The Aral Sea before drying up. The main reasons for the drying up of the Aral Sea? Changing parameters of the Aral Sea

Notorious Aral Sea, or rather, what is left of it is located in western Asia, between Uzbekistan and Kazakhstan. Once a huge and living body of water with large stocks of fish and its own microclimate, at the end of the 20th century the Aral Sea turned into a dozen small, half-dead lakes, as a result of the Soviet experiment to turn Uzbek rivers south to grow cotton. The Kazakh authorities are trying to preserve the remnants of the Aral Sea, but their Uzbek comrades are in no hurry to turn the rivers back, since water from the Syr Darya and Amu Darya rivers still feeds their cotton plantations.

Coordinates: 44.9784775 northern latitude, 58.4369659 east longitude



Aral Sea on the map, which can be controlled (scaled and moved)



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The Aral Sea is an endorheic salt lake in Central Asia, on the border of Kazakhstan and Uzbekistan. Since the 1960s of the 20th century, sea level (and the volume of water in it) has been rapidly declining due to water withdrawal from the main feeding rivers Amu Darya and Syr Darya. Before the start of shallowing, the Aral Sea was the fourth largest lake in the world.

Excessive water withdrawal for agricultural irrigation has turned the world's fourth largest lake-sea, once rich in life, into a barren desert. What is happening to the Aral Sea is a real environmental disaster, the blame for which lies with the Soviet government. Currently, the drying Aral Sea has moved 100 km from its former coastline near the city of Muynak in Uzbekistan

Almost the entire influx of water into the Aral Sea is provided by the Amu Darya and Syr Darya rivers. Over the course of thousands of years, it happened that the channel of the Amu Darya went away from the Aral Sea (towards the Caspian Sea), causing a decrease in the size of the Aral Sea. However, with the return of the river, the Aral was invariably restored to its former boundaries. Today, intensive irrigation of cotton and rice fields consumes a significant part of the flow of these two rivers, which sharply reduces the flow of water into their deltas and, accordingly, into the sea itself. Precipitation in the form of rain and snow, as well as underground springs, provide the Aral Sea with much less water than is lost through evaporation, as a result of which the water volume of the lake-sea decreases and the level of salinity increases.

In the Soviet Union, the deteriorating condition of the Aral Sea was hidden for decades, until 1985, when M.S. Gorbachev made this environmental disaster public. At the end of the 1980s. The water level dropped so much that the entire sea was divided into two parts: the northern Small Aral and the southern Great Aral. By 2007, the deep western and shallow eastern reservoirs, as well as the remains of a small separate bay, were clearly visible in the southern part. The volume of the Greater Aral Sea decreased from 708 to only 75 km3, and the salinity of the water increased from 14 to more than 100 g/l, this is quite enough to explain. With the collapse of the USSR in 1991, the Aral Sea was divided between the newly formed states: Kazakhstan and Uzbekistan. Thus, the grandiose Soviet plan to transfer the waters of distant Siberian rivers here was put to an end, and competition for the possession of melting water resources began. One can only be glad that it was not possible to complete the project to transfer the rivers of Siberia, because it is unknown what disasters would have followed this.

Collector-drainage waters flowing from the fields into the bed of the Syrdarya and Amu Darya have caused deposits of pesticides and various other agricultural pesticides, appearing in places over 54 thousand km? former seabed covered with salt. Dust storms carry salt, dust and toxic chemicals up to 500 km. Sodium bicarbonate, sodium chloride and sodium sulfate are airborne and destroy or retard the development of natural vegetation and crops. The local population suffers from a high prevalence of respiratory diseases, anemia, cancer of the larynx and esophagus, and digestive disorders. Liver and kidney diseases and eye diseases have become more frequent.

The drying up of the Aral Sea had dire consequences. Due to a sharp decrease in river flow, spring floods, which supplied the floodplains of the lower reaches of the Amu Darya and Syr Darya with fresh water and fertile sediments, ceased. The number of fish species living here decreased from 32 to 6 - the result of an increase in water salinity, loss of spawning grounds and feeding areas (which were preserved mainly only in river deltas). If in 1960 the fish catch reached 40 thousand tons, then by the mid-1980s. local commercial fishing simply ceased to exist, and more than 60,000 associated jobs were lost. The most common inhabitant remained the Black Sea flounder, adapted to life in salty sea water and brought here back in the 1970s. However, by 2003, it also disappeared in the Greater Aral, unable to withstand water salinity of more than 70 g/l - 2–4 times more than in its usual marine environment.

Shipping on the Aral Sea has stopped because... The waters have receded many kilometers from the main local ports: the city of Aralsk in the north and the city of Muynak in the south. And maintaining ever longer channels to ports in navigable condition turned out to be too expensive. As the water level dropped in both parts of the Aral Sea, the groundwater level also dropped, which accelerated the process of desertification of the area. By the mid-1990s. Instead of lush green trees, shrubs and grasses, on the former seashores only rare bunches of halophytes and xerophytes were visible - plants adapted to saline soils and dry habitats. However, only half of the local species of mammals and birds have survived. Within 100 km from the original coastline, the climate changed: it became hotter in summer and colder in winter, the level of air humidity decreased (the amount of precipitation decreased accordingly), the duration of the growing season decreased, and droughts began to occur more often

Despite its vast drainage basin, the Aral Sea receives almost no water due to irrigation canals, which, as the photo below shows, take water from the Amu Darya and Syr Darya along hundreds of kilometers of their flow across several states. Other consequences include the extinction of many species of animals and plants.

However, if we look at the history of the Aral Sea, the sea has already dried up, while returning to its former shores. So, what was the Aral like over the past few centuries and how did its size change?

During the historical era, significant fluctuations in the level of the Aral Sea occurred. Thus, on the retreated bottom, the remains of trees that grew in this place were discovered. In the middle of the Cenozoic era (21 million years ago), the Aral was connected to the Caspian Sea. Until 1573, the Amu Darya flowed along the Uzboy branch into the Caspian Sea, and the Turgai River into the Aral. The map compiled by the Greek scientist Claudius Ptolemy (1800 years ago) shows the Aral and Caspian seas, the Zarafshan and Amu Darya rivers flow into the Caspian. At the end of the 16th and beginning of the 17th centuries, due to lowering sea levels, the islands of Barsakelmes, Kaskakulan, Kozzhetpes, Uyaly, Biyiktau, and Vozrozhdeniya were formed. Since 1819, the Zhanadarya and Kuandarya rivers have stopped flowing into the Aral since 1823. From the beginning of systematic observations (19th century) until the middle of the 20th century, the level of the Aral Sea remained virtually unchanged. In the 1950s, the Aral Sea was the fourth largest lake in the world, occupying about 68 thousand square kilometers; its length was 426 km, width - 284 km, greatest depth - 68 m.

In the 1930s, large-scale construction of irrigation canals began in Central Asia, which especially intensified in the early 1960s. Since the 1960s, the sea began to become shallow due to the fact that the water of the rivers flowing into it was diverted in ever-increasing volumes for irrigation. From 1960 to 1990, the area of ​​irrigated land in Central Asia increased from 4.5 million to 7 million hectares. Have the region's national economy's water needs increased from 60 to 120 km? per year, of which 90% comes from irrigation. Since 1961, sea level has dropped at an increasing rate from 20 to 80-90 cm/year. Until the 1970s, 34 species of fish lived in the Aral Sea, more than 20 of which were of commercial importance. In 1946, 23 thousand tons of fish were caught in the Aral Sea; in the 1980s, this figure reached 60 thousand tons. On the Kazakh part of the Aral there were 5 fish factories, 1 fish canning plant, 45 fish receiving points, on the Uzbek part (Republic of Karakalpakstan) - 5 fish factories, 1 fish canning plant, more than 20 fish receiving points.

In 1989, the sea split into two isolated bodies of water - the Northern (Small) and Southern (Big) Aral Sea. As of 2003, the surface area of ​​the Aral Sea is about a quarter of the original, and the volume of water is about 10%. By the early 2000s, the absolute water level in the sea had dropped to 31 m, which is 22 m below the initial level observed in the late 1950s. Fishing was preserved only in the Small Aral, and in the Large Aral, due to its high salinity, all the fish died. In 2001, the South Aral Sea was divided into western and eastern parts. In 2008, geological exploration work (search for oil and gas fields) was carried out on the Uzbek part of the sea. The contractor is the PetroAlliance company, the customer is the government of Uzbekistan. In the summer of 2009, the eastern part of the Southern (Great) Aral Sea dried up.

The retreating sea left behind 54 thousand km2 of dry seabed, covered with salt, and in some places also with deposits of pesticides and various other agricultural pesticides that were once washed away by runoff from local fields. Currently, strong storms carry salt, dust and toxic chemicals up to 500 km away. Northern and northeastern winds have an adverse effect on the delta of the Amu Darya River located to the south - the most densely populated, most economically and environmentally important part of the entire region. Airborne sodium bicarbonate, sodium chloride and sodium sulfate destroy or slow down the development of natural vegetation and crops - in a bitter irony, it was the irrigation of these crop fields that brought the Aral Sea to its current deplorable state.

According to medical experts, the local population suffers from a high prevalence of respiratory diseases, anemia, cancer of the throat and esophagus, as well as digestive disorders. Liver and kidney diseases have become more frequent, not to mention eye diseases.

Another, very unusual problem is associated with Renaissance Island. When it was far out at sea, the Soviet Union used it as a biological weapons testing site. The causative agents of anthrax, tularemia, brucellosis, plague, typhoid, smallpox, as well as botulinum toxin were tested here on horses, monkeys, sheep, donkeys and other laboratory animals. In 2001, as a result of the withdrawal of water, Vozrozhdenie Island connected with the mainland on the southern side. Doctors fear that dangerous microorganisms have remained viable, and infected rodents can spread them to other regions. In addition, dangerous substances may fall into the hands of terrorists. Waste and pesticides that were once thrown into the waters of the Aralsk harbor are now in plain sight. Severe storms carry toxic substances, as well as huge amounts of sand and salt, throughout the region, destroying crops and harming human health. You can read more about Vozrozhdeniya Island in the article: The most terrible islands in the world

Restoring the entire Aral Sea is impossible. This would require a fourfold increase in the annual inflow of water from the Amu Darya and Syr Darya compared to the current average of 13 km3. The only possible remedy would be to reduce irrigation of fields, which consumes 92% of water intake. However, four of the five former Soviet republics in the Aral Sea basin (with the exception of Kazakhstan) intend to increase irrigation of farmland - mainly to feed growing populations.

In this situation, a transition to less moisture-loving crops would help, for example replacing cotton with winter wheat, but the two main water-consuming countries in the region - Uzbekistan and Turkmenistan - intend to continue to grow cotton for sale abroad. It would also be possible to significantly improve the existing irrigation canals: many of them are ordinary trenches, through the walls of which a huge amount of water seeps and goes into the sand. Modernizing the entire irrigation system would save about 12 km3 of water annually, but would cost $16 billion.

As part of the project “Regulation of the bed of the Syrdarya River and the Northern Aral Sea” (RRSSAM), in 2003-2005, Kazakhstan built the Kokaral dam with a hydraulic gate (which allows the passage of excess water to regulate the level of the reservoir) from the Kokaral Peninsula to the mouth of the Syrdarya, which fenced off the Small Aral from the rest of the (Greater Aral). Thanks to this, the flow of the Syr Darya accumulates in the Small Aral, the water level here has increased to 42 m abs., the salinity has decreased, which makes it possible to breed some commercial varieties of fish here. In 2007, the fish catch in the Small Aral amounted to 1910 tons, of which flounder accounted for 640 tons, the rest were freshwater species (carp, asp, pike perch, bream, catfish).

It is expected that by 2012 the fish catch in the Small Aral will reach 10 thousand tons (in the 1980s, about 60 thousand tons were caught in the entire Aral Sea). The length of the Kokaral dam is 17 km, height 6 m, width 300 m. The cost of the first phase of the RRSSAM project amounted to $85.79 million ($65.5 million comes from a World Bank loan, the rest of the funds are allocated from the republican budget of Kazakhstan). It is expected that an area of ​​870 square km will be covered with water, and this will allow the flora and fauna of the Aral Sea region to be restored. In Aralsk, the Kambala Balyk fish processing plant (capacity 300 tons per year), located on the site of a former bakery, now operates. In 2008, it is planned to open two fish processing plants in the Aral region: Atameken Holding (design capacity 8,000 tons per year) in Aralsk and Kambash Balyk (250 tons per year) in Kamyshlybash.

Fishing is also developing in the Syrdarya delta. On the Syrdarya-Karaozek channel, a new hydraulic structure with a throughput capacity of more than 300 cubic meters of water per second (Aklak hydroelectric complex) was built, which made it possible to irrigate lake systems holding more than one and a half billion cubic meters of water. As of 2008, the total area of ​​lakes is more than 50 thousand hectares (it is expected to increase to 80 thousand hectares), the number of lakes in the region has increased from 130 to 213. As part of the implementation of the second phase of the RRSSAM project in 2010-2015, it is planned to build a dam with a hydroelectric complex in the northern part of the Small Aral, separate the Saryshyganak Bay and fill it with water through a specially dug canal from the mouth of the Syr Darya, bringing the water level in it to 46 m abs. It is planned to build a shipping canal from the bay to the port of Aralsk (the width of the canal along the bottom will be 100 m, length 23 km). To ensure transport links between Aralsk and the complex of structures in Saryshyganak Bay, the project provides for the construction of a category V highway with a length of about 50 km and a width of 8 m parallel to the former coastline of the Aral Sea.

The sad fate of the Aral Sea is beginning to be repeated by other large bodies of water in the world - primarily Lake Chad in Central Africa and Lake Salton Sea in the south of the American state of California. Dead tilapia fish litter the shores, and due to excessive water extraction for irrigating fields, the water is becoming increasingly salty. Various plans are being considered to desalinate this lake. As a result of the rapid development of irrigation since the 1960s. Lake Chad in Africa has shrunk to 1/10 of its former size. Farmers, shepherds and local people from the four countries surrounding the lake often fight fiercely for the remaining water (bottom right, blue), and the lake is now only 1.5 m deep. Experiences of loss and then partial restoration of the Aral Sea can benefit everyone.
Pictured is Lake Chad in 1972 and 2008

The Aral Sea was once the fourth largest lake in the world and provided the region's economy with thousands of tons of fish every year. However, it has been steadily drying up since the 1960s.

In the 1920s, the Soviet Union converted the lands of the Uzbek SSR into cotton plantations and ordered the construction of irrigation canals to provide water for crops in the region's mid-plateau.

These manual irrigation canals took water from the Amu Darya and Syr Darya rivers, which fed the freshwater Aral Sea.

Until the 1960s, the Aral Sea canal and river system was fairly stable. However, in the 1960s, the Soviet Union decided to expand the canal system and drain more water from the rivers feeding the lake.

Destruction of the Aral Sea

Aral Sea: 2014 on the left and 2000 on the right. The thin black line shows the boundaries of the lake in 1960.

Thus, in the 1960s, the Aral Sea began to shrink rapidly. By 1987, it was divided into two parts: northern and southern lakes. In 2002, the southern lake shrank and split into eastern and western lakes. In 2014, the eastern lake completely evaporated and disappeared.

The Soviet Union considered cotton crops more valuable than the Aral Sea fisheries that had once been the mainstay of the regional economy. Today you can visit former coastal settlements and see long-abandoned piers, harbors and boats.

Before drying up, the Aral Sea provided between 20,000 and 40,000 tons of fish per year. At the height of the crisis, the catch fell by 1,000 tons of fish per year, but now everything is moving in a positive direction.

Restoration of the Northern Aral Sea region

In 1991, the Soviet Union collapsed, and Uzbekistan and Kazakhstan became home to the drying up Aral Sea. Since then, Kazakhstan has been working to revive the lake.

The first innovation that helped preserve part of the Aral Sea fishery was Kazakhstan's construction of the Kokaral Dam on the southern shore of the northern lake, thanks to support from the World Bank. The dam has ensured that the northern lake has grown by 20% since 2005.

The second innovation is the construction of a fish hatchery on the northern lake, where sturgeon, carp and flounder are grown and released into the Northern Aral Sea. The fish hatchery was built with Israeli support.

Predictions are that the northern Aral Sea lake could soon supply 10,000 to 12,000 tons of fish per year thanks to these two major innovations.

The future of the western lake is not so bright

However, with the flooding of the northern lake in 2005, the fate of the two southern lakes was all but sealed, and the autonomous Uzbek region of Karakalpakstan will experience negative consequences as the western lake continues to evaporate.

Soviet leaders considered the Aral Sea unnecessary, since the water that flowed into it evaporated into nowhere. Scientists believe that the Aral Sea was formed about 5.5 million years ago when geological uplift prevented two rivers from flowing further.

However, cotton continues to grow in the now independent country of Uzbekistan, which does not bode well for the remnants of the Aral Sea.

Ecological catastrophy

The huge dried lake is a source of pathogenic dust, which is carried by winds throughout the region. The dried remains of the lake contain not only salt and minerals, but also pesticides that were once used in huge quantities by the Soviet Union.

In addition, on one of the islands in the Aral Sea, the USSR set up a laboratory for testing biological weapons. Although it is now closed, there is a risk of deadly rodent infestations spreading to surrounding areas.

The Aral Sea is an endorheic salt lake located in Central Asia, or more precisely, on the border of Uzbekistan and Kazakhstan. Since the 60s of the last century, the sea, as well as its size, has decreased significantly. Why is the Aral Sea drying up? There are several main reasons. Scientists suggest that a similar phenomenon occurs as a result of water intake for various needs through the feeders and the Amu Darya.

The water is leaving

River flows

It has been proven that the boundaries of the Aral Sea have fluctuated over many centuries. The eastern part of this reservoir dried up for the first time not in our time. This lasted for 600 years. It all started with the fact that one of the branches of the Amu Darya began to direct its flows to Naturally, this led to the fact that the Aral Sea began to receive less water. The reservoir gradually began to decrease in size.

Where it leads

Now many people know where the Aral Sea is disappearing to. Why did the lake dry up? What is it paying for? The reservoir is shrinking. Where ships once drifted, you can see a sandy plateau that divided the water area into several parts: Small Sea - 21 km 3, Big Sea - 342 km 3. However, she didn’t stop there. Its scale continues to grow.

According to experts, in the near future the water level in the Great Sea will gradually decrease, which will lead to an increase in its salinity. In addition, certain species of marine animals and plants may disappear. In addition, the wind gradually carries salt from the drained areas. And this leads to a deterioration in soil composition.

Is it possible to stop?

The reasons why the Aral Sea is drying up have long been identified. However, no one is in a hurry to correct the consequences. After all, this requires a lot of effort, as well as financial costs. If wastewater continues to be discharged into the lake, it will simply turn into a septic tank, which will be unsuitable for agriculture. At the moment, all work should be aimed at recreating the natural boundaries of the reservoir.

Since the Aral Sea has not yet completely dried up, but only its eastern part, the strategy for saving it should be aimed at stabilizing the ecological system. It is necessary to restore her ability to self-regulate. First, you should repurpose the planting areas for other crops, for example, fruits or vegetables. They require less moisture. All efforts in this case should be directed to the main reasons that caused the drainage of the large salt lake. This is the only way to save the blue pearl

April 14, 2014 The process of shallowing and drying of the Aral Sea, once the fourth largest lake in the world, was noticed in the 80s of the last century. The reason for the degradation was a decrease in fresh water flows from the main water arteries feeding the Aral Sea - the Syrdarya and Amu Darya...

In the 60s, cotton growing and agriculture in general began to actively develop in the Central Asian republics of the USSR - Uzbekistan, Turkmenistan and southern Kazakhstan, for which water from the Syr Darya and Amu Darya began to be actively diverted through canals for reclamation and other needs. The largest such canal, the Karakum canal, 1,445 km long, laid from the Amu Darya to the Caspian Sea, takes about 45% of its water from the river.

In some years, the water level in the Aral Sea dropped by 0.7 m, and a huge area of ​​the former bottom turned into a lifeless desert. The Aral Sea is actually a salt lake; due to the decrease in the influx of fresh water, fish have almost disappeared in it, although previously its annual catch amounted to tens of thousands of tons. Numerous ports and fishing factories on the coast ceased operations. Winds carry a huge amount, about 150 tons, of sand mixed with pesticides and other chemicals used in cotton production from the dry bottom across the vast territory of Kazakhstan and Uzbekistan.

Currently, the area of ​​the Aral Sea is no more than a quarter of its original size; during shallowing, according to scientists, the lake has lost about one hundred cubic kilometers of water. The Aral Sea actually split into two separate bodies of water - the Big and Small Aral. The Aral Sea problem could be solved by reducing the area under cotton in the countries of Central Asia, but the economic and demographic situation in these countries does not yet allow even considering such a prospect.

 

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