Mapping of Glacial Lakes and Glacial Lake Outburst Flood in Lahul and Spiti District Using Remote Sensing and GIS

Glacial lake outburst floods (GLOFs) refers to the sudden release of water from a glacial lake. This has the potential to endanger human lives as well as cause environmental and economic damage. Climate change is causing glaciers to retreat and subsequent formation of new glacial lakes. GLOFs are one of the most common climate change hazards in India's Himalayan region of Himachal Pradesh. In the present study, GLOFs mapping has been carried out using remote sensing (RS) and geographic information system (GIS). For glacial lake mapping, Landsat-7 and 8 data from 2005, 2010, 2015, and 2019 were employed. Landsat images were employed for classification and change detection using normalized difference water index (NDWI) to identify the temporal variation of Samudra Tapu glacier lake and Geepang Gath glacial lake, which are two major glacial lakes in the Lahul and Spiti district. A 30 m digital elevation model (DEM) was created by the data providers by the shuttle radar topography mission (SRTM) 1arc sec global used for calculating the parameters such as maximum, minimum, mean elevation, slope, and aspect. The lake volume and depth have been calculated using Huggel empirical formulae, and other parameters such as area, slope, aspect, and drainage network have been prepared using ArcGIS 10.8. The maps for land use and land cover (LULC) were produced using the supervised classification technique by considering the maximum likelihood classification (MLC) algorithm. The lake size has increased from 0.542 to 0.929 km2 for Geepang Gath glacial lake and 0.849–1.239 km2 for Samudra Tapu glacial lake during the time period of 2005–2019. The findings indicate that there is a need to build risk management plans, improve spatial planning in order to be well prepared for future potential GLOF hazards.