The term describes the river system of an area or the flow of water through different channels. Many of the small streams and rivers come together to form the main river from different directions which drain into a large water body such as a lake sea or ocean.
The area drained by a single river and its tributaries is termed a drainage basin. The Amazon River is the world’s largest drainage basin. In India, The Ganga River is the largest drainage basin.
Any mountain or an upland that separates or divides the two drainage basins is termed as water divide.
Importance of lakes
Lakes in India
India has a variety of lakes some are permanent and some are seasonal as some lakes contain water only at the time of rainy season like the lakes in the basins of inland drainage or semi-arid region, they differ from each other in size and some other characteristics also.
The major points about the Lakes found in India are as follows:
- Lakes in India are the result of the melting of glaciers and ice sheets whereas the others have been formed by wind, river action, and human activities. A meandering river that is across a floodplain forms cut-offs that later develop into oxbow lakes.
- Spit (which is a deposition of bar or beach landform off coasts or lake shores ), Bar (an elevated region of sediment in a river that has been deposited by the flow ) form lagoons in coastal areas. For Example the Chilika, Pulicat, and Kolleru lakes.
- Lakes in the inland regions are seasonal. For example, the saltwater lake in Rajasthan is also known as Sambhar lake and is used for the production of salt.
- Freshwater lakes are mostly in the Himalayas region and are from the glacial region. they are formed when glaciers create a basin that on later filled with snowmelt. For Example, the wular lake one of India’s largest freshwater lakes in Jammu and Kashmir is the result of tectonic activity.
- Some other Fresh water lakes are The Dal Lake, Bhimtal, Nainital, Loktak, and Barapani.
- By damming of the rivers for the generation of hydel power has also led to the formation of various lakes like Guru Gobind Sagar which is formed by the damming of the Satluj river.
As per the given data, 71% of the world’s surface is covered with water but out of this, 97% of that is saltwater and 3% is available as freshwater, three-quarters of it covered as ice.
Importance of Lakes
- Lakes are very useful to human beings as they are used as tourist destinations and also used for the sports activities like boating, water sports, etc. It’s directly related to the income of the individual.
- Lakes are also helpful for the prevention of floods during heavy rainfall and in the dry season, it helps to maintain an even flow of water. Lakes help in maintaining the flow of a river.
- Lakes can be used for the production or development of hydel power. They moderate the climate surroundings by maintaining the aquatic ecosystem, enhancing the natural beauty, and also helping in developing tourism and providing recreation.
- Saltwater lake is also used for the production of salt.
Water Pollution in Lakes
The main cause of Water Pollution is
- A high number of untreated sewage and Industrial effluents are being emptied into the lakes. This excess decomposition has caused the water body to become highly polluted.
- Cremation near water bodies, dead animals, and leaching out of nitrogen compounds from fertilized agricultural lands also increase pollution.
- Runoff nutrients in stormwater from sheet flow over an agricultural field or a forest is also another cause of pollution in lakes.
FAQs on Lakes
What percentage of freshwater is found in rivers and lakes?
Only around 3 percent of available water is freshwater, which is only 1 percent of world’s freshwater is found in rivers, ponds and lakes. About aroun 67 percent of freshwater is locked in ice form in snow and glacier.
How are oxbow lakes formed?
Oxbow lake starts out as a curve, or a meander in a river. A lake form as the river finds a more different shorter course. The meander becomes an oxbow lake along with lake along side of river.
Which city is known as the city of lakes?
Udaipur is known as the city of lakes.
Which country is known as the land of thousands of lakes?
Finland is the country which is known as land of thousands of lakes.
What is the water divide? Give an example.
Any mountain that separates or divides the two drainage basin, an upland is termed as water divide.
Example of water divide –
- Western ghats act as water divide between the west flowing rivers meeting the Arabian sea and east flowing rivers meeting the Bay of Bengal.
- The water divide between the Indus and the Ganga river systems is one of the major Water divide at Ambala. The Indus, the Sutlej and the Brahmaputra rivers rise very close to each other but because of the water divides they flow in different directions.