Inventory and topographic analysis of glacial and high-altitude lakes in Kargil district, Union Territory of Ladakh

A glacial lake, characterized by its significant water volume, exists in association with a glacier (under, besides, and in front). They form due to glacial activities influenced by climatic variations. Glacial lakes generally impounded behind weak materials and can rupture suddenly due to various triggers, resulting to catastrophic floods known as Glacial Lake Outburst Floods (GLOFs). Lake’s topography particularity plays a crucial role in its formation and sustenance. Glacial lake related hazards are increasingly gaining attention due to their potential for causing significant damage and loss of life and property in high mountain regions worldwide. Therefore, it is imperative to regularly map and analyze various lake characteristics to understand any potential hazards originating from them.  Considering this, current study aims to present a comprehensive and updated inventory of glacial and high-altitude lakes in the Kargil district of Ladakh and systematically analyzes their types and topographic attributes. With the analysis of recent Sentinel-2 MSI imagery (2022), we identified a total of 355 glacier and high-altitude lakes in the Kargil district, encompassing an area of 4.8 ± 1.2 km². These lakes are divided into four classes mainly based on their relationship with the glaciers: proglacial lakes away from the glacier (PGLA), proglacial lake in contact with glacier (PGLC), supraglacial lakes (SGL) and other lakes (OL). Results reveal that though PGLCs are comparatively low in number (85) but they occupy the largest area share of 60% in total glacial lakes covering an area of 2.88 ± 0.7 km². PGLAs are 138 in number and occupy the second largest area of 0.9 ± 0.2 km². There are large number (103) of SGLs with an area coverage of 0.32 ± 0.07 km². OLs are limited in number (29) and cover 0.6 ± 0.1 km² of area.  The lake sizes range from 0.001 km² to 0.579 km² with an average lake area of 0.013 km² indicating that the lakes in the region are small in size and are in their initial phase of development. The mean elevation for the lakes is 4605 m and notably, ~21% of them predominantly oriented in a southward direction. The majority of lakes are situated on slopes with a gradient ranging 2-8° which reflects their potential to grow in size. It can be deduced from the analysis that the glaciated areas in Kargil region is dominated by large number of PGLC and PGLAs which are likely expand in future posing serious threat to the communities living in immediate proximities to the glaciers. Overall, this research contributes to our understanding of glacier lakes in the Kargil district of the Ladakh region, providing essential data for informed decision-making in order to minimize the glacial lake related hazards.

Keywords: Glacial lake inventory; High altitude lakes; Ladakh Himalaya; Remote sensing; Glacier Lake hazards.