REMOTE SENSING AND
GLACIER LAKES - ENVIRONMENT
News: ISRO tracks notable expansion
of glacial lakes in Indian Himalayas
What's in the news?
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Recently, the Indian Space Research Organisation
(ISRO) unveiled a satellite-data-driven analysis regarding the enlargement of
glacial lakes within the catchment areas of the Indian Himalayan River basins.
Key takeaways:
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ISRO conducted an analysis of satellite data archives spanning four decades to examine changes in
the glaciated environment.
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Long-term satellite imagery covering the catchments
of Indian Himalayan River basins, extending from 1984 to 2023, was utilized in
the study.
Key Highlights of ISRO's
Study on Glacial Lakes:
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ISRO's data revealed a notable increase in the size of glacial lakes.
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Out of 2,431 lakes larger than 10 hectares
identified during 2016-17, 676 glacial lakes exhibited significant expansion
since 1984.
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Of these expanded lakes, 130 are located in India,
distributed across the Indus, Ganga, and
Brahmaputra river basins.
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The expansion of these lakes is attributed to the
accelerating retreat of glaciers caused by global warming.
Glacial Lakes:
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Glacial lakes are bodies of water formed in
depressions or basins created by the erosive
action of glaciers.
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They are commonly found in regions where glaciers
once existed or are currently present.
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These lakes vary in size and shape, ranging from
small ponds to large, deep bodies of water.
Classification:
ISRO categorized glacial lakes into four main types based on their
formation processes such as
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Moraine-dammed
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Ice-dammed
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Erosion-based
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Others
Formation Mechanisms:
1. Glacial Erosion:
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Glaciers erode and shape the landscape, creating
depressions and basins.
2. Deposition of Glacial
Moraines:
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Sediment and debris carried by glaciers form
natural dams, blocking water flow and creating depressions for lake formation.
3. Melting Ice:
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Rising temperatures or glacier retreat leads to the
melting of ice, filling depressions with water and forming glacial lakes.
4. Terminal Moraine
Formation:
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Glaciers deposit sediment at their terminus,
creating dams that impound water and form terminal moraine lakes.
Use of Remote-Sensing
Technology:
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Monitoring glacial lakes in the Himalayan region is
challenging due to rugged terrain, making satellite remote sensing a valuable
tool.
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Satellite data analysis allows for tracking changes
in glacial lakes over time, aiding in understanding their environmental impact
and developing strategies to manage risks like glacial lake outburst floods and
adapt to climate change.
Risk Mitigation
Strategies:
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Lowering lake levels by 10 to 30 meters can significantly reduce the
impacts of downstream flooding.
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Syphoning off lake water using long High-Density
Polyethylene (HDPE) pipes is one effective method employed for risk mitigation.
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In 2016, the Sikkim State Disaster Management
Authority utilized this approach to lower water levels in South Lhonak Lake.