Tectonic lakes are formed in the basin along the Earth’s crust. In the narrow sense, these lakes are called potolin. Large lakes in America belong to this group of lakes. The Great American Lakes lie in cryptopression 6. In cryptodepressions lie the lakes whose water level is higher than the sea level, while the bottom of their basins is lower than the sea surface 7. Although quite large, the Great Lakes are significantly different from the morphometric indicators.
There are two groups of lakes in terms of water balance. Unautic, characteristic of dry areas, which lose water exclusively by evaporation, and Island Lakes which cause most of the water to lose an island with water flowing throughout the year. Such lakes are found in areas of humid and moderate climate, including the Great American Lakes. The dimensions of lake waves depend on the size of the lake-the surface of its aquatorium and average depth. It is therefore understandable that the largest waves appear on large lakes. At Michigan, it reaches a height of 6 to 9 meters, and on a smaller Irius up to 3.6 meters.
The study of the level of denivalation of the lake level is very important for the design of various buildings on natural and artificial lakes, as well as for studying the thermal regime of the lake. Denivelation Lake level is significant on elongated and shallow ones lakes, but these phenomena are also recorded on other lakes. On Irius and Ontario, where the longitude of the aquatorium is great the wind acts in the same direction for several hours, the denivelation of the lake level reaches a few centimeters, and sometimes it is 1-2 meters.
It was found that winds, on the direction of currents in the western part of Lake Iri, are influenced by the appearance of seas and water of the Detroit River.
The water of the Great Lakes clear in the open sea. In the vicinity of large ports it is highly contaminated, and special measures are taken to protect the water purity.