Kuybyshev Reservoir
In the 1940s–1950s five bridges of reinforced concrete were built, the embankment was covered with iron grate, slopes were matted by the project of Ü.G. Alparov and Ye.Yu. Brudny. With the infill of Kuybyshev Reservoir and the constructing of check dams the lower stream of Bolaq was covered up with earth and divided from Kazanka in 1955–56. In 1967 the subterranean channel, long, was constructed to connect Bolaq and Volga. As natural the level of Bolaq and Qaban is much lower than that of Kuybyshev Reservoir, pumps throw out the effluent water.