Biriusa

Biriusa

 

or Ona, or Bol’shaia Biriusa, a river in Irkutsk Oblast and Krasnoiarsk Krai, RSFSR. It merges with the Chuna River to form the Taseeva River (a left tributary of the Angara). It is 1,012 km long, drains a basin of 55,800 sq km, and rises from the Dzhuglymskii Ridge in Vostochnyi Saian. In its middle and lower reaches it flows across the Central Siberian Plateau. Its chief tributaries are the Tagul, Tumanshet, and Poima on the left, and the Malaia Biriusa and Toporok on the right. The Biriusa basin includes about 300 lakes with a combined area of 14.3 sq km. Snow and rain constitute 80 percent of its annual discharge. The Biriuza freezes over in October or November and opens up again in late April or early May. It is used for floating timber. The city of Biriusinsk is located on the river.