Lakes in Rajasthan
Definition
A lake is a body of water that is surrounded by land. There are millions of lakes in the world. They are found on every continent and in every kind of environment—in mountains and deserts, on plains and near seashores.
How lakes are formed?
All lakes fill bowl-shaped depressions in the earth’s surface called basins. Lake basins are formed in several ways. Many lakes were formed by glaciers that covered large areas of land during the most recent ice age, about 18,000 years ago.
The huge masses of ice carved out great pits and scrubbed the land as they moved slowly along. When the glaciers melted, water filled those depressions, forming lakes. Glaciers also carved deep valleys and deposited large quantities of earth, pebbles and boulders as they melted. These materials sometimes formed dams that trapped water and created more lakes.
Some lake basins form where plate tectonics changed the Earth’s crust, making it buckle and fold or break apart. When the crust breaks, deep cracks, called faults, may also form. These faults make natural basins that may fill with water from rainfall or from streams flowing in the basin. When these movements occur near the ocean, part of the ocean may be trapped by a new block of land thrust up from below the Earth’s surface. The Caspian Sea was formed by this process. Lake Baikal was also formed by the movement of tectonic plates.
Many lakes form as a result of volcanoes. After a volcano becomes inactive, its crater may fill with rain or melted snow. Sometimes the top of a volcano is blown off or collapses during an eruption, leaving a depression called a caldera. It, too, may fill with rainwater and become a lake. All the lakes are not created by basins filling with water; some lakes are formed by rivers. Mature rivers often wind back and forth across a plain in wide loops called meanders. During periods of flooding, a swollen, rushing river may create a shortcut and bypass a meander, leaving a body of standing water. This type of small lake is called an oxbow lake, because its shape resembles the U-shaped frame that fits over an ox’s neck when it is harnessed to pull a wagon or a plow.
Lakes may also be created by landslides or mudslides that send soil, rock, or mud sliding down hills and mountains. The debris piles up in natural dams that can block the flow of a stream, forming a lake. Dams that beavers build out of tree branches can plug up rivers or streams and make large ponds or marshes.
People make lakes by digging basins or by damming rivers or springs. These artificial lakes can become reservoirs, storing water for irrigation, hygiene and industrial use. Artificial lakes also provide recreational use for boating, swimming or fishing.
Artificial lakes can provide electricity through hydroelectric power plants at the dam.
Chemical and Physical Aspects of Lakes
Temperature, light and wind are three of the main factors that affect the physical characteristics of a lake. Temperature and light vary from lake to lake. Depth, plant growth, dissolved materials; time of day, season and latitude can all affect light’s ability to pass through the lake’s water.
Light and wind affect the temperature in lakes. Sunlight warms the water and wind cools it down. Most lakes go through a process called thermal stratification. Thermal stratification refers to a lake’s three main layers, each with a different temperature range. A lake’s shallowest layer is the Epilimnion. Its middle layer is the metalimnion or Thermocline. The deepest layer is the Hypolimnion.
The most important chemicals in a lake are nitrogen and phosphorus. These chemicals allow nutrient-rich plants and algae to grow. Other organisms feed off these plants and algae, creating a complex, healthy ecosystem.
The chemistry of a lake is affected by biological, geological and human processes. The balance of nutrients may be altered by biological phenomena such as “algal blooms,” when algae reproduces so rapidly it prevents any nutrients from reaching below the lake’s surface. Natural processes such as the eruption of a nearby volcano can alter the chemical aspect of a lake by introducing new gases or minerals. Pollution, such as the introduction of toxic chemicals from industry or agriculture, can also affect a lake’s chemistry.
The amount of oxygen and the pH level can also affect a lake’s chemistry. A lake must have a healthy amount of oxygen to sustain life. Lakes that do not have enough oxygen to sustain life are abiotic.
The Life Cycle of Lakes: Once formed, lakes do not stay the same. Like people, they go through different life stages—youth, maturity, old age and death. All lakes, even the largest, slowly disappear as their basins fill with sediment and plant material. The natural aging of a lake happens very slowly over the course of hundreds and even thousands of years. But with human influence, it can take only decades.
Some of the lakes are a gift of nature to Rajasthan, while others have been carved out in the earth’s surface by the efforts of man to be the source of the drinking water for the civilization and were used as a reservoir to conserve rainwater.
In Rajasthan, Lakes are divided into two categories
- Saltwater Lake and
- Fresh (Sweet) Water Lake
Salt Water Lakes
Definition: A salt lake or saline lake is a landlocked body of water that has a concentration of salts and other dissolved minerals significantly higher than most lakes. In some cases, salt lakes have a higher concentration of salt than sea water; such lakes can also be termed hyper saline lakes.
Some important salt water lakes in Rajasthan are discussed below:
1. Sambhar Lake
- It is India’s largest inland Salt Water Lake.
- It has been designated as a Ramsar site (A Ramsar site is a wetland site designated to be of international importance under the Ramsar Convention. The Convention on Wetlands, known as the Ramsar Convention, is an intergovernmental environmental treaty established in 1971 by UNESCO, which came into force in 1975)because this wetland is a favourite spot for migratory birds like Pink Flamingo and other birds that migrate from northern Asia and Siberia..
- The total area of the lake is 150 sq. km.
- The lake receives water from five rivers Merta, Samand, Mantha, Roopangarh and khandel. The Mendha and Rupangarh are main streams. The Mendha flows from north to south and the Rupangarh flows from south to north.
- The lake is elliptically shaped with a length of approximately 35.5 km and a breadth varying between 3 km and 11 km. The lake straddles Nagaur and Jaipur districts and borders on the Ajmer district. The circumference of the lake is 96 km and it is surrounded by the Aravali hills on all sides.
2. Didwana Lake
- It is a natural lake and is located at Nagaur district of Rajasthan.
- It is 2km broad and 4km long.
- The Production of salt produced is non-edible grade because of high fluoride.
3. Pachpadra Lake
- It is located in Barmer district.
- This is also a Natural Lake, Pachpadra Lake is a salt water Lake lies near town of Pachpadra in Barmer district in Rajasthan
- Its sodium chloride level is marked at Approx 98%.
- The famous Mata Rani Bhatiyani temple which is located near this lake. The total area of this Lake is 25 Sq. km.
4. Lunkaransar Lake
- Lunkaransar lake in Rajasthan is a playa lake formed due to deflation.
- It is located in Lunkaransar, 80 km away from Bikaner.
- It is also Natural and a salt water lake.
- Some other famous Salt Water Lakes are Phalodi, Kuchaman, Kovaad, Kachhor, Rewasa, etc.