Tendency of digging of artificial reservoirs appeared long ago when developing of America by foreign guests. More than 60 artificial lakes appeared because of it. Russia took another way: it needs nothing artificially built, because natural is enough. Thus in Russia 30% of the land are busy by water.
Russia is the only country, near the banks of which there are 12 seas, belonging to the basins of the three oceans: the Arctic, the Pacific and the Atlantic oceans. There is also one inland sea – Caspian sea, the area of which makes up 371,000 sq.km. and depth – 1,025 m. To the 12 external seas belong: the Barents sea (area – 1,424,000 sq.km, depth – 600 m.), the White sea (area – 90,000 sq.km., depth – 330 m. ), the Kara sea (883; 620), the Laptev sea (662; 3385), the East-Siberian (913; 915) and the Chukchee (595; 1256) seas. These are the seas of the Arctic ocean. In the Pacific ocean there are Bering sea (2304; 4191), the Okhotsk (1585; 3372), the Japanese (978; 3669) seas. Water depths of the Atlantic ocean border with the Baltic sea (419; 456), the Black sea(422; 2211) and the Sea of Azov (39; 13). There are 2,5 mln. rivers on the territory of Russia. 120 thousand have the length more than 10 km.
The river system belongs to the basins of the three oceans. The great rivers such as the North Dvina, the Pechora, the Ob, the Enisei, the Hatanga, the Olenek, the Lena, the Yana, the Indigirka, the Kolima. The total area of the columbine of this ocean on the territory is 12,8 mln. sq.km. To the basin of the Pacific ocean belong such great rivers as: the Anadir, the Pengina and the Amur. The waters of the Neva, the Don, the Kuban flow down into the seas of the Atlantic ocean. The rivers Volga, Ural and Terek belong to the basin of the interior drainage and fall into the Caspian sea. As a whole 84 % of the drainage flow into the Arctic ocean, 8% - into the Pacific ocean, 3% - into the Atlantic and 5% - into the Caspian seas. The total volume of the drainage of the all rivers is 4,300 km³ a year – this is about 10% of the world river system.