; careful use of water for domestic needs.

However, each of these methods of conserving water resources has one or another impact on 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.

 WATER SUPPLY

The sources of water supply and reservoirs themselves are important only when water is delivered in sufficient volume to consumers to residential buildings and institutions, to fire hydrants (devices for collecting water for fire needs) and other public utility facilities, industrial and agricultural facilities.

Modern water filtration, purification and distribution systems are not only convenient, but also help prevent the spread of water-borne diseases such as typhoid and dysentery. A typical city water supply system involves drawing water from a river, passing it through a coarse filter to remove most of the pollutants, and then through a measuring station where its volume and flow rate are recorded. The water then enters the water tower, where it is passed through an aeration plant (where impurities are oxidized), a microfilter to remove silt and clay, and a sand filter to remove remaining impurities. Chlorine, which kills microorganisms, is added to the water in the main pipe before entering the mixer. Ultimately, purified water is pumped into a storage tank before being sent to the distribution network to consumers.

The pipes at the central waterworks are usually cast iron and have a large diameter, which gradually decreases as the distribution network expands. From street water mains with pipes with a diameter of 1025 cm, water is supplied to individual houses through galvanized copper or plastic pipes.

Irrigation in agriculture. Since irrigation requires enormous amounts of water, water supply systems in agricultural areas must have a large capacity, especially in arid conditions. Water from the reservoir is directed into a lined, or more often unlined, main canal and then through branches into distribution irrigation canals of various orders to farms. Water is released onto the fields as a spill or through irrigation furrows. Because many reservoirs are located above irrigated land, water flows primarily by gravity. Farmers who store their own water pump it from wells directly into ditches or storage reservoirs.

For sprinkler or drip irrigation practiced in Lately, use low power pumps. 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.

WATER RESOURCES (a. water resources; n. Wasserschatze, Wassersquellen; f. ressources d'eau; i. recursos de agua) - suitable for use waters of rivers, lakes, canals, reservoirs, seas and oceans, soil moisture, as well as water (ice) of polar and mountain glaciers, precipitation.

In the process of circulation (the continuous movement of water in, liquid, vapor and solid states) natural renewal of water resources occurs (Table 1). Freshwater resources account for less than 2% of hydrosphere reserves. But if we exclude the polar glaciers, in which about 24 million km 3 of unused water (ice) is conserved, then the share of fresh water most accessible for use accounts for only 0.3% of the total volume of the hydrosphere. However, these waters are the most reliable source for use, because... they are continuously renewed through the water cycle. Intensively renewable fresh water resources consist of two parts that are unequal in use: more or less stable over time and unstable. For example, river water resources are divided into underground (sustainable), in general view characterizing the renewable resources of groundwater, zones of active water exchange, as well as runoff regulated by flowing lakes, and less stable ones - surface (flood). Highly mineralized underground deep waters are practically non-renewable, because... do not participate in the cycle. To assess the water resources of continents, countries, river basins and their individual parts, a six-component system of water balance equations has been developed, which makes it possible to evaluate various sources of renewable water resources interconnectedly, in accordance with the natural water cycle (Table 2).

Theoretically, with rational use, water resources are inexhaustible. However, the demand for them is growing so quickly that in many countries there is an acute shortage of water resources. An increase in the water resources available for use is possible due to their expanded reproduction (the use of agro- and forestry measures, the creation of reservoirs and other measures). Some types of expanded reproduction of water resources have reached global proportions. Thus, the global volume of regulated flood flow by reservoirs around the globe is 2000 km 3 per year, as a result of which the natural sustainable flow of the world’s rivers has increased by 16%.

Intensive economic use of water resources in many areas of the world leads to their significant pollution. Wastewater is generated which, even after treatment, contains residual contaminants. The number of such urban and industrial waste dumped into the rivers and reservoirs of the world now reaches approximately 500 km 3 per year. For their more or less complete neutralization, considering that half of them are subject to thorough biological treatment, it is necessary to consume about 6000 km 3 per year of clean water, which is about 17% of the total world river flow, and in the future, subject to more complete treatment for this the goal would require using up all of the world's river flow.

The discharge of wastewater into rivers and reservoirs, even after treatment, which is incomplete due to the complex composition of pollutants, disrupts the desalination effect of the water cycle. To prevent this unfavorable phenomenon, industrial pollution is eliminated before being discharged into the environment; municipal wastewater containing valuable fertilizers (nitrogen, phosphorus, potassium), after appropriate preparation, is used to fertilize fodder crops or forests, in some cases it is reused after purification in those sectors of the economy that do not require clean water, for example, for cooling turbine generators of thermal power plants . The neutralization of industrial wastewater involves transferring treatment to a local basis, i.e. purification of wastewater from one production line containing one type of contaminant. This system, and in some cases a change in production technology, makes it possible to switch to closed recycling water supply. In this way, isolation of the industrial part of the water cycle from the natural one is achieved, as well as the use of valuable production waste. In the future, the most rational protection of water resources is to completely stop the discharge of wastewater into rivers and reservoirs.

Even though about 70% of the earth's surface is covered with water, it is still a very valuable resource. Especially when it comes to quality. What are water resources? What is their structure and world reserves? What are the most pressing water problems of our time? All this will be discussed in the article.

What are water resources?

Geographic, as is known, consists of five spheres: litho-, atmospheric-, bio-, techno- and hydrosphere. What are water resources? This is all the water that is contained in the hydrosphere. It is found in oceans and seas, lakes and rivers, glaciers and reservoirs, in the soil and in the air (in the form of water vapor).

About 70% of the earth's surface is covered with water. Only 2.5% of this volume is fresh water, which humanity needs. IN absolute values- this is at least 30 million cubic kilometers, which is thousands of times greater than the needs of world civilization. However, we should not forget that the bulk of these reserves are contained in the “ice shells” of Antarctica, the Arctic and Greenland. In addition, the state of water resources available to humans is often unsatisfactory.

Structure of planetary water resources

The planet's water resources are divided into two classes:

  • waters of the World Ocean;
  • terrestrial (or surface) waters.

Rivers, lakes, reservoirs and glaciers contain only four percent of the world's water reserves. Moreover, most of them (by volume) are confined specifically to glaciers. And the largest “reservoir” of fresh water on the planet is Antarctica. Underground flows also belong to the Earth's water resources, but their quantitative estimates vary greatly in numbers.

Pure is the most valuable for humans and any other living organisms. Its protection and rational use is one of the most important tasks of humanity at the present stage.

Water resource update

Features of water resources include the possibility of self-purification and renewal. However, the renewability of water depends on several factors, in particular the type of hydrological body.

For example, water in rivers is completely renewed in about two weeks, in a swamp - in five years, and in a lake - in 15-17 years. This process takes the longest time in ice sheets (on average it takes 10 thousand years), and the fastest in the biosphere. In a living organism, water goes through a full renewal cycle in a few hours.

Distribution of water resources by macroregion and country

The Asian region leads the world in terms of total water resources. It is followed by South America, North America and Europe. The poorest corner of the planet in terms of water reserves is Australia.

However, there is one important nuance here. So, if you calculate the volume of water reserves per capita of a continent or part of the world, you get a completely different picture. With this calculation, Australia comes out on top, but Asia comes in last. The thing is that in Asia the population is growing at a rapid pace. Today it has already reached the milestone of four billion people.

Which countries don't have to worry about water? Below are the top five states with the largest fresh water reserves. This:

  1. Brazil (6950 km 3).
  2. Russia (4500 km 3).
  3. Canada (2900 km 3).
  4. China (2800 km 3).
  5. Indonesia (2530 km 3).

It is worth noting the uneven distribution of water resources on Earth. Thus, in the equatorial and temperate climate zones they are even found in abundance. But in the so-called “arid” (tropical and subtropical climate) the population experiences an acute shortage of life-giving moisture.

Water resources and people

Water is in demand in everyday life, energy, industry, and recreation. The use of this resource may be accompanied by its extraction from a natural source (for example, from a river bed) or without it (for example, for the operation of water transport).

The largest consumers of water resources are:

  • Agriculture;
  • industrial and energy enterprises;
  • communal sphere.

The volumes of municipal water consumption are constantly growing. According to environmentalists, in large cities of economically developed countries, one person uses at least 300 liters of liquid daily. This level of consumption could lead to shortages of this resource in the near future.

Pollution and depletion of the world's waters

Pollution of water resources is very acute. Today it has reached catastrophic levels in some regions of the planet.

Every year, millions of tons of chemicals, oil and petroleum products, phosphorus compounds, and municipal solid waste enter the World Ocean. The latter form huge ones out of garbage. The waters of the Persian Gulf, North and Caribbean seas are very polluted with oil. Already about 3% of the surface of the North Atlantic is covered with an oil film, which has a detrimental effect on living organisms of the ocean.

A big problem is also the reduction of the planet's water resources. However, the deterioration of the quality of life-giving moisture is no less dangerous. After all, one cubic meter of untreated waste can end up in the natural riverbed and spoil tens of cubic meters of clean water.

In developing countries of the world, according to statistics, every third resident suffers from poor-quality drinking water. She serves main reason many diseases of the population of the “arid zone” of Africa and Latin America.

Main types and sources of pollution of world waters

In ecology, water pollution is understood as exceeding the maximum permissible concentrations of substances contained in them (harmful chemical compounds). There is also such a thing as depletion of hydro resources - deterioration in water quality due to constant activity.

There are three main types of water pollution:

  • chemical;
  • biological;
  • thermal;
  • radiation.

The role of a pollutant can be any substance that enters a hydrological body due to human activity. At the same time, this substance significantly worsens natural qualities water. One of the most dangerous modern pollutants is oil and its products.

Sources of pollution can be permanent, periodic or seasonal. They can be of both anthropogenic and natural origin, be point, linear or areal.

The largest source of pollution are the so-called ones, that is, those that are formed as a result of industrial, construction or communal human activities. They are usually oversaturated with harmful organic and inorganic substances, heavy metals and microorganisms. There are industrial (including mine), municipal, agricultural and other types of wastewater.

Characteristics of water resources in Russia

Russia is one of the countries in the world that does not experience water shortages. The country's modern water resources are 2.5 million rivers and watercourses, about two million lakes and hundreds of thousands of swamps. The territory of Russia is washed by twelve seas. A huge amount of fresh water is stored in glaciers (mountain and polar).

To improve water supply, thousands of reservoirs have been created on the territory of our state. different sizes. In total, they contain about 800 km 3 of fresh water. These objects not only serve as artificial reservoirs of valuable natural resource, but also regulate the regime of rivers, prevent floods and floods. Thus, their importance cannot be overestimated.

Among the main problems of water resources in Russia, the following should be highlighted:

  • irrational water use;
  • deterioration in the quality of drinking water;
  • unsatisfactory condition of waterworks and hydraulic structures.

Finally...

What are water resources? This is all the water that is contained in the hydrosphere. Countries such as Brazil, Russia, Canada, China, Indonesia and the USA have the largest reserves of water resources.

In modern realities, the problem of pollution and irrational use of world waters is becoming very urgent, and in some regions - especially acute. Its solution is impossible without consolidating the efforts of all countries on the planet and effectively implementing joint global projects.

If you look at our planet from space, the Earth appears as a blue ball completely covered with water. And the continents are like small islands in this endless ocean. This is understandable. Water occupies 70.8% of the planet's surface, leaving only 29.2% of land. Water shell our planet is called the hydrosphere. Its volume is 1.4 billion cubic meters.

Water appeared on our planet about 3.5 billion years ago in the form of vapor that was formed as a result of degassing of the mantle. Currently, water is the most important element in the Earth's biosphere, since it cannot be replaced by anything. Fortunately, water resources are considered inexhaustible because scientists have come up with a way to desalinate salt water.

The main purpose of water as a natural resource is to support the life of all living things - plants, animals and humans. It is the basis of all life on our planet, the main supplier of oxygen in the most important process on Earth - photosynthesis.

Water is the most important factor in climate formation. By absorbing heat from the atmosphere and releasing it back, water regulates climate processes.

It is impossible not to note the role of water sources in the modification of our planet. From time immemorial, people have settled near reservoirs and water sources. Water serves as one of the main means of communication. There is an opinion among scientists that if our planet were entirely dry land, then, for example, the discovery of America would be delayed for several centuries. And we would hardly have learned about Australia for another 300 years.

Types of Earth's water resources

The water resources of our planet are the reserves of all water. But water is one of the most common and most unique compounds on Earth, since it is present in three states at once: liquid, solid and gaseous. Therefore, the Earth's water resources are:

. Surface water(oceans, lakes, rivers, seas, swamps)

. The groundwater.

. Artificial reservoirs.

. Glaciers and snowfields (frozen water from glaciers in Antarctica, the Arctic and highlands).

. Water contained in plants and animals.

. Atmospheric vapors.

The last 3 points relate to potential resources, because humanity has not yet learned to use them.

Fresh water is the most valuable; it is used much more widely than sea, salt water. Of the total water reserves in the world, 97% of water comes from seas and oceans. 2% of fresh water is contained in glaciers, and only 1% is fresh water reserves in lakes and rivers.

Use of water resources

Water resources are the most important component of human life. People use water in industry and at home.

According to statistics, most water resources are used in agriculture (about 66% of all fresh water reserves). About 25% is used by industry and only 9% goes to meet the needs of utilities and households.

For example, to grow 1 ton of cotton, about 10 thousand tons of water are needed, for 1 ton of wheat - 1,500 tons of water. To produce 1 ton of steel, 250 tons of water are required, and to produce 1 ton of paper, at least 236 thousand tons of water are needed.

A person needs to drink at least 2.5 liters of water per day. However, on average, 1 person in large cities spends at least 360 liters per day. This includes the use of water in sewers, water supply, for watering streets and extinguishing fires, for washing vehicles, etc., etc.

Another option for using water resources is water transport. Every year, over 50 million tons of cargo are transported across Russian waters alone.

Don't forget about fisheries. Breeding marine and freshwater fish plays an important role in the economies of countries. Moreover, fish farming requires clean water, saturated with oxygen and free of harmful impurities.

An example of the use of water resources is also recreation. Who among us doesn’t like to relax by the sea, barbecue on the river bank or swim in the lake? In the world, 90% of recreational facilities are located near water bodies.

Water conservation

Today there are only two ways to preserve water resources:

1. Preservation of existing fresh water reserves.

2. Creation of more advanced collectors.

The accumulation of water in reservoirs prevents its flow into the world's oceans. And storing water, for example, in underground cavities, allows you to protect water from evaporation. The construction of canals allows us to solve the issue of delivering water without it seeping into the ground. New methods of irrigating agricultural land are also being developed that make it possible to use wastewater.

But each of these methods has an impact on the biosphere. Thus, the reservoir system prevents the formation of fertile silt deposits. The canals impede the replenishment of groundwater. And water filtration in canals and dams is the main risk factor for swamps, which leads to disturbances in the planet’s ecosystem.

Today, the most effective measure for protecting water resources is considered to be the method of wastewater treatment. Various ways allow you to remove up to 96% harmful substances of water. But this is often not enough, and the construction of more advanced treatment facilities often turns out to be economically unprofitable.

Water pollution problems

Population growth, development of production and agriculture - these factors have led to a shortage of fresh water for humanity. The share of polluted water resources is growing every year.

Main sources of pollution:

. Industrial wastewater;

. Wastewater from municipal routes;

. Drains from fields (when the water is oversaturated with chemicals and fertilizers);

. Disposal of radioactive substances in water bodies;

. Drains from livestock complexes (such water contains a lot of biogenic organic matter);

. Shipping.

Nature provides for the self-purification of reservoirs, which occurs due to the water cycle in nature, due to the life activity of plankton, irradiation ultraviolet rays, sedimentation of insoluble particles. But all these processes can no longer cope with the mass of pollution that human activity brings to the planet’s water resources.