Facts for Prelims (FFP)
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:
| Findings | Details |
| Indian lakes | More 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 lakes | Global 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 affected | Nearly 33% of the global population resides in a basin with a large, drying lake. |
| Role of climate change | Climate change, including temperature, precipitation, and runoff, was identified as one of the main drivers of water losses |
| Other factors contributing to lake decline | Human water consumption, potential evapotranspiration, and sedimentation were identified as additional factors contributing to the decline of lakes. |
| Measures needed | Integrated approaches to lake management are crucial to address the declining trends |
About Lakes:
| Lakes | Description | Examples |
| Definition | A 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 Lakes | Lakes formed temporarily after heavy showers with evaporation greater than precipitation | Small lakes of deserts |
| Permanent Lakes | Lakes with deep water that carry more water than can be evaporated, with evaporation less than precipitation | Great Lakes of North America, East African Rift Lakes |
| Freshwater Lakes | Lakes fed by rivers and without-flowing streams | Great Lakes of North America |
| Saline Lakes | Lakes with no natural outlet or rapid evaporation cause high salt content in the water | Great Salt Lake, Aral Sea, Dead Sea |
| Tectonic Lakes | Lakes formed due to the earth’s movements such as warping, subsidence, bending, and fracturing of the Earth’s crust | Lake Titicaca, Caspian Sea |
| Rift Valley Lakes | Lakes formed along rift valleys, deep and narrow, with water collecting in troughs below sea level | Lakes Tanganyika, Malawi, Rudolf, Albert, Dead Sea |
| Crater and Caldera Lakes | Lakes formed in volcanic craters or calderas with no superficial outlet | Lonar (Maharashtra, India), Krakatao (Indonesia) |
| Uses of Lakes | Inland 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 India | Largest 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) |
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