19. World water resources

The concept of water resources can be interpreted in two senses – broad and narrow.

In a broad sense- this is the entire volume of water in the hydrosphere contained in rivers, lakes, glaciers, seas and oceans, as well as in underground horizons and in the atmosphere. The definitions are quite applicable to it huge, inexhaustible, and this is not surprising. After all, the World Ocean occupies 361 million km2 (about 71% of the total area of ​​the planet), and glaciers, lakes, reservoirs, swamps, and rivers account for another 20 million km2 (15%). As a result, the total volume of the hydrosphere is estimated at 1390 million km 3 . It is not difficult to calculate that with such a total volume, each inhabitant of the Earth now accounts for approximately 210 million m 3 of water. This amount would be enough to supply a large city for a whole year!

However, it is necessary to take into account the possibilities of using these enormous resources. Indeed, of the total volume of water contained in the hydrosphere, 96.4% falls on the share of the World Ocean, and of the water bodies on land, the largest amount of water contains glaciers (1.86%) and groundwater (1.68%), the use of which is possible, but more partly very difficult.

That's why when they talk about water resources in the narrow sense of the word, they mean suitable for consumption fresh waters, which constitute only 2.5% of the total volume of all waters of the hydrosphere. However, significant adjustments must be made to this indicator. It is impossible not to take into account the fact that almost all fresh water resources are “conserved” either in the glaciers of Antarctica, Greenland, mountainous regions, in the ice of the Arctic, or in groundwater and ice, the use of which is still very limited. Lakes and reservoirs are used much more widely, but their geographical distribution is by no means ubiquitous. It follows that the main source of meeting humanity’s needs for fresh water has been and remains river (channel) water, the share of which is extremely small, and the total volume is only 2100 km 3 .

This amount of fresh water would not be enough for people to live by now. However, due to the fact that the duration of the conditional moisture cycle for rivers is 16 days, during the year the volume of water in them is renewed on average 23 times and, therefore, the river flow resources can be purely arithmetically estimated at 48 thousand km 3 /year. However, the prevailing figure in the literature is 41 thousand km 3 /year. It characterizes the “water ration” of the planet, but reservations are also necessary here. It is impossible not to take into account that more than half of the channel waters flow into the sea, so that the resources of such waters actually available for use, according to some estimates, do not exceed 15 thousand km 3.

If we consider how the total river flow is distributed between large regions of the world, it turns out that foreign Asia accounts for 11 thousand km 3, South America - 10.5, North America - 7, CIS countries - 5.3, Africa – 4.2, Australia and Oceania – 1.6 and foreign Europe – 1.4 thousand km 3 . It is clear that behind these indicators are, first of all, the largest river systems in terms of flow: in Asia - the Yangtze, Ganges and Brahmaputra, in South America - the Amazon, Orinoco, Parana, in North America - the Mississippi, in the CIS - the Yenisei, Lena, in Africa - Congo, Zambezi. This fully applies not only to regions, but also to individual countries. (Table 23).

Table 23

TOP TEN COUNTRIES BY SIZE OF FRESHWATER RESOURCES

Figures characterizing water resources cannot yet give a complete picture of water availability, since the provision of total flow is usually expressed in specific indicators - either per 1 km 2 of territory or per inhabitant. Such water availability of the world and its regions is shown in Figure 19. Analysis of this figure suggests that with a global average of 8000 m 3 /year, Australia and Oceania, South America, the CIS and North America have indicators above this level, and below - Africa, foreign Europe and foreign Asia. This situation with water supply in the regions is explained both by the overall size of their water resources and by the size of their population. No less interesting is the analysis of differences in water availability in individual countries. (Table 24). Of the ten countries with the greatest water availability, seven are located within the equatorial, subequatorial and tropical zones, and only Canada, Norway and New Zealand are within the temperate and subarctic zones.

Rice. 19. Availability of river flow resources in large regions of the world, thousand m3/year

Table 24

COUNTRIES WITH THE HIGHEST AND LEAST AVAILABILITY OF FRESHWATER RESOURCES

Although based on the above per capita indicators of water availability for the whole world, its individual regions and countries, it is quite possible to imagine its general picture, it would be more correct to call such availability potential. To imagine real water availability, it is necessary to take into account the size of water intake and water consumption.

World water consumption in the twentieth century. grew as follows (in km 3): 1900 – 580, 1940 – 820, 1950 – 1100, 1960 – 1900, 1970 – 2520, 1980 – 3200, 1990 – 3580 , 2005 – 6000. These general indicators of water consumption are very important: they indicate that throughout the 20th century. global water consumption increased 6.8 times. Already, almost 1.2 billion people do not have access to clean drinking water. According to the UN forecast, universal access to such water can be achieved: in Asia - by 2025, in Africa - by 2050. The structure, i.e., the nature of water consumption, is no less important. Nowadays, 70% of fresh water is consumed by agriculture, 20% by industry, and 10% goes to meet domestic needs. This ratio is quite understandable and natural, but from the point of view of saving water resources, it is rather unprofitable, primarily because in agriculture (especially in irrigated agriculture) there is a very high irrevocable water consumption According to available calculations, in 2000, irreversible water consumption in world agriculture amounted to 2.5 thousand km 3, while in industry and public utilities, where recycled water supply is more widely used, only 65 and 12 km 3, respectively. From all that has been said, it follows, firstly, that today humanity already uses quite a significant part of the planet’s “water ration” (about 1/10 of the total and more than 1/4 of the actually available) and, secondly, that irreversible water losses amount to more than 1/2 of its total consumption.

It is no coincidence that the highest rates of per capita water consumption are characteristic of countries with irrigated agriculture. The record holder here is Turkmenistan (7000 m3 per person per year). It is followed by Uzbekistan, Kyrgyzstan, Kazakhstan, Tajikistan, Azerbaijan, Iraq, Pakistan, etc. All these countries are already experiencing a significant shortage of water resources.

In Russia, the total river flow reaches 4.2 thousand km 3 /year, and, therefore, the resource availability of this flow per capita is 29 thousand m 3 /year; This is not a record, but quite a high figure. Total fresh water intake in the second half of the 1990s. Due to the economic crisis, there was a tendency to decrease slightly. In 2000 it was 80–85 km 3 .

The structure of water consumption in Russia is as follows: 56% is used for production, 21% for household and drinking needs, 17% for irrigation and agricultural water supply, and 6% for other needs. It is easy to calculate that in Russia as a whole, the total water intake is only 2% of the total river flow resources. However, this is an average figure, and in some river basins it reaches 50–75% or more. The same applies to individual economic regions of the country. Thus, in the Central, Central Chernozem and Volga regions, water availability per inhabitant is only 3000–4000 m 3 /year, and in the Far East - 300 thousand m 3.

The general trend for the whole world and its individual regions is a gradual decrease in water availability, therefore, various ways to save water resources and new ways of water supply are being sought.

It is expected that by 2025, the number of people experiencing moderate or severe water stress will increase to 5.5 billion, accounting for two-thirds of the world's population.

Currently, water, especially fresh water, is an extremely important strategic resource. Global water consumption has increased in recent years, and there are fears that there simply won't be enough for everyone. According to the World Commission on Water, today every person needs from 20 to 50 liters of water daily for drinking, cooking and personal hygiene.

However, about a billion people in 28 countries around the world do not have access to as many vital resources. About 2.5 billion people live in areas experiencing moderate or severe water stress. This number is expected to rise to 5.5 billion by 2025, accounting for two-thirds of the world's population.

, in connection with the negotiations between the Republic of Kazakhstan and the Kyrgyz Republic on the use of transboundary waters, I compiled a rating of 10 countries with the largest reserves of water resources in the world:

10th place

Myanmar

Resources – 1080 cubic meters. km

Per capita - 23.3 thousand cubic meters. m

The rivers of Myanmar - Burma are subject to the country's monsoon climate. They originate in the mountains, but are fed not by glaciers, but by precipitation.

More than 80% of the annual river nutrition comes from rain. In winter, rivers become shallow and some of them, especially in central Burma, dry up.

There are few lakes in Myanmar; the largest of them is the tectonic Lake Indoji in the north of the country with an area of ​​210 square meters. km.

9th place

Venezuela

Resources – 1,320 cubic meters. km

Per capita – 60.3 thousand cubic meters. m

Nearly half of Venezuela's thousand rivers flow from the Andes and Guiana Plateau into the Orinoco, Latin America's third largest river. Its basin covers an area of ​​about 1 million square meters. km. The Orinoco drainage basin covers approximately four-fifths of Venezuela's territory.

8 Place

India

Resources – 2085 cubic meters. km

Per capita - 2.2 thousand cubic meters. m

India has a large number of water resources: rivers, glaciers, seas and oceans. The most significant rivers are: Ganges, Indus, Brahmaputra, Godavari, Krishna, Narbada, Mahanadi, Kaveri. Many of them are important as sources of irrigation.

Eternal snow and glaciers in India cover about 40 thousand square meters. km of territory.

7 Place

Bangladesh

Resources – 2,360 cubic meters. km

Per capita – 19.6 thousand cubic meters. m

There are many rivers flowing through Bangladesh, and large rivers can flood for weeks. Bangladesh has 58 transboundary rivers and issues arising in the use of water resources are very sensitive in discussions with India.

6 Place

Resources – 2,480 cubic meters. km

Per capita – 2.4 thousand cubic meters. m

The United States occupies a vast territory with many rivers and lakes.

5 Place

Indonesia

Resources – 2,530 cubic meters. km

Per capita – 12.2 thousand cubic meters. m

In the territories of Indonesia, a fairly large amount of precipitation falls all year round, because of this the rivers are always full and play a significant role in the irrigation system.

4 Place

China

Resources – 2,800 cubic meters. km

Per capita – 2.3 thousand cubic meters. m

China has 5-6% of the world's water reserves. But China is the most densely populated country in the world, and water is distributed extremely unevenly across its territory.

3rd place

Canada

Resources – 2,900 cubic meters. km

Per capita – 98.5 thousand cubic meters. m

Canada is one of the richest countries in the world with lakes. On the border with the United States are the Great Lakes (Superior, Huron, Erie, Ontario), connected by small rivers into a huge basin with an area of ​​more than 240 thousand square meters. km.

Less significant lakes lie on the territory of the Canadian Shield (Great Bear, Great Slave, Athabasca, Winnipeg, Winnipegosis), etc.

2nd place

Russia

Resources – 4500 cubic meters. km

Per capita – 30.5 thousand cubic meters. m

Russia is washed by the waters of 12 seas belonging to three oceans, as well as the inland Caspian Sea. On the territory of Russia there are over 2.5 million large and small rivers, more than 2 million lakes, hundreds of thousands of swamps and other water resources.

1 place

Brazil

Resources – 6,950 cubic meters. km

Per capita - 43.0 thousand cubic meters. m

The rivers of the Brazilian Plateau have significant hydroelectric potential. The largest lakes in the country are Mirim and Patos. Main rivers: Amazon, Madeira, Rio Negro, Parana, Sao Francisco.

Also list of countries by total renewable water resources(based on the CIA World Factbook).

How technology will change our cities in the future

And why now people don’t like their megacities?

“Cities are the centers of civilization” is already a hackneyed statement. We know of cities with populations in the tens of millions. We know that London generates a third of UK GDP. About the future of cities, digital and “live”, in the material of “Cursive”.

Professor at the Stockholm School of Economics Kjell Nordstrom I am sure: states are dying as structures. In his opinion, in 50 years, instead of more than 200 countries, there will be about 600 cities, and the remaining territory will turn into a location for post-apocalyptic films.

“This process is already happening in Russia, Australia, the USA and even China. We are now seeing the birth of multicity corporations instead of multinational ones. We see how cities are beginning to feel their independence from the country and demand freedom,” Nordström never tires of repeating.

The future, according to the professor, belongs to gigapolises - the fruits of the most perverted, final form of capitalism, for which Edward Luttwak coined the term “turbocapitalism.”

Against the backdrop of these gloomy Matrix-style sketches Andrey Chernikhov, first vice-president of the International Academy of Architecture, told at the forum “Digital Kazakhstan: sustainable development of urban planning systems in the 21st century” how cities will develop in the medium term, and warned: digitalization without ethical regulation will be a disaster for residents of megacities.

The city copies its inhabitants

“The city is striving hard to become like the human body.”

This paradoxical idea of ​​Chernikhov can be strengthened by multiplying it with the current situation, when modern digital technologies not only “highlight” trends, but accelerate them many times over. While it is impossible in principle to copy the human brain, digital technologies are trying to imitate it, creating centralized control systems. This is not yet a brain, not like that of humans, but it may soon become one.

“In fact, we are creating a mirror of the analog city, calling it digital. Almost everything that is done in the field of green technologies, energy saving technologies, what we call digital technologies, is the creation of a mirror city in digital form. And the final step in this process is the digitization of a person,” reflects Chernikhov.

The subject of transformation is the management system of all infrastructures in the city - from garbage collection, housing and communal services to trade services, entertainment and what is called society in the broadest sense.

“It is clear that this digital civilization, which is advancing on all fronts, is penetrating even the most conservative industries, and can no longer be contained. We know that cities are beginning to compete, like entire countries, in terms of the pace and levels of digitalization. But a number of interesting aspects arise within the digital city,” the urbanist intrigues.

As long as we are talking about some engineering systems, about the digitalization of processes in them, it seems to be no big deal. But then the problem of total control arises.

“George Orwell spoke about this in his dystopian novel “1984,” and this question still occupies the minds of cultural scientists. What to do when medicine, education, culture, and even society becomes digital, when a person is completely “described”, completely copied (information about him, his family, his passions, how he spends his leisure time, what he buys) )? Further more. Almost everyone will know about us,” continues Chernikhov, focusing on the ethical side of total digitalization. Just a few decades ago, people naively believed that machines would save humanity. But neither cars, nor planes, nor computers are capable of ridding a person of his vices. “It’s worth thinking that by introducing “digital” in such a total way into all areas, we are doing very little work on creating a so-called ethical shield. It is necessary to create committees that should create and maintain “digital” immunity,” says Andrei Chernikhov.

Why don't people like their own cities?

Indeed, why? It would seem that in the metropolis everything is thought out to the smallest detail, but the person remains dissatisfied - the city oppresses him.

“The metropolis is completely uncontrollable from an architectural point of view - it is simply immense. It cannot be grasped even by thought, not to mention any physical parameters. The city has gone beyond the boundaries of perception, we have lost control over space. And I assure you: no “numbers”, no technical ideas will save cities from sprawl,” argues the first vice-president of the International Academy of Architecture.

And he cites Almaty as an example, noting: the trends are noticeable even in a relatively small city on a global scale. There were, of course, attempts to implement a new universal concept of the city - since the middle of the last century, architects have tried to stretch the city, as it were, creating cores around which communities would be concentrated. Did not work.

“But we know the importance of public spaces. And in a digital city this also remains important; without them, cities turn into deserts,” says the expert.

What cities do we need?

“There are timid attempts and models that suggest that the ideal city is a small city, designed for, say, 250 thousand inhabitants. And in such a city, up to 30% are public spaces: fitness, parks, alleys, and only part of the city is accessible to transport. There is another model – “slow” cities. The demand for such cities in the world is already beginning to take shape. And here, too, all public spaces are thought out with filigree precision. These cities are either without cars or with limited use of them,” Andrey Chernikhov envisions.

And this vision is more consistent with the “homey” Alma-Ata, with small streets immersed in greenery, with the “cores” that the architect speaks of, with developed communities and not yet destroyed courtyard concert venues in Tastak - the Alma-Ata that many now yearn for . And not at all this city, which is increasingly encased in concrete and glass, languishing from the abundance of cars and interchanges, separated from the rest of the world by a strip of smog and leaving less and less space for people to live.

The following countries are most endowed 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 (1,046 km 3).

Volume of water resources per capita by country of the world (m 3 per year per capita)

The largest water resources per capita are found in French Guiana (609,091 m3), Iceland (539,638 m3), Guyana (315,858 m3), Suriname (236,893 m3), Congo (230,125 m3), 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), Central African Republic (33,280 m3), Russia (31,833 m3).
The fewest water resources per capita are found in Kuwait (6.85 m3), the United Arab Emirates (33.44 m3), Qatar (45.28 m3), the Bahamas (59.17 m3), and Oman (91.63 m 3), Saudi Arabia (95.23 m 3), Libya (95.32 m 3).
On average, on Earth, each person accounts for 24,646 m3 (24,650,000 liters) of water per year.

The next map is even more interesting.

Share of transboundary flow in the total annual flow of rivers in the world (in%)
Few countries in the world rich in water resources can boast of having river basins “at their disposal” that are not separated by territorial boundaries. Why is this so important? Let's 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 for more than 500 km through the territory of China, crosses the state border and about 1800 km flows through the territory of Kazakhstan, then the Irtysh flows 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 needs, Kazakhstan half of what will remain after China. As a result, this can greatly affect the full flow of the Russian section of the Irtysh (including hydropower resources). Currently, China annually supplies Russia with 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 located outside the country. Let's see how things are going with 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 from the total volume of water resources of the country (A country with a value of 0% does not “receive” water resources from the territories of neighboring countries at all; 100% - all water resources come from outside the state).

The map shows that the following states are most dependent on “supplies” of water from 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 ranking 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 compose our rating of countries whose water resources are least dependent on the potential reduction in transboundary flow caused by water withdrawal by upstream countries.

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 water is not limited to water intake alone. We should not forget also about the transboundary transfer of pollutants, which can significantly deteriorate the quality of river water in sections of the river located in the territory of other countries downstream.

You can familiarize yourself with the map of groundwater reserves.

(Visited 48,700 times, 9 visits today)

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 FOOD PROBLEM

© 2014 A. P. Demin

Institute of Water Problems RAS 119333 Moscow, st. Gubkina, 3 E-mail: [email protected] Received by the editor on June 13. 2012

Data on the volume of renewable water resources and specific water availability of 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 presented. The measures taken by foreign countries to increase the availability of water resources in 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 food security in Russia is shown.

Key words: renewable water resources, water availability, food security, water pollution, irrigated lands, wastewater, salt water, reclamation.

DOI: 10.7868/S0321059614030055

Global renewable water resources range, according to various estimates, from 42,000 to 43,800 km3/year and are distributed extremely unevenly across 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 and Oceania (5%). The countries that are most and least endowed with renewable water resources are listed in Table. 1.

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 availability 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. Availability 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 per year) in Kuwait . Of the large countries in the world, Russia is one of the few where the specific water availability indicator is at a fairly high level.

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

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 talk about a state of water stress, with 500-1000 m3 - about a water resource deficit, and less than 500 m3 - about an absolute water deficit. Today, ~700 million people in 43 countries live under water stress. With annual water availability averaging 1,200 m3/capita, the Middle East is the region experiencing the greatest 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, with almost a quarter of its population currently living under water stress, and a portion of this population that is growing steadily .

Temporal variability of water availability is also extremely high. Combined with inadequate water storage infrastructure and poor river basin protection, this variability puts millions of people at risk of droughts and floods. In countries where water availability is dependent on monsoons or short periods of rain, national averages provide a distorted picture of actual water availability. Huge territories in Asia receive a significant share

Table 1. Information on the most and least endowed countries with renewable water resources

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

Countries most endowed with water resources

Brazil 8233 31 795

Russia 4507 29642

Canada 2902 92662

Indonesia 2838 13381

China 2830 2245

Colombia 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 creates the risk 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 flow and the 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%) load on water resources.

The amount of water a person needs for drinking and domestic purposes is insignificant in relation to the volumes required for food production. For drinking purposes, a person needs 2-4 liters of water per day, for domestic needs - 30-300 liters. To grow daily necessary food, a person needs 3000 liters of water per day. In 2000, 65% of global fresh water consumption was accounted for by agriculture, 20% by industry, 10% by municipal services, and 5% by additional water losses due to evaporation from the surface of reservoirs. In the structure of irreversible water consumption, the share of agriculture exceeded 84%.

IMPACT OF WATER SCARCITY ON AGRICULTURE

Over 50 years (1950-2000), water consumption in agriculture in the world increased by 1525 (64% of the total increase in water consumption), by industry - by 572, and by municipal services - by 297 km3. Irrigated agriculture has the greatest impact on the depletion of the planet's water resources in agriculture. The question arises: how great is the tendency for 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. The population of least developed and developing countries will grow in the coming decades. Depletion of water resources, deterioration of water quality and increasing water scarcity have little effect on population growth, but have an extremely negative impact on the economic growth and well-being of countries. As a result, the ability to solve the problem of water scarcity is 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 taken from water bodies) (Table 2). Modern indicators on water consumption, areas of irrigated land, and population are given according to data from FAO, Eurostat, OECD, and the CIS Statistical Committee (for the 80 largest countries in the world in terms of the volume of water withdrawn by agriculture). In some cases, materials from national publications were used

Table 2. Fresh water intake for agricultural needs and the area of ​​irrigated land in the countries of the world in 2003-2007.

No. Collected Including agriculture, km3 Share of water intake by rural population Population, million people Volume of water withdrawn Area of ​​irrigated land, million hectares Area of ​​irrigated land per person, hectares

A country with freshwater farming and agriculture

water, km3 total volume managed

used water, % per 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 Türkiye 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

statistical, water and environmental organizations of some countries and cross-checked using various sources.

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

NOVITSKAYA NATALIA NIKOLAEVNA - 2007

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, attitudes towards land water resources have changed. This is explained by the fact that fresh water resources account for only 2.5% of the total volume of the hydrosphere. In absolute terms, this is a huge value (30-35 million m3), which exceeds the current needs of humanity by more than 10 thousand times! However, the overwhelming 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 World Ocean; 1% - saline groundwater; 2.5% - fresh water resources.

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

Table 11. Distribution of global freshwater resources by major region.

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

Individual countries differ even more in their reserves and availability of fresh water. Based on the principle of “the best,” 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, the ranking of resources also does not coincide with the ranking of specific provision, and in each individual case such a difference can be explained. For example, in China and India there is a huge population, therefore, low security per capita. But there are countries in the world that are even less supplied with fresh water, where there is less than 1 thousand m 3 of water per capita (i.e., 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 sub-Saharan part of Africa (Algeria - 520 m3, Tunisia - 440 m3, Libya - 110 m3) and in the Arabian Peninsula (Saudi Arabia - 250 m3, Kuwait - 100 m3).

These individual examples are interesting because they allow us to make an important generalization: at the end of the 20th century. approximately 2/5 of our planet's population experiences a chronic lack of fresh water. In this case, we are talking mainly about those developing countries that are located in the Earth's arid belt. It should also be taken into account 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 irrecoverable 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 unchanged river flow resources creates a real threat of fresh water shortage.

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 person suffers from a lack of drinking water. Consumption of contaminated water is the source of 3/4 of all diseases and 1/3 of all deaths. In Asia, more than 1 billion people do not have access to clean water, in sub-Saharan Africa - 350 million and in Latin America - 100 million people.

But, in addition, fresh water supplies 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-rich countries are located here, with more than 25 thousand m3 per capita per year. In the arid zone of the Earth, which covers about 1/3 of the land area, water shortages are especially acute. Here are the most water-scarce countries, where per capita there is less than 5 thousand m 3 per year, and agriculture is possible only with artificial irrigation.

There are several ways to solve humanity's water problem. The main one is reducing the water intensity of production processes and reducing irretrievable water losses. First of all, this applies to such technological processes as the production of steel, synthetic fiber, pulp and paper, cooling of power units, and irrigation of rice and cotton fields. The construction of reservoirs that regulate river flow is of great importance for solving the water problem. Over the past fifty years, the number of reservoirs on the globe has increased approximately 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 larger than 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. Large and large reservoirs play a particularly important role in transforming river flow. The problem is that the main source of satisfying humanity’s needs for fresh water has been and remains river (channel) waters, which determine the planet’s “water ration” - 40 thousand km 3 . It's not that significant, especially considering that you can actually use about 1/2 of this amount.

In terms of the number of large reservoirs, the United States, Canada, Russia, and some countries in 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 for the territorial redistribution of river flow through its transfer have been implemented or are being designed. However, recently the largest inter-basin transfer projects have been canceled for economic and environmental reasons. In the countries of the Persian Gulf, the Mediterranean, Turkmenistan, the Caspian Sea, the southern USA, Japan, and the islands of the Caribbean, seawater desalination is used; The world's largest producer of such water is Kuwait. Fresh water has already become a global trade commodity: it is transported in sea tankers and through long-distance water pipelines. Projects are being developed to tow icebergs from Antarctica, which sends 1,200 million tons of fresh water preserved in them to the countries of the arid zone every polar summer.

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

Table 14 . World economic hydro potential and its use