Irtiash

or Irtiazh, a freshwater lake in the northern part of Cheliabinsk Oblast, RSFSR, near the city of Kasli. Area, 53.5 sq km. Lake Irtiash is fed by a number of small rivers and is drained by the Techa (Tetsa), a right-bank tributary of the Iset’ (in the Irtysh basin). The lake is about 16 m deep and holds large numbers of fish, including pike, perch, and bream. Whitefish and carp have in addition been acclimatized.