Caspian Sea Basin: area, extent, rivers and coastal states

2024 Author: Henry Conors | [email protected]. Last modified: 2024-02-12 02:44

The Caspian Sea Basin is a huge and unique geographical feature. It has not yet been fully explored, so it is still of interest not only among tourists, but also among scientists. They say that once upon a time the Caspian Sea was even larger than it is now. At one time, the Aral Sea, which has now become very small, may have been a single system along with the Caspian Sea. But this is just a hypothesis. This article will discuss which basin the Caspian Sea belongs to, what are the environmental problems of this region and ways to solve them.

General information

The Caspian Sea is a huge water reservoir located within Central Asia. It is also considered the largest lake (although this is not geographically correct), but still it is a sea. It is the only inland sea on Earth. Millions of tourists come here every year. This reservoir is considered as a singleecosystem. Everyone asks the question: to which basin does the Caspian Sea belong? Answer: to the internal drainage basin. The fact is that it has no outlet to the World Ocean.

The reservoir has a huge amount of different resources, including minerals. Some unscrupulous people regularly extract minerals from here in unmeasured quantities, and also catch too many fish. Poaching can harm the ecosystem as a whole. To avoid this, environmentalists are trying by any means to influence the stop of this process.

Pool

The area of the internal runoff basin of the Caspian Sea is 392,000 square kilometers. The size is equal to two such states as Great Britain. Here are waters of high mineralization. The total volume is 78640 km³. The object itself is located at the crossroads of Europe and Asia and washes the coasts of countries such as:

Turkmenistan;
Kazakhstan;
Iran;
Azerbaijan;
Russia.

The sea has unique flora and fauna. Also, an oceanic type of earth crust was formed here. This is due to the fact that the current Caspian Sea is part of the very ancient Tethys Ocean, which included the basins of not only the Caspian, but the Aral and Black Seas with the Sea of Azov.

Relief

Caspian Sea basin which ocean does it belong to? Answer: this sea does not belong to any ocean, since it is an endorheic waterartery.

The Caspian Sea is a complex and specific body of water, which has individual characteristics. There is no such relief anywhere on earth. Despite the fact that now the area is 392 thousand km², it is still small, because about 90 years ago its area was even larger - as much as 422 thousand km.

In the north is the Caspian lowland, and in the south is Mount Elbrus. In the western part, you can see the Greater Caucasus, and in the southwest, the foothills of the Talysh Mountains and the Kura and Lankaran lowlands.

The length of the entire coastline is approximately 6500-6700 kilometers. The average depth is about six hundred meters.

There are ten small bays on the territory of the Caspian Sea. One of the most famous is Kara-Bogaz-Gol. It is a natural desalinator of the Caspian Sea. The water level in the Caspian was constantly falling, so it was decided to separate the Kara-Bogaz-Gol bay with a dam, as a result of which it completely dried up in three years and practically turned into a s alt desert. But then the s alt began to be carried by the winds and polluted the soil. As a result, many crops were damaged. After that, in 1984, it was decided to remove the dam and start up the waterworks, which helped to extract mineral s alt. To date, the bay has been almost completely restored, and the Caspian is again with a normal water level.

What is unique?

Here unique climatic features that are not found anywhere else on Earth. The sea is located within different climatic zones: continental - innorthern part, moderate - in the middle part and subtropical - in the southern part. Most of the reservoir is in a temperate climate. The average air temperature in winter is within ten degrees below zero. In summer, this figure is within thirty degrees of heat. The maximum heat of +44 degrees was recorded in the summer on the east coast.

This sea is considered a partially freezing body of water. Only the northern part of the Caspian freezes in winter. The average ice thickness here is from sixty to ninety centimeters. Freeze lasts from November to March. If winters are warm, then there may be no ice cover at all.

The main problem is sea level fluctuations. It is constantly changing up and down. Scientists say that this has been happening throughout the history of the existence of the reservoir. Now the level has stabilized for a while, but after a while it will change constantly again, which may cause problems for local residents.

Which ocean basin does the Caspian Sea belong to? The Caspian Sea is very sensitive to climate change as it does not belong to any of the oceans.

According to archeology and written sources, a high level of the Caspian Sea is recorded at the beginning of the 14th century. This confirms that the level of the Caspian changed periodically. The oscillation amplitude reaches fifteen meters. Precipitation, runoff and evaporation strongly influence the Caspian's annual water fluctuations.

Which rivers belong to the Caspian Sea basin?

As many as 130 flows into the Caspian Searec. Which are the largest rivers? The internal runoff basin of the Caspian Sea includes:

Better;
Kuma;
Volga;
Samug;
Sulak;
Ural;
Volga.

The largest river in Europe and at the same time the largest source of water for the Caspian Sea is the Volga. The river covers almost the entire European part of Russia. She herself is divided into 3 parts. It is the lower Volga that flows into the Caspian Sea. The river has about 150 thousand tributaries, which feed it a little. It delivers all this in transit to the Caspian Sea. Recall that most of the entire drainage of the Caspian Sea belongs to the Volga.

The tributaries of the Volga get most of their water from melting snow and rainfall. The water level in the river decreases significantly in summer and winter, and increases in spring and autumn.

Lower Volga freezes in December, and the other two parts - in November. Melt begins in March and April respectively.

Most of the drainage basin of the Caspian Sea belongs to the Volga. Other rivers have much less impact on the Caspian.

Scientists have found that such a huge number of large and not very rivers formed a powerful drainage basin of the Caspian Sea with an area of 3.5 million square kilometers.

As many as 80% of the Caspian's drainage comes from the Volga, Sudak, Terek and Emba. For example, the average annual runoff of the Volga is 215-224 cubic kilometers. The rivers of the Caspian Sea basin have a huge impact not only on the reservoir itself, but also on the climate of the region.

Urgentproblems

Due to the huge damage to the economy, which is provoked by fluctuations in the level of the Caspian Sea, all countries in this region are interested in this issue. When water fluctuations begin, then all sorts of entrepreneurs suffer enormous losses due to the elements.

When there is a shallowing, then the port cities are unable to receive important cargo, which disrupts millions of deals. In case of a sharp rise in water, agricultural land is flooded, and power lines are damaged or destroyed.

Despite its closeness, the Caspian Sea is quite well saturated with oxygen. The highest oxygen saturation is observed in winter on the territory of the Middle Caspian. Recently, there has been an increase in oxygen in the upper layers.

Plant and animal life

Despite the fact that the biological productivity of the Caspian Sea is quite high, it is still poorer in terms of species diversity compared to the Black Sea, although the water bodies are almost the same in area.

1809 species of animals live here, of which 415 are vertebrates. 101 species of fish are registered in the Caspian Sea, and most of the world's stocks of sturgeons are concentrated in it, as well as such freshwater fish as vobla, carp, pike perch. The pond is the habitat of such fish as carp, mullet, sprat, kutum, bream, salmon, perch, pike. The Caspian Sea is also inhabited by a marine mammal - the Caspian seal.

The flora of the Caspian Sea and its coast is represented by 728types. Of the plants in the Caspian Sea, algae predominate - blue-green, diatoms, red, brown, char and others, of flowering - zostera and ruppia.

A little about the relief

Northern Caspian. There are many petrified drying shallows in the Northern Caspian. The Ural furrow is located between the deltas of the Ural rivers and the Mangyshlak Bay. Its depth is from 5 to 8 meters. The bottom of the northern part is slightly inclined to the south. Also covered with sand and shell rock. The waters of the river, which filled the shallows, flooded the estuarine sections

A distinctive feature of the morphological structure is the presence of relic forms of banks, channels and river deltas. Many relict channels are located on the territory of the Northern Caspian.

There are very few islands in the Caspian Sea. There are unique seal islands here.

Most of the sea islands of the North Caspian are accumulative formations such as bars formed by waves on the periphery of the seabed.

Middle Caspian. The entire territory of the Middle Caspian up to the city of Makhachkala is considered lowland. But already in the direction of Baku, the narrow spurs of the Caucasus Mountains stretch. Abrasion and accumulative shores stretch in the region of Absheron and Dagestan

It is also dominated by abrasive shores, which are in limestone, and in structure resemble desert and semi-desert plateaus. A basin, a continental slope and a shelf have been recorded on the territory of the Middle Caspian. The average depth is 20 meters.

South Caspian. Mud volcanoes and tectonic uplifts -this is how the topography of the bottom and the shelf zone of the South Caspian looks like. The coasts of this part are very diverse. In the Baku region, spurs of the southeastern part of the Caucasus Mountains are observed. Further semi-deserts will be located. Numerous rivers can be observed near the territory of Iran

Hydrological regime

Since 1985, the observation program has been drastically reduced. This is due to the fact that it is almost impossible to find the true cause of the moisture deficit in the region. Meteorological information is completely absent in the region of the Iranian coast. Measurement accuracy is almost always low. Therefore, it is very difficult to explore the climate regime and the whole sea in general.

It's very difficult to establish patterns in research. This is because the timing of observations is constantly changing. For example, until 1968, observations at the station in Makhachkala were carried out 4 times a day, then 3, and then again four. The time of observations also changed periodically.

Ship observations are a good source of information. But they cannot be permanent, since they determine conditions only in those places where the routes of these ships pass.

Based on this information, we can conclude that now there is no way to study the intensity of evaporation in the Caspian Sea in more detail.

Environmental Issues

These problems are related to water pollution due to oil production and transportation. The unfavorable situation in the region was exacerbated by a sharp rise in the water level at the end of the 20th century. Complete flooding of individualsettlements led not only to the loss of food that grew on this land, but also to the fact that everything was contaminated with oil products. In addition, soil salinization has progressed. This provoked an increase in infectious diseases in the region.

The observation system was completely disrupted as the water level changed dramatically.

Also, the problem of sea pollution has become threatening, not only with oil products, but also with a large amount of garbage. This affected:

Changing the hydrological regime.
Change in the hydrochemical regime.
Natural and socio-economic indicators of the region and adjacent states.
Heavy metal pollution.

90% of pollution the sea received from the rivers that flow into the Caspian Sea. The reservoir receives the largest percentage of pollution from the Volga and other large rivers such as the Urals.

Water pollution is becoming a growing problem for the five states as the Caspian Sea has no outlet to the world's oceans. All these accumulations of garbage can provoke an ecological catastrophe not only in the Caspian Sea, but also in the internal drainage basin of the Caspian Sea.

Ways to solve problems

Caspian problems were aggravated by a number of reasons:

The water has risen by as much as 2.5 meters since 1978-1995, which is a lot for such a short period of time.
The ecosystem of the Caspian region is now experiencing great degradation and destruction.
Insufficient funds allocated to deal with the consequences.

Physical geographicFeatures

The Caspian Sea is located 28 meters below the level of the World Ocean. It is the largest closed reservoir in the world and has about 130 small rivers belonging to the area of the basin of the internal flow of the Caspian Sea. The reservoir is called the sea because of its enormous size, although it is still considered a lake in its structure and location.

Multi-year fluctuations smooth out the Kara-Bogaz-Gol Bay, which was mentioned earlier in the article. Also Dead Kultuk and Kaydak also regulate and restrain sea level fluctuations. These shallow waters evaporate and dry up during the hot season, and fill their reservoirs during the rainy season.

The average depth of the sea is 4-8 meters, and the maximum is 1025 meters (in the South Caspian depression). The depth of 2 meters is reached in the area of the continental shelf. Shallow waters here make up 28% of the area, and continental shallows 69%.

The entire basin of the Caspian Sea from 130 rivers receives about 300 km3 of water per year. Sulak, Terek, Ural and Volga supply about 90% of all water, as mentioned above. In addition, 2600 rivers flow into the Volga itself.

The total area of the Caspian Sea basin is 1380 km². This refers to the catchment area.

Precipitation

Precipitation also strongly influences the formation of the Caspian Basin. Since the sea is located in different time and climatic zones, the indicators at two different stations in two years can differ greatly from each other.

The Caspian precipitation regime directly depends on the interaction of various air masses that pass along thisterritory. Precipitation is unevenly distributed over the area. The largest number of them falls in the region of humid subtropics in Iran. Scientists estimate about 1700 millimeters per year. This is the territory of the Lankaran lowland.

In the area of the settlement of Neftyanye Kamni, the minimum amount of precipitation was recorded - 110 mm per year.

Many are wondering: which ocean basin does the Caspian Sea belong to? This neutral object, which is both a lake and a sea at the same time, does not belong to any of the ocean basins.

Most of the year, warm air masses come to the Caspian Sea. The average amount of precipitation that falls on the water table is 180 mm per year, and about 900 mm per year evaporates. The evaporation rate is 8 times higher than the amount of rain and snow. But large rivers do not allow the Caspian Sea to become shallow.

During the cold period of the year from September to March, the Caspian receives the largest amount of precipitation.

Surface inflow of river waters

The main positive component of the water balance of the Caspian Sea is the river runoff, which does not allow it to dry out, as it once happened to the Aral Sea, which is now not even noticed by satellites.

The number of rivers has already been mentioned, but it remains to analyze how the largest of them affect the Caspian and determine its water balance.

After analyzing the course of long-term fluctuations of the main rivers that flow into the Caspian Sea, it was possible to identify three characteristic periods, due to which the sea began to change dramatically and not for the betterside.

Until 1950, the state of the Caspian Sea basin was natural, because the reservoir, which was built in the 1930s, had no effect on it. The Rybinsk reservoir operated here from 1932 to 1952.

But when large reservoirs began to be built on the Volga and its major tributary Kama, then the second period of change in the water regime of the world's largest closed water artery began. These were the 1950s and 1970s. During this period, 9 huge reservoirs were built. Now the flow of rivers has become regulated. Such actions led to the fact that the hydrological regime of the Caspian Sea began to change dramatically.

First of all, this is due to the fact that the rivers of the Caspian Sea basin of Russia were the first to be regulated, and these are the largest water bodies flowing into the Caspian.

Now, reservoirs have been built on absolutely all rivers flowing into the Caspian, with the exception of the Terek.

But in 1970 the third period began, when the channels of all rivers were regulated. Then it was time for intensive water consumption from rivers for irrigation purposes.

But these three periods have already passed, and by 1995 the Caspian Sea had more or less stabilized its water regime. And yet, the sea has received the maximum level of anthropogenic influence in the last decade.

Underground inflow of waters

This component is still the least studied aspect of the water balance in the Caspian Sea. The fluctuation ranges from 2 to 40 km³ per year. Scientists say that it is not yet clear why such a largescatter in the passage of water from underground. Perhaps there are secret sources of fresh water that no one knows about? Unknown!

But it is very difficult to estimate the actual quantitative volume of groundwater runoff.

Water balance assessment

Scientists say that in 1900-1929 there was a high and stable position of the sea. This is due to the equilibrium ratio of the water balance. But in the period from 1930 to 1941 there was a sharp shortage of water. Further, until 1977, a period of insignificant deficit was determined. And a sharp rise in the water level, which was associated with the regulation of rivers, occurred in the period from 1978 to 1995.

All these problems have been identified through years of research. And it was proved that a sharp level of change in the water balance, as well as the Caspian Sea basin, is associated primarily with anthropogenic activities. And fluctuations in water levels occur due to instability in the ratio of water coming from the basin and the level of their evaporation, as well as due to the fact that a lot of water every year, for unknown reasons, goes underground.

Also, tectonic movements have a strong influence on this process. But nevertheless, in the course of research, it was possible to come to the following conclusion: all the changes that have occurred in the Caspian Sea basin and directly in the reservoir itself over the past 200 years have been provoked by the impact of not only anthropogenic, but also climatic factors.

Legal Status

After the collapse of the USSR, the division of the Caspian Sea was for a long time the subject of unsettled disagreements related to the division of resourcesthe Caspian shelf - oil and gas, as well as biological resources. For a long time there were negotiations between the Caspian states on the status of the Caspian Sea - Azerbaijan, Kazakhstan and Turkmenistan insisted on dividing the Caspian along the median line, Iran - on dividing the Caspian along one fifth between all the Caspian states.

Negotiations on the legal status of the Caspian Sea were completed with the signing of the Convention on the Legal Status of the Caspian Sea, held on August 12, 2018 in Aktau. According to the final document, the Caspian Sea remains in the common use of the parties, and the bottom and subsoil are divided by neighboring states into sections by agreement between them on the basis of international law. Shipping, fishing, scientific research and laying of main pipelines are carried out in accordance with the rules agreed by the parties. In particular, when laying a main pipeline on the seabed, only the consent of the party through whose sector the pipeline will run is required

Recreation

The Caspian Sea is famous for its sandy beaches and therapeutic mud. If you want to visit a cozy but comfortable place near the rocks, then many tourists advise the small city of Aktau with a population of 300 thousand people.

Despite the high development of resorts, the Caspian still loses to the Caucasian coast of the Black Sea. Turkmenistan cannot receive a large number of tourists on the Caspian Sea due to political isolation, and Sharia law in Iran. Therefore, the best option is Kazakhstan, in the Aktau region or other small towns.

Poolocean of the Caspian Sea is very diverse. In the future, perhaps, this area will become the main resort center of the world.

Conclusion

Now it is clear which basin the Caspian Sea belongs to. Officially, this body of water is not considered to be either a sea or a lake. It's just a huge inland body of water that has no outlet to the oceans.

Its total area is 371,000 km². In total, 130 rivers flow into this water body, 7 of which are large. Sharp drops in water took place from 1978 to 1995, when all rivers were regulated and reservoirs were built on them. Now the Caspian Sea has a relatively stable water level.