STUDY OF GLACIAL LAKES AND GLOF IN HIMALAYAN BASIN USING GEOSPATIAL TECHNIQUES

Abstract

The glaciers in the Himalayas region are essential components of the cryosphere which plays important role in the regional climate system. It is now widely accepted that most of the Himalayan glaciers are retreating and thinning. Due to this melting of glaciers, glacial lakes are forming. In other words, glacial lakes are indirect evidence of climate change as most of the glacial lakes are fed by glacier melt which is increasing due to climate change. Due to increase in rate of recession of glaciers there is increase in number of lakes as well as increase in aerial extent which is enhancing chances of glacier related hazard like Glacial Lake Outburst Flood (GLOF). In order to monitor the GLOF, it is important to have knowledge and information about evolution, distribution pattern and development of glacial lakes. The research investigated the glacier and glacial lake fluctuations using Landsat datasets. A complete and detailed glacial lake inventory is prepared which certainly helps in better understanding of the variation in climate and its impact on cryosphere. Two basins Chenab and Alaknanda where considered for GLOF study. Total basin area of Chenab is of 17,470 sqkm with an elevation range of 871 m to 7079 m and Alaknanda of 5000 sqkm with an elevation range of 1124 m to 7799 m. A total number of 80 lakes in Chenab basin and 89 lakes in Alaknanda basin with area more than 1000m2 are mapped having a total of 3115sqkm glacier area in Chenab basin and 1086sqkm in Alaknanda basin. The largest lake in Chenab basin covers an area of 1.42sqkm and 0.231sqkm for the largest lake in Alaknanda basin Not all the lakes pose threat to society or unstable, moreover most of the lakes are stable. The instability and vulnerability depends on the many characteristics like rate of expansion, type of lake, location etc. In the present study potentially dangerous lake is identified and the simulation is carried out using MIKE-11 Model. Considering breach width of 140 m, the flood peak was simulated for the lake in Chenab basin. It was considered more vulnerable as compared to the other lake of Alaknanda basin. The continuous expansion of dammed lakes is the main attribute to the recent climatic warming