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Facts for Prelims (FFP)

Source: IE, DTE

 Context: As per a recent study published in the Journal of Science, more than half of the world’s large lakes are drying up.


Major Findings of the Study:

Indian lakesMore than 30 large lakes in India experienced a drying trend from 1992 to 2020. E.g., Mettur, Krishnarajasagar, Nagarjuna Sagar, and Idamalayar, showed a decline in lake levels and storage
Global lakesGlobal lakes contribute to 95% of the total lake water storage on Earth. 53% of the world’s largest lakes have been losing water, while 24% have seen an increase in water levels.
Global population affectedNearly 33% of the global population resides in a basin with a large, drying lake.
Role of climate changeClimate change, including temperature, precipitation, and runoff, was identified as one of the main drivers of water losses
Other factors contributing to lake declineHuman water consumption, potential evapotranspiration, and sedimentation were identified as additional factors contributing to the decline of lakes.
Measures neededIntegrated approaches to lake management are crucial to address the declining trends


About Lakes:

DefinitionA lake is a large body of water that is surrounded by land. It is generally localized in a basin or depression and is separate from rivers or other outlets that serve to feed or drain the lake.
Types of Lakes
Temporary LakesLakes formed temporarily after heavy showers with evaporation greater than precipitationSmall lakes of deserts
Permanent LakesLakes with deep water that carry more water than can be evaporated, with evaporation less than precipitationGreat Lakes of North America, East African Rift Lakes
Freshwater LakesLakes fed by rivers and without-flowing streamsGreat Lakes of North America
Saline LakesLakes with no natural outlet or rapid evaporation cause high salt content in the waterGreat Salt Lake, Aral Sea, Dead Sea
Tectonic LakesLakes formed due to the earth’s movements such as warping, subsidence, bending, and fracturing of the Earth’s crustLake Titicaca, Caspian Sea
Rift Valley LakesLakes formed along rift valleys, deep and narrow, with water collecting in troughs below sea levelLakes Tanganyika, Malawi, Rudolf, Albert, Dead Sea
Crater and Caldera LakesLakes formed in volcanic craters or calderas with no superficial outletLonar (Maharashtra, India), Krakatao (Indonesia)
Uses of LakesInland waterways for transportation; Economic and industrial development; Water storage; Hydroelectric power generation; Agricultural purposes etc.Great Lakes-St. Lawrence Waterways, Kolleru Lake, Hirakud Dam, Dead Sea, Lake Chilka
Lakes in IndiaLargest Freshwater: Wular Lake (J&K)

Largest Brackish water: Chilika (Odisha)

Largest Saltwater: Sambhar (RJ)

Largest Artificial: Gobind Ballabh Pant Sagar (UP)

Longest: Vembanad (Kerala)

High altitude: Cholamu (Sikkim)