river in west-central Russia. Rising in the Upper Kama Upland of Udmurtia, it flows north, then east, south, and southwest for 1,122 miles (1,805 km) until it enters the Volga River below Kazan, in the Samara Reservoir. It drains a basin of 202,000 square miles (522,000 square km). The spring maximum flow following the snowmelt accounts for nearly 60 percent of the annual flow; freeze-up lasts from mid-November or early December until April. Navigation is possible to Rudnichny, some 954 miles (1,535 km). The Kama is one of the most important rivers of Russia—historically as the routeway to the Urals and Siberia and economically as part of the vast Volga system of waterways. There are large barrages and hydroelectric stations at Perm, at Chaykovsky near Votkinsk, and at Nizhnekamsk, downstream.