April 20, 2021

Indian Himalayan area: One other disaster within the making?

The catastrophic catastrophe attributable to compounding results resulting in flash flood in Rishiganga basin in Chamoli, Uttarakhand on February 7 is paying homage to the Kedarnath tragedy.

An avalanche/landslide along side breakage of rock/ice glacier may very well be the rationale.

Nevertheless, an avalanche/landslide and/or breakage of rock/ice glacier couldn’t be the only purpose for sudden deluge of water quantity resulting in flash flood. There have to be trapped water at floor or sub-surface, resulting in an evaluation if a glacial lake is shaped concurrently.

In excessive mountainous terrains, melting of glaciers attributable to international warming resulting in greater warming charges over greater elevation than decrease elevation is seen. This case will increase threat of glacial-related hazards.

One among these dangers is Glacial Lake Outburst Floods (GLOFs)—shaped attributable to glacier(s) retreat, principally forming water physique behind moraine or ice ‘dams’. These ‘dams’, which act as an embankment, as soon as damaged and/or weak, will result in glacial lake breaching. It’s going to instantly discharge enormous volumes of water, particles, slurries, and so on. Such outbursts have the potential of releasing thousands and thousands of cubic meters of water in just a few hours, inflicting catastrophic flooding downstream with critical harm to life and property. GLOFs evolve as a consequence of a collection of various processes, for instance, mass motion into lakes, glacier/ice entrance calving into lake, progressive enlargement of lake, rising lake ranges resulting in overflow, mechanical rupture/failure of dam, hydrostatic failure, degradation of dam or melting of ice cores in dam, earthquakes, a flood wave from lake situated upstream and intensive rainfall or snow soften.

GLOFs have emerged as a critical hazard within the mountain area in latest a long time attributable to elevated human settlements, anthropogenic and different developmental actions into areas which have been inhabited and weren’t developed beforehand. There are tons of of glacial lakes in Indian Himalayan area (IHR).

A quickly to be revealed examine (in press) by a bunch of scientists together with me, examines the difficulty of GLOFs within the Indian Himalayan Area. A complete stock reveals a complete of 4,418 glacial lakes inside the Indian Himalayan Area. In addition to, a complete l of 636 Trans Boundary glacial lakes, which might doubtlessly flood the IHR, have been additionally recognized.

Glacial lakes within the IHR cowl an space of 428.71 sq km. Of the 4 main kinds of lakes, bedrock (67%) and morainedammed (25%) are most frequent. In Jammu & Kashmir, Sikkim, and Arunachal Pradesh 57-84% of the lakes are dammed by bedrock, whereas in Uttarakhand and Himachal Pradesh 76-80% of the lakes are moraine-dammed. Ice-dammed and different lakes aren’t so widespread, in comparison with different lake sorts.

To the perfect of our understanding, that is the newest and most full stock of glacial lakes in IHR, and the primary examine to systematically embody the lakes from which Trans Boundary GLOFs might originate and affect the downstream areas of IHR.

The author is Professor, College of Environmental Sciences, Jawaharlal Nehru College.