a river in Perm’ Oblast, RSFSR; a left tributary of the Vishera (Kama River basin). The Iaz’va measures 162 km in length and drains an area of 5,900 sq km. It is formed at the confluence of the Severnaia Iaz’va and the Poludennaia Iaz’va, which flow from the Kvarkush Range. The river then flows mainly through a swampy lowland. It is fed mainly by snow. The mean flow rate is approximately 70 cu m per sec. The Iaz’va freezes over in late October to early November, and the ice breaks up from late April to early May. The river is used to float timber.