a river in the Chuvash ASSR, a right tributary of the Volga. The Tsivil’ is 170 km long and drains an area of 4,690 sq km. It is formed by the confluence of the Bol’shaia Tsivil’ and Malaia Tsivil’, which rise in the Volga Upland. The river empties into the Kuibyshev Reservoir and is fed primarily by snow. The mean flow rate 51 km from the mouth is 17.2 cu m per sec. The river freezes over in November, and the ice breaks up in April. The Tsivil’ is navigable. The city of Tsivil’sk is situated on the Bol-’shaia Tsivil’ near its confluence with the Malaia Tsivil’.