VOLGA (Tatar: Etil, Itil or Atel; Finnish: Rau; in ancient times Rha and Oarus), the longest and most important river of European Russia, and the longest river of Europe. Its length is 2,325 m. ; its drainage area covers 563,30o sq.m. and includes middle and eastern Russia, as well as part of south-eastern Russia. The Volga rises on the Valdai plateau at a height of 665 ft., in a small spring in 57° 15' N., 32° 3o' E., west of Lake Seliger, flows through several small lakes, and after its confluence with the Runa, enters Lake Volga. Below that lake is a dam storing I0,000 million cu.ft. of water, so as to make possible the deepen ing of the channel ss far as the Sheksna, during dry periods. After receiving the Sheksna the Volga flows south-east along a broad valley, consisting of a string of former wide lake beds, with a depth of 150-200 ft., in Permian and Jurassic deposits. It re ceives numerous tributaries from the north including the Unzha (365 miles). The Oka from the south-west (95o m.) rises in Orel, near the sources of tributaries of the Don and Dnieper, and receives the Upa, Zhizdra, Ugra, Moskva and Klyazma (left), and the Tsna with the Moksha (right).
The Oka and Volga unite at Nizhniy-Novgorod, and the Volga then enters a broad lacustrine depression which must have corn municated with the Caspian in post-pliocene times. Its low water level in this section is only 190 ft. above sea-level, and its width ranges from 35o to 1,750 yards. Islands appear and dis appear each year after the spring floods. The Sura, bringing a volume of 2,700 to 22,000 cu.ft. per second enters on the right, as do the Svyaga and many smaller tributaries. The Volga then turns south-eastward and descends into another lacustrine depres sion, receiving the Kama, volume 52,500 to 144,400 cu.ft. per second, below Kazan, along which come the products of the Ural mining region; remains of molluscs still extant in the Caspian occur in this depression and in the lower Kama. The Volga then flows south-south-west, making a great bend at Samara to avoid the Zheguli extension of the Russian plateau. The Volga at Samara is only 54 ft. above sea-level. Along the whole of the bend, cliffs fringe the right bank, which the river is constantly undercutting, while from the left bank extends a great plain in tersected by former channels of the river. At Stalingrad (Tsar itsyn) the river reaches its extreme south-western limit and is only 45 m. from the Don. In 1928 the Soviet government ac cepted estimates for the construction of a canal with sluices on the Don, to link these two rivers; it is hoped that the canal will be opened in 1935. The river then turns sharply to the south
east, flowing through the low Caspian steppes. A few miles above Stalingrad it sends off a branch, the Akhtuba, which accompanies it to the sea for 33o m. Low hills skirt the right bank, but on the left it anastomoses freely with the Akhtuba and often floods the country for 15 to 35 miles.
Efforts are being made to control the Volga here so as to lessen the annual washing away of fertile alluvial gardens. The delta be gins 4o m. above Astrakhan and contains as many as zoo mouths. The Volga is constantly eroding its banks, especially during the spring floods, and towns and loading ports have constantly to be moved back, consequently the volume of suspended matter de posited on the Caspian shores is great ; the level of that sea rises during the Volga floods.