Russian Internal waters: Lakes
On the territory of Russia there are over 2 million lakes. Basically it is a small lake with a water surface area less 1 km2. Large lakes are few. Two Russian lakes — Baikal and Ladoga, are among the 18 largest lakes in the world (the area of each of these, more than 10 000 km 2 ), near Onega lake (table 5).
Table 5. The largest lakes of Russia
The deepest lake in the world is the Baikal lake (maximum depth is 1637 meters).
The number of lakes in Russia is 2.1%.
Across the country the lake is unevenly spread. There are areas where the lakes are many, but there are others where there are almost no lakes (forest-steppe and steppe of the East European plain). The most numerous lakes, where they contribute to the existence of climatic conditions and topography. Especially large area of the lake is on the Yana-Indigirka and Kolyma lowlands, in places where the number of lakes exceeds 50%, and in Karelia, where the area of the lakes amounts to 12-13% of the surface. Many lakes and in the North-Western regions of Russia, in Central Yakutia, in the Surgut lowland and, paradoxical as it may sound, in the forest-steppe zone of Western Siberia.
The fact that the emergence of lakes requires excessive moisture (so the majority of lakes located in areas of excessive moisture) and the presence of water, i.e. depressions. Where there are no hollows, there is a waterlogging of the territory and the surplus of moisture accumulated in the swamps.
The origin of lake basins in the vastness of Russia is quite different. Large lakes are mainly of tectonic basins (Baikal, Teletskoye, etc.) or glacial-tectonic origin (Ladoga, Onega, and Imandra, lake, Putorana plateau — a Salmon, Alexander, Lama, Deep, etc.). Characteristic for these lakes are usually large and deep. There are lakes of volcanic origin . They are found in Kamchatka and the Kuril Islands and dated to the craters of volcanoes (the Circular lake in the crater of the volcano Krenitsyn on the island of Onekotan, Turquoise lake in the crater of Zavaritsky volcano on the island of Simushir, Kuril lake in Kamchatka, etc.). Are beautiful with glacial lakes . located on the bottoms of the glacial hollows. They are common in mountains with glacial relief (Kluhorsky, Budecska lake in the Caucasus and many others). In the mountains are also formed dammed . or dammed lake .
Moraine lakes occupy depressions between moraine hills, mezhmorennye depression. They often have a fancy blade shape (lake Seliger in the Valdai hills, etc.). Such lakes number in the hundreds and thousands in parts of the last glaciation. Karst lake is a karstic depression, the bottom of which is covered by clayey rocks that serve as a confining layer. In the areas of distribution of permafrost thermokarst lakes are abundant . and in the presence of loess and loess-like loams are formed suffosion-subsiding basin. Floodplain (oxbow) lakes are abundant in the Ob, the Volga-Akhtuba floodplains and other rivers. The number in Russia most of the lakes are of thermokarst origin.
The regime of the lakes largely depends on whether it is derived from the river. In the lake usually carries its waters more or less considerable number of rivers and streams. If from the lake the river flows, the lake is flowing . Sometimes in areas of excess moisture and a large number of lakes there is a lake-river system . the river starts from the lake into another lake, which, in turn, derives the river. Thus it appears that the river strung chain of lakes. Especially typical of such systems for Karelia. Flow-through lakes are usually fresh . even if they are in the southern drylands.
If the outflow from lake no, the salt coming from the surrounding areas, including river flow, accumulate with it. Such closed lakes can have not only fresh but salt water. Salt lakes exist in the Northern regions, if their pool complex salt-bearing strata, but the most typical are they for South of the drylands. The largest salt lake in Russia is lake Chany in Western Siberia.
Salt lakes are divided into brackish and salt (in that case if the salinity increases up to complete saturation and salt begin to precipitate). Examples are salt lakes Baskunchak . where precipitated sodium chloride, and Kuchuk in Kulunda is the only lake in Russia, where the precipitation of Glauber’s salt (mirabilite). Usually in lakes of Kulunda is the accumulation of self-deposited soda.