Land water resources. Earth's water resources

The following countries are most provided with water resources: Brazil (8,233 km 3), Russia (4,508 km 3), USA (3,051 km 3), Canada (2,902 km 3), Indonesia (2,838 km 3), China (2 830 km 3), Colombia (2,132 km 3), Peru (1,913 km 3), India (1,880 km 3), Congo (1,283 km 3), Venezuela (1,233 km 3), Bangladesh (1,211 km 3), Burma (1046 km 3).

The volume of water resources per capita by country (m 3 per year per capita)

Most of the water resources per capita are in French Guiana (609,091 m 3), Iceland (539,638 m 3), Guyana (315,858 m 3), Suriname (236,893 m 3), Congo (230,125 m 3), Papua New Guinea (121,788 m3), Gabon (113,260 m3), Bhutan (113,157 m3), Canada (87,255 m3), Norway (80,134 m3), New Zealand (77.305 m3), Peru (66,338 m3), Bolivia (64,215 m3), Liberia (61,165 m3), Chile (54,868 m3), Paraguay (53,863 m3), Laos (53,747 m3), Colombia ( 47,365 m3), Venezuela (43,846 m3), Panama (43,502 m3), Brazil (42,866 m3), Uruguay (41,505 m3), Nicaragua (34,710 m3), Fiji (33,827 m3 3), the Central African Republic (33,280 m3), Russia (31,833 m3).
The least water resources per capita are in Kuwait (6.85 m 3), the United Arab Emirates (33.44 m 3), Qatar (45.28 m 3), the Bahamas (59.17 m 3), in Oman (91.63 m 3), Saudi Arabia (95.23 m 3), Libya (95.32 m 3).
On average on Earth, each person has 24,646 m 3 (24,650,000 liters) of water per year.

The next map is even more interesting.

Share of transboundary runoff in the total annual runoff of the rivers of the countries of the world (in %)
Few countries in the world rich in water resources can boast of having "at their disposal" river basins that are not separated by territorial boundaries. Why is it so important? Take for example the largest tributary of the Ob - the Irtysh. () . The source of the Irtysh is located on the border of Mongolia and China, then the river flows through the territory of China for more than 500 km, crosses the state border and flows through the territory of Kazakhstan for about 1800 km, then the Irtysh flows for about 2000 km through the territory of Russia until it flows into the Ob. According to international agreements, China can take half of the annual flow of the Irtysh for its own needs, Kazakhstan - half of what remains after China. As a result, this can greatly affect the full flow of the Russian section of the Irtysh (including hydropower resources). At present, China annually Russia 2 billion km 3 of water. Therefore, the water supply of each country in the future may depend on whether the sources of rivers or sections of their channels are outside the country. Let's see how things stand with the strategic "water independence" in the world.

The map presented to your attention above illustrates the percentage of the volume of renewable water resources entering the country from the territory of neighboring states, of the total volume of the country's water resources. (A country with a value of 0% does not “receive” water resources at all from the territories of neighboring countries; 100% - all water resources come from outside the state).

The map shows that the following states are the most dependent on the “supplies” of water from the territory of neighboring countries: Kuwait (100%), Turkmenistan (97.1%), Egypt (96.9%), Mauritania (96.5%) , Hungary (94.2%), Moldova (91.4%), Bangladesh (91.3%), Niger (89.6%), Netherlands (87.9%).

In the post-Soviet space, the situation is as follows: Turkmenistan (97.1%), Moldova (91.4%), Uzbekistan (77.4%), Azerbaijan (76.6%), Ukraine (62%), Latvia (52. 8%), Belarus (35.9%), Lithuania (37.5%), Kazakhstan (31.2%), Tajikistan (16.7%) Armenia (11.7%), Georgia (8.2%) , Russia (4.3%), Estonia (0.8%), Kyrgyzstan (0%).

Now let's try to do some calculations, but first let's make rating of countries by water resources:

1. Brazil (8,233 km 3) - (Share of transboundary flow: 34.2%)
2. Russia (4,508 km 3) - (Share of transboundary flow: 4.3%)
3. USA (3,051 km 3) - (Share of transboundary flow: 8.2%)
4. Canada (2,902 km 3) - (Share of transboundary flow: 1.8%)
5. Indonesia (2,838 km 3) - (Share of transboundary flow: 0%)
6. China (2,830 km 3) - (Share of transboundary flow: 0.6%)
7. Colombia (2,132 km 3) - (Share of transboundary flow: 0.9%)
8. Peru (1,913 km 3) - (Share of transboundary flow: 15.5%)
9. India (1,880 km 3) - (Share of transboundary flow: 33.4%)
10. Congo (1,283 km 3) - (Share of transboundary flow: 29.9%)
11. Venezuela (1,233 km 3) - (Share of transboundary flow: 41.4%)
12. Bangladesh (1,211 km 3) - (Share of transboundary flow: 91.3%)
13. Burma (1,046 km 3) - (Share of transboundary flow: 15.8%)

Now, based on these data, we will compile our rating of countries whose water resources are least dependent on the potential reduction in transboundary flow caused by water intake by countries located upstream.

1. Brazil (5,417 km 3)
2. Russia (4,314 km 3)
3. Canada (2,850 km 3)
4. Indonesia (2,838 km 3)
5. China (2,813 km 3)
6. USA (2,801 km 3)
7. Colombia (2,113 km 3)
8. Peru (1,617 km 3)
9. India (1,252 km 3)
10. Burma (881 km 3)
11. Congo (834 km 3)
12. Venezuela (723 km 3)
13. Bangladesh (105 km 3)

In conclusion, I would like to note that the use of river waters is not limited to water intake alone. We should also not forget about the transboundary transfer of pollutants, which can significantly worsen the quality of river waters in river sections located on the territory of other countries downstream.

You can familiarize yourself with the map of groundwater reserves.

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WATER RESOURCES LAND

Until relatively recently, water, like air, was considered one of the free gifts of nature, only in areas of artificial irrigation it always had a high price. Recently, the attitude towards land water resources has changed. This is explained by the fact that fresh water resources make up only 2.5% of the total volume of the hydrosphere. In absolute terms, this is a huge value (30-35 million m 3), which exceeds the current needs of mankind by more than 10 thousand times! However, the vast majority of fresh water is, as it were, conserved in the glaciers of Antarctica, Greenland, in the ice of the Arctic, in mountain glaciers and forms a kind of "emergency reserve" that is not yet available for use.

Indicators:
96.5% - salty waters of the oceans; 1% - saline groundwater; 2.5% - fresh water resources.

Fresh water: 68.7 - glaciers; 30.9% - groundwater.

Table 11. Distribution of world fresh water resources by major regions.

The data in this table allow us to draw interesting conclusions. First of all, about the extent to which the ranking of countries according to the first indicator does not coincide with their ranking according to the second. It can be seen that Asia has the largest fresh water resources, and the smallest - Australia and Oceania, while in terms of their specific provision they change their places. Of course, it's all about the population, which in Asia has already reached 3.7 billion people, and in Australia it barely exceeds 30 million. If we discount Australia, then South America will be the region of the world most provided with fresh water. And it is no coincidence, because it is here that the Amazon is located - the most full-flowing river in the world.

Individual countries differ even more in terms of reserves and availability of fresh water. Based on the principle of "most-most", we will show which of them belong to the category of the richest and poorest in fresh water.

Table 12. Top ten countries by freshwater resources.

In it, too, the ranking of resources does not coincide with the ranking of the specific endowment, and in each individual case, such a difference can be explained. For example, in China and India - a huge population, therefore - low security per capita. But there are also countries in the world that are even less provided with fresh water, where per capita there is less than 1 thousand m 3 of water (that is, the amount that a resident of a large European or American city consumes in about two days). The most striking examples of this kind can be found in the Saharan part of Africa (Algeria - 520 m 3, Tunisia - 440 m 3, Libya - 110 m 3) and in the region of the Arabian Peninsula (Saudi Arabia - 250 m 3, Kuwait - 100 m 3).

These individual examples are interesting in that they allow us to make an important generalization: at the end of the 20th century. Approximately 2/5 of the population of our planet experience a chronic lack of fresh water. In this case, we are talking mainly about those developing countries that are located in the arid belt of the Earth. One cannot ignore the fact that even the available fresh water in these countries is so polluted that it is the main cause of most diseases.

The main consumer of fresh water is agriculture, where irretrievable water consumption is very high, especially for irrigation. Industrial-energy and municipal water consumption is also growing all the time. In economically developed countries, a city dweller uses 300-400 liters of water per day. Such an increase in consumption with constant river runoff resources creates a real threat of fresh water shortages.

In this case, it is necessary to take into account not only the quantity, but also the quality of water. In developing countries, every third inhabitant suffers from a lack of drinking water. The consumption of polluted water is the source of 3/4 of all diseases and 1/3 of all deaths. More than 1 billion people in Asia lack access to clean water, 350 million in sub-Saharan Africa and 100 million in Latin America.

But, in addition, fresh water reserves on Earth are distributed extremely unevenly. In the equatorial zone and in the northern part of the temperate zone, it is available in abundance and even in excess. The most water-abundant countries are located here, where more than 25 thousand m 3 per capita per year. In the arid belt of the Earth, which covers about 1/3 of the land area, water shortage is felt especially acutely. The countries with the least water per capita are located here, where per capita is less than 5 thousand m 3 per year, and agriculture is possible only with artificial irrigation.

There are several ways to solve the water problem of mankind. The main one is the reduction of the water intensity of production processes and the reduction of irretrievable water losses. First of all, this applies to such technological processes as the production of steel, synthetic fiber, cellulose and paper, to the cooling of power units, to the irrigation of rice and cotton fields. Of great importance for solving the water problem is the construction of reservoirs that regulate river flow. Over the past fifty years, the number of reservoirs on the globe has increased by about 5 times. In total, more than 60 thousand reservoirs have been created in the world, the total volume of which (6.5 thousand km 3) is 3.5 times greater than the one-time volume of water in all the rivers of the globe. Taken together, they occupy an area of ​​400 thousand km 2, which is 10 times the area of ​​the Sea of ​​Azov. Such large rivers as the Volga, Angara in Russia, Dnieper in Ukraine, Tennessee, Missouri, Columbia in the USA, and many others, have actually turned into cascades of reservoirs. A particularly important role in the transformation of river runoff is played by large and largest reservoirs. The problem is that the main source of meeting the needs of mankind in fresh water has been and remains river (channel) water, which determines the "water ration" of the planet - 40 thousand km 3. It is not so significant, especially considering that about 1/2 of this amount can actually be used.

According to the number of large reservoirs, the United States, Canada, Russia, some countries of Africa and Latin America stand out.

Table 13. Largest reservoirs in the world by volume of water (countries)

In the USA, Canada, Australia, India, Mexico, China, Egypt, and a number of CIS countries, numerous projects have been implemented or are being planned for the territorial redistribution of river flow with the help of its transfer. However, most major inter-basin transfer projects have recently been canceled for economic and environmental reasons. In the countries of the Persian Gulf, the Mediterranean, in Turkmenistan, on the Caspian Sea, in the south of the USA, in Japan, on the Caribbean islands, sea water desalination is used; the world's largest producer of such water is Kuwait. Fresh water has already become a commodity of world trade: it is transported in sea tankers, along long-distance water pipelines. Projects are being developed to tow icebergs from Antarctica, which each polar summer sends 1200 million tons of fresh water preserved in them to the countries of the arid zone.

You know that river runoff is also widely used to generate hydropower. World hydropower potential, suitable for use, is estimated at almost 10 trillion kWh. possible power generation. About 1/2 of this potential falls on only 6 countries: China, Russia, USA, Congo (former Zaire), Canada, Brazil.

Table 14 . World economic hydro potential and its use

Looking at our planet from the height of space, a comparison immediately suggests itself with a blue ball, which is completely covered with water. The continents at this time seem like small islands in this endless ocean. This is quite natural, because water occupies 79.8% of the entire surface, and 29.2% falls on land. The water shell of the Earth is called the hydrosphere, its volume is 1.4 billion m 3.

Water resources and their purpose

Water resources- it is suitable for use in the economy of the water of rivers, lakes, canals, reservoirs, seas and oceans. This also includes groundwater, soil moisture, swamps, glaciers, and atmospheric water vapor.

Water arose on the planet about 3.5 billion years ago and initially it had the form of vapors that were released during the degassing of the mantle. Today, water is the most important element in the Earth's biosphere, because nothing can replace it. However, recently, water resources have ceased to be considered limited, because scientists have managed to desalinate salt water.

Purpose of water resources- support the vital activity of all life on Earth (human, plants and animals). Water is the basis of all living things and the main supplier of oxygen in the process of photosynthesis. Water also takes part in climate formation - taking heat from the atmosphere in order to give it away in the future, thereby regulating climatic processes.

We should also remember that water sources play an honorable role in the modification of our planet. People have always settled near reservoirs or water sources. Thus, water promotes communication. There is a hypothesis among scientists that if there were no water on Earth, the discovery of America would be postponed by several centuries. And Australia would still be unknown today.

Types of water resources

As already said water resources is all the water on the planet. But on the other hand, water is the most common and most specific compound on Earth, because only it can exist in three states (liquid, gaseous and solid).

The earth's water resources are made up of:

• surface water(oceans, seas, lakes, rivers, swamps) is the most valuable source of fresh water, but the thing is that these objects are distributed quite unevenly over the Earth's surface. So, in the equatorial zone, as well as in the northern part of the temperate zone, water is in excess (25 thousand m 3 per year per person). And the tropical continents, which consist of 1/3 of the land, are very acutely aware of the shortage of water reserves. Based on this situation, their agriculture develops only under the condition of artificial irrigation;
• groundwater;
• reservoirs created artificially by man;
• glaciers and snowfields (frozen water of the glaciers of Antarctica, the Arctic and snowy mountain peaks). It contains the largest part of fresh water. However, these reserves are practically inaccessible for use. If all the glaciers are distributed over the Earth, then this ice will cover the earth with a ball 53 cm high, and having melted it, we thereby raise the level of the World Ocean by 64 meters;
• moisture what is found in plants and animals;
• vapor state of the atmosphere.

Water consumption

The total volume of the hydrosphere is striking in its quantity, however, only 2% of this figure is fresh water, moreover, only 0.3% is available for use. Scientists have calculated the fresh water resources that are necessary for all mankind, animals and plants. It turns out that the supply of water resources on the planet is only 2.5% of the water of the required volume.

Around the world, about 5 thousand m 3 are consumed annually, while more than half of the water consumed is irretrievably lost. In percentage terms, the consumption of water resources will have the following characteristics:

• agriculture - 63%;

• industrial water consumption - 27% of the total;

• household needs take 6%;
• reservoirs consume 4%.

Few people know that it takes 10,000 tons of water to grow 1 ton of cotton, 1,500 tons of water to grow 1 ton of wheat, 250 tons of water to produce 1 ton of steel, and 1 ton of paper requires at least 236,000 tons of water.

A person should consume at least 2.5 liters of water per day, but on average, this same person spends at least 360 liters per day in a large city, since this figure includes all kinds of water use, including watering streets, washing vehicles and even fire fighting.

But the consumption of water resources does not end there. This is evidenced, for example, by water transport or the process of breeding both marine and fresh fish. Moreover, for breeding fish, you will need exceptionally clean water, saturated with oxygen and without the content of harmful impurities.

A huge example of the use of water resources are recreational areas. There is no such person who would not like to relax by the pond, relax, swim. In the world, almost 90% of recreational areas are located near water bodies.

The need to protect water resources

Considering the current situation, we can conclude that water requires a careful attitude towards itself. Currently, there are two ways to save water resources:

• reduce fresh water consumption;
• creation of modern collectors of high quality.

The conservation of water in reservoirs limits its flow into the world's oceans. Storing water underground helps prevent evaporation. The construction of canals can easily solve the problem of water delivery without its penetration into the ground. Humanity is also thinking about the latest methods of irrigating agricultural land, allowing to moisten the territory using wastewater.

But each of the above ways actually affects the biosphere. The system of reservoirs, for example, does not allow the formation of fertile silt deposits, channels interfere with the replenishment of groundwater. Therefore, today one of the most effective ways to conserve water resources is wastewater treatment. Science does not stand still in this regard, and various methods can neutralize or remove up to 96% of harmful substances.

The problem of water pollution

Population growth, the rise of production and agriculture ... These factors contributed to the shortage of fresh water. In addition to everything, the share of polluted water resources is also growing.

Main sources of pollution:

• industrial effluents;
• sewage from utility lines;
• plums from the fields (meaning when they are oversaturated with chemicals and fertilizers;
• burial of radioactive substances near water bodies;
• effluents coming from livestock complexes (water is characterized by an excess of biogenic organic matter);
• shipping.

Nature provides for the self-purification of water bodies. This happens due to the presence of plankton in the water, the ingress of ultraviolet rays into the water, and the settling of insoluble particles. But unfortunately, pollution is much greater and nature alone is not able to cope with such a mass of harmful substances that man and his activities provide to water resources.

Extraordinary sources of drinking water

Recently, mankind has thought about how to use non-traditional sources of water resources. Here are the main ones:

• tow icebergs from the Arctic or Antarctica;
• carry out desalination of sea waters (actively used at the moment);
• condense the water of the atmosphere.

In order to obtain fresh water by desalination of salt water, desalination stations are installed on ships. In the whole world, there are already about a hundred such units. The world's largest producer of such water is Kuwait.

Fresh water has recently acquired the status of a world commodity, it is transported in tankers using long-distance water pipelines. This scheme has been successful in the following areas:

• the Netherlands receives water from Norway;
• Saudi Arabia receives a resource from the Philippines;
• Singapore imports from Malaysia;
• water is pumped from Greenland and Antarctica to Europe;
• The Amazon transports drinking water to Africa.

One of the latest achievements is the installations with the help of which the heat of nuclear reactors is used simultaneously for the desalination of sea water and the production of electricity. At the same time, the price of one liter of water costs a little, since the productivity of such installations is quite large. Water that has passed through this path is recommended to be used for irrigation.

Reservoirs can also help overcome fresh water scarcity by regulating river flow. In total, more than 30 thousand reservoirs have been built in the world. In most countries, there are projects for the redistribution of river flow through its transfer. But, the largest such programs have been rejected due to environmental considerations.

Water resources of the Russian Federation

Our country has a unique water resource potential. However, their main drawback is their extreme uneven distribution. So, if we compare the Southern and Far Eastern federal districts of Russia, then in terms of the size of local water resources they differ from each other by 30 times, and in terms of water supply - by 100 times.

Rivers of Russia

Thinking about the water resources of Russia, first of all, it should be noted the rivers. Their volume is 4,270 km3. There are 4 water basins on the territory of Russia:

• the seas of the Arctic and Arctic Oceans, as well as the large rivers flowing into them (Northern Dvina, Pechora, Ob, Yenisei, Lena, Kolyma);
• the seas of the Pacific Ocean (Amur and Anadyr);
• seas of the Atlantic Ocean (Don, Kuban, Neva);
• the inner basin of the Caspian Sea and the flowing Volga and Ural.

Since in the central regions the population density is greater than, for example, in Siberia, this leads to the disappearance of small rivers and water pollution in general.

Lakes and swamps of Russia

Half of all fresh water in the country falls on lakes. Their number in the country is approximately 2 million. Of these, large:

• Baikal;
• Ladoga;
• Onega;
• Taimyr;
• Khanka;
• Vats;
• Ilmen;
• White.

A special position should be given to Lake Baikal, because 90% of our fresh water reserves are concentrated in it. In addition to being the deepest lake on earth, it is also characterized by a unique ecosystem. Baikal is also included in the UNESCO list of natural heritage.

The lakes of the Russian Federation are used for irrigation and as sources for water supply. Some of the listed lakes have a decent supply of therapeutic mud and therefore they are used for recreation purposes. As well as for rivers, lakes are characterized by their uneven distribution. They are mainly concentrated in the North-Western part of the country (Kola Peninsula and the Republic of Karelia), the Ural region, Siberia and Transbaikalia.

The swamps of Russia also play an important role, although many people treat them disrespectfully, draining them. Such actions lead to the death of entire huge ecosystems, and as a result of this, rivers do not have the opportunity to cleanse themselves naturally. The swamps also feed the rivers, act as their controlled object during floods and floods. And of course, swamps are a source of peat reserves.

These elements of water resources are distributed in the North-West and North-Central parts of Siberia, the total area of ​​swamps in Russia is 1.4 million km2.

As you can see, Russia has a large water resource potential, but we should not forget about the balanced use of this resource, treat it with care, because anthropogenic factors and huge consumption lead to pollution and depletion of water resources.

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The total volume of water on Earth (including saline, brackish, etc.) is estimated at about 1400 million km 3 . At the same time, two-thirds of this volume is permanently in the solid state, although this proportion is decreasing due to global warming. Despite the fact that water is the most common substance on Earth, only 2.5% (35 million km 3) of it is fresh.

Approximately half of the continental water (60 million km 3) is located at a depth of tens and hundreds of meters from the surface. Somewhat less water - about 50 million km 3 - is concentrated in the upper layers of the earth's surface, at a depth of several meters and in the soil. Even less - about 20 million km 3 of water - in the form of glaciers covers Antarctica, Greenland, the islands of the Arctic Ocean and the tops of mountain ranges. Water available for human consumption is mainly found in lakes (750 thousand km 3), in the atmosphere - in the form of steam and clouds (13 thousand km 3) and only about 1 thousand km 3 - in rivers. The operational part of these resources is about 200 thousand km3, i.e. less than 1% of all fresh water and 0.01% of all water on Earth.

The difference between the amount of precipitation (119 thousand km 3 /year) falling on land and evaporation from its surface (72 thousand km 3 /year) is due to runoff and replenishment of groundwater (47 thousand km 3 /year).

The main average long-term characteristics of the renewal of fresh water resources in the world, Russia and a number of foreign countries are presented in Table. 1.1.

Table 1.1. The main average long-term characteristics of the renewal of fresh water resources in the world, Russia and a number of foreign countries, km 3 / year 1

1 For European countries, Eurostat data; for Russia, Rosvodresursy data; for other countries, World Resources Institute estimates for the latest available year.

2 The volume of water released from the earth's surface into the atmosphere as a result of evaporation or transpiration of plants.

3 The total volume of natural river runoff and the natural replenishment of groundwater resources formed only due to precipitation that fell on the given territory.

4 The total volume of river water and groundwater inflow from the territories of other states.

5 The total volume of outflow of river water and groundwater as a result of flowing into the sea and entering the territory of other states.

The distribution of water resources in the world is characterized by a significant imbalance (Table 1.2, Figure 1.1).

Table 1.2. Regional availability of water resources, % of the world indicator

Rice. 1.1. Water supply of the population of different countries, m 3 / person. in year

In terms of reserves, Russia accounts for more than 20% of the world's fresh water resources (excluding glaciers and groundwater). Among the six countries of the world with the largest river flow (Brazil, Russia, Canada, the USA, China, India), in absolute terms, Russia ranks second in the world after Brazil, and third in terms of water supply per capita (after Brazil and Canada). In calculating the volume of fresh water per inhabitant of Russia, there are about 30 thousand m 3 of river runoff per year. This is about 5.5 times more than the world average, 2.5 times more than in the United States and 14 times more than in China (Table 1.1.3).

Table 1.3. Average freshwater resources per capita, m3 (estimated by the World Resources Institute for the latest available year)

1 Average long-term volume of river runoff according to Roshydromet data

According to the UN, by 2025 Russia, together with Scandinavia, South America and Canada, will remain the regions with the best supply of fresh water - more than 20 thousand m 3 /year per capita.

According to the UN, water will play a decisive role in the agenda of the third millennium. If in 2000 the deficit of fresh water, including agricultural and industrial needs, was estimated at 230 billion m 3 /year, then by 2025 this deficit on the planet will increase to 1.3-2.0 trillion cubic meters. m 3 / year.

In terms of the total volume of fresh water resources, Russia occupies a leading position among European countries (Table 1.4).

If we take all Russian water resources as 100%, then almost a third of them are concentrated in lakes (1st place in the world), a fourth in swamps and a fifth in rivers.

Table 1.4. The total volume of fresh water resources in a number of European countries, km 3 / year

However, not all of this volume of fresh water is regularly redistributed. A certain part is in a static (secular) form, which significantly slows down the circulation (movement) of fresh water. In quantitative terms, the water resources of Russia are presented in Table. 1.5.

Table 1.5. Total water resources of Russia

Static (secular) reserves of water resources on the territory of Russia, most of which are concentrated in lakes (26.5 thousand km 3) and underground (28.0 thousand km 3) waters, total 88.9 thousand km 3 / year. About 18 thousand km 3 of ice are concentrated in glaciers, in which more than 15 thousand km 3 of static fresh water reserves are conserved.

Renewable water resources, estimated by the volume of annual river flow, on the territory of Russia make up 10% of the world river flow. Explored groundwater deposits have a total operational reserves of more than 30 km 3 /year (potential operational groundwater resources belonging to this category exceed 300 km 3 /year).

Thus, the total renewable fresh water resources of Russia are estimated at 10,803 km 3 /year, the main volume of which is accounted for by river runoff (45%) and soil water (33%). Over the past 15-20 years, in Russia as a whole, the specific water supply (per inhabitant) has increased markedly, including due to a decrease in the population. However, the main drawback of Russian water resources - their uneven distribution across the country, which is not consistent with the real needs for fresh water - has been preserved. In many regions of Russia, there are serious problems with water supply due to the indicated uneven distribution, their very large temporal variability (especially in the southern regions), and a high degree of pollution. In terms of local water resources, the Southern and Far Eastern Federal Districts of Russia differ by almost 30 times, and by about 100 times in terms of water supply for the population (Fig. 1.3, Table 1.6).

Among the constituent entities of the Russian Federation, the largest total water resources are in the Krasnoyarsk Territory and the Republic of Sakha (Yakutia) - respectively 947 and 896 km W / year, the smallest - in the Republic of Kalmykia, Belgorod, Kurgan and Kursk regions (respectively 1.83; 2.72; 3.52 and 3.70 km 3 / year); in another 10 regions and republics, water resources do not exceed 8 km 3 /year.

Preliminary research results obtained in recent years by Russian and foreign scientists using various climate scenarios and hydrological models show that in the predominant part of the territory of Russia in the first half of the XXI century. one should expect an increase in water resources and a decrease in their intra-annual unevenness. In particular, an increase in runoff in the basins of the Volga and northern rivers is expected, and an increase in the inflow of river waters from the Russian territory into the Arctic Ocean is predicted up to 10-20%. At the same time, in the southern regions, in the basins of the Don and Dnieper and in the adjacent territories, which still have limited water resources, it is quite likely that they will decrease significantly due to climate change.

Table 1.6. Water resources of Russia by federal districts

WATER RESOURCES, 2014, Volume 41, No. 3, p. 235-246

WATER RESOURCES AND REGIME OF WATER BODIES

UDC 556.18:338.439:628.1

WATER RESOURCES AND THE FOOD PROBLEM

A. P. Demin © 2014

Institute of Water Problems of the Russian Academy of Sciences 119333 Moscow, st. Gubkina, 3 [email protected] Received 13.06. 2012

The data on the volume of renewable water resources and the specific water supply of the countries with the most and least water resources are presented. Modern data on the volume of withdrawal of water resources, the area of ​​irrigated land, and the population of the largest countries of the world are given. The measures taken by foreign countries to increase the availability of water resources for agriculture are shown. It was revealed that a further increase in the area of ​​arable and irrigated land while maintaining existing technologies in agriculture is unacceptable. The role of land reclamation in ensuring the food security of Russia is shown.

Key words: renewable water resources, water supply, food security, water pollution, irrigated land, wastewater, saline water, land reclamation.

DOI: 10.7868/S0321059614030055

According to various estimates, global renewable water resources range from 42,000 to 43,800 km3/year and are extremely unevenly distributed over the land area depending on the climatic and physical-geographical conditions of their formation. Most of the water resources (47%) are concentrated in the Americas, followed by Asia (32), Africa (10), Europe (6) and Australia with Oceania (5%). The countries most and least provided with renewable water resources are listed in Table. one.

To assess the state of water resources in countries and regions of the world, in addition to volume, two criteria are usually used: the specific water supply of the region, calculated as the provision of water resources per capita, and the degree of use of water resources, characterized by the ratio of total water consumption to renewable water resources. Provision of water resources per capita - from 90-100 thousand m3 / (person per year) and more in countries such as Canada, Iceland, Gabon, Suriname, to less than 10 m3 / (person year) in Kuwait . Of the large countries of the world, Russia is one of the few where the indicator of specific water supply is at a fairly high level.

According to the UN, the minimum required water consumption for the needs of agriculture, industry, energy and so-

storage of environmental equilibrium is assumed to be 1700 m3/(person per year). With a specific water supply of 1000-1700 m3, it is customary to speak of a state of water stress, with 500-1000 m3 - a shortage of water resources, and less than 500 m3 - an absolute water shortage. Today, ~700 million people in 43 countries live under water stress. With an annual water supply averaging 1200 m3/person, the Middle East is the region experiencing the most water stress in the world. Sub-Saharan Africa is generally well endowed with water, but has more water stressed countries than any other region in the world, nearly a quarter of its population now lives under water stress, and part of this population is steadily growing .

The temporal variability of water availability is also extremely high. Combined with underdeveloped water storage infrastructure and poor protection of river basins, this variability puts millions of people at risk from droughts and floods. In countries where water availability depends on monsoons or short periods of rainfall, national averages give a distorted picture of real water availability. Huge territories in Asia receive a significant part

Table 1. Data on the most and least provided countries with renewable water resources

Country Volume of renewable water resources, km3/year Specific water supply, m3/person

Countries most endowed with water resources

Brazil 8233 31 795

Russia 4507 29642

Canada 2902 92662

Indonesia 2838 13381

China 2830 2245

Columbia 2132 50160

USA 2071 7153

Peru 1913 62973

India 1897 1249

Countries least endowed with water resources

Israel 1.67 245

Jordan 0.88 154

Libya 0.60 99

Mauritania 0.40 131

Cape Verde 0.30 578

Djibouti 0.30 366

Qatar 0.05 61

Malta 0.05 123

Gaza Strip 0.06 320

Bahrain 0.12 163

Kuwait 0.02 7

annual precipitation over a period of several weeks. This gives rise to the danger of short-term but intense flooding during these periods and prolonged drought during the rest of the year. The actual availability of water during the year depends not only on the amount of precipitation, but also on the water reserves in reservoirs, the volume of river runoff and replenishment of groundwater reserves.

In the middle of the twentieth century. the ratio of water consumption to renewable water resources was low (<10%) или умеренным (10-20%) в подавляющем большинстве регионов, где проживает более 75% населения Земли. Лишь в одном регионе - Северной Африке степень использования водных ресурсов превышала 40%. К концу ХХ в. ситуация кардинальным образом изменилась: в 1995 г. более 40% населения проживало в регионах с очень высокой (40-60%) и критически высокой (>60%) pressure on water resources.

The amount of water a person needs for drinking and domestic purposes is insignificant in relation to the volumes needed for food production. For drinking purposes, a person needs 2-4 liters of water per day, for domestic needs - 30-300 liters. A person needs 3,000 liters of water per day to grow the daily necessary food. In 2000, 65% of the world's fresh water consumption was accounted for by agriculture, 20% by industry, 10% by domestic utilities, and 5% by additional water losses due to evaporation from the surface of reservoirs. In the structure of non-returnable water consumption, the share of agriculture exceeded 84%.

IMPACT OF WATER SCARCITY ON AGRICULTURE

Over 50 years (1950-2000), water consumption by agriculture in the world increased by 1525 (64% of the total increase in water consumption), by industry - by 572, and by households - by 297 km3. Irrigated agriculture has the greatest impact on the depletion of the planet's water resources in agriculture. The question arises: how big is the trend of a further increase in the withdrawal of water resources in connection with the growing population of the planet and the need to provide it with food?

Currently, most of the population lives in developing countries. According to demographers, by 2030 the world population will approach 8 billion, and by 2050 it will exceed 9 billion people. In the coming decades, the population of the least developed and developing countries will grow. The depletion of water resources, the deterioration of water quality and the growth of its scarcity have little effect on population growth, but have an extremely negative impact on economic growth and the well-being of countries. As a result, the possibilities of solving the problem of water scarcity are decreasing, while population growth continues.

Currently, the main users of water on the planet are developing countries, especially Asian countries (~70% of the annual volume of water withdrawn from water bodies) (Table 2). Modern indicators on water consumption, irrigated land, population are given according to FAO, Eurostat, OECD, CIS Statistical Committee (for 80 largest countries in the world in terms of water withdrawal by agriculture) . In some cases, materials from national publications were used

Table 2. Fresh water withdrawal for agriculture and area of ​​irrigated land in the countries of the world in 2003-2007

No. Withdrawn Including agriculture, km3 Share of water intake by rural areas Population, mln. Volume of water withdrawn Area of ​​irrigated land, mln ha Area of ​​irrigated land per person, ha

Freshwater farming in the ob- rural

water, km3

brine water, % per 1 person, m3

1 India 761.0 688.0 90.4 1134.0 607 55.8 0.049

2 China 581.9 360.0 61.9 1329.1 271 54.5 0.041

3 USA 482.2 186.8 38.7 301.3 620 24.7 0.082

4 Pakistan 183.5 172.4 94.0 159.6 1080 18.2 0.114

5 Iran 95.0 86.0 90.5 71.5 1203 7.65 0.107

6 Indonesia 86.0 78.5 91.3 225.6 348 4.50 0.020

7 Philippines 79.0 65.6 83.0 88.7 740 1.88 0.021

8 Mexico 78.9 60.6 76.8 105.8 573 6.32 0.060

9 Egypt 69.3 59.3 85.6 74.0 806 3.42 0.046

10 Japan 83.4 56.2 67.4 127.8 440 2.59 0.020

11 Uzbekistan 60.0 54.0 90.0 27.1 1993 4.28 0.158

12 Iraq 66.0 52.0 78.8 28.5 1825 3.52 0.124

13 Thailand 57.3 51.8 90.4 66.0 785 5.00 0.076

14 Vietnam 75.0 51.1 68.1 85.2 599 3.00 0.035

15 Sudan 37.3 36.1 96.8 37.2 970 1.86 0.050

16 Turkey 45.0 34.0 75.6 70.6 482 4.85 0.069

17 Brazil 58.5 31.9 54.5 19.0 166 2.92 0.015

18 Bangladesh 35.9 31.5 87.7 142.6 221 4.73 0.033

19 Mnyama 33.2 32.6 98.2 49.6 659 1.84 0.037

20 Italy 58.0 28.8 49.7 59.6 483 2.75 0.046

21 Spain 33.8 24.5 72.5 45.3 540 3.78 0.083

22 Turkmenistan 25.0 24.0 96.0 6.7 3582 1.74 0.260

23 Afghanistan 23.2 22.8 98.3 28.4 804 3.20 0.113

24 Argentina 29.2 21.5 73.6 39.5 544 1.55 0.039

25 Russia 74.6 21.5 28.8 142.2 151 4.60 0.032

26 Saudi Arabia 23.7 20.8 87.8 25.2 827 1.62 0.064

statistics, water management and environmental organizations in some countries and cross-checked with various sources.

The main consumers of water among developing countries are India, China, Pakistan. In most countries of Asia, Africa, Latin America, 75-90 (in some - up to 98)% of the volume of annually used water falls on the agricultural sector and only 10-25% - on industry and utilities. However, in many of these countries, agriculture takes up the vast majority of the water resources used. So, In India, Pakistan, Iran, Indonesia, Uzbekistan, Thailand, Sudan, Myanmar and other countries

NOVITSKAYA NATALIA NIKOLAEVNA - 2007