CaspAndmOre(Caspian) - the largest enclosed body of water on Earth. In size, the Caspian Sea is much larger than such lakes as the Upper, Victoria, Huron, Michigan, Baikal. According to formal features, the Caspian Sea is an endorheic lake. However, considering it big sizes, brackish waters and a regime similar to the sea, this body of water is called the sea.

According to one hypothesis, the Caspian Sea (among the ancient Slavs - the Khvalyn Sea) got its name in honor of the Caspian tribes who lived before our era on its southwestern coast.

The Caspian Sea washes the shores of five states: Russia, Azerbaijan, Iran, Turkmenistan and Kazakhstan.

The Caspian Sea is elongated in the meridional direction and is located between 36°33' and 47°07' N latitude. and 45°43΄ and 54°03΄ E (without Kara-Bogaz-Gol Bay). The length of the sea along the meridian is about 1200 km; the average width is 310 km. north coast Caspian Sea bordered by the Caspian lowland, the eastern one by the deserts of Central Asia; in the west, the mountains of the Caucasus approach the sea, in the south, near the coast, the Elburz ridge stretches.

The surface of the Caspian Sea is much lower than the level of the World Ocean. Its current level fluctuates around -27 ... -28 m. These levels correspond to the sea surface area of ​​​​390 and 380 thousand km 2 (without the Kara-Bogaz-Gol Bay), the volume of water is 74.15 and 73.75 thousand km 3, average depth is about 190 m.

The Caspian Sea is traditionally divided into three large parts: the North (24% of the sea area), the Middle (36%) and the South Caspian (40%), which differ significantly in morphology and regime, as well as the large and isolated Kara-Bogaz-Gol Bay. The northern, shelf part of the sea is shallow: its average depth is 5–6 m, maximum depths are 15–25 m, and the volume is less than 1% of the total water mass of the sea. The Middle Caspian is a separate basin with the area of ​​maximum depths in the Derbent depression (788 m); its average depth is about 190 m. In the South Caspian, the average and maximum depths are 345 and 1025 m (in the South Caspian depression); 65% of the water mass of the sea is concentrated here.

There are about 50 islands in the Caspian Sea with a total area of ​​approximately 400 km2; the main ones are Tyuleniy, Chechen, Zyudev, Konevsky, Dzhambaysky, Durneva, Ogurchinsky, Apsheronsky. length coastline about 6.8 thousand km, with islands - up to 7.5 thousand km. The shores of the Caspian Sea are diverse. In the northern and eastern parts, they are quite strongly indented. There are large bays Kizlyarsky, Komsomolets, Mangyshlaksky, Kazakhsky, Kara-Bogaz-Gol, Krasnovodsky and Turkmensky, many bays; off the western coast - Kyzylagach. The largest peninsulas are Agrakhansky, Buzachi, Tyub-Karagan, Mangyshlak, Krasnovodsky, Cheleken and Apsheronsky. The most common banks are accumulative; areas with abrasion shores are found along the contour of the Middle and South Caspian.

More than 130 rivers flow into the Caspian Sea, the largest of which is the Volga. , Ural, Terek, Sulak, Samur, Kura, Sefidrud, Atrek, Emba (its runoff enters the sea only in high-water years). Nine rivers have deltas; the largest are located at the mouths of the Volga and Terek.

The main feature of the Caspian Sea, as a drainless reservoir, is instability and a wide range of long-term fluctuations in its level. This most important hydrological feature of the Caspian Sea has a significant impact on all its other hydrological characteristics, as well as on the structure and regime of river mouths, on coastal zones. In the Caspian Sea level varied in the range of ~200 m: from -140 to +50 m BS; in from -34 to -20 m BS. From the first third of the 19th century and until 1977, sea level dropped by about 3.8 m - to the lowest point in the last 400 years (-29.01 m BS). In 1978–1995 The level of the Caspian Sea rose by 2.35 m and reached -26.66 m BS. Since 1995, a certain downward trend has dominated - to -27.69 m BS in 2013.

During major periods, the northern shore of the Caspian Sea shifted to Samarskaya Luka on the Volga, and perhaps even further. At maximum transgressions, the Caspian turned into a sewage lake: excess water flowed through the Kuma-Manych depression into the Sea of ​​Azov and further into the Black Sea. During the extreme regression, the southern coast of the Caspian was shifted to the Apsheron threshold.

Long-term fluctuations in the level of the Caspian are explained by changes in the structure of the water balance of the Caspian Sea. The sea level rises when the incoming part of the water balance (primarily river runoff) increases and exceeds the outgoing part, and decreases if the inflow of river waters decreases. The total water flow of all rivers averages 300 km 3 /year; while the five largest rivers account for almost 95% (the Volga provides 83%). During the period of the lowest sea level, in 1942–1977, the river flow was 275.3 km 3 / year (of which 234.6 km 3 / year is the flow of the Volga), precipitation - 70.9, underground flow - 4 km 3 /year, and evaporation and outflow to the Kara-Bogaz-Gol Bay - 354.79 and 9.8 km 3 /year. During the period of intensive sea level rise, in 1978-1995, respectively, 315 (Volga - 274.1), 86.1, 4, 348.79 and 8.7 km 3 / year; in the modern period - 287.4 (Volga - 248.2), 75.3, 4, 378.3 and 16.3 km 3 / year.

The intra-annual changes in the level of the Caspian Sea are characterized by a maximum in June–July and a minimum in February; the range of intra-annual level fluctuations is 30–40 cm. Surge-surge level fluctuations are manifested throughout the sea, but they are most significant in the northern part, where, with maximum surges, the level can rise by 2–4.5 m and the edge “retreat” by several tens of kilometers inland, and in case of surges - to drop by 1–2.5 m. Seiche and tidal level fluctuations do not exceed 0.1–0.2 m.

Despite the relatively small size of the reservoir in the Caspian Sea, there is strong excitement. highest heights waves in the South Caspian can reach 10–11 m. Wave heights decrease in the direction from south to north. Storm waves can develop at any time of the year, but more often and more dangerously in the cold half of the year.

The Caspian Sea is generally dominated by wind currents; nevertheless, runoff currents play an appreciable role on the estuarine coasts of large rivers. Cyclonic water circulation prevails in the Middle Caspian, and anticyclonic circulation in the South Caspian. In the northern part of the sea, the patterns of wind currents are more irregular and depend on the characteristics and variability of the wind, bottom topography and coastlines, river runoff and aquatic vegetation.

The water temperature is subject to significant latitudinal and seasonal changes. IN winter period it varies from 0–0.5 o C at the ice edge in the north of the sea to 10–11 o C in the south. In summer, the water temperature in the sea averages 23–28 o C, and in shallow coastal waters in the Northern Caspian it can reach 35–40 o C. At depths, a constant temperature is maintained: deeper than 100 m it is 4–7 o C.

In winter, only the northern part of the Caspian Sea freezes; in severe winter - the entire Northern Caspian and the coastal zones of the Middle Caspian. Freezing in the Northern Caspian lasts from November to March.

The salinity of water changes especially sharply in the northern part of the sea: from 0.1‰ on the estuarine coasts of the Volga and Urals to 10–12‰ on the border with the Middle Caspian. In the Northern Caspian, the temporal variability of water salinity is also great. In the middle and southern parts of the sea, salinity fluctuations are small: it is mainly 12.5–13.5‰, increasing from north to south and from west to east. The highest water salinity is in the Kara-Bogaz-Gol Bay (up to 300‰). With depth, the salinity of water increases slightly (by 0.1–0.3‰). The average salinity of the sea is about 12.5‰.

More than a hundred species of fish live in the Caspian Sea and the mouths of the rivers flowing into it. There are Mediterranean and Arctic invaders. The object of fishing is goby, herring, salmon, carp, mullet and sturgeon fish. The latter number five species: sturgeon, beluga, stellate sturgeon, spike and sterlet. The sea is capable of producing up to 500-550 thousand tons of fish annually if overfishing is not allowed. Of the marine mammals, the endemic Caspian seal lives in the Caspian Sea. Every year 5-6 million waterfowl migrate through the Caspian region.

The economy of the Caspian Sea is connected with oil and gas production, shipping, fishing, extraction of seafood, various salts and minerals (Kara-Bogaz-Gol Bay), with the use of recreational resources. The explored oil resources in the Caspian Sea are about 10 billion tons, the total resources of oil and gas condensate are estimated at 18–20 billion tons. Oil and gas are being produced on an ever-increasing scale. Used by the Caspian Sea and water transport, including along the river-sea and sea-river routes. The main ports of the Caspian Sea: Astrakhan, Olya, Makhachkala (Russia), Aktau, Atyrau (Kazakhstan), Baku (Azerbaijan), Nowshahr, Bender-Enzeli, Bender-Torkemen (Iran) and Turkmenbashi (Turkmenistan).

The economic activity and hydrological features of the Caspian Sea create a number of serious environmental and water management problems. Among them: anthropogenic pollution of river and sea waters (mainly with oil products, phenols and synthetic surfactants), poaching and reduction of fish stock, especially sturgeons; damage to the population and coastal economic activity due to large-scale and rapid changes in the level of the reservoir, the impact of numerous hazardous hydrological phenomena and hydrological and morphological processes.

The total economic damage for all the Caspian countries associated with the rapid and significant recent rise in the level of the Caspian Sea, the flooding of part of the coastal land, the destruction of coasts and coastal structures, was estimated at 15 to 30 billion US dollars. It took urgent engineering measures to protect the coast.

A sharp drop in the level of the Caspian Sea in the 1930s–1970s. led to less damage, but they were significant. The navigable approach channels became shallow, the shallow seashore at the mouths of the Volga and the Urals became heavily overgrown, which became an obstacle to the passage of fish into the rivers for spawning. It was necessary to build fish passages through the seasides mentioned above.

Among the unresolved problems is the lack of an international agreement on the international legal status of the Caspian Sea, the division of its water area, bottom and subsoil.

The Caspian Sea is the object of many years of research by specialists from all the Caspian states. Such domestic organizations as the State Oceanographic Institute, the Institute of Oceanology of the Russian Academy of Sciences, the Hydrometeorological Center of Russia, the Caspian Research Institute of Fisheries, the Faculty of Geography of Moscow State University, etc. took an active part in the study of the Caspian Sea.

The Caspian Sea is the largest lake on planet Earth. It is called the sea because of its size and bed, which is folded like an ocean basin. The area is 371,000 square meters, the depth is 1025 m. The list of rivers flowing into the Caspian Sea includes 130 names. The largest of them are: Volga, Terek, Samur, Sulak, Ural and others.

Caspian Sea

It took 10 million years before the Caspian was formed. The reason for its formation is that the Sarmatian Sea, which lost its connection with the World Ocean, was divided into two reservoirs, which were called the Black and Caspian Seas. Between the latter and the World Ocean stretch thousands of kilometers of waterless path. It is located at the junction of two continents - Asia and Europe. Its length in the north-south direction is 1200 km, west-east - 195-435 km. The Caspian Sea is an internal drainless basin of Eurasia.

Near the Caspian Sea, the water level is below the level of the World Ocean, and besides, it is subject to fluctuations. According to scientists, this is due to many factors: anthropogenic, geological, climatic. At present, the average water level reaches 28 m.

The network of rivers and sewage is unevenly distributed along the coast. Few rivers flow into the part of the sea from the north side: Volga, Terek, Ural. From the west - Samur, Sulak, Kura. The east coast is characterized by the absence of permanent watercourses. Differences in space in the flow of water that rivers bring to the Caspian Sea is an important geographical feature of this reservoir.

Volga

This river is one of the largest in Europe. In Russia, it ranks sixth in size. In terms of catchment area, it is second only to Siberian rivers flowing into the Caspian Sea, such as the Ob, Lena, Yenisei, Irtysh. For the source, from where the Volga originates, the key is taken near the village of Volgoverkhovye, Tver Region, on the Valdai Upland. Now there is a chapel at the source, which attracts the attention of tourists, for whom it is a pride to step over the very beginning of the mighty Volga.

A small fast stream gradually gains strength and becomes a huge river. Its length is 3690 km. The source is 225 m above sea level. Among the rivers flowing into the Caspian Sea, the largest is the Volga. Her path runs through many regions of our country: Tver, Moscow, Nizhny Novgorod, Volgograd and others. The territories through which it flows are Tatarstan, Chuvashia, Kalmykia and Mari El. The Volga is the location of millionaire cities - Nizhny Novgorod, Samara, Kazan, Volgograd.

Volga Delta

The main riverbed is divided into channels. A certain shape of the mouth is formed. It's called the delta. Its beginning is the place of separation of the Buzan branch from the bed of the Volga river. The delta is located 46 km north of the city of Astrakhan. It includes channels, branches, small rivers. There are several main branches, but only Akhtuba is navigable. Among all the rivers of Europe, the Volga is distinguished by the largest delta, which is a rich fish region in this basin.

It lies 28 m lower than the ocean level. The mouth of the Volga is the location of the southernmost Volga city of Astrakhan, which in the distant past was the capital of the Tatar Khanate. Later, at the beginning of the 18th century (1717), Peter 1 gave the city the status of "the capital of the province of Astrakhan." During his reign, the main attraction of the city, the Assumption Cathedral, was built. Its Kremlin is made of white stone, brought from the capital of the Golden Horde, the city of Saray. The mouth is divided by branches, the largest of which are: Bolda, Bakhtemir, Buzan. Astrakhan is a southern city located on 11 islands. Today it is a city of shipbuilders, sailors and fishermen.

Currently, the Volga needs protection. For this purpose, a reserve has been established at the place where the river flows into the sea. The delta of the Volga, the largest river flowing into the Caspian Sea, abounds in unique flora and fauna: sturgeon, lotuses, pelicans, flamingos and others. Immediately after the revolution of 1917, a law was passed on their protection by the state as part of the Astrakhan Reserve.

Sulak River

It is located in Dagestan, flows through its territory. It feeds on the waters of melted snows that flow down from the mountains, as well as tributaries: Small Sulak, Chvakhun-bak, Akh-su. Water also enters Sulak through a canal from the Aksai and Aktash rivers.

The source is formed by the confluence of two rivers that originate in the basins: Didoyskaya and Tushinskaya. The length of the Sulak River is 144 km. Its pool has a fairly large area - 15,200 square meters. It flows through the canyon with the same name as the river, then through the Akhetlinsky gorge and finally comes to the plane. Going around the Agrakhan Bay from the south side, Sulak flows into the sea.

The river provides drinking water to Kaspiysk and Makhachkala, it is home to hydroelectric power plants, the urban-type settlements of Sulak and Dubki, and small town Kizilyurt.

Samur

The river got its name not by chance. The name translated from the Caucasian language (one of them) means "middle". Indeed, the border between the states of Russia and Azerbaijan is marked along the waterway along the Samur River.

The sources of the river are glaciers and springs, originating in the spurs of the Caucasus Range from the northeast side, not far from the Guton mountain. The height above sea level is 3200 m. Samur has a length of 213 km. The height in the upper reaches and the mouth differs by three kilometers. The catchment basin has an area of ​​almost five thousand square meters.

The places where the river flows are narrow gorges located between the mountains. high altitude, composed of shale and sandstone, which is why the water here is muddy. The Samur basin has 65 rivers. Their length reaches 10 km or more.

Samur: the valley and its description

The valley of this river in Dagestan is the most densely populated region. Derbent is located near the mouth - ancient city peace. The banks of the Samur River are home to twenty or more species of relict representatives of the flora. Endemic, endangered and rare species listed in the Red Book grow here.

In the river delta, a relict forest is comfortably located, which is the only one in Russia. Liana forest is a fairy tale. Huge trees of the rarest and most common species grow here, intertwined with lianas. The river is rich in valuable species of fish: mullet, pike perch, pike, catfish and others.

Terek

The river got its name from the Karachay-Balkar peoples who lived along its banks. They called it "Terk Suu", which means "rushing water" in translation. Ingush and Chechens called it Lomeki - "mountain water".

The beginning of the river is the territory of Georgia, the Zigla-Khokh glacier - a mountain located on the slope of the Caucasus Range. It is under glaciers all year round. One of them melts when sliding down. A small stream is formed, which is the source of the Terek. It is located at an altitude of 2713 m above sea level. The length of the river flowing into the Caspian Sea is 600 km. At the confluence with the Caspian, the Terek is divided into many branches, as a result of which a vast delta is formed, its area is 4000 square meters. In some places it is very swampy.

The course in this place has changed several times. The old arms have now been turned into channels. The middle of the last century (1957) was marked by the construction of the Kargaly hydroelectric complex. It is used to supply water to the channels.

How is the Terek replenished?

The river has a mixed supply, but for the upper reaches, water from the melting of glaciers plays an important role, they fill the river. In this regard, 70% of the runoff occurs in spring and summer, that is, at this time the water level in the Terek is the highest, and the lowest - in February. The river freezes if the winters are characterized by a harsh climate, but the freeze-up is unstable.

The river is not distinguished by cleanliness and transparency. The turbidity of the water is large: 400-500 g/m 3 . Every year, the Terek and its tributaries pollute the Caspian Sea, pouring into it from 9 to 26 million tons of various suspensions. This is due to the rocks of which the shores are composed, and they are clayey.

Terek mouth

The Sunzha is the largest tributary flowing into the Terek, the lower reaches of which are measured precisely from this river. By this time, the Terek flows for a long time over the flat terrain, leaving the mountains located behind the Elkhot Gates. The bottom here is composed of sand and pebbles, the current slows down, and in some places stops altogether.

The mouth of the Terek River has an unusual appearance: the channel here is elevated above the valley, in appearance it resembles a canal, which is fenced with a high embankment. The water level rises above the land level. This phenomenon is due to a natural cause. Since the Terek is a turbulent river, it brings sand and stones in large quantities from the Caucasus Range. Given that the current in the lower reaches is weak, some of them settle here and do not reach the sea. For the inhabitants of the area, sediments are both a threat and a boon. When they are washed away by water, floods of great destructive power occur, this is very bad. But in the absence of floods, the soils become fertile.

Ural river

In ancient times (until the second half of the 18th century), the river was called Yaik. It was renamed into the Russian style by the decree of Catherine II in 1775. Just at this time, the Peasant War was suppressed, the leader of which was Pugachev. The name is still preserved in the Bashkir language, and in Kazakhstan it is official. The Urals are the third longest in Europe, only the Volga and the Danube are larger than this river.

The Ural originates in Russia, on the slope of the Kruglyaya Sopka of the Uraltau Ridge. The source is a spring gushing out of the ground at an altitude of 637 m above sea level. At the beginning of its journey, the river flows in a north-south direction, but after meeting a plateau on the way, it makes a sharp turn and continues to flow in a north-westerly direction. However, beyond Orenburg, its direction again changes to the southwestern, which is considered the main one. Having overcome the winding path, the Ural flows into the Caspian Sea. The length of the river is 2428 km. The mouth is divided into branches and tends to shallow.

The Ural is a river along which the natural water boundary between Europe and Asia passes, with the exception of the upper reaches. This is an internal European river, but its upper reaches to the east of the Ural Range are the territory of Asia.

Importance of the Caspian rivers

The rivers flowing into the Caspian Sea are of great importance. Their waters are used for human and animal consumption, domestic needs, agricultural and industrial needs. Hydroelectric power plants are being built on the rivers, the energy of which is in demand by man for various purposes. River basins are full of fish, algae, shellfish. Even in ancient times, people chose river valleys for future settlements. And now cities and towns are being built on their banks. Rivers ply passenger and transport ships, performing important tasks for the transport of passengers and goods.

There are still disputes about the status of the Caspian Sea. The fact is that, despite its common name, it is still the largest endorheic lake in the world. It was called the sea because of the features that the structure of the bottom has. It is formed by oceanic crust. In addition, the water in the Caspian Sea is salty. As at sea, storms and strong winds are often observed here, raising high waves.

Geography

The Caspian Sea is located at the crossroads of Asia and Europe. In its shape, it resembles one of the letters of the Latin alphabet - S. From south to north, the sea stretches for 1200 km, and from east to west - from 195 to 435 km.

The territory of the Caspian Sea is heterogeneous in terms of its physical and geographical conditions. In this regard, it is conventionally divided into 3 parts. These include the Northern and Middle, as well as the Southern Caspian.

coastal countries

Which countries are washed by the Caspian Sea? There are only five of them:

1. Russia, located in the northwest and west. The length of the coastline of this state along the Caspian Sea is 695 km. Kalmykia, Dagestan and the Astrakhan region, which are part of Russia, are located here.
2. Kazakhstan. This is a country on the shores of the Caspian Sea, located in the east and northeast. The length of its coastline is 2320 km.
3. Turkmenistan. The map of the Caspian states indicates that this country is located in the southeast of the water basin. The length of the line along the coast is 1200 km.
4. Azerbaijan. This state, stretching along the Caspian for 955 km, washes its shores in the southwest.
5. Iran. The map of the Caspian states indicates that this country is located near southern shores drainless lake. At the same time, the length of its sea borders is 724 km.

Caspian sea?

Until now, the dispute about how to name this unique reservoir has not been resolved. And it is important to answer this question. The fact is that all countries on the Caspian Sea have their own interests in this region. However, the question of how to divide this huge body of water, the governments of the five states have not been able to decide for a long time. The main dispute revolved around the name. Is the Caspian still a sea or a lake? Moreover, the answer to this question is more of interest to non-geographers. First of all, politicians need it. This is due to the application of international law.

Caspian states such as Kazakhstan and Russia believe that their borders in this region are washed by the sea. In this regard, representatives of the two indicated countries insist on the application of the UN Convention, adopted in 1982. It concerns the law of the sea. The provisions of this document state that the coastal states are assigned a twelve-mile water zone along it. In addition, the country is granted the right to an economic maritime territory. It is located at a distance of two hundred miles. The coastal state also has the right to, however, even the widest part of the Caspian Sea is narrower than the distance specified in the international document. In such a case, the principle of the median line can be applied. At the same time, the Caspian states, which have the largest length of coastal borders, will receive a large sea area.

Iran has a different opinion on this matter. Its representatives believe that the Caspian should be divided fairly. In this case, all countries will get twenty percent of the sea area. One can understand the position of official Tehran. With such a solution to the problem, the state will control a larger zone than when dividing the sea along the median line.

However, the Caspian from year to year significantly changes its water level. This does not allow determining its median line and dividing the territory between states. Countries such as Azerbaijan, Kazakhstan and Russia have signed an agreement among themselves defining those bottom zones on which the parties will exercise their economic rights. Thus, a certain legal truce has been achieved in the northern territories of the sea. The southern countries of the Caspian Sea have not yet come to a unified decision. At the same time, they do not recognize the agreements reached by their northern neighbors.

The Caspian is a lake?

Adherents of this point of view proceed from the fact that the reservoir, located at the junction of Asia and Europe, is closed. In this case, it is impossible to apply the document on the norms of international maritime law to it. Supporters of this theory are convinced that they are right, referring to the fact that the Caspian Sea has no natural connection with the waters of the World Ocean. But here another difficulty arises. If the lake is the Caspian Sea, according to what international standards should the borders of states be defined in its water spaces? Unfortunately, such documents have not yet been developed. The fact is that the issues of the international lake were not discussed anywhere and by anyone.

Is the Caspian a unique body of water?

In addition to those listed above, there is another, third point of view on the ownership of this amazing reservoir. Its supporters are of the opinion that the Caspian should be recognized as an international water basin, belonging equally to all countries bordering on it. In their opinion, the resources of the region are subject to joint exploitation by the countries bordering the reservoir.

Solving Security Issues

The Caspian states are doing everything possible to eliminate all existing differences. And there are positive developments in this regard. One of the steps towards solving problems related to the Caspian region was an agreement signed on November 18, 2010 between all five countries. It concerns issues of cooperation in the field of security. In this document, the countries agreed on joint activities to eliminate terrorism, drug trafficking, smuggling, poaching, money laundering, etc. in the region.

environmental protection

Particular attention is paid to solving environmental issues. The territory on which the Caspian states and Eurasia are located is a region under the threat of industrial pollution. Kazakhstan, Turkmenistan and Azerbaijan are dumping waste from exploration and production of energy carriers into the waters of the Caspian Sea. Moreover, it is in these countries that a large number of abandoned oil wells that are not operated due to their unprofitability, but nevertheless continue to have an adverse impact on the environmental situation. As for Iran, it dumps agricultural waste and sewage into the sea. Russia threatens the ecology of the region with industrial pollution. This is due to the economic activity that has unfolded in the Volga region.

Countries on the Caspian Sea have made some progress in solving problems environment. Thus, since August 12, 2007, the Framework Convection has been in force in the region, which sets itself the goal of protecting the Caspian Sea. This document developed provisions on the protection of bioresources and the regulation of anthropogenic factors affecting the aquatic environment. According to this convection, the parties must cooperate in carrying out activities to improve the environmental situation in the Caspian.

In 2011 and 2012, all five countries also signed other documents significant for the protection of the marine environment. Among them:

• Protocol on Cooperation, Response and Regional Preparedness for Oil Pollution Events.
• Protocol concerning the protection of the region against pollution from land-based sources.

Development of the gas pipeline construction

To date, another problem is unresolved in the Caspian region. It concerns the laying This idea is an important strategic task of the West and the United States, which continue to look for sources of energy resources alternative to Russian ones. That is why, when resolving this issue, the parties do not turn to such countries as Kazakhstan, Iran and, of course, the Russian Federation. Brussels and Washington supported the statement made in Baku on November 18, 2010 at the summit of the heads of the Caspian countries. He expressed the official position of Ashgabat regarding the laying of the pipeline. The Turkmen authorities believe that the project should be carried out. At the same time, only those states, on the territories of the bottom of which it will be located, must give their consent to the construction of the pipeline. These are Turkmenistan and Azerbaijan. Iran and Russia opposed this position and the project itself. At the same time, they were guided by the issues of protecting the Caspian ecosystem. To date, the construction of the pipeline is not carried out due to disagreement between the project participants.

Hosting the first summit

The countries on the Caspian Sea are constantly looking for ways to solve the problems that have matured in this Eurasian region. For this, special meetings of their representatives are organized. Thus, the first summit of the heads of the Caspian states took place in April 2002. Ashgabat became its venue. However, the results of this meeting did not meet expectations. The summit was considered unsuccessful due to Iran's demands for the division of the sea into 5 equal parts. This was strongly opposed by other countries. Their representatives defended their own point of view that the size of national water areas should correspond to the length that the coastline of the state has.

The failure of the summit was also provoked by a dispute between Ashgabat and Baku over the ownership of three oil fields located in the center of the Caspian Sea. As a result, the heads of the five states did not develop a unanimous opinion on any of all the issues raised. However, at the same time, an agreement was reached to hold a second summit. It was supposed to take place in 2003 in Baku.

Second Caspian Summit

Despite the existing agreements, the scheduled meeting was postponed every year. The heads of the Caspian littoral states gathered for the second summit only on October 16, 2007. The venue was Tehran. At the meeting, topical issues related to determining the legal status of a unique reservoir, which is the Caspian Sea, were discussed. The borders of the states within the framework of the division of the water area were preliminarily agreed during the development of the draft of the new convention. The problems of security, ecology, economy and cooperation of coastal countries were also raised. In addition, the results of the work that the states have carried out since the first summit were summed up. In Tehran, representatives of the five states also outlined ways for further cooperation in the region.

Meeting at the third summit

Once again, the heads of the Caspian countries met in Baku on November 18, 2010. The result of this summit was the signing of an agreement on expanding cooperation regarding security issues. During the meeting, it was pointed out that which countries werehes the Caspian Sea, only those should ensure the fight against terrorism, transnational crime, weapons proliferation, etc.

Fourth summit

Once again, the Caspian states raised their problems in Astrakhan on September 29, 2014. At this meeting, the presidents of the five countries signed another statement.

In it, the parties fixed the exclusive right of the coastal countries to deploy armed forces in the Caspian. But even at this meeting, the status of the Caspian was not finally settled.

V. N. MIKHAILOV

The Caspian Sea is the largest drainless lake on the planet. This body of water is called the sea for its huge size, brackish water and sea-like regime. The level of the Caspian Sea-lake lies much lower than the level of the World Ocean. At the beginning of 2000, he had a mark of about - 27 abs. m. At this level, the area of ​​the Caspian Sea is ~ 393 thousand km2 and the volume of water is 78,600 km3. The average and maximum depths are 208 and 1025 m, respectively.

The Caspian Sea is elongated from south to north (Fig. 1). The Caspian washes the shores of Russia, Kazakhstan, Turkmenistan, Azerbaijan and Iran. The reservoir is rich in fish, its bottom and banks are rich in oil and gas. The Caspian Sea is quite well studied, but many mysteries remain in its regime. The most characteristic feature of the reservoir is the instability of the level with sharp drops and rises. The last rise in the level of the Caspian took place before our eyes from 1978 to 1995. It gave rise to many rumors and speculation. Numerous publications appeared in the press, which spoke about catastrophic floods and ecological catastrophe. It was often written that the rise in the level of the Caspian Sea led to the flooding of almost the entire Volga delta. What is true in the statements made? What is the reason for such behavior of the Caspian Sea?

WHAT HAPPENED TO THE CASPIAN IN THE 20TH CENTURY

Systematic observations over the level of the Caspian Sea were started in 1837. In the second half of the 19th century, the average annual values ​​of the Caspian Sea level were in the range of marks from -26 to -25.5 abs. m and showed a slight downward trend. This trend continued into the 20th century (Fig. 2). In the period from 1929 to 1941, the sea level dropped sharply (by almost 2 m - from - 25.88 to - 27.84 abs. m). In subsequent years, the level continued to fall and, having decreased by approximately 1.2 m, reached in 1977 the lowest mark for the observation period - 29.01 abs. m. Then the sea level began to rise rapidly and, having risen by 2.35 m by 1995, reached a mark of 26.66 abs. m. In the next four years, the average sea level decreased by almost 30 cm. Its average marks were 26.80 in 1996, 26.95 in 1997, 26.94 in 1998 and 27.00 abs. m in 1999.

The decrease in sea level in the years 1930-1970 led to the shallowing of coastal waters, the extension of the coastline towards the sea, and the formation of wide beaches. The latter was perhaps the only positive consequence of the level drop. There were many more negative consequences. With a decrease in the level, the areas of forage land for fish stocks in the northern Caspian have decreased. The shallow estuarine coast of the Volga began to quickly overgrow with aquatic vegetation, which worsened the conditions for the passage of fish to spawn in the Volga. Catches of fish, especially valuable species such as sturgeon and sterlet, have sharply decreased. Shipping began to suffer damage due to the fact that the depths in the approach channels decreased, especially near the Volga delta.

The rise in the level from 1978 to 1995 was not only unexpected, but also led to even greater negative consequences. After all, both the economy and the population of coastal areas have already adapted to a low level.

Many sectors of the economy began to suffer damage. Significant territories turned out to be in the zone of flooding and flooding, especially in the northern (flat) part of Dagestan, in Kalmykia and the Astrakhan region. The cities of Derbent, Kaspiysk, Makhachkala, Sulak, Caspian (Lagan) and dozens of other smaller settlements suffered from the level rise. Significant areas of agricultural land have been flooded and flooded. Roads and power lines, engineering structures of industrial enterprises and public utilities are being destroyed. A threatening situation has developed with fish-breeding enterprises. Abrasion processes in the coastal zone and the effect of seawater surges have intensified. IN last years the flora and fauna of the seashore and the coastal zone of the Volga delta suffered significant damage.

Due to the increase in depth in the shallow waters of the Northern Caspian and the reduction in the areas occupied by aquatic vegetation in these places, the conditions for the reproduction of stocks of anadromous and semi-anadromous fish and the conditions for their migration to the delta for spawning have somewhat improved. However, the predominance of negative consequences from the rising sea level made us speak of an ecological catastrophe. The development of measures to protect national economic objects and settlements from the advancing sea began.

HOW UNUSUAL IS CURRENT CASPIAN BEHAVIOR?

Research into the life history of the Caspian Sea can help answer this question. Of course, there are no direct observations of the past regime of the Caspian Sea, but there are archaeological, cartographic and other evidence for historical time and the results of paleogeographic studies covering a longer period.

It is proved that during the Pleistocene (the last 700-500 thousand years) the level of the Caspian Sea underwent large-scale fluctuations in the range of about 200 m: from -140 to + 50 abs. m. In this period of time in the history of the Caspian, four stages are distinguished: Baku, Khazar, Khvalyn and New Caspian (Fig. 3). Each stage included several transgressions and regressions. The Baku transgression occurred 400-500 thousand years ago, the sea level rose to 5 abs. m. During the Khazar stage, there were two transgressions: the early Khazar (250-300 thousand years ago, the maximum level is 10 abs. m) and the late Khazar (100-200 thousand years ago, the highest level is 15 abs. m). The Khvalyn stage in the history of the Caspian included two transgressions: the largest for the Pleistocene period, the early Khvalyn (40-70 thousand years ago, the maximum level is 47 abs. m, which is 74 m higher than the modern one) and the late Khvalyn (10-20 thousand years ago, the rise level up to 0 abs. m). These transgressions were separated by a deep Enotaevskaya regression (22-17 thousand years ago), when the sea level dropped to -64 abs. m and was 37 m lower than the modern one.

Rice. 4. Fluctuations in the level of the Caspian Sea over the past 10 thousand years. P is the natural range of fluctuations in the level of the Caspian Sea under climatic conditions characteristic of the subatlantic epoch of the Holocene (risk zone). I-IV - stages of the New Caspian transgression; M - Mangyshlak, D - Derbent regression

Significant fluctuations in the level of the Caspian also occurred during the New Caspian stage of its history, which coincided with the Holocene (the last 10 thousand years). After the Mangyshlak regression (10 thousand years ago, a level decrease to -50 abs. m), five stages of the New Caspian transgression were noted, separated by small regressions (Fig. 4). Following sea level fluctuations, its transgressions and regressions, the outline of the reservoir also changed (Fig. 5).

Over the historical time (2000 years), the range of changes in the average level of the Caspian Sea was 7 m - from - 32 to - 25 abs. m (see Fig. 4). The minimum level in the last 2000 years was during the Derbent regression (VI-VII centuries AD), when it decreased to - 32 abs. m. During the time that has passed since the Derbent regression, the average sea level has changed in an even narrower range - from -30 to -25 abs. m. This range of level changes is called the risk zone.

Thus, the level of the Caspian has experienced fluctuations before, and in the past they were more significant than in the 20th century. Such periodic fluctuations are a normal manifestation of the unstable state of a closed reservoir with variable conditions at the outer boundaries. Therefore, there is nothing unusual in the lowering and rising of the level of the Caspian Sea.

Fluctuations in the level of the Caspian Sea in the past, apparently, did not lead to the irreversible degradation of its biota. Of course, sharp drops in sea level created temporary unfavorable conditions, for example, for fish stocks. However, with the rise in the level, the situation corrected itself. The natural conditions of the coastal zone (vegetation, benthic animals, fish) experience periodic changes along with fluctuations in sea level and, apparently, have a certain margin of stability and resistance to external influences. After all, the most valuable sturgeon herd has always been in the Caspian basin, regardless of fluctuations in sea level, quickly overcoming the temporary deterioration of living conditions.

Rumors that rising sea levels have caused flooding throughout the Volga Delta have not been confirmed. Moreover, it turned out that the increase in water levels, even in the lower part of the delta, is inadequate to the magnitude of the sea level rise. The increase in the water level in the lower part of the delta during the low water period did not exceed 0.2-0.3 m, and almost did not manifest itself during the flood. At the maximum level of the Caspian Sea in 1995, the backwater from the sea extended along the deepest branch of the Bakhtemir delta by no more than 90 km, and along other branches by no more than 30 km. Therefore, only islands on the seashore and a narrow coastal strip of the delta were flooded. Flooding in the upper and middle parts of the delta was associated with high floods in 1991 and 1995 (which is normal for the Volga delta) and with the unsatisfactory condition of protective dams. The reason for the weak effect of sea level rise on the regime of the Volga delta is the presence of a huge shallow coastal zone, which dampens the effect of the sea on the delta.

With regard to the negative impact of sea level rise on the economy and life of the population in the coastal zone, the following should be recalled. At the end of the last century, the sea level was higher than at present, and this was not perceived as an ecological disaster. And before the level was even higher. Meanwhile, Astrakhan has been known since the middle of the 13th century, and Sarai-Batu, the capital of the Golden Horde, was located here in the 13th - mid-16th centuries. These and many more settlements on the coast of the Caspian Sea did not suffer from high level standing, since they were located on elevated places and during abnormal flood levels or during surges, people temporarily moved from low places to higher ones.

Why, then, are the consequences of a rise in sea level even to smaller levels now perceived as a catastrophe? The reason for the enormous damage that the national economy suffers is not the rise in the level, but the thoughtless and short-sighted development of a strip of land within the mentioned risk zone, freed (as it turned out, temporarily!) From under the sea level after 1929, that is, with a decrease in the level below the mark - 26 abs. m. The buildings erected in the risk zone, of course, turned out to be flooded and partially destroyed. Now, when the territory developed and polluted by man is flooded, a dangerous ecological situation is really created, the source of which is not natural processes, but unreasonable economic activity.

ABOUT THE REASONS FOR THE CASPIAN LEVEL VARIATIONS

Considering the issue of the causes of fluctuations in the level of the Caspian Sea, it is necessary to pay attention to the confrontation in this area of ​​two concepts: geological and climatic. Significant contradictions in these approaches were revealed, for example, at the international conference "Caspian-95".

According to the geological concept, two groups of processes are attributed to the causes of changes in the level of the Caspian Sea. The processes of the first group, according to geologists, lead to a change in the volume of the Caspian depression and, as a result, to changes in sea level. Such processes include vertical and horizontal tectonic movements of the earth's crust, accumulation of bottom sediments, and seismic events. The second group includes processes that, as geologists believe, affect the underground runoff into the sea, either increasing it or decreasing it. Such processes are called periodic extrusion or absorption of water, which saturate bottom sediments under the influence of changing tectonic stresses (changes in periods of compression and tension), as well as technogenic destabilization of the subsoil due to oil and gas production or underground nuclear explosions. It is impossible to deny the fundamental possibility of the influence of geological processes on the morphology and morphometry of the Caspian depression and underground runoff. However, at present, the quantitative relationship of geological factors with fluctuations in the level of the Caspian Sea has not been proven.

There is no doubt that tectonic movements played a decisive role in the initial stages of the formation of the Caspian basin. However, if we take into account that the Caspian Sea basin is located within a geologically heterogeneous territory, which results in a periodic rather than linear nature of tectonic movements with repeated sign changes, then one should hardly expect a noticeable change in the capacity of the basin. Not in favor of the tectonic hypothesis is the fact that the coastlines of the New Caspian transgressions in all sections of the Caspian coast (with the exception of certain areas within the Apsheron archipelago) are at the same level.

There are no grounds to consider the change in the capacity of its basin due to the accumulation of precipitation as the reason for fluctuations in the level of the Caspian Sea. The rate of filling the basin with bottom sediments, among which the main role is played by river discharges, is estimated, according to modern data, at a value of about 1 mm/year or less, which is two orders of magnitude less than the currently observed changes in sea level. Seismic deformations, which are noted only near the epicenter and attenuate at close distances from it, cannot have any significant effect on the volume of the Caspian Basin.

As for the periodic large-scale discharge of groundwater into the Caspian Sea, its mechanism is still unclear. At the same time, this hypothesis is contradicted, according to E.G. Maev, firstly, the undisturbed stratification of interstitial waters, indicating the absence of noticeable migrations of waters through the thickness of bottom sediments, and secondly, the absence of proven powerful hydrological, hydrochemical and sedimentation anomalies in the sea, which should have accompanied a large-scale discharge of groundwater capable of affect changes in water levels.

The main evidence of the insignificant role of geological factors at present is the convincing quantitative confirmation of the plausibility of the second, climatic, or rather, water-balance concept of Caspian level fluctuations.

CHANGES IN THE COMPONENTS OF THE CASPIAN WATER BALANCE AS THE MAIN CAUSE OF ITS LEVEL FLUCTUATIONS

For the first time, fluctuations in the level of the Caspian Sea were explained by a change climatic conditions(more specifically, the runoff of rivers, evaporation and precipitation on the surface of the sea) by E.Kh. Lenz (1836) and A.I. Voeikov (1884). Later, the leading role of changes in the components of the water balance in sea level fluctuations was again and again proved by hydrologists, oceanologists, physicogeographers and geomorphologists.

The key to most of the studies mentioned is the compilation of the water balance equation and the analysis of its components. The meaning of this equation is as follows: the change in the volume of water in the sea is the difference between the incoming (river and underground runoff, atmospheric precipitation on the sea surface) and outgoing (evaporation from the sea surface and outflow of water into the Kara-Bogaz-Gol Bay) components of the water balance. The change in the level of the Caspian is the quotient of dividing the change in the volume of its waters by the area of ​​the sea. The analysis showed that the leading role in the water balance of the sea belongs to the ratio of the flow of the Volga, Ural, Terek, Sulak, Samur, Kura rivers and visible or effective evaporation, the difference between evaporation and atmospheric precipitation on the sea surface. An analysis of the components of the water balance revealed that the largest contribution (up to 72% of the dispersion) to the level variability comes from the inflow of river waters, and more specifically, the runoff formation zone in the Volga basin. As for the reasons for the change in the flow of the Volga itself, they are associated, as many researchers believe, with the variability of atmospheric precipitation (mainly winter) in the river basin. And the mode of precipitation, in turn, is determined by the circulation of the atmosphere. It has long been proven that the latitudinal type of atmospheric circulation contributes to an increase in precipitation in the Volga basin, while the meridional type contributes to a decrease.

V.N. Malinin revealed that the root cause of moisture entering the Volga basin should be sought in the North Atlantic, and specifically in the Norwegian Sea. It is there that the increase in evaporation from the sea surface leads to an increase in the amount of moisture transferred to the continent, and, accordingly, to an increase in precipitation in the Volga basin. The latest data on the water balance of the Caspian Sea, received by the staff of the State Oceanographic Institute R.E. Nikonova and V.N. Bortnik, are given with the author's clarifications in Table. 1. These data convincingly prove that the main reasons for both the rapid drop in sea level in the 1930s and the sharp rise in 1978-1995 were changes in river flow, as well as apparent evaporation.

Keeping in mind that river runoff is one of the main factors affecting the water balance and, as a result, the level of the Caspian Sea (and the Volga runoff provides at least 80% of the total river runoff to the sea and about 70% of the incoming part of the Caspian water balance), it would be interesting to find a connection between sea level and the flow of one Volga, measured most accurately. Direct correlation of these quantities does not give satisfactory results.

However, the relationship between the sea level and the Volga runoff is well traced if the river runoff is not taken into account for each year, but the ordinates of the difference integral runoff curve are taken, that is, the sequential sum of the normalized deviations of the annual runoff values ​​from the long-term average value (norm). Even a visual comparison of the course of the average annual levels of the Caspian Sea and the difference integral curve of the Volga runoff (see Fig. 2) makes it possible to reveal their similarity.

For the entire 98-year period of observations of the Volga runoff (the village of Verkhneye Lebyazhye at the head of the delta) and the sea level (Makhachkala), the correlation coefficient of the relationship between the sea level and the ordinates of the difference integral runoff curve was 0.73. If we discard years with small level changes (1900-1928), then the correlation coefficient increases to 0.85. If for analysis we take a period with a rapid decline (1929-1941) and a rise in the level (1978-1995), then the overall correlation coefficient will be 0.987, and separately for both periods 0.990 and 0.979, respectively.

The presented calculation results fully confirm the conclusion that during periods of a sharp decrease or increase in sea level, the levels themselves are closely related to the runoff (more precisely, to the sum of its annual deviations from the norm).

A special task is to assess the role of anthropogenic factors in fluctuations in the level of the Caspian Sea, and above all, the reduction in river flow due to its irretrievable losses for filling reservoirs, evaporation from the surface of artificial reservoirs, and water withdrawal for irrigation. It is believed that since the 1940s, irretrievable water consumption has been steadily increasing, which has led to a reduction in the inflow of river waters to the Caspian Sea and an additional decrease in its level compared to the natural one. According to V.N. Malinin, by the end of the 1980s, the difference between the actual sea level and the restored (natural) level reached almost 1.5 m. about 26 km3/year). If it were not for the withdrawal of river runoff, then the rise in sea level would have begun not at the end of the 70s, but at the end of the 50s.

The increase in water consumption in the Caspian basin by 2000 was predicted first to 65 km3/year, and then to 55 km3/year (36 of them were in the Volga). Such an increase in irretrievable losses of river runoff should have lowered the level of the Caspian by more than 0.5 m by 2000. In connection with the assessment of the impact of irreversible water consumption on the level of the Caspian, we note the following. First, estimates of water withdrawal volumes and evaporation losses from the surface of reservoirs in the Volga basin found in the literature seem to be significantly overestimated. Secondly, forecasts of water consumption growth turned out to be erroneous. The forecasts included the rate of development of water-consuming sectors of the economy (especially irrigation), which not only turned out to be unrealistic, but also gave way to a decline in production in recent years. In fact, as A.E. Asarin (1997), by 1990 water consumption in the Caspian basin was about 40 km3/year, and has now decreased to 30-35 km3/year (in the Volga basin to 24 km3/year). Therefore, the "anthropogenic" difference between the natural and actual sea levels is currently not as large as predicted.

ON POSSIBLE FLUCTUATIONS OF THE CASPIAN LEVEL IN THE FUTURE

The author does not set himself the goal of analyzing in detail the numerous forecasts of fluctuations in the level of the Caspian Sea (this is an independent and difficult task). The main conclusion from the assessment of the results of forecasting fluctuations in the level of the Caspian can be drawn as follows. Although the forecasts were based on completely different approaches (both deterministic and probabilistic), there was not a single reliable forecast. The main difficulty in using deterministic forecasts based on the sea water balance equation is the lack of development of the theory and practice of ultra-long-term forecasts of climate change over large areas.

When the sea level decreased in the 1930s and 1970s, most researchers predicted its further fall. In the last two decades, when sea level rise began, most forecasts predicted an almost linear and even accelerating rise in level to -25 and even -20 abs. m and above at the beginning of the XXI century. In this case, three factors were not taken into account. First, the periodic nature of fluctuations in the level of all endorheic reservoirs. The instability of the Caspian level and its periodic nature are confirmed by the analysis of its current and past fluctuations. Secondly, at sea level close to - 26 abs. m, the flooding of large sor bays dried up at a low level will begin in the north east coast Caspian - Dead Kultuk and Kaydak, as well as low-lying territories in other places of the coast. This would lead to an increase in the area of ​​shallow waters and, as a consequence, an increase in evaporation (up to 10 km3/year). With a higher sea level, the outflow of water to Kara-Bogaz-Gol will increase. All this should stabilize or at least slow down the level growth. Thirdly, level fluctuations under the conditions of the modern climatic epoch (the last 2000 years), as shown above, are limited by the risk zone (from -30 to -25 abs. m). Taking into account the anthropogenic decrease in runoff, the level is unlikely to exceed the mark of 26-26.5 abs. m.

The decrease in average annual levels in the last four years by a total of 0.34 m, possibly indicates that in 1995 the level reached its maximum (-26.66 abs. m), and a change in the trend of the Caspian level. In any case, the prediction that sea level is unlikely to exceed 26 abs. m, apparently justified.

In the 20th century, the level of the Caspian Sea changed within 3.5 m, first dropping and then rising sharply. Such behavior of the Caspian Sea is the normal state of a closed reservoir as an open dynamic system with variable conditions at its inlet.

Each combination of incoming (river runoff, precipitation on the sea surface) and outgoing (evaporation from the surface of the reservoir, outflow to the Kara-Bogaz-Gol Bay) components of the Caspian water balance corresponds to its own level of equilibrium. Since the components of the water balance of the sea also change under the influence of climatic conditions, the level of the reservoir fluctuates, trying to reach an equilibrium state, but never reaches it. Ultimately, the trend in the level of the Caspian in given time depends on the ratio of precipitation minus evaporation in the watershed (in the basins of the rivers that feed it) and evaporation minus precipitation over the reservoir itself. There is really nothing unusual about the recent rise of the Caspian Sea level by 2.3 m. Such level changes have occurred many times in the past and did not cause irreparable damage. natural wealth Caspian. The current rise in sea level has become a catastrophe for the economy of the coastal zone only because of the unreasonable development of this risk zone by man.

Vadim Nikolaevich Mikhailov, Doctor of Geographical Sciences, Professor of the Department of Terrestrial Hydrology of the Faculty of Geography of Moscow State University, Honored Worker of Science of the Russian Federation, full member of the Academy of Water Management Sciences. Area of ​​scientific interests - hydrology and water resources, interaction of rivers and seas, deltas and estuaries, hydroecology. Author and co-author of about 250 scientific papers, including 11 monographs, two textbooks, four scientific and methodological manuals.

The coastline of the Caspian Sea is estimated at about 6500 - 6700 kilometers, with islands - up to 7000 kilometers. The shores of the Caspian Sea in most of its territory are low-lying and smooth. In the northern part of the coastline is indented water streams and the islands of the Volga and Ural deltas, the shores are low and swampy, and the water surface in many places is covered with thickets. The east coast is dominated by limestone shores adjacent to semi-deserts and deserts. The most winding coasts are on the west coast in the area of ​​the Apsheron Peninsula and on the east coast in the area of ​​the Kazakh Gulf and Kara-Bogaz-Gol.

Peninsulas of the Caspian Sea

Large peninsulas of the Caspian Sea:
* Agrakhan Peninsula
* Absheron peninsula, located on the western coast of the Caspian Sea in the territory of Azerbaijan, at the northeastern end of the Greater Caucasus, the cities of Baku and Sumgayit are located on its territory
* Buzachi
* Mangyshlak, located on the eastern coast of the Caspian Sea, on the territory of Kazakhstan, on its territory is the city of Aktau.
* Miankale
* Tub-Karagan

There are about 50 large and medium-sized islands in the Caspian Sea with a total area of ​​approximately 350 square kilometers.

Most major islands:

* Ashur-Ada
* Garasu
* Gum
* Dash
* Zira (island)
* Zyanbil
* Kur Dasha
* Hara Zira
* Sengi-Mugan
* Chechen (island)
* Chygyl

Large bays of the Caspian Sea:

* Agrakhan Bay,
* Komsomolets (bay),
* Mangyshlak,
* Kazakh (bay),
* Turkmenbashi (Gulf) (former Krasnovodsk),
* Turkmen (bay),
* Gyzylagach,
* Astrakhan (Bay)
* Gyzlar
* Hyrcanus (former Astarabad) and
* Anzali (former Pahlavi).

Rivers flowing into the Caspian Sea

130 rivers flow into the Caspian Sea, of which 9 rivers have a mouth in the form of a delta. Large rivers flowing into the Caspian Sea are the Volga, Terek (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Samur (Russian border with Azerbaijan), Atrek (Turkmenistan) and others. largest river, which flows into the Caspian Sea - the Volga, its average annual drainage is 215-224 cubic kilometers. The Volga, Ural, Terek and Emba provide up to 88 - 90% of the annual drainage of the Caspian Sea.

Caspian Sea Basin

The area of ​​the Caspian Sea basin is approximately 3.1 - 3.5 million square kilometers, which is approximately 10 percent of the world's closed water basins. The length of the Caspian Sea basin from north to south is about 2,500 kilometers, from west to east - about 1,000 kilometers. The Caspian Sea basin covers 9 states - Azerbaijan, Armenia, Georgia, Iran, Kazakhstan, Russia, Uzbekistan, Turkey and Turkmenistan.

coastal states

The Caspian Sea washes the shores of five coastal states:
* Russia (Dagestan, Kalmykia and Astrakhan region) - in the west and north-west, the length of the coastline is 695 kilometers
* Kazakhstan - in the north, northeast and east, the length of the coastline is 2320 kilometers
* Turkmenistan - in the southeast, the length of the coastline is 1200 kilometers
* Iran - in the south, coastline length - 724 kilometers
* Azerbaijan - in the southwest, the length of the coastline is 955 kilometers

Cities on the coast of the Caspian Sea

The largest city - a port on the Caspian Sea - Baku, the capital of Azerbaijan, which is located in the southern part of the Absheron Peninsula and has 2,070 thousand people (2003). Other large Azerbaijani Caspian cities are Sumgayit, which is located in the northern part of the Absheron Peninsula, and Lankaran, which is located near the southern border of Azerbaijan. To the South-East of the Absheron Peninsula, there is a settlement of oil workers Neftyanye Kamni, whose facilities are located on artificial islands, overpasses and technological sites.

Large Russian cities - the capital of Dagestan Makhachkala and the most Southern City Russia's Derbent - located on the western coast of the Caspian Sea. port city Astrakhan is also considered to be part of the Caspian Sea, which, however, is not located on the shores of the Caspian Sea, but in the Volga delta, 60 kilometers from north coast Caspian Sea.

On the eastern shore of the Caspian Sea is the Kazakh city - the port of Aktau, in the north in the Ural delta, 20 km from the sea, the city of Atyrau is located, south of Kara-Bogaz-Gol on the northern shore of the Krasnovodsk Bay - the Turkmen city of Turkmenbashi, formerly Krasnovodsk. Several Caspian cities are located on the southern (Iranian) coast, the largest of them is Anzali.

Area, depth, volume of water

The area and volume of water in the Caspian Sea varies significantly depending on fluctuations in water levels. At a water level of -26.75 m, the area was approximately 392,600 square kilometers, the volume of water was 78,648 cubic kilometers, which is approximately 44 percent of the world's lake water reserves. The maximum depth of the Caspian Sea is in the South Caspian depression, 1025 meters from its surface level. In terms of maximum depth, the Caspian Sea is second only to Baikal (1620 m) and Tanganyika (1435 m). The average depth of the Caspian Sea, calculated from the bathygraphic curve, is 208 meters. At the same time, the northern part of the Caspian Sea is shallow, its maximum depth does not exceed 25 meters, and the average depth is 4 meters.

Water level fluctuations

The water level in the Caspian Sea is subject to significant fluctuations. According to modern science, over the past 3 thousand years, the amplitude of changes in the water level of the Caspian Sea has amounted to 15 meters. Instrumental measurement of the level of the Caspian Sea and systematic observations of its fluctuations have been carried out since 1837, during this time the highest water level was recorded in 1882 (-25.2 m.), the lowest - in 1977 (-29.0 m.) , since 1978 the water level has been rising and in 1995 it reached -26.7 m, since 1996 there has again been a downward trend in the level of the Caspian Sea. Scientists associate the causes of changes in the water level of the Caspian Sea with climatic, geological and anthropogenic factors.

Water temperature

The water temperature is subject to significant latitudinal changes, most pronounced in winter, when the temperature changes from 0-0.5 °C at the ice edge in the north of the sea to 10-11 °C in the south, i.e. the water temperature difference is about 10 °C. For shallow water areas with depths less than 25 m, the annual amplitude can reach 25-26 °C. On average, the water temperature near the western coast is 1-2 °C higher than that of the eastern one, and in the open sea the water temperature is 2-4 °C higher than near the coasts. By the nature of the horizontal structure of the temperature field in the annual cycle of variability, three time interval in the upper 2-meter layer. From October to March, the water temperature increases in the south and east, which is especially evident in the Middle Caspian. Two stable quasi-latitudinal zones can be distinguished, where the temperature gradients are increased. This is, firstly, the border between the North and Middle Caspian, and, secondly, between the Middle and South. At the ice edge, in the northern frontal zone, the temperature in February-March increases from 0 to 5 °C, in the southern frontal zone, in the area of ​​the Apsheron threshold, from 7 to 10 °C. During this period, the least chilled waters are in the center of the South Caspian, which form a quasi-stationary core.

In April-May, the area of ​​minimum temperatures moves to the Middle Caspian, which is associated with faster warming of waters in the shallow northern part of the sea. True, at the beginning of the season in the northern part of the sea, a large amount of heat is spent on melting ice, but already in May the temperature rises here to 16-17 °C. In the middle part, the temperature at this time is 13-15 °C, and in the south it rises to 17-18 °C.

The spring warming of the water evens out the horizontal gradients, and the temperature difference between the coastal areas and the open sea does not exceed 0.5 °C. The heating of the surface layer, which begins in March, breaks the uniformity in the temperature distribution with depth. In June-September, horizontal uniformity is observed in the temperature distribution in the surface layer. In August, which is the month of the greatest warming, the water temperature throughout the sea is 24-26 ° C, and in southern regions rises to 28 °C. In August, the water temperature in shallow bays, for example, in Krasnovodsk, can reach 32 °C. The main feature of the water temperature field at this time is upwelling. It is observed annually along the entire eastern coast of the Middle Caspian and partially penetrates even into the South Caspian.

The rise of cold deep waters occurs with varying intensity as a result of the influence of northwestern winds prevailing in the summer season. The wind of this direction causes the outflow of warm surface waters from the coast and the rise of colder waters from the intermediate layers. Upwelling starts in June, but it reaches its highest intensity in July-August. As a result, a decrease in temperature (7-15 °C) is observed on the surface of the water. Horizontal temperature gradients reach 2.3 °C at the surface and 4.2 °C at a depth of 20 m.

The center of upwelling is gradually shifting from 41-42° N. latitude in June, to 43-45 ° north. latitude in September. Summer upwelling is of great importance for the Caspian Sea, radically changing the dynamic processes in the deep water area. In the open areas of the sea, in late May - early June, the temperature jump layer begins to form, which is most pronounced in August. Most often, it is located between the horizons of 20 and 30 m in the middle part of the sea and 30 and 40 m in the southern part. Vertical temperature gradients in the shock layer are very significant and can reach several degrees per meter. In the middle part of the sea, due to the surge near the eastern coast, the shock layer rises close to the surface.

Since there is no stable baroclinic layer in the Caspian Sea with a large potential energy reserve similar to the main thermocline of the World Ocean, with the cessation of the effect of the prevailing winds that cause upwelling, and with the onset of autumn-winter convection in October-November, the temperature fields are rapidly reorganized to the winter regime. In the open sea, the water temperature in the surface layer drops in the middle part to 12-13 °C, in the southern part to 16-17 °C. In the vertical structure, the shock layer is washed out due to convective mixing and disappears by the end of November.

Water composition

The salt composition of the waters of the closed Caspian Sea differs from that of the ocean. There are significant differences in the ratios of the concentrations of salt-forming ions, especially for the waters of areas under the direct influence of continental runoff. The process of metamorphization of sea waters under the influence of continental runoff leads to a decrease in the relative content of chlorides in the total amount of salts in sea waters, an increase in the relative amount of carbonates, sulfates, calcium, which are the main components in the chemical composition of river waters. The most conservative ions are potassium, sodium, chlorine and magnesium. The least conservative are calcium and bicarbonate ion. In the Caspian, the content of calcium and magnesium cations is almost two times higher than in the Sea of ​​Azov, and sulfate anion is three times higher. The salinity of the water changes especially sharply in the northern part of the sea: from 0.1 units. psu in the mouth areas of the Volga and Urals up to 10-11 units. psu on the border with the Middle Caspian.

Mineralization in shallow saline bays-kultuks can reach 60-100 g/kg. In the Northern Caspian, during the entire ice-free period from April to November, a quasi-latitudinal salinity front is observed. The greatest desalination associated with the spread of river runoff over the sea area is observed in June. The formation of the salinity field in the Northern Caspian is greatly influenced by the wind field. In the middle and southern parts of the sea, salinity fluctuations are small. Basically, it is 11.2-12.8 units. psu, increasing in the southern and eastern directions. Salinity increases insignificantly with depth (by 0.1–0.2 psu).

In the deep-water part of the Caspian Sea, in the vertical salinity profile, characteristic troughs of isohalines and local extrema are observed in the area of ​​the eastern continental slope, which indicate the processes of near-bottom creep of waters becoming saline in the eastern shallow waters of the South Caspian. The salinity value also strongly depends on the sea level and (which is interrelated) on the amount of continental runoff.

Bottom relief

The relief of the northern part of the Caspian is a shallow wavy plain with banks and accumulative islands, the average depth of the Northern Caspian is about 4-8 meters, the maximum does not exceed 25 meters. The Mangyshlak threshold separates the Northern Caspian from the Middle. The Middle Caspian is quite deep, the depth of water in the Derbent depression reaches 788 meters. The Apsheron threshold separates the Middle and South Caspian. The South Caspian is considered deep water, the depth of water in the South Caspian depression reaches 1025 meters from the surface of the Caspian Sea. Shell sands are common on the Caspian shelf, deep-water areas are covered with silty sediments, and in some areas there is an outcrop of bedrock.

Climate

The climate of the Caspian Sea is continental in the northern part, temperate in the middle part and subtropical in the southern part. In winter, the average monthly temperature of the Caspian varies from -8 -10 in the northern part to +8-10 in the southern part, in summer - from +24-25 in the northern part to +26-27 in the southern part. The maximum temperature recorded on the east coast is 44 degrees.

The average annual rainfall is 200 millimeters per year, ranging from 90-100 millimeters in the arid eastern part to 1,700 millimeters off the southwestern subtropical coast. Evaporation of water from the surface of the Caspian Sea is about 1000 millimeters per year, the most intense evaporation in the area of ​​the Absheron Peninsula and in the eastern part of the South Caspian is up to 1400 millimeters per year.

Winds often blow on the territory of the Caspian Sea, their average annual speed is 3-7 meters per second, northern winds prevail in the wind rose. In the autumn and winter months, the winds increase, the wind speed often reaches 35-40 meters per second. The most windy territories are the Apsheron Peninsula and the environs of Makhachkala - Derbent, where the highest wave was recorded - 11 meters.

currents

The circulation of water in the Caspian Sea is connected with the runoff and winds. Since most of the water flow falls on the Northern Caspian, the northern currents predominate. An intense northern current carries water from the Northern Caspian along the western coast to the Absheron Peninsula, where the current is divided into two branches, one of which moves further along the western coast, the other goes to the Eastern Caspian.

Animal world

The fauna of the Caspian is represented by 1809 species, of which 415 are vertebrates. 101 species of fish are registered in the Caspian world, and most of the world's stocks of sturgeon are concentrated in it, as well as such freshwater fish as vobla, carp, pike perch. The Caspian Sea is the habitat of such fish as carp, mullet, sprat, kutum, bream, salmon, perch, pike. A marine mammal, the Caspian seal, also lives in the Caspian Sea. Since March 31, 2008, 363 dead seals have been found on the coast of the Caspian Sea in Kazakhstan.

Vegetable world

The flora of the Caspian Sea and its coast is represented by 728 species. Of the plants in the Caspian Sea, algae predominate - blue-green, diatoms, red, brown, char and others, of flowering - zoster and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were brought into the Caspian Sea by man either consciously or on the bottoms of ships.

Origin of the Caspian Sea

The Caspian Sea is of oceanic origin - its bed is composed of oceanic-type earth's crust. It was formed about 10 million years ago, when the closed Sarmatian Sea, which lost contact with the world's oceans about 70 million years ago, was divided into two parts - the "Caspian Sea" and the Black Sea.

Anthropological and cultural history of the Caspian Sea

Finds in the Khuto cave near the southern coast of the Caspian Sea indicate that a person lived in these parts about 75 thousand years ago. The first mention of the Caspian Sea and the tribes living on its coast are found in Herodotus. Approximately in the V-II centuries. BC e. Saka tribes lived on the coast of the Caspian Sea. Later, during the period of the settlement of the Turks, in the period of the IV-V centuries. n. e. Talysh tribes (Talysh) lived here. According to ancient Armenian and Iranian manuscripts, the Russians sailed the Caspian Sea from the 9th - 10th century.

Exploration of the Caspian Sea

The exploration of the Caspian Sea was started by Peter the Great, when, on his orders, an expedition was organized in 1714-1715 under the leadership of A. Bekovich-Cherkassky. In the 1820s, hydrographic studies were continued by I.F. Soyomov, and later by I.V. Tokmachev, M.I. Voinovich and other researchers. At the beginning of the 19th century, instrumental surveying of the coast was carried out by I.F. Kolodkin, in the middle of the 19th century. - instrumental geographic survey under the guidance of N. A. Ivashintsev. Since 1866, for more than 50 years, expeditionary research on the hydrology and hydrobiology of the Caspian Sea has been carried out under the leadership of N. M. Knipovich. In 1897, the Astrakhan Research Station was founded. In the first decades of Soviet power in the Caspian Sea, geological research by I. M. Gubkin and other Soviet geologists was actively carried out, mainly aimed at finding oil, as well as research on the study of the water balance and fluctuations in the level of the Caspian Sea.

Mining of oil and gas

Many oil and gas fields are being developed in the Caspian Sea. The proven oil resources in the Caspian Sea are about 10 billion tons, the total resources of oil and gas condensate are estimated at 18-20 billion tons.

Oil production in the Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf. In the second half of the 19th century, oil production began on an industrial scale on the Absheron Peninsula, and then on other territories.

In addition to oil and gas production, salt, limestone, stone, sand, and clay are also mined on the coast of the Caspian Sea and the Caspian shelf.

Shipping

Shipping is developed in the Caspian Sea. Ferry crossings operate on the Caspian Sea, in particular, Baku - Turkmenbashi, Baku - Aktau, Makhachkala - Aktau. The Caspian Sea has a navigable connection with Sea of ​​Azov through the rivers Volga, Don and the Volga-Don Canal.

Fishing and seafood

Fishing (sturgeon, bream, carp, pike perch, sprat), caviar, and seal fishing. More than 90 percent of the world's sturgeon catch is carried out in the Caspian Sea. In addition to industrial production, illegal production of sturgeon and their caviar flourishes in the Caspian Sea.

Recreational resources

The natural environment of the Caspian coast with sandy beaches, mineral waters and therapeutic mud in the coastal zone creates good conditions for relaxation and treatment. At the same time, in terms of the degree of development of resorts and the tourism industry, the Caspian coast is noticeably losing Black Sea coast Caucasus. At the same time, in recent years, the tourism industry has been actively developing on the coast of Azerbaijan, Iran, Turkmenistan and Russian Dagestan.

Ecological problems

The environmental problems of the Caspian Sea are associated with water pollution as a result of oil production and transportation on the continental shelf, the flow of pollutants from the Volga and other rivers flowing into the Caspian Sea, the vital activity of coastal cities, as well as the flooding of individual objects due to the rise in the level of the Caspian Sea. Predatory harvesting of sturgeons and their caviar, rampant poaching lead to a decrease in the number of sturgeons and forced restrictions on their production and export.

Border dispute over the status of the Caspian Sea

After the collapse of the USSR, the division of the Caspian Sea has long been and still remains the subject of unsettled disagreements related to the division of the resources of the Caspian shelf - oil and gas, as well as biological resources. For a long time there were negotiations between littoral 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. In 2003, Russia, Azerbaijan and Kazakhstan signed an agreement on the partial division of the Caspian Sea along the median line.

Coordinates: 42.622596 50.041848