The Ob (Russian: Обь) is a river in Russia that flows through Western Siberia. One of the largest rivers in the world. The length of the Ob is 3650 km (from the source of the Irtysh – 5410 km), the drainage basin area is 2,990,000 km². Water flow 287 km from the mouth (near Salekhard) is 12,492 m³/s. The average long-term flow is 403.981 km³/year. It originates at the confluence of the Biya and Katun in the foothills of Altai. At the mouth it forms the Gulf of Ob and flows into the Kara Sea.
The river is fed predominantly by snow, in Altai it is mixed: the share of snow feed is 40%, glacial 22%, rain 19% and groundwater 15%; in the taiga zone the share of snow supply is 55%, rainfall – 25%, groundwater – 20%.
The rise in levels begins even during freeze-up; when the river opens up as a result of congestion, intense short-term rises in levels occur. Because of this, some tributaries may experience a reversal of flow direction. In the upper reaches, the flood ends in July, the summer low water is unstable, and in September – October there is a rain flood.
In the middle and lower reaches, the decline of the flood with overlapping rain floods continues until freeze-up. On average, the river is under ice for 180 to 220 days a year, depending on how severe the winter is.
At the end of the 19th century, the Ob-Yenisei Canal was built, connecting the Ob with the Yenisei. It is currently unused and abandoned.
The river flows through the Altai Territory, Novosibirsk Region, Tomsk Region, Khanty-Mansi Autonomous Okrug and Yamalo-Nenets Autonomous Okrug.
Cities
A significant part of the population of Western Siberia lives on the banks of the Ob and the estuaries of rivers flowing into it. On the Ob there is the third most populous city in Russia, Novosibirsk, with its own agglomeration, and the large agglomeration of Barnaul-Novoaltaisk. The territory of Western Siberia adjacent to the Ob is called the Ob River.
- Biysk
- Barnaul
- Novoaltaysk
- Stone-on-Obi
- Berdsk (on the Berdsky Bay of the Novosibirsk Reservoir)
- Novosibirsk
- Kolpashevo
- Strezhevoy (on the Pasol channel)
- Nizhnevartovsk
- Megion
- Langepas (on the Kayukovskaya channel)
- Surgut
- Nefteyugansk
- Labytnangi
- Salekhard
The main ports and marinas of the Ob-Irtysh basin: Biysk river port, Barnaul river port, Novosibirsk, Tomsk, Samus, Nizhnevartovsk, Surgut, Labytnangi, Pavlodar, Omsk, Tobolsk, Tyumen, Khanty-Mansiysk.
