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Selenga

geography Maturity 7-9 Next article →

The Selenga is a vital river system in Asia. It flows through northern Mongolia and the Russian Republic of Buryatia. The river is a major part of the Arctic Ocean Basin. It serves as the primary source of water for Lake Baikal. In fact, the Selenga provides almost half of the total riverine inflow to the lake.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude

The river begins when two headwater tributaries meet. These are the Ider and the Delger mörön. The Delger flows from the Sangilen Mountains on the border of Mongolia and Tyva. The Ider starts in the Hangyn Mountains of central Mongolia. After these rivers converge, the Selenga moves northeast. It joins the Orkhon River at Suhbaatar. Then, the water flows north into Russia. It turns east toward Ulan-Ude before moving north to Tataurovo. Finally, it flows west into a wide delta. This delta is lobate in shape and is 40 km wide.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude

The climate of the Selenga basin is driven by the Siberian High. This is a powerful anti-cyclone, or a large system of high pressure. It forms in September and October. It disappears in April and May. This system creates harsh winters with very low temperatures. In January, the mean air temperature is -19.4 degrees Celsius. The river is covered in ice from November to April. Summers are warm, with a mean temperature of 14 degrees Celsius in July. The river is ice-free from May to October. During spring and early summer, snowmelt causes the maximum discharge. This means the river flows with its greatest volume.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude

Flooding is a regular feature of the Selenga. Scientists classify these floods by their impact. They use terms like "ordinary," "large," or "catastrophic." A catastrophic flood covers most of the river basin. These events can flood entire settlements and cause human casualties. They are estimated to occur three to four times per century. Between 1730 and 1900, there were twenty-six documented floods. Only three of these were catastrophic. The catastrophic floods occurred in 1830, 1869, and 1897. The 1830 flood was the first to be recorded in great detail. It caused the city of Verkhneudinsk, now Ulan-Ude, to flood.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude

Archaeology provides deep links to the past in this region. At the end of the 19th century, stone implement artifacts were found. These artifacts belonged to a Paleolithic culture. In 1928 and 1929, G. P. Sosnovskii led a study near Kiakhta. Later, from 1947 to 1958, A. P. Okladnikov directed a large expedition. This study uncovered 30 new sites. One important site was called Ust-Kyakhta-3. It was excavated in 1976 and 1978. Researchers found over 40,000 stone artifacts and many faunal remains. In 2012, scientists found two human tooth fragments at this site. A study in the journal Cell used these teeth. It established a link between Native Americans and ancestors in East Asia.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude

The Selenga delta is a highly significant ecological area. It is a Ramsar site, which is a protected wetland. The area is surrounded by marshlands. It is home to over 170 species of birds. It also provides a habitat for the Siberian Baikal sturgeon. This fish is an endemic species, meaning it is found nowhere else. However, human activities have caused environmental changes. Mining, agriculture, and wastewater dumping have lowered water quality. These are known as anthropogenic factors. Erosion and weathering also affect the water naturally.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude

River modifications have also changed the delta's environment. The Irkutsk Hydroelectric Power Station was completed in 1956. It sits on the Angara River. The station was built to raise the water level of the Angara. This was done to match the level of Lake Baikal. This causes water-level fluctuations in the lake. These changes can make parts of the Selenga Delta waterlogged. In 2015, Mongolia planned the Shuren Hydropower Plant Project. Environmental groups protested this plan. They feared it would disrupt river flow. They also worried about the breeding grounds of endemic fish in Lake Baikal.

Bridge over the Selenga River in Ulan-Ude
Bridge over the Selenga River in Ulan-Ude
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