Bolshoy Yenisei River

Bolshoy Yenisei River (Tuvan: Бии-Хем/Bii-Khem) is a river in the Republic of Tuva, the right source of the Yenisei.

The name Bii-Khem in Tuvan means "big river".

The length is 650-kilometre (400 mi), its basin area is 56,800-square-kilometre (21,900 sq mi). The river is navigable for 285-kilometre (177 mi) from the mouth. It flows out of Lake Kara-Balik. High water level of the river is due to the fact that the catchment area of the river includes Todzha hollow, which relief forms a unique catchment basin. The river receives numerous tributaries, the largest of them are right Toora-Khem, Khamsara, Systyg-Khem. The basin of the Bolshoy Yenisei is a mountainous region, which borders in the north and east are the administrative boundaries of Tuva with Buryatia, Irkutsk Oblast and Krasnoyarsk Krai. The river flows through the Tuva basin in its lower course. Near the city of Kyzyl it joins the Kaa-Hem, forming the Ulug-Khem, which is actually the beginning of the Upper Yenisei. The whole Todzhinsky District of the Republic of Tuva is located in the basin of the river, its centre, Toora-Khem, is located at the confluence of the Toora-Khem tributary.

The upper course of the river is virtually untouched virgin territory. A unique area of the nine extinct volcanoes with unique geological features is also located here. A beautiful lake Azas (its other name is Todzha) is located on the Toora-Khem tributary, the lake is one of the most interesting tourist sites of the Republic. Almost the entire lake and the area of the river are included in the Azas Federal Reserve.