Glacial Lake Outburst Flood (GLOF) Hazard Mitigation at Himalayan Region, Nepal

Abstract

Glacier retreat is a strong indicator of climate change and global warming. The anthropogenic changes in the Earth's atmosphere are mostly to blame for the climate extremes and their consequences in the last few decades. The Himalayan region is no exclusion to the trend. As glaciers begin to retreat, the glacial lake starts to fill or form behind the natural moraine or ice dam in the glaciers. The sudden release of the water, known as the Glacial Lake Outburst Flood (GLOF), can release a large amount of water and sediment. There have been various destructive GLOFs recorded in Nepal since the 1960s. It is vital to understand the GLOF dynamics, geomorphology and historical events to mitigate the GLOF hazards in the region. An advanced approach based on remote sensing data and empirical evidence is more suitable to tackle these issues. This research investigated 11 among 30 past events recorded in the HKH region (Nepal) to establish the causes and triggering factors that led to the catastrophic failure, which helped establish the vulnerability assessment of these glacial lakes. This eventually led to creating a GLOF vulnerability assessment framework that is unique and useful to the communities. This research concluded that 40% of the GLOF events was due to the moraine dam failure. In the retrospective approach, 5 out of 11 glacial lakes scored a very high total vulnerability score (TVR), which suffered catastrophic events in the past. The TVR of the currently existing 21 potential dangerous glacial lakes (PDGL) in Nepal was also conducted using the proposed assessment framework that concluded the 7 very high, 4 high, 5 medium, and the rest are low. Hence, this assessment tool's reliability is very high. This research also concluded that there should integrated approach to climate change adaptation and hazard mitigations in the region.