Selenga

thumb|Bridge over the Selenga River in Ulan-Ude

The Selenga ( ) or Selenge is a major river in Mongolia and Buryatia, Russia. Originating from its headwater tributaries, the Ider and the Delger mörön, it flows for before draining into Lake Baikal. The Selenga therefore makes up the most distant headwaters of the Yenisey-Angara river system.

Carrying of water into Lake Baikal, it makes up almost half of the riverine inflow into the lake, and forms a wide delta of when it reaches the lake.

Periodic annual floods are a feature of the Selenga River. The floods can be classified as “ordinary”, “large” or “catastrophic” based on the degree of impact. Of the twenty-six documented floods that occurred between 1730 and 1900, three were “catastrophic”. The three “catastrophic” floods were the floods of 1830, 1869 and 1897.

The Selenga River basin is a semi-arid region occupying . It is part of the Arctic Ocean Basin and mainly located in northern Mongolia. Stone implement artifacts found on the Selenga River at the end of the 19th century have been used to form a link between Native Americans and their ancestors in East Asia. The climate of the Selenga basin is influenced by the Siberian High, a powerful anti-cyclone, and consists of harsh winters, with the river freezing from November to April, and warm summers.

The Selenga River delta is a Ramsar site, surrounded by marshlands. Found in the administrative region of the Republic of Buryatia, the wetlands are the habitat of a large number of threatened and endemic species, including the Siberian Baikal sturgeon and over 170 species of birds. The Selenge-Orkhon forest steppe includes the areas of the Orkhon and Selenge river basins. The region has scattered forests and extensive mountain ranges.

River modifications like the Irkutsk Hydroelectric Power Station have affected the environment of the Selenga Delta, causing it to become waterlogged. Activities including mining, agriculture, breeding and dumping of wastewater have also affected the environment of the river. There has been an observed degradation of water quality from these anthropogenic factors. Natural factors like erosion processes and weathering have also contributed to the decline in water quality.

The proposed Shuren Hydropower Plant Project was protested against by environmental groups because of the potential ecological ramifications it would have on the Selenga Delta. The reasons cited included potential disruption to the flow of the river and the breeding grounds of endemic fish species in Lake Baikal.

Name

The name Selenge comes from Mongolian seleh, which means "to swim". 'Selenga' is the russified version of the same.

An alternate source believes the name originated with the Evenki word sele ("iron") to which the possessive nge suffix was added.

The Selenge Province of Mongolia is named after the river.

File:The bridge across the Selenga River in the city of Ulan-Ude.jpg|Automobile bridge over the Selenga River in the city of Ulan-Ude

File:Selenga River bridge.jpg|Railway bridge over the Selenga River outside of Ulan-Ude, Russia

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History

Archaeology

At the end of the 19th century, evidence of Paleolithic culture was discovered in the Selenga River basin. The artifacts found were collections of stone implements. During 1928 and 1929, G. P. Sosnovskii, under the purview of the Academy of Sciences of the U.S.S.R., directed an archaeological Stone Age study in the Selenga Valley near Kiakhta. In this expedition, Sosnovokii discovered remains of local Paleolithic culture in an area that stretched from "the valley of the Selenga River from the Mongolian Frontier down to Selenginsk."

The "Buriat-Mongol Archaeological Expedition from the Institute for the History of Material Culture, Academy of Sciences of the U.S.S.R and the Institute of Culture of the Buriat-Mongol A.S.S.R", undertook a Paleolithic study in the Trans-Baikal region from 1947 to 1958. Directed by A. P. Okladnikov, the study uncovered 30 new sites, including one that covered the area from Selenginsk to the Selenga River mouth, which provided evidence of a Paleolithic-type culture. Among these 30 sites was one called Ust-Kyakhta-3.

In a study published in volume 181 of the journal Cell, the link between Native Americans and their ancestors in East Asia was established using one of the tooth fragments found at the Ust-Kyakhta-3 site.

Floods

Periodic floods are characteristic of the Selenga River, with small flooding events observed annually.

The flood of 1830 is the first flood that was recorded in some detail. On August 1, 1830, the Selenga River and its tributaries, the Chikoy, Dzhida, Khilok and Temnik Rivers, burst their banks. The flood plains and the islands in the Selenga River were completely flooded. On August 16, Verkhneudinsk, the city now known as Ulan-Ude, was flooded and the water level in the city reached . The flood destroyed fifty-four buildings in Selenginsk. After the flood, the town was moved to higher ground on the left bank of the Selenga River. There were also heavy losses in agriculture, with the flood making some pastures and hayfields unusable for an extended period after the flood. The river retreated to its banks by September 27.

Climate

A powerful Siberian anti-cyclone is the major influence on the climate of the Selenga basin. It is formed in September and October and disappears in April and May. Due to the anti-cyclone, the basin has a climate of harsh winters, which consist of sunny days and low air temperatures, and warm summers. The river experiences "...extended summer floods and short occasional (event-driven) floods in the other seasons."

Tributaries

The largest tributaries of the Selenga are, from source to mouth:

Ider (right)
Delger mörön (left)
Khanui (right)
Egiin Gol (left)
Orkhon (right)
Dzhida (left)
Chikoy (right)
Khilok (right)
Uda (right)

Watershed

The Selenga River basin is part of the larger international Arctic Ocean Basin and is located in northern Mongolia. A semi-arid region and Mongolia's largest basin, the basin occupies . The basin has two main rivers: the Selenga and its chief tributary, the Orkhon. The "major sub-basins are the Egiin, Ider, Orkhon and Tuul river basins" with Lake Baikal occupying 47% of the Selenga River basin. The sediment balance of the delta is dependent on physical processes, and this, in turn, affects the geochemical barrier functions of the area. During the period of the Irkutsk dam construction (1950–56), there was "increased sediment delivery to the delta" according to an article published in 2017 by Chalov et al. The wetlands of the Selenga River delta are classified as a Ramsar site and are found within the administrative region of the Republic of Buryatia. The wetlands support a large number of threatened and endemic species, including over 170 species of bird. Built on the Angara River, the station was designed to raise the water level of the Angara River to match the water level of Lake Baikal. It would then raise the water level of Lake Baikal by . On September 27, 2017, the World Bank froze its tender process on the Shuren Hydropower Plant Project.

Natural history

Fish

Leocottus kesslerii gussinensis and Leocottus kesslerii arachlensis are endemic subspecies of fish that are found in the Selenga River headwaters and the upper Khilok River. Lake Baikal is the habitat of the Siberian Baikal sturgeon. The Selenga river is a breeding ground for the sturgeon, with migration taking place within the river system. The fish has two migration periods, which occur during the warmer part of the year. The first migration period begins in the second half of April when the water temperature is , and finishes in approximately mid-June. The second migration of the Baikal sturgeon is the main migration period. It coincides with the summer floods of the Selenga. When the water temperature begins to cool, this signals the end of the migration. There is also a non-migrating species of sturgeon that inhabits the Selenga catchment.

Birds

Large populations of migrating, breeding and moulting waterbirds assemble at the wetlands in the Selenga Delta, which has been recognised as an Important Bird Area by BirdLife International. Migratory species include: The escalation of anthropogenic factors can be correlated with pollution by "potentially toxic elements, including metals and persistent organic pollutants."

Human use

The Selenga River has an influential role in managing the economic futures of Mongolia and Russia.