a river in Moscow and Vladimir oblasts, RSFSR, flowing partially along their border with Ivanovo and Gorky oblasts; a left tributary of the Oka.
The Kliaz’ma is 686 km long and has a basin area of 42,500 sq km. It originates in the Moscow Upland and flows through the Meshchera Lowland; it is fed primarily by snow. The average rate of flow at the city of Kovrov (185 km from the mouth) is 147 cu m per sec. The river freezes over in November and thaws in mid-April.
The Kliaz’ma’s main tributaries are the Ucha, Voria, Kirzhach, Peksha, Nerl’, Uvod’, Teza, and Lukh on the left and the Sudogda and Suvoroshch’ on the right. The waters of the Kliaz’ma and its tributaries are used as a water supply; the flow in the upper reaches is regulated by the Kliaz’ma, Akulovskii, and Pestovo reservoirs. Most of the flow in the upper reaches is used to feed the Moscow Canal. The Kliaz’ma is navigable for 120 km from its mouth and in the area of the Kliaz’ma Reservoir. The cities of Shchelkovo, Losino-Petrovskii, Noginsk, Pavlovskii Posad, Orekhovo-Zuevo, Sobinka, Vladimir, Kovrov, Viazniki, and Gorokhovets are located on the Kliaz’ma.