Potential GLOF Impacts in High Mountains: An Example from Bhotkhola and Makalu Rural Municipality, Nepal.

Events of Glacial Lake Outburst Flood (GLOF) are increasing in last decades and are projected to be more frequent in coming years. The Lower Barun Glacial Lake is one of the largest glacial lakes of Nepal at high risk of GLOF and its impact could be instrumental in planning Disaster Risk Reduction (DRR) initiatives. In this work, we assess the GLOF potential for the Lower Barun Glacial Lake, its extent in downstream up to the boundary of Makalu Rural Municipality in Arun River Basin and the Impact of possible GLOF in terms of direct economic loss , relevant sustainable development goal (SDG) indicators and also in terms of energy considering dam breach scenario executed in HEC-RAS 5.0.7. Direct economic impact is assessed considering the replacement cost of the lifelines across the flooding plane. Similarly, impact on some other important sectors is assessed by comparing the changes in SDG indicators, viz. Rural Access Index (RAI), population affected by disaster per 100,000 people, Forest area as a proportion of total land area, and Mountain Green cover Index (MGCI). Apart from this, we assessed Impact on energy sector in terms of power dynamics of the projects under preparation and construction. The results indicate that the direct economic loss in the two rural municipalities is 8.14 million US$ for possible GLOF scenario. The Rural access index indicates that entire population of Bhotkhola rural municipality will lose direct and uninterrupted access to the district downtown after the GLOF. Meanwhile only 16 % of people living in Makalu Rural Municipality will have uninterrupted access to district downtown, which is the major economic center nearby. Similarly, number of people affected by disaster per 100000 is observed to be increased by about 464% and 5% as compared to highest recorded casualties till date for Bhotkhola and Makalu Rural Municipalities , respectively. In total, 2465.2 MW of clean electric power generation is estimated to be affected due to the possible GLOF. The sum of findings outlines that enormous losses of lives and properties will be incurred in the mountainous basins with high susceptibility of GLOF.