Permafrost structures identified in Jhelum basin

News Excerpt:

More than 100 active permafrost structures in the Jhelum basin holding significant volumes of water have been identified, further underlining the need to explore their hydrological potential.

Jhelum River and Basin

  • It rises from a deep spring at Verinag, in western Jammu and Kashmir, Kashmir region.
    • It meanders northwestward from the northern slope of the Pir Panjal Range in a deep gorge through the valley of Kashmir to Wular Lake at Srinagar, which controls its flow.
    • The Jhelum (Vyeth in Kashmiri, Vetesta in Sanskrit and Hydaspes in Greek) is the main waterway of the Kashmir valley.
  • It is a major tributary out of five major tributaries viz. Satluj, Beas, Ravi Chenab and Jhelum which are ultimately merging with river Indus in Pakistan is the west flowing river.
  • The total geographical area of Jhelum basin upto Indo-Pakistan border is about 34775 Sq.Kms, with a total length of 402 Kms.
    • But the length of Jhelum in India upto existing ceasefire line is about 165 Kms.
  • Important Tributaries: Nallah Lidder, Nalah Sindh, Nallah Vishow, Rambiara Nallah, Dudhganga river, Pohru.

Key highlights of the report: 

  • This report was published in the American Geophysical Union’s Earth and Space Science journal.
    • Scientists from the Geological Survey of India, Indian Institute of Technology Bombay-Monash Research Academy, Northumbria University, the United Kingdom, ISRO Headquarters and Indian Institute of Science, Bangalore co-authored it.
  • Research was carried out about the rock glaciers of the Himalayas.
    • The Kashmir Himalayas are dotted with permafrost structures called ‘rock glaciers’, with significant ice volumes within.
  • A statistical model based on topographic and climatic variables like temperature, solar radiation, and slope aspects was used to build a “Permafrost Zonation Map”, pin-pointing around 207 rock glaciers spread over 50 square kilometres.
  • During researchers' trip to the Jhelum basin during the summer months, some water bodies were spotted right in the middle of vegetation some kilometres uphill from Kulgam town, which suggested that there was permafrost underground.
    • These resembled “thermokarst lakes” because no stream or glacier could feed them.
      • Thermokarst lakes are formed when permafrost thaws, creating surface depressions that fill with melted water.
      • These are a prominent feature of Arctic landscapes.
  • Rock glaciers will become a more common mountain landform in the future as debris concentrations increase in the melting glaciers with global warming and deglaciation.
    • It is already being witnessed in the Jhelum basin.

Rock Glaciers: 

  • As the glacier retreats or melts over time, the ice covered with debris undergoes a transformation into a rock glacier.
    • The process involves an existing glacier gathering rocks and debris during its movement. 
  • They typically develop in mountainous areas where permafrost, rock debris, and ice converge. 
  • This recent study proved that these rock glaciers occur in highly elevated regions with steep slopes.
  • To the naked eye, the rock glaciers look like regular ground, and habitations are often planned on them.

Significance of Permafrost structures: 

  • These permafrost structures hold large volumes of water, and at a time when water sources are fast disappearing, these can be valuable reserves.

Risk associated with Permafrost structures: 

  • These permafrost structures particularly increase the risk of glacial lake outburst floods (GLOFs), which cause massive damage in the lake's surrounding areas. 
  • In case of a slope failure due to the upper debris layer giving away, the underlying permafrost will be exposed to warming and may eventually melt and feed into the lake.
  • It may also make landslides more frequent, with the land on the melting ice becoming loose.

Way forward: 

  • The authors called for more research to understand the distribution of permafrost across the mountainous regions of India, specifically the western Himalayas, where the glacial retreat is fast and significant, to assess risks associated with them. 
  • The importance of remote sensing and modelling techniques in studying these frozen landforms becomes crucial because the region's complex topography and limited accessibility make field investigations challenging.

 

Prelims PYQ: 

Q: With reference to the Indus river system, of the following four rivers, three of them pour into one of them which joins the Indus direct. Among the following, which one is such river that joins the Indus direct?​ (UPSC 2021)

(a). Chenab ​

(b). Jhelum​

(c). Ravi ​

(d). Sutlej​

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