The water level in the Aral. Why did the Aral Sea dry up

The Aral Sea is a salty drainless lake located between Kazakhstan and Uzbekistan. The sea was most recently the fourth largest lake in the world. Before the shallowing of the sea, fishing boats and warships sailed, fish factories stood on its shores, and life was in full swing in the ports. Flocks of birds flew over the Aral, gardens bloomed in coastal villages. Now map Aral Sea shows that the sea is shrinking catastrophically, and scientists predict its complete drying up in the near future.

Studies have shown that in early historical epochs there were already fluctuations in sea level, which is proved by the remains of mausoleums, settlements, and trees found on the shallow bottom. About 21 million years ago Aral lake connected with the Caspian Sea. IN XVI-XVII centuries sea ​​levels dropped and islands formed early XIX centuries, the Zhanadarya and Kuandarya rivers stopped flowing into the Aral Lake.

In 1849, under the leadership of A. Butakov, the first expedition to study the Aral Sea was held, as a result of which Nautical chart reservoir. From the moment of Butakov's first surveys until the middle of the 20th century, the sea level remained almost unchanged. In the photo of the Aral Sea from the time of the middle of the last century, the reservoir is shown as full-flowing and large-scale. The construction of irrigation canals, especially intensive in the 60s of the last century, led to the fact that the water of the Amudarya and Syrdarya rivers flowing into the Aral Sea was used in large volumes to irrigate fields.

In 1989, the reservoir dried up so that two parts formed - the Small and Large Aral Seas. In 2003, the Big Aral Sea was divided into separate zones - western and eastern. According to scientists, by 2020, only in the pictures and videos of the Aral Sea will it be possible to see its southern part, since it will completely dry up by this time. Kazakhstan in 2003-2005 erected a dam that separated a small part from a larger one, in an attempt to save at least a small part of the reservoir.

Map of the Aral Sea in different years.

Today, in the vicinity of the Aral Sea, in the places where it is located, the Aralkum desert is being formed. The ecology of the entire region is in a deplorable state. The climate has changed - the summer has become dry and hot, and the winter is cold. Periodically, clouds of dust and sand rise into the air above the dried bottom and scatter throughout the district, spreading the salt and pesticides, fungicides, herbicides, and fertilizers contained in them from the fields. People have been leaving these places for a long time.

Video: Muynak, graveyard of ships. Bottom of the Aral Sea.

The tragedy of the Aral Sea is well known today. Its rapid disappearance from the world map is considered one of the largest environmental disasters of our time. In place of the water surface, the Aralkum desert now spreads. Whether the shrinking of the once vast lake-sea is a consequence of climate change or human activity remains a moot point. Most likely, a combination of a number of factors has led to the current deplorable state. Now Aral Sea can only boast of a sandy-saline plain, dry grass and lonely lakes of water. Its desert beauty fascinates and continues to attract travelers, lovers vivid impressions and antiquities.

The birth of the sea in the place of the desert

Aral Sea arose on the site of a desert pit twenty-four thousand years ago. By the standards of history, it can be considered quite young.

Probably, the change in the channel of the Amu Darya served as the reason for its occurrence. fast and deep river fed the Caspian, however, due to soil erosion and landscape changes, it deviated, carrying its waters to the Aral. Together with it, the Amu Darya filled the Syrykamysh depression, forming a large bitter-salty lake. It was located between the Aral and Caspian seas. When the depression overflowed, water poured out of it into the Caspian, forming a natural outflow - the now dried-up branch of Uzboy.

At the very beginning of its inception Aral Sea fed by other rivers, such as Turgay, powerful tributaries of the Syr Darya: Zhanadarya and Kuandarya. The abundance of water resources has turned the Aral Sea into one of largest lakes in the world, but not for long.

Aral in the works and maps of scientists of the ancient world

Famous historians and travelers Ancient Greece and Rome in their treatises have repeatedly mentioned the Aral Sea. Some descriptions can be considered controversial and contradictory. An important fact one thing remains: in ancient times, the Aral Sea was known and did not just exist as an internal water resource, but was a significant center of the ancient world.

Great ancient historians such as Hecateus of Miletus, Herodotus, Aristotle, Erastofen did not know about the Aral Sea. But they were well aware of the existence of the Caspian Sea. It was Herodotus in the 5th century BC. e. concluded, and quite rightly, that the Caspian or Hyrcanian Sea is cut off from big water an independent body of water, while on ancient maps it was depicted as connected with the oceans.

The Aral was first mentioned by historians of the late Hellenistic period. In the famous "Geography" of Strabo (I century AD) Aral Sea called Oxian or Oxian Lake. The name comes from the obsolete name of the Amudarya River - Oxus. Interestingly, a century later, the second great scientist-geographer Claudius Ptolemy, describing the Caspian Sea in detail, does not mention the Aral Sea at all. Meanwhile, the map compiled by him very accurately conveys the outlines of these two seas as if they had merged into one. The scientist, following Herodotus, wrote about him as one.

Aral Sea in medieval view

The first accurate descriptions and maps of the Aral Sea appear among Arab scientists since the 10th century. If ancient authors relied on the stories of merchants and navigators, theoretical calculations and legends, then medieval historians from the Arab countries relied on their own observations.

The tenth-century traveler and scholar Al-Istakhri was the first to describe in detail Aral Sea and mapped it out. He has it called the Khorezm Sea. Right here, between the water surface salt lake and the sands of the Karakum grew the ancient Khorezm civilization.

Interestingly, the Aral Sea as an independent sea does not appear on European medieval maps until the 16th century. According to the tradition originating from the “Geography” of Claudius Ptolemy, it continued to be depicted as merging with the Caspian for a long time.

In 1562, the world saw the famous Jenkinson's Map of Russia, compiled by an English merchant during his journey through Central Asia. It shows a certain Lake China (Kitaia), which originates from the Syr Darya River and flows into the Ob. Most likely, this is Aral Sea. Despite obvious inaccuracies, confused names and the absence of many objects that the traveler was unaware of, Jenkinson's map for a long time considered the most detailed guide for this region.

Mysteries of the Aral Sea

The absence of a large natural reservoir on the maps for many centuries still causes some bewilderment of scientists. As a rule, this is explained by the imperfection of knowledge of that time, however, other versions appear. One of possible causes- the confluence of the Aral Sea with the Caspian, as it was indicated by Herodotus. Perhaps, at some period, the high water of these two seas reached such proportions that the space between them was flooded. Another reason is the drying up of the sea, which has already taken place in its history.

Due to the constant processes of soil degradation and changes in the surface topography, the connection with the rivers was interrupted. The channels deviated, dried up, and were lost in the sands of the Karakum. As studies show at least twice in the twenty-four thousand years of its existence Aral Sea dwindled to almost complete extinction.

Today, archaeological excavations are underway on the surface. The mausoleum of Kedderi and the remains of settlements of the Khorezm culture of the 11th-14th centuries testify that the sea dried up during this period. Subsequently, the water level recovered, and the buildings were at a depth of 20 meters.

The rapid disappearance of the reservoir in the last 50 years can be both a consequence of technogenic factors, and the result of a changing climate and a natural cyclical phenomenon.

Why go to the Aral

Despite the sand and wind, poor ecology and the remains of a dying lake salted through and through, the Aral attracts travelers. Fans of wild recreation and harsh nature will like the snow-white Aralkum. The atmosphere of the desert is mesmerizing and seems to take you back millions of years. The earth before the beginning of time, and here it stops. People come here for the beauties of nature in order to get in touch with the tragedy and think about what unreasonable human intervention leads to.

Among the popular objects is the ship cemetery in the former port city of Muynak. Dozens of forgotten fishing schooners and cargo trawlers lie among the sands and salt marshes, gradually rusting and crumbling. The sea has long receded, the city is dying, and only the remains of ships blacken against the white background of the desert. It may seem that this is just a fantastic decoration for the film, but no - it is harsh reality modern Aral, very impressive.

For lovers of history, a trip to the site of excavations of the remains of the mausoleum and medieval settlements of Khorezm will be interesting. You should definitely include a visit to Nukus in the program. In the city itself there is a museum with a huge collection of decorative and applied arts of Central Asia. In the village of Khodjeyli near Nukus, the architectural ensemble of the Belaya Khanaka caravanserai, the remains of an ancient fortress, and the medieval mausoleums of the rulers of Khorezm have been preserved.

This article will talk about one of the corners of the earth, which has turned into a barren desert as a result of the mismanagement of agriculture by people. economic activity.

general information

Previously, the size of the Aral Sea was the fourth body of water in the world. The death of the Aral Sea was the result of excessive water withdrawal for irrigation of the vast agricultural lands of Kazakhstan and Uzbekistan. Everything that happens to the Aral Sea is an irreparable ecological catastrophe.

A little more about this and many other things related to this natural reservoir will be discussed later in the article.

It’s even scary to imagine, but the area of ​​the Aral Sea and its volume today are only a quarter and about 10% of the original values, respectively.

The meaning of the name of the sea

In this natural reservoir there are a considerable number of islands. In this regard, it was called Aral. From the language of the indigenous population of these places, this word is translated as "sea of ​​islands."

Aral Sea today: general characteristics, location

In fact, today it is drainless, salty, Its location is - central Asia, the territory of the borders of Uzbekistan and Kazakhstan. In connection with the change in the currents and the Amu Darya that feed the sea, since the middle of the 20th century there has been a huge loss of water volume with a corresponding decrease in their surface, which caused an ecological catastrophe of unimaginable proportions.

Back in 1960, the Big Aral Sea was indeed such. The surface of the water mirror was 53 meters above sea level, and total area was 68,000 square kilometers. It stretched for about 435 km from north to south and for 290 km from east to west. Its average depth reached 16 meters, and the most deep places- 69 meters.

The Aral Sea today is a drying lake that has shrunk in size. It has gone 100 km from its former coastline (for example, near the Uzbek city of Muynak).

Climate

The territory of the Aral Sea is characterized by continental with a large amplitude of temperature changes, with very hot summers and rather cold winters.

Insufficient rainfall (approximately 100 mm per year) slightly balances evaporation. The factors that determine the water balance are river water supply from existing rivers and evaporation, which used to be about the same.

About the reasons for the disappearance of the Aral Sea

In fact, over the past 50 years, the death of the Aral Sea has occurred. Since about 1960, the level of the surface of its waters began to decrease rapidly and systematically. This was led to the artificial unfolding of the currents and the Amu Darya in order to irrigate local fields. The authorities of the USSR began to transform the vast wastelands of Kazakhstan, Uzbekistan and Turkmenistan into beautiful cultivated fields.

Due to such large-scale actions, the amount of water entering the natural reservoir, began to decrease slowly. Since the 1980s, during periods summer months, two huge rivers began to dry up, not flowing to the sea, and the reservoir, deprived of these tributaries, began to shrink. The Aral Sea is in a deplorable state today (the photo below demonstrates this).

The sea naturally divided into 2 parts. Thus, two reservoirs were created: in the south, the Big Aral Sea (Great Aral); in the north - Small Aral. Salinity at the same time increased by 3 times compared with the 50s.

According to 1992 data, the total area of ​​both reservoirs decreased to 33.8 thousand square meters. km, and the level of the water surface decreased by 15 meters.

Of course, there were attempts by the governments of the Central Asian countries to arrange a water-saving policy. Agriculture in order to stabilize the level of the Aral Sea by releasing the volumes of river water. However, difficulties in coordinating decisions among Asian countries made it impossible to complete projects on this issue.

Thus, the Aral Sea was divided. Its depth has been greatly reduced. Over time, almost 3 separate small lakes were formed: the Big Aral (western and east lake) and the Small Aral.

According to scientists, by 2020 the southern part of the reservoir is also expected to disappear.

Consequences

The dried Aral Sea by the end of the 80s lost more than 1/2 of its volume. In this regard, the amount of salts and minerals sharply increased, which led to the extinction of the rich in the old days in this region fauna, especially many fish species.

The existing ports (in the north of Aralsk and in the south of Muynak) today are already many kilometers away from the line of the lake shore. Thus, the region was devastated.

In the 1960s, the total catch of fish reached 40 thousand tons, and in the mid-80s commercial fishing in the area ceased to exist. Thus, approximately 60,000 jobs were lost.

The most common inhabitant of the sea was adapted to life in salty sea water (it was introduced in the 1970s). It disappeared in the Greater Aral in 2003, since the salinity of the water began to reach values ​​of more than 70 g / l, which is almost 4 times more than in sea water, familiar to such fish.

The state in which the Aral Sea is today has led to the fact that there has been a strong climate change and an increase in temperature amplitude.

And navigation here stopped due to the retreat of water for many kilometers from the main ports of the Aral Sea.

In the process of lowering in both reservoirs, the groundwater level fell, respectively, and this, in turn, accelerated the inevitable process of desertification of the area.

Renaissance Island

Subject special attention and worries in the late 90s became about. Renaissance. In those days, only 10 km. water separated the islet from the mainland. The rapidly increasing accessibility of this island has become a particular problem, since in times cold war the site has been the focus of various research related to Union bioweapons.

Also, in addition to such studies, hundreds of tons of dangerous anthrax bacteria were buried on it. The unrest of scientists was due to the fact that in this way anthrax could spread again in areas inhabited by people. In 2001, Fr. Renaissance has already connected with the mainland from its southern side.

The Aral Sea (photo of a modern reservoir above) is in a terribly deplorable state. And the living conditions in the area began to deteriorate. For example, the inhabitants of Karakalpakstan, living in the territories located south of the Aral Sea, suffered the most.

Most of the open bottom of the lake is the cause of numerous dust storms, carrying toxic dust with salts and pesticides throughout the region. In connection with these phenomena, people living in the area where the so-called Great Aral Sea is located began to develop serious health problems, especially many cases of cancer of the larynx, kidney disease and anemia. And the infant mortality rate in this region is the highest in the world.

About flora and fauna

Already in the 1990s (in the middle), instead of the greenery of lush trees, grasses and shrubs, only rare bunches of plants (xerophytes and halophytes) were seen on the former magnificent seashores, somehow adapted to dry and highly saline soils.

Also, only 1/2 of the local species of birds and mammals have survived here due to climate change within 100 km from the original coastline (a strong change in temperature and air humidity).

Conclusion

The catastrophic ecological state that the once large Big Aral Sea has today brings a lot of trouble to distant regions.

Surprisingly, dust from the areas of the Aral Sea has been found even on the glaciers of Antarctica. And this is evidence that the disappearance of this area had a strong impact on global ecosystem. It should be thought about the fact that humanity should conduct its life activities deliberately, without causing such catastrophic harm. environment that gives life to all living things.

The Aral Sea is unique lake(sea) in Central Asia. Aral Sea - Aral ... This word, which has come down to us from ancient times, means "island". The sea and suddenly - the island! Isn't it strange? But remember, by the way, that the most precious lands were called "islands" in Rus'.

The Aral Sea - the story of death

The biosphere is a very vulnerable shell of the Earth. If certain ties are broken, then only yesterday the fertile spaces turn into a desert.

The Aral Sea was fed by the Amudarya and Syrdarya rivers. Now all this is in the past. These great rivers, which are among the 34 largest water arteries peace, they do not reach the Aral Sea today.

The death of the Aral Sea - a conscious work of human hands - is put in second place among the world's environmental disasters (after the threat of destruction rainforest in the Amazon basin). But the consequences of the disappearance of the sea for the vast Central Asian region, and not only for it, can hardly be called anything other than a comparable catastrophe. First of all, because the question is raised about the very existence of people inhabiting this region.

Water inflow to the Aral Sea, until the 1960s balanced by evaporation (about 65 km3/year), in Lately ranged from zero to 20 km3/year. The main reason is the increase in water consumption for irrigation, for new, imperfect irrigation systems and reservoirs, which parse and evaporate water on the way to the sea. As a result, the level of the Aral Sea has now decreased compared to the level of 1957. (then the absolute mark was 54m) by more than 14m.

Its area has decreased from 66.5 thousand km2 to about 36 thousand km2, the volume of water has decreased from 1000 km3 to almost 320 km3. During this time, water salinity increased from 8-14 g/l to 25-50 g/l. The shoal separating the Aral into Small (Northern) and Large has completely left the water. The Syr Darya has changed its course and now flows not into the Big Aral, as before, but to the north, into the Small Aral. The meridional ridge dividing the Big Aral into eastern and western parts was largely exposed. The drained former bottom of the sea is a desert. freshwater fish, whose production used to be more than 40 thousand tons per year, has practically disappeared. Due to the high salinity, animals cannot drink water.

The area of ​​the exposed bottom is approximately 3 million hectares. And these lifeless spaces covered with salty sand are expanding. Salt dust storms have become common in the Aral Sea region. Every year, according to the laboratory of space monitoring, about 72 million tons of salt are carried away by the wind outside the Aral Sea region. It carries this caustic dust in a southerly direction up to 500 km, in the east - to the Yangieg region of Uzbekistan, which is near Tashkent, it settles both in the Tien Shan and in the Pamirs, where the Amu Darya and Syr Darya originate. But their water is used by millions of people living in Turkmenistan, Kazakhstan, Tajikistan, Uzbekistan.

Aral Sea - forecasts for the future

Based on the above facts, it is not difficult to imagine what will happen in the future. After all, today total salts falling on the soil surface in the Aral Sea region during the year reached an average of 520 kg per ha. This was one of the reasons for soil degradation here, and in Karakalpakstan, Kyzyl-Orda and Tashauz regions, the most difficult situation has developed for people's health.

Scientists foresters, having examined the exposed bottom of the Aral Sea, came to the conclusion that it is possible to grow a forest on soils of light composition, to carry out extensive phytomelioration. Experience in fixing sands has been accumulated at the Institute of Deserts of the Academy of Sciences of Turkmenistan. The fundamental possibility of its forest reclamation development by sowing and planting desert species of trees - saxaul, kandym, cherkez - has been established. The first landings have been made. Now birds and reptiles settle in these green islands, a new ecosystem has arisen with its own biogeocenosis.

Recommendations on forest reclamation development of the southern part of the drained Aral Seabed have also been published. A project was developed for fixing moving sands and planting seedlings of desert plant species on 326 hectares of the former bottom of the Rybatsky Bay. We also started studying technologies for creating protective plantings. Four years later, up to a thousand plants took root on one hectare of land, and even more in some areas.

The bushes have already reached a height of two meters, developed dense crowns, bloomed and bore fruit. And this means that self-seeding will soon begin forest species and their number will reach 3 thousand per hectare. Such a process is observed on the drained bottom of the former Muynak and Rybatsky bays.

A new generation of desert plants will completely fix the top layer of soil in a given area, protect it from being blown away by the wind. At the same time, it should be noted that the created crops formed a significant reserve of green mass 4-5 centners per 1 ha in 2-3 years.

At the age of five, this stock has already reached more than 7-10 centners per 1 ha. Without human help, such self-overgrowth would take many years.

The shifting sands do not wait. The desert, if not stopped in time, quickly begins to increase its borders. Creation of protective forest plantations - the only way block the way to sand and dust storms.

Academician A. S. Berg, in his book “The Aral Sea”, written at the beginning of the century, warned that if a reservoir dries up, a layer of salt forms on its bottom. The local winds are strong, the salt will rise up and settle for many hundreds of kilometers from the Aral Sea, including on the Pamir glaciers, where the rivers that feed the sea begin. A disaster will begin. And so it happened.

How to save the Aral Sea

At present, the water level in the Aral can stabilize only if the inflow into the sea increases to 30-35 km3 per year, i.e., to the level of evaporation from the new area of ​​the sea.

Changing the size of the Aral Sea. Some scientists propose to return to the Aral Sea drainage water that flows from the fields after irrigation or soil washing. Their runoff can reach a total of 10 km3. Collector canals laid to the right and left of the Amu Darya channel will carry from its middle course these water flows withdrawn from reservoirs like Syrkamysh Lake, which was born due to drainage waters.

It is quite easy to imagine that in the very near future it will be difficult to distinguish the Aral water from the water of Sarykamysh in terms of composition. The concentration of salts in Sarykamysh is 2.5 times higher than in the Aral Sea, and the water there is much more poisonous. 5 km3 of waste water to replenish the Aral Sea must travel almost a thousand kilometers along each of the collectors. How much water will reach the sea?

What part of it will be absorbed by natural filtration into the soil? The largest in Central Asia, the Karakum Canal loses to filtration, according to various estimates, from 18 to 47% of the portable volume of water. This is what caused the formation of salt marshes in the desert and flooding of the soil in the Ashgabat region.

If this project is implemented, the Aral Sea will never receive this even untreated water, it will spread across the desert and turn into a "poisonous evaporator".

According to the most conservative estimates of specialists, taking into account the true efficiency of the systems, from 35 to 40 km3 of water is annually lost to filtration and evaporation in the irrigated areas of the Syrdarya and Amudarya basins, which is almost half of the total river flow. According to various estimates, from 5 to 10 km3 of collector-drainage water flows into various depressions and depressions in the middle of the desert, 5 km3 evaporates from the surface of man-made reservoirs.

These reservoirs have already flooded hundreds of thousands of fertile hectares, the lack of which is so sad for other masterminds of the recent massive attack on the desert. Let us take the lower limits of the given estimates. It turns out that at least 45 km3 of water goes anywhere, but not to the Aral Sea.

Watch a video about the Aral Sea:

The Aral Sea will be saved:

ARAL SEA, Aral (Turk. "Aral" - an island; the original name of the area at the mouth of the Amu Darya River, and then the entire lake), a large drainless salty reservoir with characteristic sea and lake features, in the Turan lowland, in Kazakhstan and Uzbekistan. The Aral Sea depression was formed as a result of a deflection earth's crust in the Upper Pliocene. His age is ca. 140 thousand years. The outlines changed quite significantly as a result of climatic fluctuations, economic activity in its basin, migration of the channels of the main rivers flowing into the sea - the Syr Darya and, especially, the Amu Darya. In the Quaternary, the Amu Darya ended its course alternately either in the Sarykamysh depression, not reaching the Aral Sea, or in the Aral Basin. Accordingly, the Aral Sea either grew shallow or increased in size. Over the past 4–6 thousand years, the amplitude of sea oscillations was more than 20 m. The great medieval regression occurred 400–800 years ago, when the level dropped to 31 m. The remains of saxaul thickets, ancient settlements, and the Kerderi mausoleum were found on the shallow bottom of the Aral Sea. All R. 20th century sea ​​level was relatively stable (minor fluctuations around 53 m). The Aral Sea was the fourth largest lake in the world. At this level, the area was 66.6 thousand km 2, volume 1068 km 3, maximum length 428 km, width 235 km, maximum depth 69 m (with an average depth of 16 m and prevailing depths of 20–25 m), average water salinity 10 -12‰. The water of the Aral Sea was distinguished by high transparency, especially in its central and western parts, far from the mouths of the Amudarya and Syrdarya, the water of which is characterized by increased turbidity. The color of the water in the center of the sea was blue, and off the coast it was greenish. The water was characterized by an alkaline reaction - the pH value was 8.2–8.4. IN chemical composition water was dominated by sulfate and carbonate with a relatively small amount of chloride ions. The water was characterized by a low content of the main biogenic elements, and according to the trophic level, the reservoir was characterized as mesotrophic. In the Aral Sea to Ser. 20th century lived approx. 20 species of fish (thorn, bream, carp, roach, pike perch, etc.). In the 1950s–60s. 13 more species of fish were introduced. There were more than a thousand islands in the sea, the largest of which are Kokaral, Barsakelmes, Lazareva, Vozrozhdenie. In the south, the Akpetka archipelago was located, which is a flooded sea ​​waters sand dunes of the Kyzylkum desert. The northern coast is high in some places, low in some places, was indented by bays, the eastern one is low-lying, sandy with big amount small islands and bays; The average air temperature in summer is 24–26 °С, in winter from –7 to –13.5 °С. The water temperature of the surface layer in summer is 28–30 °C. In winter, the northeastern and northern parts of the sea usually freeze. The input part of the water balance (64–65 km 3 /year) was mainly (about 90%) the river runoff of the Amudarya and Syrdarya. To share precipitation and a small influx of groundwater accounted for slightly more than 10%. The runoff of the Amudarya averaged 44–46 km 3 /year, the flow of the Syrdarya was approx. 10 km 3 / year.

From the beginning 1960s the relative stability of the state of the sea, supported by the inflow of the Amu Darya and Syr Darya waters, was disturbed, mainly due to the rapid increase in water withdrawals, mainly for irrigation needs. From 1960 to 2000, the area of ​​irrigated land in the Aral Sea basin increased from 4.5 to 8 million hectares. The total water intake accordingly increased from 60 to more than 100 km 3 /year. Prior to this, water withdrawal also increased, but the increase in irrigated lands was mainly due to tugai thickets along the rivers, which evaporate a lot of water, and as a result, the river flow changed little. Water intake began to significantly affect the flow of rivers, as soon as from the middle. 20th century irrigation began, often with an excess amount of water, of desert foothill areas remote from rivers, from where only a small part (10–20%) of the withdrawn water returned to the rivers in the form of collector-drainage water from irrigation systems. These waters, saturated with fertilizers and pesticides leached from agricultural fields, made up the bulk of the sharply reduced river inflow into the Aral Sea, which in some years approached zero not only due to water withdrawal, but also due to natural low water, determined by climatic conditions. According to most researchers, a 20% decrease in inflow to the Aral Sea is due to climate change, and 80% to anthropogenic factors.

During the period 1961–89, the sea level decreased by more than 14 m, the area of ​​​​the water area decreased by 2 times, and the volume - by 3 times. In 1988–89, at a mark of 39 m, the Aral Sea divided into two independent bodies of water - the Big Sea (Great Aral, southern Aral, the Aral Sea itself), fed by the waters of the Amu Darya, and the Small Sea (Small Aral, northern Aral), fed by the waters of the Syr Darya. The area of ​​the Big Aral at its separation was 33.5 thousand km 2, and the Small Aral - approx. 3 thousand km 2. During 1989–2000, the volume of water decreased from 329 to 175 km 3, the area decreased from 36.4 to 24.4 thousand km 2, the level decreased from 39.1 to 34.0 m (see table). The coastline has receded former position in many cases for tens of kilometers (see map). The salinity of the water increased from 29 to 46–59‰. Subsequently, the drying of the sea continued (see table). At a mark of 29 m, the Big Aral was divided into eastern and western parts, and now it has turned into a group of several reservoirs with water salinity in some of them exceeding 200‰.

The shrinkage of the Aral Sea in recent decades has occurred mainly due to the Large Aral, mainly due to the fact that the Small Aral was separated from the Large Aral by a dam. The dam, built in 1994, was washed away in 1999 during a spring storm, but in 2003-05 a more powerful Kokaral earthen dam 13 km long, 6 m high, 100-150 m wide was erected. surplus water to the Big Aral. Due to this, the flow of the Syr Darya accumulates in the Small Aral. By 2008, the water level in it had risen to 42 m, the salinity had decreased to 10–13‰, which made it possible to begin the restoration of the fishery.

Changing parameters of the Aral Sea

In general, the drying up of the Aral Sea is one of the largest environmental disasters of the 2nd half. 20 - early. 21st century, which had an extremely negative impact on the economy of the region. If in ser. 20th century 30-50 thousand tons of fish were caught in the sea, then by the beginning. 1990s it has completely lost its fishery significance. A significant part of the population has lost their jobs. In the beginning. 21st century fish have completely disappeared in most of the Aral Sea. Fishing is now carried out only in the Small Aral. In 2007 the catch was approx. 2 thousand tons and tends to grow. Shipping stopped. The remains of ships can be seen tens of kilometers from the shores of the Big Aral - on the dry bottom of the sea, which has turned into a desert with vast salt marshes and highly saline lands. The dried part of the seabed became the source of the emergence of large dust storms and wind removal (over 100 thousand tons annually) of salt mixed with various chemicals and poisons, adversely affecting all living things at a distance of up to 500 km. The drying up of the sea affected the climate of the region immediately adjacent to the former water area of ​​the sea (at a distance of up to 100 km from the former coastline), which became more continental: summers became drier and hotter, winters colder and longer.

Economic losses associated with the drying up of the Aral Sea are estimated at several hundred million to several billion US dollars annually.

In the near future, the Great Aral Sea is threatened with complete disappearance, unless the states in its basin take measures to reduce water withdrawal by modernizing the existing irrigation system, switching to less water-consuming irrigation methods and cultivating less moisture-loving crops, transferring part of the production from irrigated lands to non-irrigated ones. It is also important to streamline the use of fertilizers and pesticides. These measures would make it possible to maintain in an acceptable ecological state, if not the entire Big Aral, then water bodies and adjacent ecosystems at the mouth of the Amu Darya.

The fate of the Small Aral is more optimistic. To keep it up ecological state only 2.5 km 3 /year of pure Syrdarya water is needed. But in the Syr Darya basin, measures to save water and improve its quality are very relevant.

The expected warming of the climate, leading to a decrease in the stock of snow and ice in mountainous areas the Aral Sea basin, the main source of water for the Amudarya and Syrdarya.