Water is one of the irreplaceable sources of existence of any living creature on Earth. With the development of new technologies, the need for it is growing every day.

Water resources of the Earth: general characteristics

The world's water resources (hydrosphere) are the totality of all possible sources of water on planet Earth. It is no secret that any sphere of life requires water components. Statistics show that the volume of the hydrosphere is quite large - 1.3 billion km. However, this figure does not reflect the sufficiency of water in the world, since fresh drinking water plays a strategic role, and its amount ranges from 2 to 2.6%.

The world's water resources (fresh) include ice blocks in Antarctica and the Arctic, natural lakes and mountain rivers. However, it is unfortunately impossible to gain full access to these sources.

Problems of world water resources

At the moment, only a few countries in the world are sufficiently supplied with water, and according to statistical data, about 89 countries generally suffer from water deficiency. The role of water is difficult to overestimate, and its poor quality is the cause of 31% of diseases on Earth. The problems of the world's water resources should not be ignored by any state in the world, but should be resolved promptly and collectively.

Every year the need for water increases, this is directly related to population growth and economic development. Many states are now introducing new methods for obtaining water, purifying it, and enriching it with minerals. Unfortunately, water accumulates very slowly, and therefore belongs to the group of non-renewable resources.

World water use

Water resources on planet Earth are distributed extremely unevenly. If the equatorial regions (Brazil, Peru, Indonesia) and the northern temperate zones are provided with water above the norm, then all tropical regions (accounting for 63% of the total area of ​​the globe) experience an acute shortage of water.

Global water use is generally stable. The largest percentage of water comes from agriculture and heavy industry (metallurgy, oil refining, automotive, chemical and woodworking industries). Modern thermal power plants are no less competitive with these sources of use. Despite their cheapness, obtaining energy by this method not only significantly reduces the amount of target water, but also pollutes and makes water in nearby bodies of water unsuitable for consumption.

The World Water Council was founded in 1996 with the support of 50 countries and 300 international organizations. This is a universal international platform whose main goal is to solve global water problems. To attract the attention of the international community, the Council periodically holds the World Water Forum. Once every three years (May 22), members of this organization nominate competent specialists and professors who propose new methods for solving present and future problems, demonstrate existing indicators and other information about water resources.

The world's water resources come from a variety of sources: mountains, oceans, rivers, glaciers. The vast majority of them offer low quality water due to natural and anthropogenic factors:

• drainage of used (polluted) waters into rivers and seas;
• use of fresh water for domestic needs (washing cars in reservoirs);
• entry of petroleum products and chemicals into water bodies;
• imperfect water purification system;
• inaction of environmental protection authorities;
• lack of financial resources.

Only 4% of the world's water resources are polluted from natural sources. This is usually the release of aluminum from the earth's crust.

Contaminated water is a source of infectious diseases

Clean fresh water resources of the countries of the world currently exist in nature in practically inaccessible sources (glaciers, mountain lakes), and therefore people more often resort to purifying simple river water. However, if it is poorly processed, then the risk of getting an infectious disease is extremely high. Dirty water is a source of severe, intractable diseases, such as typhus, tuberculosis, cholera, dysentery, glanders, etc. During the 18th and 19th centuries, most terrible pandemics began with the consumption of dirty water.

The statistics on this issue are quite disappointing, since about half of humanity suffers from bad water. Residents of Africa and Central Asia not only do not have access to fresh water, but also do not have the ability to purify the available water.

World Water Day

World Water Day was introduced by the UN in 1993 and is celebrated annually on May 22. In honor of this day, the UN Secretary-General holds various forums, meetings, round tables, and meetings on global water problems. Also on May 22, UN statistics show new data on the increase or decrease in the level of water resources in various countries of the world (geography of world water resources).

Selected annually new topic, which is of most concern to international consumers. These include questions about the amount of water in modern water basins, water diseases, water natural disasters, water resource shortages, fresh water sources, and water supply problems in cities.

Ways to overcome deficit

The characteristics of the world's water resources show that this resource is non-renewable, therefore most civilized countries of the world are trying in various ways use water rationally. Ways to overcome water deficit include:

1. Installation of meters that will correctly and accurately calculate the amount of water used.

2. Creation of a strong information base, dissemination of information about water shortages in society through the media, journalism, etc.

3. Improvement of the sewer system.

4. Savings. Simple rules for saving water by the population can help significantly reduce its consumption for more useful purposes.

5. Creation of fresh water reservoirs.

6. Introduction of sanctions for violation of water legislation.

7. Desalination of salt water or detoxification of dirty water with chemicals. If previously aggressive chemicals were used to destroy microbes, now, as a rule, harmless compounds of iodine or chlorine are common.

Water resources play a significant role in the life of modern society. Its quality, quantity, physical condition, temperature and other characteristics directly affect the life activity of all living things on planet Earth. However modern society abandoned this valuable resource, and therefore the urgent issue is the creation of an effective mechanism for the purification and rational use of water.

Water resources consist of many sources, but they all make up the hydrosphere. Its unsatisfactory condition can lead to the extinction of people, animal populations, the disappearance of plants, and the spread of infectious diseases.

The problem of water in the world is urgent and requires surgical intervention. If the international community ignores such issues, then there is a threat of a complete shortage of water resources on the planet.

The most important component water resources of Russia – 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 wettest area in the world Western Siberia. Here, swamps occupy almost 3 million km2, and more than 1/4 of the world's peat reserves are concentrated in them.

Big economic importance have underground water. 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- source clean water. They are much better surface waters protected from contamination. 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 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.

Contents of the article

WATER RESOURCES, 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.).

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 dissolved substances are precipitated minerals. 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. 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.

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 it moves in the form of ocean currents, and in the air - in clouds.

Geographical 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 as much annual precipitation as Australia, and almost twice as much as North America, Africa, Asia, and Europe (listed in order of decreasing annual precipitation). Some 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, more than 2000 mm of precipitation falls annually, in most of central Africa - from 1000 to 2000 mm, but in some northern regions (Sahara and Sahel deserts) the amount precipitation is only 500–1000 mm, and in southern Botswana (including the Kalahari Desert) and Namibia - less than 500 mm.

Eastern India, Burma and parts of Southeast Asia receive more than 2000 mm of rainfall per year, and most of the rest of India and China receive between 1000 and 2000 mm, with northern China receiving only 500–1000 mm. Northwestern India (including the Thar Desert), Mongolia (including the Gobi Desert), Pakistan, Afghanistan and much of the Middle East receive less than 500 mm of annual rainfall.

In South America, annual precipitation in Venezuela, Guyana and Brazil exceeds 2000 mm, most of the eastern regions of this continent receive 1000–2000 mm, but Peru and parts of Bolivia and Argentina receive only 500–1000 mm, and Chile receives 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 - 500–1000 mm mm, while in central Canada and the western United States it is less than 500 mm.

In the far north of Australia, annual rainfall is 1000–2000 mm, in some other northern areas it ranges from 500 to 1000 mm, but most of the mainland and especially its central regions receive less than 500 mm.

Much of the former USSR 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 explained by the fact that from dawn to dusk vegetation uses groundwater for transpiration, as a result of which there is 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. This may be due to the cyclical nature of 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 form, is 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 move along waterproof inclined layers rocks, 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 to greater depths, 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 the geological structure of the area is usually required.

In some parts of the world, increasing groundwater consumption is causing serious consequences. Pumping a large volume of groundwater, incomparably exceeding its natural replenishment, leads to a lack of moisture, and lowering the level of this water requires greater costs for expensive electricity used to extract it. 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, 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, dissolution and removal of minerals from soils) and anthropogenic (fertilization or excessive watering with water). high content salts). 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.

As a result of indiscriminate discharge or burial of toxic chemicals they leak into aquifers, which are sources of 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 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 highest average water consumption, and therefore the highest energy potential have the Amazon in South America, the Congo (Zaire) in Africa, the Ganges with the Brahmaputra in southern Asia, the Yangtze in China, the Yenisei in Russia and the Mississippi with the Missouri in the USA.

Natural freshwater lakes holding approx. 125 thousand km 3 of water, along with rivers and artificial reservoirs, are important source drinking water for people and animals. They are also used for irrigation of agricultural lands, navigation, recreation, fishing and, unfortunately, for the discharge of domestic and industrial wastewater. Sometimes, due to gradual filling with sediment or salinization, lakes dry up, but in the process of evolution of the hydrosphere, new lakes form in some places.

The water level of even “healthy” lakes can decrease throughout the year as a result of water runoff through the rivers and streams flowing from them, due to water seeping into the ground and its evaporation. Restoration of their levels usually occurs due to precipitation and the influx of fresh water from rivers and streams flowing into them, as well as from springs. However, as a result of evaporation, salts coming with river runoff accumulate. Therefore, after thousands of years, some lakes can become very salty and unsuitable for many living organisms.

USING WATER

Water consumption.

Water consumption is growing rapidly everywhere, but not only due to an increase in population, but also due to urbanization, industrialization and especially the development of agricultural production, in particular irrigated agriculture. By 2000 daily allowance world consumption water reached 26,540 billion liters, or 4280 liters per person. 72% of this volume is spent on irrigation, and 17.5% on industrial needs. About 69% of irrigation water has been lost forever.

Water quality,

used for different purposes, is determined depending on the quantitative and qualitative content of dissolved salts (i.e. its mineralization), as well as organic matter; solid suspensions (silt, sand); toxic chemicals and pathogenic microorganisms(bacteria and viruses); smell and temperature. Typically, fresh water contains less than 1 g/l of dissolved salts, brackish water contains 1–10 g/l, and salt water contains 10–100 g/l. Water with high content salts is called brine, or brine.

Obviously, for navigation purposes, water quality (salinity of sea water reaches 35 g/l, or 35‰) is not significant. Many species of fish have adapted to life in salt water, but others live only in fresh water. Some migratory fish (such as salmon) begin and complete their life cycles in inland fresh waters, but spend most of their lives in the ocean. Some fish (for example, trout) need vital cold water, while others (like perch) prefer warm.

Most industries use fresh water. But if such water is in short supply, then some technological processes, such as cooling, may proceed based on the use of low-quality water. Water for domestic purposes must be of high quality, but not absolutely pure, since such water is too expensive to produce, and the lack of dissolved salts makes it tasteless. In some areas of the world, people are still forced to use low-quality muddy water open reservoirs and springs. However, in industrial countries now all cities are supplied with piped water, filtered and treated special treatment water that meets at least minimum consumer standards, especially with regard to potability.

An important characteristic of water quality is its hardness or softness. Water is considered hard if the content of calcium and magnesium carbonates exceeds 12 mg/l. These salts are bound by some components of detergents, and thus foam formation is impaired; an insoluble residue remains on washed items, giving them a matte gray tint. Calcium carbonate from hard water forms scale (lime crust) in kettles and boilers, which reduces their service life and the thermal conductivity of the walls. The water is softened by adding sodium salts that replace calcium and magnesium. In soft water (containing less than 6 mg/l of calcium and magnesium carbonates), soap foams well and is more suitable for washing and washing. Such water should not be used for irrigation, since excess sodium is harmful to many plants and can disrupt the loose, clumpy structure of soils.

Although elevated concentrations of trace elements are harmful and even poisonous, small amounts of them can have beneficial effects on human health. An example is water fluoridation to prevent caries.

Reuse of water.

Used water is not always completely lost; some or even all of it can be returned to the cycle and reused. For example, water from a bath or shower passes through sewer pipes to city wastewater treatment plants, where it is treated and then reused. Typically, more than 70% of urban runoff returns to rivers or underground aquifers. Unfortunately, in many large coastal cities, municipal and industrial wastewater is simply dumped into the ocean and not recycled. Although this method eliminates the cost of cleaning them and returning them to circulation, there is a loss of potentially usable water and pollution of marine areas.

In irrigated agriculture, crops consume huge amounts of water, sucking it up with their roots and irreversibly losing up to 99% in the process of transpiration. However, when irrigating, farmers typically use more water than is needed for their crops. Part of it flows to the periphery of the field and returns to the irrigation network, and the rest seeps into the soil, replenishing groundwater reserves, which can be pumped out using pumps.

Use of water in agriculture.

Agriculture is the largest consumer of water. In Egypt, where there is almost no rain, all agriculture is based on irrigation, while in Great Britain almost all crops are provided with moisture from precipitation. In the United States, 10% of agricultural land is irrigated, mostly in the west of the country. A significant portion of agricultural land is artificially irrigated in the following Asian countries: China (68%), Japan (57%), Iraq (53%), Iran (45%), Saudi Arabia (43%), Pakistan (42%), Israel ( 38%), India and Indonesia (27% each), Thailand (25%), Syria (16%), Philippines (12%) and Vietnam (10%). In Africa, besides Egypt, a significant share of irrigated land is in Sudan (22%), Swaziland (20%) and Somalia (17%), and in America - in Guyana (62%), Chile (46%), Mexico (22% ) and in Cuba (18%). In Europe, irrigated agriculture is developed in Greece (15%), France (12%), Spain and Italy (11% each). In Australia, approx. 9% agricultural land and approx. 5% – in the former USSR.

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 (and 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; application of fertilizers; reducing air and soil temperatures in summer; for caring for livestock; evacuation of processed waste water used for irrigation (mainly grain crops); and processing of harvested crops.

Food industry.

Processing of different food crops requires different 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. Canning fruits and vegetables requires 10,000 to 50,000 liters of water per ton in Canada, but only 4,000 to 1,500 in Israel, where water is a great scarcity. 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 industries 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 1,000 liters of high-quality aviation gasoline, 25,000 liters of water are required, 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 required, 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 - 12,000 liters. Iron and steel production in the US requires approximately 86,000 L of water for every ton of production, but up to 4,000 L of this is deadweight loss (mainly evaporation), and therefore approximately 82,000 L 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 plants.

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 increasing 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 pollutants from infiltrating into groundwater and untreated wastewater flowing into rivers, lakes and seas.

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 occurs when evaporation exceeds precipitation, so a moderate decrease in water reserves is common. 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 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 conservation 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, but if imported water crosses state borders, then the number of potential complications increases. 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 3 of water would be redistributed annually, a through 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 3 of water annually (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, the Arabian Peninsula, is attracting much attention, which will make it possible to annually provide fresh water from 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 the environment. For example, dams are spoiled natural beauty unregulated rivers and prevent the accumulation of fertile silt sediments on the 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 implemented by reducing irrigation costs due to high cost 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 utilities, 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. After this, the water enters water tower, from where it is passed through an aeration plant (where oxidation of impurities occurs), 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 10–25 cm, water is supplied to individual houses through galvanized copper or plastic pipes.

Irrigation in agriculture.

Since irrigation requires huge 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 types 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.



Message on the topic

Water resources of the Earth

students

Ι course group 251(b)

Sazonova Daria

Kazan 2006.

1. General characteristics of water resources

2. Water balance of the Earth

3. Hydrosphere as a natural system

4. Oceans

5. Water sushi

6. Water management

7. Sources of water pollution

8. Measures for the protection and economical use of water resources

9. International Decade: “Water for Life”.

1. General characteristics of water resources.

The watery shell of the globe - oceans, seas, rivers, lakes - is called the hydrosphere. It covers 70.8% of the earth's surface. The volume of the hydrosphere reaches 1370.3 million km3, which is 1/800 of the total volume of the planet. 96.5% of the hydrosphere is concentrated in the oceans and seas, 1.74% in polar and mountain glaciers and only 0.45% in fresh waters. rivers, swamps and lakes.

The aquatic environment includes surface and groundwater. Surface water is mainly concentrated in the ocean, containing 1 billion 338 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 saline, brackish (less salinity) and fresh; existing geothermal waters have an elevated temperature (more than 30 ° WITH.). For production activities Humanity and its domestic needs require fresh water, 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, falls on infertile and sparsely populated areas. 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. In order to combat the spread of diseases through aquatic environment The World Health Organization (WHO) has declared the current decade the decade of drinking water.

2. Water balance of the earth.

To imagine how much water is involved in the cycle, let us characterize the different parts of the hydrosphere. More than 94% of it is made up of the World Ocean. The other part (4%) is groundwater. It should be taken into account that most of them belong to deep brines, and fresh water makes up 1/15 of the share. The volume of ice of the polar glaciers is also significant: when converted to water, it reaches 24 million km, or 1.6% of the volume of the hydrosphere. Lake water is 100 times less - 230 thousand km, and river beds contain only 1200 m of water, or 0.0001% of the entire hydrosphere. However, despite the small volume of water, rivers play a very important role: they, like groundwater, satisfy a significant part of the needs of the population, industry and irrigated agriculture. There is quite a lot of water on Earth. The hydrosphere makes up about 1/4180 of the mass of our planet. However, the share of fresh water, excluding water trapped in polar glaciers, accounts for a little more than 2 million km, or only 0.15% of the total volume of the hydrosphere.

3. Hydrosphere as a natural system

The hydrosphere is the discontinuous water shell of the Earth, a collection of seas, oceans, continental waters (including groundwater) and ice sheets. Seas and oceans occupy about 71% of the earth's surface, containing about 96.5% of the total volume of the hydrosphere. The total area of ​​all inland water bodies is less than 3% of its area. Glaciers account for 1.6% of the water reserves in the hydrosphere, and their area is about 10% of the area of ​​the continents.

The most important property of the hydrosphere is the unity of all types of natural waters (the World Ocean, land waters, water vapor in the atmosphere, groundwater), which occurs in the process of the water cycle in nature. The driving forces of this global process are the thermal energy of the Sun arriving at the Earth's surface and the force of gravity, ensuring the movement and renewal of natural waters of all types.

Under the influence of solar heat, water in nature undergoes a continuous cycle. Water vapor, which is lighter than air, rises to the upper layer of the atmosphere, condenses into tiny droplets, forming clouds, from which water returns to the surface of the earth in the form of precipitation - rain, snow. The water that falls on the surface of the globe partially arrives

directly into natural reservoirs, partially collected in the upper layer

soils, forming surface and groundwater.

Evaporation from the surface of the World Ocean and from the land surface is the initial link the water cycle in nature, ensuring not only the renewal of its most valuable component - the fresh waters of the land, but also their high quality. An indicator of the activity of water exchange of natural waters is the high rate of their renewal, although different natural waters are renewed (replaced) at different rates. The most mobile agent of the hydrosphere is river water, the renewal period of which is 10-14 days.

The predominant part of hydrosphere waters is concentrated in the World Ocean. The world ocean is the main closing link of the water cycle in nature. It releases most of the evaporated moisture into the atmosphere. Aquatic organisms inhabiting the surface layer of the World Ocean provide the return of a significant part of the planet’s free oxygen to the atmosphere.

The huge volume of the World Ocean indicates the inexhaustibility of the planet’s natural resources. In addition, the World Ocean is a collector of river waters on land, receiving about 39 thousand m3 of water annually. The pollution of the World Ocean that has emerged in certain areas threatens to disrupt the natural process of moisture circulation in its most critical link - evaporation from the ocean surface.

4. World ocean.

The average depth of the World Ocean is 3700 m, the greatest is 11022 m (Mariana Trench). The volume of water in the World Ocean, as mentioned above, is cubic. km.

Almost all substances known on Earth are dissolved in sea water, but in different quantities. Most of them are difficult to detect due to their low content. The main part of the salts dissolved in sea water are chlorides (89%) and sulfates (almost 11%), significantly less carbonates (0.5%). Table salt (NaCl) gives water a salty taste, magnesium salts (MqCl) - bitter. The total amount of all salts dissolved in water is called salinity. It is measured in thousandths - ppm (%o).

The average salinity of the World Ocean is about 35%.

The salinity of ocean water depends primarily on the ratio of precipitation and evaporation. The salinity of river waters and melting ice waters reduces the salinity. In the open ocean, the distribution of salinity in surface layers water (up to 1500 m) has a zonal character. In the equatorial zone, where there is a lot of precipitation, it is low, in tropical latitudes it is high.

Inland seas differ noticeably in salinity. The salinity of water in the Baltic Sea is up to 11%o, in the Black Sea - up to 19%o, and in the Red Sea - up to 42%o. This is explained by the different ratio of inflow (precipitation, river runoff) and outflow (evaporation) of fresh water, i.e., climatic conditions. Ocean - heat regulator

The highest temperature at the surface of the water in the Pacific Ocean is 19.4 ° C; The Indian Ocean has 17.3°C; Atlantic - 16.5 °C. At these average temperatures, water in the Persian Gulf regularly reaches 35°C. As a rule, water temperature decreases with depth. Although there are exceptions due to the rise of deep warm waters. An example is the western part of the Arctic Ocean, where the Gulf Stream invades. At a depth of 2 km throughout the entire waters of the World Ocean, the temperature usually does not exceed 2-3 °C; in the Arctic Ocean it is even lower.

The world's oceans are a powerful heat accumulator and regulator of the Earth's thermal regime. If there were no ocean, the average temperature of the Earth's surface would be - 21 °C, that is, it would be 36 ° lower than what actually exists.

Currents of the World Ocean

Ocean waters are in constant motion under the influence of various forces: cosmic, atmospheric, tectonic, etc. The most pronounced are surface sea currents, mainly of wind origin. But 3 currents are very common, arising due to different mass densities. Currents in the World Ocean are divided according to their prevailing direction into zonal (going to the west and east) and meridional (carrying water to the north and south). Currents moving towards neighboring, more powerful currents are called countercurrents. Equatorial currents (along the equator) are specially distinguished. Currents that change their strength from season to season, depending on the direction of the coastal monsoons, are called monsoon currents.

The most powerful in the entire World Ocean is the Circumpolar, or Antarctic, circular current, caused by strong and stable westerly winds. It covers a zone 2500 km wide and kilometer deep, carrying about 200 million tons of water every second. For comparison, the world's largest river, the Amazon, carries only about 220 thousand tons of water per second.

In the Pacific Ocean, the strongest is the Southern Trade Wind Current, moving from east to west, at a speed of 80-100 miles per day. To the north of it there is a countercurrent, and even further north there is the Northern Trade Wind Current from east to west. Knowing the direction of the currents, local residents have long used them for their movements. Following them, T. Heyerdahl used this knowledge for his famous trip to the Kon-Tiki. There are analogues of trade wind (literally “favorable for movement”) currents and countercurrents in the Indian and Atlantic oceans.

Of the meridional currents, the most famous are the Gulf Stream and Kuroshio, which transport 75 and 65 million tons of water per second, respectively.

Many areas of the World Ocean (the western shores of North and South America, Asia, Africa, Australia) are characterized by upwelling, which can be caused by wind driven surface waters from the coast. Rising deep waters often contain large amounts of nutrients, and upwelling sites are associated with a zone of high biological productivity.

The role of the ocean in people's lives

It is difficult to overestimate the role of the World Ocean in the life of mankind. It largely determines the face of the planet as a whole, including its climate and the water cycle on Earth. The ocean contains vital waterways connecting continents and islands. Its biological resources are colossal. The World Ocean is home to more than 160 thousand species of animals and about 10 thousand species of algae. The annually reproduced number of commercial fish is estimated at 200 million tons, of which approximately 1/3 is caught. More than 90% of the world's catch comes from the coastal shelf, especially in the temperate and high latitudes of the Northern Hemisphere. The share of the Pacific Ocean in the world catch is about 60%, the Atlantic - about 35%.

The shelf of the World Ocean has huge reserves of oil and gas, large reserves of iron-manganese ores and other minerals. Humanity is just beginning to use the energy resources of the World Ocean, including tidal energy. The World Ocean accounts for 94% of the volume of the hydrosphere. The desalination of sea waters is associated with the solution to many water problems of the future.

Unfortunately, humanity does not always use wisely natural resources World ocean. In many areas its biological resources have been depleted. A significant part of the water area is polluted by waste from anthropogenic activities, primarily petroleum products.

Sushi waters.

Land waters include waters, rivers, lakes, swamps, glaciers. They contain 3.5% total number waters of the hydrosphere. Of these, only 2.5% are fresh waters.

Groundwater is found in the rock strata of the upper part of the earth's crust in liquid, solid and vapor states. The bulk of them is formed due to the seepage of rain, melt and river water from the surface.

According to the conditions of occurrence, groundwater is divided into:

1) soil, located in the uppermost soil layer;

2) soil, lying on the first permanent waterproof layer from the surface;

3) interstratal, located between two impermeable layers;

The latter are often pressure and are then called artesian.

Groundwater feeds rivers and lakes.

Rivers are constant water streams flowing in the depressions they themselves develop - channels.

The most important characteristic of rivers is their nutrition. There are four sources of nutrition: snow, rain, glaciers and underground.

The regime of rivers largely depends on the feeding of rivers, i.e. changes in the amount of water flow according to the seasons of the year, fluctuations in level, changes in water temperature. The water regime of a river is characterized by water flow and runoff. Flow rate is the amount of water passing through cross section flow in one second. Water consumption per long time– month, season, year – called runoff. The volume of water that rivers carry on average per year is called their water content. The most abundant river in the world is the Amazon, at its mouth the average annual water flow is 220,000 cubic meters. m./s. In second place is Congo (46,000 cubic meters per second), then the Yangtze. In our country, the most abundant river is the Yenisei (19,800 cubic meters per second). Rivers are characterized by a very uneven distribution of flow over time. Most Russian rivers carry 60-70% of their water volume during a relatively short period of spring floods. At this time, melt water flows over the frozen and well-moistened surface of the catchment areas with minimal losses due to filtration and evaporation.

It is during the flood period that rivers most often overflow their banks and flood the surrounding areas. In summer and winter, there is usually low water - low water, when rivers are fed by groundwater, the resources of which are also significantly replenished in spring period. In summer, most of the precipitation is spent on evaporation; only a small part of the precipitation reaches the groundwater level and, especially, reaches the rivers. In winter, precipitation accumulates in the form of snow. Only in autumn there are small floods on Russian rivers.

The rivers of the Far East and the Caucasus differ from the lowland rivers of Russia in their hydrological regime. The first ones flood in the fall - during the monsoon rains; On Caucasian rivers, maximum water flows are observed in the summer, when high-mountain glaciers and snowfields melt.

River flow varies from year to year. Low-water and high-water periods often occur when the river is characterized by low or, on the contrary, high water content. For example, in the 1970s, there was low water on the Volga, due to which the level of the endorheic Caspian Sea, for which the Volga is the main supplier of water, quickly fell. Since 1978, a phase of increased humidity began in the Volga basin, its runoff annually began to exceed the long-term average, and the level of the Caspian Sea began to rise, as a result of which coastal areas were flooded. Most of Russia's rivers are covered with ice every year. The duration of freeze-up in northern Russia is 7-8 months (from October to May). The opening of rivers from ice - ice drift - is one of the most impressive spectacles, often accompanied by flooding.

Rivers have played an outstanding role in the history of mankind; the formation and development of human society is associated with them. Since historical times, rivers have been used as routes of communication, for fishing and fish farming, timber rafting, field irrigation and water supply. People have long settled along the banks of rivers - this is confirmed by folklore, in which the Volga is called “mother”, and the Amur is called “father”. The river is the main source of hydropower and the most important transport route. Rivers are of great aesthetic and recreational importance as an integral element of the environment. The widespread involvement of rivers in economic circulation has led to the complete transformation of many of them. The flow of rivers such as the Volga, Dnieper, and Angara is largely regulated by reservoirs. Many of them, especially those occurring in the southern regions where the need for irrigation is great, are dismantled for irrigation needs. For this reason, the Amu Darya and Syr Darya practically no longer flow into the Aral Sea, and it is rapidly drying up.

One of the most negative results of anthropogenic impact on rivers is their massive pollution by sewage and other waste from economic activities. The threat of qualitative depletion of river water resources can be avoided if a set of water management measures is implemented, including not only traditional wastewater treatment, but also such drastic measures as changing production technology in order to significantly reduce water consumption and waste generation.

Lakes are natural bodies of water in depressions of land (basins), filled within the lake bowl (lake bed) with heterogeneous water masses and without a one-way slope. Lakes are characterized by the absence of a direct connection with the World Ocean. Lakes occupy about 2.1 million km2, or almost 1.4% of the land area. This is approximately 7 times the surface of the Caspian Sea, the largest lake in the world.

A swamp is an area of ​​land with excessive stagnant soil moisture, overgrown with moisture-loving vegetation. Swamps are characterized by the accumulation of undecomposed plant debris and the formation of peat. Swamps are distributed mainly in the Northern Hemisphere, especially in lowland areas where permafrost soils are developed, and cover an area of ​​about 350 million hectares

Glaciers are moving natural accumulations of ice of atmospheric origin on the earth's surface; are formed in those areas where more solid atmospheric precipitation is deposited than melts and evaporates. Within the glaciers, areas of feeding and ablation are distinguished. Glaciers are divided into terrestrial, shelf and mountain ice sheets. The total area of ​​modern glaciers is approx. 16.3 million km2 (10.9% land area), total ice volume approx. 30 million km3.

6. Water resources management.

One of the directions for solving water problems is to attract currently underutilized water resources from desalinated waters of the World Ocean, groundwater and glacier waters for the purpose of water supply. Currently, the share of desalinated water in the total volume of water supply in the world is small - 0.05%, which is explained by the high cost and significant energy intensity of desalination processes. Even in the United States, where the number of desalination plants has increased 30 times since 1955, desalinated water accounts for only 7% of water consumption.

In Kazakhstan, in 1963, the first pilot industrial desalination plant came into operation in Aktau (Shevchenko). Due to the high cost, desalination is used only where surface or groundwater fresh water resources are completely absent or extremely difficult to access, and their transportation is more expensive compared to desalination

increased mineralization directly on site. In the future, water desalination will be carried out in a single technical complex with extraction from it useful components: sodium chloride, magnesium, potassium, sulfur, boron, bromine, iodine, strontium, non-ferrous and rare metals, which will increase economic efficiency desalination plants.

An important reserve of water supply is groundwater. Fresh groundwater is of greatest value to society, accounting for 24% of the volume of the fresh part of the hydrosphere. Brackish and saline groundwater can also serve as a reserve for water supply when used in a mixture with fresh water or after its artificial desalination. Factors limiting underground water intake include:

1) the unevenness of their distribution over the territory of the earth;

2) difficulties in processing saline groundwater;

3) rapidly decreasing rates of natural regeneration with

increasing the depth of aquifers.

The utilization of water in the solid phase (ice, ice sheets) is assumed, firstly, by increasing the water yield of mountain glaciers, and secondly, by transporting ice from the polar regions. However, both of these methods are practically difficult to implement and the environmental consequences of their implementation have not yet been studied.

Thus, at the current stage of development, the possibilities of attracting additional volumes of water resources are limited. It should also be noted that the distribution of water resources across the globe is uneven. The highest provision of resources for river and underground runoff occurs in the equatorial belt South America and Africa. In Europe and Asia,

Where 70% of the world's population lives, only 39% of river waters are concentrated. The largest rivers in the world are the Amazon (annual flow 3780 km3), Congo (1200 km3), Mississippi (600 km3), Zamberi (599 km3), Yangtze (639 km3), Irrawaddy (410 km3), Mekong (379 km3), Brahmaputra ( 252 km3). In Western Europe, the average annual surface runoff is 400 km3, including about 200 km3 in the Danube, 79 km3 on the Rhine, 57 km3 on the Rhone. The largest lakes in the world are the Great American Lakes (total area - 245 thousand km3), Victoria (68 thousand km3), Tanganyika (34 thousand km3), Nyasa (30.8 thousand km3).

The Great American Lakes contain 23 thousand km3 of water, the same as Lake Baikal. To characterize the distribution of hydro resources, the volume of total river flow per unit of territory (1 km3) and population is calculated. Per 1 million inhabitants of the USSR there is 5.2 km3 of total sustainable flow (including that regulated by reservoirs) versus 4 km3 for the total

globe; 19 km3 of total river flow versus 13 km3; 4.1 sustainable underground flow versus 3.3 km3. The average water supply per 1 km2 is 212 thousand m3 in the CIS, and 278 thousand m3 on the globe. The main methods of water resource management are the creation of reservoirs and territorial transfer of flow.

7. Sources of water pollution.

The Earth's hydrosphere has great value in the exchange of oxygen and carbon dioxide with the atmosphere. Oceans and seas have a softening, regulating effect on air temperature, accumulating heat in summer and releasing it to the atmosphere in winter. The circulation and mixing of warm and cold waters occurs in the ocean. The biomass of vegetation of the oceans and seas is many times

less than sushi, but the animal biomass is at least an order of magnitude greater. Oceans and seas absorb carbon dioxide. The hydrosphere is an important source of food for humans and other land inhabitants. The fish catch, which amounted to 3 million tons per year at the beginning of this century, currently reaches 80 million tons. This growth is associated with the progress of technology, the widespread use of special trawlers, seiners with hydroacoustic devices for detecting fish accumulations, equipment for impact on her

light, electric current.

Fish pumps, nylon nets, trawling, freezing and canning of fish on board appeared. As a result of the increased catch, its composition deteriorated, the specific gravity of herring decreased,

Sardines, salmon, cod, flounder, halibut and increased proportions of tuna, mackerel, sea bass and bream. With significant investments, it is realistically possible to increase seafood catches to 100-130 million tons. These figures include, for example, krill, small crustaceans, the reserves of which are huge in the southern seas. Krill contains protein; these crustaceans can be used for food and other purposes. A large number of fish are being caught. Not for food, but for food

livestock or processed into fertilizers. Over a number of years, especially post-war, a significant part of the whales have been exterminated, and some of their species are on the verge of complete destruction. By international agreement, further whale catches are limited. The destruction of the inhabitants of the oceans and seas as a result of their unreasonable fishing raises the question of the advisability of the transition from extensive fishing to artificial fish farming. In this regard, we can recall the transition from hunting and collecting fruits and roots in the earlier stages of social development to the breeding of animals and plants.

8. Measures for the protection and economical use of water resources.

Serious measures are being taken to prevent the growing pollution of water bodies by wastewater. Wastewater is water discharged after use in human household and industrial activities. By their nature, pollution is divided into mineral, organic, bacteriological and biological. The criterion for the harmfulness of wastewater is the nature and degree of limitation of water use. The quality of natural waters in Kazakhstan is standardized in places of water use. Developed standard indicators– maximum permissible concentrations of harmful substances in the water of water bodies for various purposes - relate to the composition of water in reservoirs, and not to the composition of wastewater.

In accordance with the Regulations on state accounting of waters and their

use (1975) primary accounting of discharged water bodies wastewater is managed by water users themselves. This control is carried out unsatisfactorily by the majority of water users. This is evidenced by the fact that only 20% of discharged wastewater is controlled by hydraulic engineering

equipment, and the rest - by indirect methods. Currently, a transition to a system of maximum permissible emissions (MPE) standards is underway. MAC values ​​are determined for each specific emission source in such a way that total emissions from all sources in the region do not exceed the MAC standard. The use of MPE standards will facilitate planning and control of environmental activities, increase

the enterprise's responsibility for compliance with environmental requirements will eliminate conflict situations. Of the total amount of wastewater, 69% is conditionally clean, 18% is polluted and 13% is purified to standard standards. There are no strict criteria for dividing industrial wastewater into standard-treated, polluted and conditionally clean. Untreated wastewater requires repeated dilution with clean

water. The oil refining, pulp and paper and chemical industries are especially polluting. Standard purified water

The main market method of regulating environmental activities is payment for pollution. There are two types of fees per unit of emissions and fees for the use of public wastewater treatment plants. The level of payment in the first case is determined by the desired quality of the environment. The mechanism of such a board automatically ensures optimal resource allocation. The fee for the use of treatment facilities includes

a basic fee for the discharge of standard wastewater, an additional fee for excess discharge, a fee for water transportation and a fee for service by the water inspectorate. To assess river water pollution, a conditional pollution indicator is used. The size of the fee depends on the age of the treatment facilities, the ability of reservoirs to self-purify, and the composition of the wastewater. The board mechanism is most effective in conditions of pure competition, when each firm strives to minimize costs per unit

release. Under conditions of monopolies, firms may not set themselves such a goal, therefore, in monopolized industries, methods of direct administrative regulation gain advantages.

10. International Decade "Water for Life"

4,000 children die every day due to diseases caused by undrinkable water; 400 million children do not have even the bare minimum of safe water they need to live; As many as 2.6 billion people live without sanitation - all of which challenges the UN's fight for clean water.

The United Nations Children's Fund (UNICEF) has highlighted the fact that a lack of clean water is responsible for at least 1.6 million of the 11 million avoidable child deaths each year. Almost three children die every minute due to diseases caused by undrinkable water, such as diarrhea and typhoid fever. In sub-Saharan Africa, where one in five children die before their fifth birthday, 43% of children drink unsafe water, risking illness and death with every sip.

The Office of the United Nations High Commissioner for Refugees (UNHCR) spoke about the situation in Zhegriyad - the “Valley of Death” in Somalia. It got its name because people die of thirst here every year, primarily drivers whose trucks or cars break down on the way to Djibouti.

It's just small part challenges facing UNHCR, an organization that tries to help 17 million people in more than 116 countries. In Tindouf, Algeria, a project is currently underway to improve the water supply of the Smara camp in the middle of the Sahara Desert, where tens of thousands of refugees from Western Sahara live.

In another camp in eastern Chad, where more than 200,000 refugees are fleeing conflict in Sudan's Darfur, UNHCR continues to work to provide water to refugees by delivering water, drilling boreholes, digging wells and using high-tech searches. additional sources water.

On March 22, 2005, the UN celebrated World Water Day, proclaiming Messrs. International Decade “Water for Life”. Data on the scale of the problem and the stories of individual people are what, in addition to the speeches of UN leaders, bring home just how difficult it will be for the world to meet one of the Millennium Development Goals: to halve the number of people living in poverty by 2015. clean drinking water and minimum sanitation conditions.

List of used literature:

1. Geography. A complete exam preparation course. Moscow. AST-press; 2004

2. , “Environmental protection”

3. B. Nebel “Environmental Science” Moscow. "Science" 2002

4. Great Soviet Encyclopedia. Moscow. "Soviet Encyclopedia", 1972

The water resources considered are surface runoff (rivers, lakes and other bodies of water), underground runoff (groundwater and groundwater), glacier water, and precipitation, which are sources of water to meet economic and domestic needs. Water is a unique type of resource. It combines the nature of both exhaustible (groundwater) and inexhaustible (surface runoff) reserves. Water in nature is in continuous movement, so its distribution over the territory, seasons and years is subject to significant fluctuations.

Russia has significant reserves of fresh water. River waters are most widely used in the national economy. The rivers of Russia belong to the basins of three oceans, as well as to the internal Caspian basin, which occupies most of the European part of Russia. Most of the rivers in Russia belong to the Arctic Ocean basin. The rivers flowing into the northern seas are the longest and deepest. The longest river is the Lena (4400 km), the deepest river is the Yenisei. In the southern parts of Siberia the rivers are swift and rapid. The largest hydroelectric power stations in the country were built on these sections - Krasnoyarsk and Sayano-Shushenskaya on the Yenisei, Novosibirsk on the Ob, Irkutsk, Bratsk, Ust-Ilimsk on the Angara, etc. The rivers of the European part of the Arctic Ocean basin - Pechora, Mezen, Northern Dvina, Onega - are much shorter than Siberian rivers. Many rivers belong to the Pacific Ocean basin. The main rivers of this basin are the Amur and its tributaries the Zeya, Bureya, and Ussuri.

The Atlantic Ocean basin occupies smallest area from the entire country. Rivers flow west to the Baltic Sea (Neva) and south to the Azov and Black Sea (Don, Kuban, etc.). The Neva occupies a special place. This short river (74 km) carries a huge amount of water - four times more than the Dnieper, which is over 2000 km long.

Most of European Russia is occupied by the internal basin of the Caspian Sea. The rivers Volga, Ural, Terek and others flow into the Caspian Sea. In European Russia, the longest river is the Volga (3530 km). There are many hydroelectric power stations on the Volga: Volzhskaya named after. Lenin, Saratov, Volzhskaya named after. XXI Congress of the CPSU, etc.

The main consumers of water resources in our country are water supply, hydropower, and artificial irrigation.

Water supply - totality different ways use of water resources by industry, public utilities and population with a large share irretrievable losses and varying degrees of pollution. It is this aspect of water use that creates the problem of qualitative deterioration and reduction of water reserves, which becomes increasingly aggravated as production grows. Solving it requires the redistribution of water resources between regions, careful use of reserves, construction of treatment facilities, wide application closed loops water use, etc.

Hydropower uses the energy of flowing water, the reserves of which are then completely returned to the watercourse. Russia has the world's largest hydropower reserves, which account for about 1/10 of the world's reserves. Russia's hydropower resources are distributed unevenly. Most of them are in Siberia and Far East, with the main hydropower reserves concentrated in the basins of the Yenisei, Lena, Ob, Angara, Irtysh and Amur rivers. The Lena ranks first among Russian rivers in terms of hydropower reserves. The rivers of the North Caucasus are rich in hydropower resources. A significant part of the country's technically possible hydropower resources is located in the Volga and Central regions of Russia, where the hydropower reserves of the Volga basin are especially large.

River flow and glacier resources are used for artificial irrigation. The main irrigation areas are arid territories: the North Caucasus, Trans-Volga region.