GLOF Modeling of Hongu Glacier Lake in the Nepal Himalayas: A GIS-based Approach

The objective of this project is to model a glacial lake outburst flood (GLOF) of Hongu Glacier Lake, located in the Mount Everest region of Nepal, using a physically-based GIS model. Due to recent climate change many glaciers in the Himalayas have experienced rapid retreat, resulting in the development and growth of proglacial lakes. Often dammed by terminal moraines composed of unstable and unconsolidated material, trigger events such as excessive rainfall or avalanches can cause the dam to be breached, releasing massive amounts of water over a short period. Large volumes of water combined with the steep and complex terrain of the Himalayas causes serious threat to downstream populations and infrastructure. Assessing and monitoring proglacial lakes using remotely sensed images has become a widely established practice as many glaciers, including Hongu, are in unreachable, remote area. Additionally, GIS-based flood models allow for spatial analysis of risk assessment. Using digital elevation models (DEMs) derived from remotely sensed images, land cover data, and soil data as base maps, the freely available WetSpa model is applied to Hongu Glacier Lake for flood prediction. WetSpa, or Water and Energy Transfer between Soil, Plants and Atmosphere, is a physically based GIS model that simulates hydrologic processes continuously over time and space on the catchment scale. DEMs from 2015 imagery are obtained freely through NASA’s Earth Explorer program, and soil and land use data are obtained from the International Centre for Integrated Mountain Development (ICIMOD). Outputs in the form of hydrographs from the WetSpa model are imported into ArcMap for analysis. Information on extent and intensity of the modeled GLOF can be used for risk assessment or future planning of infrastructure