(Bol’shaia Kos’va), a river flowing mainly in Perm’ Oblast, RSFSR; a left tributary of the Kama River (it flows into the Kama Reservoir). Length, 283 km; basin area, 6,300 sq km. It flows mainly along the western slopes of the middle Ural Mountains. It is fed from mixed sources, predominantly rain. The average flow 11 km from the mouth is approximately 90 cu m per sec. The river freezes over in November and thaws in the second half of April or in May. The city of Gubakha and the Shirokovskii reservoir and hydroelectric power plant are located along the river. The Kizelovskii coal basin is located in the Kos’va basin.