Assessing GLOF Susceptibility and Risk Mapping Using Optical Remote Sensing Data: A Case Chapter of Upper Alakananda River Basin

This chapter assesses the glacial lakesGlacial lake’ susceptibilitySusceptibility to glacial lake outburstFlood floodsGlacial lake outburst flood (GLOFs) in the Upper Alakananda River Basin, located in the Chamoli District of Uttarakhand (India). Glacial lakes in the region have undergone significant changes, with a threefold increase in their number from over 112 to 237 between 1992 and 2023, indicating their vulnerability to climate change. The chapter identifies 61 lakes exceeding 1 ha in size, with smaller lakes (< 1 ha) dominating the region. The largest expanses of water are located in supraglacial lakes GL-2 and GL-3, which have experienced significant growth, while 14 out of the 58 lakes in the area are proglacial, posing the highest risk of GLOFs. Multi-criteria decision-making analysis using the analytical hierarchy process (AHPAnalytical Hierarchical Process) is applied to identify risk zones. ParametersParameters like volume, area, type, elevation, slopeSlope, aspect, and rainfall intensity are used, and glacial lakesGlacial lake exceeding 1 ha are considered at risk of GLOFs. Approximately 11 out of 61 lakes exhibit the potential to cause harm, and the spatial distribution of risk reveals that most glacial lakesGlacial lake of intermediate size are situated within regions of moderate to high susceptibilitySusceptibility for GLOFs. GL-3, the lake with the largest water surface, lies within a zone of low GLOFGlacial lake outburst flood susceptibilitySusceptibility, while GL-1 and GL-3 are positioned in areas with high susceptibility. GL-5 is situated within a zone of very high susceptibilitySusceptibility. The chapter highlights the importance of conservation, management, and monitoring efforts to preserve the water resources in the Upper Alakananda River Basin.