a river in the Tatar ASSR and the Ulianovsk and Kuibyshev oblasts in the RSFSR. A left tributary of the Volga, the Bol’shoi Cheremshan flows into the Kuibyshev reservoir. It is 336 km long and has a basin of 11,500 sq km. It rises in the Bugul’ma-Belebi highland and is fed primarily by snow. Its chief tributaries are the Bol’shaia Sul’cha and the Malyi Cheremshan (to the right). For construction of the V. I. Lenin Volzhskaia Hydroelectric Power Station, the lower reaches of the Bol’shoi Cheremshan were inundated as far as Melekess (since 1972, Dimitrovgrad).