A COMPREHENSIVE FRAMEWORK FOR DEVELOPING AN INVENTORY OF GLACIAL LAKE OUTBURST FLOOD RISKS OVER NEPAL

Abstract

This study presents a comprehensive framework for assessing the risks associated with glacial lake outburst floods (GLOFs) in Nepal, focusing on the period from 1990 to 2023. Utilizing Landsat imagery and advanced modeling techniques, the research examines the dynamics of glacial lakes and their potential implications for flood hazards nationwide. Key findings reveal a significant increase in the surface area of glacial lakes over the study period, particularly at elevations between 4000-6000 meters. This increase in surface area is corroborated by data from Table 5.2, which shows a substantial rise in the number of identified and newly formed glacial lakes within these elevation ranges, indicating a heightened risk of GLOFs in these areas. Furthermore, the study highlights the total glacial lake volume, showcasing the substantial water storage capacity of these lakes, which exacerbates flood risks in the event of an outburst. The study proposes the development of a comprehensive glacial lake outburst flood atlas database for Nepal. By integrating advanced modeling tools such as LISFLOOD-FP, the research provides valuable insights for identifying vulnerable areas and implementing targeted interventions to enhance resilience to GLOF events. This study also incorporates modeling of potential GLOF scenarios based on varying increases in the glacial lake area. The research explores five scenarios wherein glacial lake areas increase by 10%, 20%, 30%, 40%, and 50%. This modeling approach provides critical insights into the potential impacts of continued glacial lake expansion on flood hazards in the region. By simulating these scenarios, the study anticipates future flood risks associated with ongoing climate change-induced glacial retreat and meltwater accumulation. The development of a comprehensive glacial lake outburst flood atlas database, as proposed in the study, holds significant value beyond the current research period. This database can serve as a valuable tool for ongoing monitoring and future risk assessment efforts. As glacial lakes continue to increase in size and number, the flood atlas database will remain relevant for identifying vulnerable areas and informing proactive measures to mitigate GLOF risks.