Lakes are large masses of water formed mainly in low-lying areas of the Earth. Their main sources are rain-water or molten snow or, at times, a small river or a stream. Do you know how these lakes are formed?
Lakes are formed in many ways. Some lakes lie in the natural hollow of an old volcano. For example, the crater lake of Oregon in South America. Due to some upheavals, like falling of a meteor large ditches were formed on the surface of the earth, which later got filled with rain water – for example, Lake Bosuntui in Ashanti crater in Ghana.
The Glacial lakes are formed because the sliding glaciers cause big ditches on the Earth’s surface which become lakes after rain-water and molten snow accumulates there. The Winnipeg Lake of Canada was formed by glaciers.
Rift valley lakes are formed when Earth’s crust slips down between long lines of faults, the water fills part of the floor of the valley e.g. Lake Malawi and Lake Turkana in East Africa.
Artificial lakes are created when people make dams to hold back river water.
While water of some lakes is saline, it is sweet in some others. The lakes, from which water does not flow out, have saline water whereas the lakes into which some rivers fall or from which rivers originate have sweet and fresh water. The Superior Lake of America has sweet water.
There are innumerable lakes in the world. The Ojera Baikal Lake of central Asia is the deepest lake. It has 22,000 cubic km. water. It is 620 km. long and about 115 km. wide. Its depth is 2,400 metres. The Superior Lake of America has 12,000 cubic km. water. Seventy percent of the world’s lakes are situated in Africa, Asia and North America.