Fresh water makes up no more than 2.5-3% of the Earth's total water supply. Most of it is frozen in glaciers and snow cover Antarctica and Greenland. Another part is numerous fresh water bodies: rivers and lakes. The third part of the reserves fresh water concentrated in underground reservoirs, deep and closer to the surface.
At the beginning of the new millennium, scientists started talking seriously about shortages. drinking water in many countries of the world. Every inhabitant of the Earth should spend from 20 to water per day on food and personal hygiene. However, there are countries where there is not enough drinking water to even sustain life. Residents of Africa are experiencing severe water shortages.
Reason one: increase in the Earth's population and development of new territories
According to the UN, in 2011 the world's population grew to 7 billion people. The number of people will reach 9.6 billion by 2050. Population growth is accompanied by the development of industry and agriculture.
Enterprises use fresh water for all production needs, while returning water that is often no longer suitable for drinking to nature. It ends up in rivers and lakes. The level of their pollution in lately has become critical for the ecology of the planet.
Agricultural development in Asia, India and China has depleted the largest rivers in these regions. The development of new lands leads to shallowing of water bodies and forces people to develop underground wells and deep-sea horizons.
Reason two: irrational use of fresh water sources
Most natural fresh water sources are replenished naturally. Moisture enters rivers and lakes with precipitation, some of which goes into underground reservoirs. Deep-sea horizons are classified as irreplaceable reserves.
The barbaric use of clean fresh water by humans is depriving rivers and lakes of their future. Rains do not have time to fill shallow reservoirs, and water is often wasted.
Some of the water used goes underground through leaks in city water supply networks. When turning on the tap in the kitchen or shower, people rarely think about how much water is wasted. The habit of saving resources has not yet become relevant for the majority of the Earth's inhabitants.
Extracting water from deep wells may also become big mistake, depriving future generations of the main reserves of fresh natural water, and irreparably disrupting the ecology of the planet.
Modern scientists see a way out in saving water resources, tightening control over waste processing and desalination of sea salt water. If humanity thinks about it now and takes action in time, our planet will forever remain an excellent source of moisture for all species of life existing on it.
Water is life. And if a person can survive for some time without food, it is almost impossible to do this without water. Since the heyday of mechanical engineering, the production industry, water has become too quickly and without special attention on the part of man to become polluted. Then the first calls about the importance of preserving water resources appeared. And if, in general, there is enough water, then the reserves of fresh water on Earth constitute a negligible fraction of this volume. Let's look into this issue together.
Water: how much is there and in what form does it exist?
Water is an important part of our life. And it is she who makes up most of of our planet. Humanity uses this extremely important resource every day: for domestic needs, production needs, agricultural work and much more.
We are used to thinking that water has one state, but in fact it has three forms:
- liquid;
- gas/steam;
- solid state(ice);
In a liquid state, it is found in all water basins on the surface of the Earth (rivers, lakes, seas, oceans) and in the depths of the soil (groundwater). In its solid state we see it in snow and ice. In gaseous form, it appears in the form of clouds of steam.
For these reasons, calculating the amount of fresh water on Earth is problematic. But according to preliminary data, the total volume of water is about 1.386 billion cubic kilometers. Moreover, 97.5% is salt water(undrinkable) and only 2.5% is fresh.
Fresh water reserves on Earth
The largest accumulation of fresh water is concentrated in the glaciers and snows of the Arctic and Antarctica (68.7%). Next comes groundwater (29.9%) and only an incredibly small part (0.26%) is concentrated in rivers and lakes. It is from there that humanity draws the water resources necessary for life.
The global water cycle changes regularly, causing numeric values change also. But in general, the picture looks exactly like this. The main reserves of fresh water on Earth are in glaciers, snow and groundwater; extracting it from these sources is very problematic. Perhaps, not in the distant future, humanity will have to turn its attention to these sources of fresh water.
Where is the most fresh water?
Let's take a closer look at the sources of fresh water and find out which part of the planet has the most of it:
- Snow and ice at the North Pole make up 1/10 of the total fresh water reserve.
- Groundwater Today they also serve as one of the main sources of water production.
- Lakes and rivers with fresh water, as a rule, are located at high elevations. This water basin contains the main reserves of fresh water on Earth. Canadian lakes contain 50% of the world's total freshwater lakes.
- River systems cover about 45% of our planet's land area. Their number is 263 units of water basin suitable for drinking.
From the above, it becomes obvious that the distribution of fresh water reserves is uneven. Somewhere there is more of it, and somewhere it is negligible. There is another corner of the planet (except Canada) where largest reserves fresh water on Earth. These are countries Latin America, 1/3 of the world's total volume is located here.
The largest freshwater lake is Baikal. It is located in our country and is protected by the state, listed in the Red Book.
Shortage of usable water
If we go from the opposite, then the continent that most needs life-giving moisture is Africa. There are many countries concentrated here, and they all have the same problem with water resources. In some areas there is extremely little of it, and in others it simply does not exist. Where the rivers flow, the water quality leaves much to be desired, it is at a very low level.
For these reasons, over half a million people do not receive water of the required quality, and, as a result, suffer from many infectious diseases. According to statistics, 80% of disease cases are associated with the quality of fluid consumed.
Sources of water pollution
Water conservation measures are a strategically important component of our lives. Fresh water supply does not apply inexhaustible resources. And, moreover, its value is small relative to the total volume of all waters. Let's look at the sources of pollution so we know how we can reduce or minimize these factors:
- Wastewater. Numerous rivers and lakes were destroyed wastewater from various industrial production, from houses and apartments (household slag), from agro-industrial complexes and much more.
- Burials household waste and equipment in the seas and oceans. This type of burial of missiles and other weapons is very often practiced. space devices who have served their term. It is worth considering that living organisms live in reservoirs, and this greatly affects their health and water quality.
- Industry ranks first among the causes of water pollution and the entire ecosystem as a whole.
- Radioactive substances, spreading through water bodies, infect flora and fauna, making the water unsuitable for drinking, as well as for the life of organisms.
- Leakage of oil-containing products. Over time, metal containers in which oil is stored or transported are subject to corrosion, and water pollution is a result of this. Atmospheric precipitation containing acids can affect the condition of the reservoir.
There are many more sources, the most common of them are described here. In order for the fresh water reserves on Earth to remain suitable for consumption for as long as possible, they need to be taken care of now.
Water reserve in the bowels of the planet
We have already found out that the largest reserve of drinking water is in glaciers, snow and soil of our planet. In the depths of fresh water reserves on Earth are 1.3 billion cubic kilometers. But, in addition to the difficulties in obtaining it, we are faced with problems associated with its chemical properties. The water is not always fresh; sometimes its salinity reaches 250 grams per 1 liter. Most often there are waters with a predominance of chlorine and sodium in their composition, less often - with sodium and calcium or sodium and magnesium. Fresh groundwater is located closer to the surface, and salt water is most often found at a depth of up to 2 kilometers.
How do we spend this most valuable resource?
Almost 70% of our water is wasted to support the agricultural industry. In each region this value varies by different ranges. We spend about 22% on all global production. And only 8% of the remainder goes to household consumption.
More than 80 countries are facing a decline in drinking water reserves. It has a significant impact not only on social but also economic well-being. It is necessary to look for a solution to this issue now. Thus, reduced consumption of drinking water is not a solution, but only aggravates the problem. Every year, the supply of fresh water decreases to 0.3%, and not all sources of fresh water are available to us.
Fresh water is water that contains no more than 0.1% salt. It can be in the form of liquid, vapor or ice. From total number water resources is 2.5-3%. But of this 3%, only 1% is available to humans.
Its distribution on globe characterized by unevenness. Europe and Asia, inhabited by 70% of the population, have only 39% at their disposal.
The main sources are:
- surface (rivers, streams, fresh lakes, glaciers);
- groundwater (springs and artesian springs);
- precipitation (snow and rain).
The largest reserve is stored in glaciers (85-90%), especially in Antarctic ones. Russia ranks second in the world in terms of fresh water reserves (first place belongs to Brazil). The main amount of water is concentrated in Lake Baikal: 80% Russian reserves and 20% - global.
The total volume of the lake is 23.6 thousand cubic kilometers. Every year it produces approximately 60 m 3 of water, characterized by extraordinary purity and transparency.
Fresh water shortage problem
Recently, humanity has been faced with the problem of shortages. Now over 1.2 billion people are experiencing constant shortages. According to forecasts, in a few decades more than 4 billion people will find themselves in such conditions, as its number will be halved. The reasons for this situation include:
- contamination of water sources;
- population growth;
- melting of glaciers as a result of the greenhouse effect.
They are trying to restore this deficit in the following ways:
- export;
- creation of artificial reservoirs;
- cost savings;
- artificial production of fresh water.
Methods for obtaining fresh water:
- desalination of sea waters;
- condensation of water vapor from the air in natural cold storage facilities, most often in coastal caves.
With the help of condensation, huge reserves of water are formed, which fall under the seabed, where they often break through with fresh springs.
Meaning and Application
First of all, water is necessary for the Earth's ecosystems to function properly. Water creates and supports life on Earth, plays the role of a universal solvent, and takes part in all chemical reactions, occurring in the human body, shapes climate and weather.
Included human body includes 70% water. Therefore, it must be constantly replenished: without it, a person cannot live for more than 3 days.
The bulk of water resources is used agriculture and industry, and only a small part (about 10%) goes to consumer needs.
Recently, consumption for household needs has increased sharply due to the introduction of automatic dishwashers and washing machines.
Compound
The water of rivers and lakes is not the same in composition. Since it is a universal solvent, its composition depends on the composition surrounding soil and the minerals contained in it. It contains dissolved gases (mainly oxygen, nitrogen and carbon dioxide), various cations and anions, organic matter, suspended particles, microorganisms.
Characteristics
An important characteristic is its purity. Water quality depends on acidity pH, hardness and organoleptics.
The acidity of water is affected by the content of hydrogen ions, and hardness is affected by the presence of calcium and magnesium ions.
Hardness can be general, carbonate and non-carbonate, removable and irremovable.
The organoleptic properties of water depend on its smell, taste, color and turbidity.
The smell may be earthy, chlorine, petroleum, etc. It is rated on a 5-point scale:
- complete absence of odor;
- the smell is almost not felt;
- the smell can only be noticed if you specifically pay attention to it;
- the smell can be easily noticed and you don’t really want to drink it;
- the smell is clearly audible, which prevents the desire to drink it;
- the smell is particularly strong, making it undrinkable.
The taste of fresh water can be salty, sour, sweet and bitter. It is also rated on a 5-point scale. It can be absent, very faint, weak, noticeable, distinct and very strong.
Color and turbidity are assessed on a 14-point scale by comparison with a standard.
Water is characterized by inexhaustibility and self-purification. Inexhaustibility is determined by its self-replenishment, which results from the natural water cycle.
What does water quality depend on?
To study its properties, qualitative and quantitative analysis. On its basis, the maximum permissible concentration is determined for each substance included in its composition. But for some substances, viruses and bacteria, the maximum permissible concentration should be zero: they should be completely absent.
Quality is affected by:
- climate (especially frequency and amount of precipitation);
- geological feature of the area (mainly the structure of the river bed);
- ecological conditions of the region.
Special devices are used for cleaning. But even when using the latest modifications of treatment systems, some of the pollutants (about 10%) remain in the water.
Freshwater classification
Divided into:
- regular;
- mineral.
Depending on the content minerals mineral water classified into:
In addition, there are also artificial fresh waters, which are divided into:
- mineral and distilled;
- desalinated and melted;
- shungite and silver;
- "alive" and "dead".
Melt water has a number of useful properties. But it is not recommended to prepare it by melting snow or ice from the street: it will contain benzopyrene, which is an organic carcinogenic compound that is characterized by the first hazard class. Its source is car exhaust gases.
Shungite water is formed when water passes through shungite deposits ( rock), purchasing medicinal properties. They also make artificial shungite water, but its effectiveness has not been proven.
Silver water is formed as a result of saturation with silver. It has bactericidal properties and can kill pathogenic microorganisms.
“Living” and “dead” water does not only exist in fairy tales. It is obtained by electrolysis ordinary water and is used to treat various diseases.
- A leaking tap, from which tap water flows in a thin stream, will carry away 840 liters per day.
- Most clean water Finland can boast.
- The most expensive water is sold in Finland: 1 liter costs $90.
- If you put hot and cold water, then the hot one will freeze faster.
- Hot water will put out a fire faster than cold water.
- At school we learned that water can be in 3 states. Scientists identify 14 states of frozen water and 5 states of liquid water.
- Modern people need 80-100 liters of water per day. During the Middle Ages, 5 liters was enough for a person.
- A person drinks 2-2.5 liters per day, and 35 tons over a lifetime.
Water shortages are increasingly making themselves felt to humanity. Something needs to be done to change the situation, otherwise the inhabitants of the blue planet, most of which is occupied by water, will be left without something to drink. In this case, all living things will have only 3 days to live.
All water reserves on Earth can be divided into liquid (salty and fresh), solid (fresh) and
gaseous (fresh) water (Table 6.9). The total volume of water is about 1.5 billion km3. Moreover, 93.96% of water is concentrated in the seas and oceans. The high salt content (up to 35 mg/l) makes this water unsuitable for domestic needs and drinking.
Freshwater makes up less than 6% of all water resources on Earth. Scientists have calculated that the world's fresh water supply is approximately 30.3 million km3. On the territory former USSR contains about 69 thousand km3 of fresh water. However, most of the world's fresh water reserves are concentrated in the glaciers of Antarctica, Greenland, the Arctic and other permafrost zones, which makes it inaccessible.
It is believed that only 0.2-0.3% of all water on Earth can actually be used for drinking purposes. Despite the world's relatively large reserves of fresh water, at the XXXV session of the UN General Assembly it was noted that more than 1 billion people experience an acute shortage of good-quality water for drinking and domestic purposes.
The first reason for water shortages is that sources of drinking water are extremely unevenly distributed both on Earth as a whole and in individual countries. For example, in the former USSR, 80% of fresh water is concentrated in Eastern Siberia, in Far East and the European North, where only 30% of the country's population lives and industry and agriculture are less concentrated.
Water consumption in developed countries is constantly increasing and is approaching the value of the entire freshwater resource. In Russia, this is especially noticeable in the south of the European part, where water consumption has already exceeded 2/3 of the total river flow and has had an extremely adverse impact on water balance Caspian Sea.
The second most important reason for the lack of fresh water is anthropogenic. This is not an absolute decrease in the amount of water, but a decrease in its quality as a result of contamination by microorganisms and chemicals when household, fecal, industrial and agricultural wastewater enters water bodies. According to UN reports, about 1 million new ones are synthesized around the world every year. chemical compounds, of which more than 15 thousand are very toxic. In general, up to 80% of all chemical compounds gradually enter the environment, including in natural reservoirs. Every year in the world total About 420 km3 of wastewater is released, which can lead to pollution of up to 7000 km3 of natural waters. This is 1.5 times more than the entire river flow of the former Soviet Union, which amounted to 4700 km3.
Due to the reduction in fresh water supplies on Earth and the decline in quality natural waters Humanity faces the problem of “water hunger.” This requires an intensive search for new scientific solutions aimed at providing high-quality water to the population, industry and agriculture.
To reduce “water hunger”, two main closely interrelated areas of action can be distinguished. The first direction should include maintaining the quality of natural waters, primarily the effective treatment of household wastewater before discharge into water bodies. However, no less important issue is the fight against environmental pollution from industrial wastewater. In this area, the solution is seen in the development and improvement of methods for treating wastewater from industrial facilities, the use of “recycling water supply”, i.e. multiple reuse of purified water for technological purposes. In the future, it is possible to use “dry technologies” that do not require water and, therefore, do not lead to pollution of water bodies.
The second direction in the fight against “water hunger” involves the rational use and increase of natural water supplies. This is a strict economy of drinking water for both domestic and industrial needs and a constant fight against losses of this
the most valuable and expensive product, including using economic methods.
The water supply to the population can be increased by creating artificial reservoirs that accumulate fresh water reserves. The construction of reservoirs simultaneously solves other important national economic issues - energy, transport, industrial, agricultural, hygienic, aesthetic. Currently, dozens of large reservoirs have been created on the Volga, Angara, Irtysh and other large rivers, which also help in providing electricity. A hydroelectric power station with a capacity of about 4,100 MW was built on the Bratsk reservoir on the Angara with a volume of 169.4 km 3 .
IN recent years Methods are also being developed for accumulating fresh water reserves in underground aquifers from surface runoff, including flood waters. The thickness of the earth through which surface water passes acts as a filter, which significantly improves the quality of surface water as it turns into groundwater. At the same time, in some regions, saline groundwater will be diluted with low-mineralized surface runoff filtered through the soil.
One hypothetical possibility for obtaining large quantities of fresh water is by melting eternal ice Arctic, as well as icebergs. However, this creates a number of complex energy, economic, technical and environmental issues, in particular a likely significant increase in sea levels.
Why did the problem of “water hunger” arise?
Over the years of human existence, water on Earth has not decreased. However, people's need for water is increasing sharply. By consuming more and more clean water, people return to nature the polluted wastewater from industrial production, public services, and the agricultural complex. And there is less and less clean water on Earth.
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, compiled a rating of 10 countries with largest reserves 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 large number water resources: rivers, glaciers, seas and oceans. The most significant rivers are: Ganges, Indus, Brahmaputra, Godavari, Krishna, Narbada, Mahanadi, Kaveri. Many of them have 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
Many rivers flow through Bangladesh, and floods large rivers can last 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
USA occupies huge territory, on which there are many rivers and lakes.
5 Place
Indonesia
Resources – 2,530 cubic meters. km
Per capita – 12.2 thousand cubic meters. m
In Indonesian territories all year round Quite a large amount of precipitation falls, 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 populous country in the world, and water on its territory is distributed extremely unevenly.
3 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.
2 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 most large lakes countries – 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).
