The Volga Delta is the largest

river delta A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creat ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

and occurs where Europe's largest river system, the Volga River, drains into the

Caspian Sea The Caspian Sea is the world's largest inland body of water, described as the List of lakes by area, world's largest lake and usually referred to as a full-fledged sea. An endorheic basin, it lies between Europe and Asia: east of the Caucasus, ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

's Astrakhan Oblast, north-east of the republic of Kalmykia. The delta is located in the Caspian Depression—the far eastern part of the delta lies in

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

. The delta drains into the Caspian approximately downstream from the city of

Astrakhan Astrakhan (, ) is the largest city and administrative centre of Astrakhan Oblast in southern Russia. The city lies on two banks of the Volga, in the upper part of the Volga Delta, on eleven islands of the Caspian Depression, from the Caspian Se ...

. The Volga delta has grown significantly in the 20th century because of changes in the level of the Caspian Sea. In 1880, the delta had an area of . Today the Volga Delta covers an area of and is approximately across. It has a classical "delta pattern". The delta lies in the arid climate zone, characterized by very little rainfall. The region receives less than one inch of rainfall in January and July in normal years. Strong winds often sweep across the delta and form linear dunes. Along the front of the delta, one will find muddy sand shoals, mudflats, and coquina banks.

Three Zones

The changing level of the Caspian Sea has resulted in three distinct zones in the delta. The higher areas of the first zone are known as "Baer's mounds," named after researcher Karl Ernst von Baer who worked in this region. These mounds are linear ridges of clayey sands, ranging from in height, and averaging about . They are between in length. Between the Baer's mounds are depressions that fill with water and become either fresh or saline bays; the height from the bottom of a depression to the peak of its neighboring mound ranges from . These depressions, called "" (from Russian through Finnish, "small lake," as in Russia's Lake Ilmen), used to form part of the early, very deep river delta but gradually became separated from it. Because of their isolation from the fresh waters of the Volga, they are becoming increasingly saline. Together they form a "vast (more than ) and extremely diverse area of western substeppe (WSI)" which, because of the varying degrees of wetness and salinization, house a wealth of flora and fauna. The origin of these mounds and is still debated: the early suggestion that they were formed by aeolian (wind) action is now discredited, and now they are thought to have arisen either underwater or through river flow.Eric Bird

'Encyclopedia of the World's Coastal Landforms, vol. 2', p. 877 The second zone, in the delta proper, generally has very little relief (usually less than one metre), and is the site of active and abandoned water channels, small dunes and algal flats. The third zone is composed of a broad platform extending up to offshore, and is the submarine part of the delta.

Wildlife

The delta has been protected since the early 1900s, with one of the first Russian nature preserves ( Astrakhan Nature Reserve) having been set up there in 1919. Much of its local

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

is considered endangered. The delta is a major staging area for many species of water birds, raptors and passerines. Although the delta is best known for its sturgeons,

catfish Catfish (or catfishes; order (biology), order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Catfish are common name, named for their prominent barbel (anatomy), barbels, which resemble a cat's whiskers, though not ...

and

carp The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and a ...

are also found in large numbers in the delta region. The lotus has been adopted as the motif of the national flag of the neighbouring Kalmyks, since it is a venerated symbol in their Buddhist beliefs – they are the sole European people of Mongolian ( Oirat) origin.

Important Bird Area

The delta has been designated an Important Bird Area (IBA) by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...

because it supports significant numbers of many waterbird species, including breeding squacco herons, great white egrets and Dalmatian pelicans.

Protection and Destruction

Industrial and agricultural modification to the delta plain has resulted in significant wetland loss. Between 1984 and 2001, the delta lost of

wetland A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

s, or an average of approximately per year, from natural and human-induced causes. The Volga discharges large amounts of

industrial waste Industrial waste is the waste produced by industrial activity which includes any material that is rendered useless during a manufacturing process such as that of factories, mills, and mining operations. Types of industrial waste include dirt and ...

and sediment into the relatively shallow northern part of the Caspian Sea. The added fertilizers nourish the algal blooms that grow on the surface of the sea, allowing them to grow larger.

References

Wetland Loss in World Deltas
Coastal Studies Institute, Louisiana State University
wetlands.orgEarth Snapshot article "The Three Zones of the Volga Delta"

External links

Volga River Delta
at NASA Earth Observatory
Volga Delta
a
Natural Heritage Protection Fund
{{Authority control Freshwater ecoregions River deltas of Europe Landforms of Russia Caspian Sea Biosphere reserves of Russia Important Bird Areas of Russia Landforms of Astrakhan Oblast Volga basin Ramsar sites in Russia