Kuybyshev Reservoir
The Sumka (; , "Sumka") is a river in Zelenodolsky District of the Republic of Tatarstan, Russia, a left-bank tributary of the Volga. It is long, and its drainage basin covers . It begins near Gremyachy Klyuch and flows to the Kuybyshev Reservoir, Volga, forming the western border of Vasilyevo, Tatarstan.