TheOb (/ˈɒb/)[5] is a major river in Russia. It is in westernSiberia, and with its tributary theIrtysh forms the world'sseventh-longest river system, at 5,410 kilometres (3,360 mi). The Ob forms at the confluence of theBiya andKatun which have their origins in theAltai Mountains. It is the westernmost of the three great Siberian rivers that flow into theArctic Ocean (the other two being theYenisei and theLena). Its flow is north-westward, then northward.
The internationally known name of the river is based on the Russian nameОбь (Obʹ,IPA:[opʲ]). Possibly fromProto-Indo-Iranian*Hā́p-, "river, water" (compareVedic Sanskritáp-,Persianāb,Tajikob, andPashtoobə, "water"). Katz (1990)[6] proposesKomiob 'river' as the immediate source of derivation for the Russian name. Katz's proposal of a common Finno-Ugric root, borrowed early on from a pre-Indo-Iranian source related to Sanskritambhas- 'water' is deemed improbable by Rédei (1992),[7] who prefers to analyse this as a later loan from a descendant of the non-nasal root form*Hā́p-.
The Ob itself is in Russia. Its tributaries extend into northernKazakhstan, a western corner of China and a tiny upland parcel of the western tip of Mongolia, where the wider borders match the drainage basin almost precisely. The river splits into more than one arm after the largeIrtysh flows into it at about 69° E. Originating in China, the Irtysh is the furthest source of the Ob. From their respective sources to the confluence, the Irtysh measures 4,248 kilometers (2,640 mi) and the Ob 2,538 km (1,577 mi). Other noteworthy tributaries are: from the east, theTom,Chulym,Ket,Tym andVakh rivers; and, from the west and south, theVasyugan, Irtysh (with theIshim andTobol rivers), andSevernaya Sosva.
The Ob zigzags west and north until it reaches 55° N, where it curves to the northwest, south of theSiberian Uvaly, at the western end of which it bends northwards, wheeling finally eastwards into theGulf of Ob, a 1,000-kilometre-long (620-mile) bay of theKara Sea, separating theYamal Peninsula from theGyda Peninsula.
The combined Ob-Irtysh system, thefourth-longest river system of Asia (afterYenisei, and China'sYangzi andYellow rivers), is 5,410 kilometres (3,360 mi) long, and the area of its basin 2,990,000 square kilometres (1,150,000 sq mi).The river basin of the Ob consists mostly ofsteppe,taiga, swamps,tundra, andsemi-desert topography. The floodplains of the Ob are characterised by many tributaries and lakes.The Ob is icebound at southernBarnaul from early in November to near the end of April, and at northernSalekhard, 150 km (93 mi) above its mouth, from the end of October to the beginning of June.[needs update][8]The Ob River crosses several climatic zones. The upper Ob valley, in the south, supports grapes, melons and watermelons, whereas the lower reaches of the Ob are Arctic tundra. The most temperate climates on the Ob are atBiysk, Barnaul, andNovosibirsk.
The Ob provides irrigation, drinking water, hydroelectric energy, and fishing (the river hosts more than 50 species of fish).There are several hydroelectric power plants along the Ob river, the largest being Novosibirskaya GES.[10]
The navigable waters within the Ob basin reach a total length of 15,000 km (9,300 mi).[8]The importance of navigation in the Ob basin for transport was particularly great before the completion of theTrans-Siberian Railway, since, despite the general south-to-north direction of the flow of Ob and most of its tributaries, the width of the Ob basin provided for (somewhat indirect) transport in the east–west direction as well.
TheNovgorodians were aware of the lands of western Siberia from at least the 11th century, which were designated by the Russian wordYugra.[11] Novgorod established two trade routes to the Ob River, both starting from the town ofUstyug.[12] The first route went along theSukhona andVychegda, then along theUsa to the lower reaches of the Ob.[12] The second route went down theNorthern Dvina, then along the coasts of theWhite Sea andKara Sea, before reaching the mouth of the Ob.[12]
The Russian settlements ofBeryozov andObdorsk were founded towards the end of the 16th century on the lower reaches of the Ob, whileSurgut was founded on the middle course of the Ob.[13]
Until the early 20th century, a particularly important western river-port wasTyumen, located on theTura, a tributary of theTobol. Reached by an extension of theYekaterinburg–Perm railway in 1885, and thus obtaining a rail link to theKama andVolga rivers in the heart of Russia, Tyumen became an important railhead for some years until the railway extended further east. In the eastern reaches of the Ob basin,Tomsk on theTom functioned as an important terminus.
Tyumen had its firststeamboat in 1836, and steamboats have navigated the middle reaches of the Ob since 1845. In 1916, there were 49 steamers on the Ob; 10 on the Yenisei.
In an attempt to extend the Ob navigable system even further, asystem of canals, utilising theKet, 900 km (560 mi) long in all, was built in the late 19th-century to connect the Ob with theYenisei, but soon abandoned as being uncompetitive with therailway.
The Trans-Siberian Railway, once completed, provided for more direct, year-round transport in the east–west direction. But the Ob river-system still remained important for connecting the huge expanses ofTyumen Oblast andTomsk Oblast with the major cities along the Trans-Siberian route, such as Novosibirsk orOmsk. In the second half of the 20th century, construction of rail links toLabytnangi,Tobolsk, and the oil and gas cities ofSurgut, andNizhnevartovsk provided more railheads, but did not diminish the importance of the waterways for reaching places still not served by the rail.
A dam built near Novosibirsk in 1956 created the then-largest artificial lake inSiberia, calledNovosibirsk Reservoir.From the 1960s through 1980s, Soviet engineers and administrators contemplated a gigantic project todivert some of the waters of Ob and Irtysh toKazakhstan and the SovietCentral Asian republics, replenishing theAral Sea as well. The project never left the drawing board, abandoned in 1986 for economic and environmental considerations.[14][15]
The water in the river is significantly polluted. In the lower reaches, the maximum permissible concentrations of petroleum products are exceeded by 9–10 times. The oxygen content in the water is 4 times lower than normal[16]
^abcd"Ob River at Salekhard".River Discharge Database. Center for Sustainability and the Global Environment. 2010-02-13. Archived fromthe original on 2010-06-12. Retrieved2010-11-06.
