The Moskva (, Moskva-reka) is a river running through western Russia. It rises about west of Moscow and flows roughly east through the Smolensk and Moscow Oblasts, passing through central Moscow. About southeast of Moscow, at the city of Kolomna, it flows into the Oka, itself a tributary of the Volga, which ultimately flows into the Caspian Sea. History In addition to Finnic tribes, the Moskva River is also the origin of Slavic tribes such as the Vyatichi tribe. Etymology Moskva and Moscow are two different renderings of the same Russian word Москва. The city is named after the river. Finnic Merya and Muroma people, who originally inhabited the area, called the river Mustajoki, in English: Black river. It has been suggested that the name of the city derives from this term, although several theories exist. To distinguish the river and the city, Russians usually call the river Moskva-reka (Moskva river) instead of just Moskva. Hydrology The river is long (or ), and the area of its drainage basin is . It has a vertical drop of (long-term average). The maximum depth is above Moscow city limits, and up to below it. Normally, it freezes in November–December and begins to thaw around late March. In Moscow, the river freezes occasionally; during an unusually warm winter in 2006–2007, ice began melting on January 25. The absolute water level in downtown Moscow is above sea level (long-term average of summer lows after World War II); a historical maximum of above sea level was set by the 1908 flood. Sources of water The main tributaries of the Moskva are, from source to mouth: Ruza (left) Istra (left) Skhodnya (left) Setun (right) Yauza (left) Pakhra (right) Pekhorka (left) Nerskaya (left) Severka (right) Sources of water are estimated as 61% thaw, 12% rain and 27% subterranean. Since completion of the Moscow Canal (1932–1937), the Moskva River has also collected a share of Upper Volga water. This has enabled reliable commercial shipping, which was previously interrupted by summer droughts (older dams built in 1785, 1836 and 1878 were not effective). The average discharge, including Volga waters, varies from near Zvenigorod to at the Oka inlet. The speed of the current, depending on the season, varies from (winter, dams closed) to (May, dams open). Cities and towns Moscow (), the capital of Russia, is situated on its banks. The river also flows through the towns of Mozhaysk,