GLACIER LAKES AND DISASTER MITIGATION

The Himalayan glaciers feed major Asian river systems sustaining the lives of more than 800 million people. With the changing climate, glaciers are shrinking and the rates of retreat may increase even further. This may lead to the formation of moraine dammed glacial lakes, which can cause outburst floods upon failure of the dam, catastrophic to human life and infrastructure. Therefore, identification of potential lake sites and predicting the expansion of existing lakes are crucial for mitigation. In the present study, glacier surface velocity and slope are used to calculate ice thickness, by applying a parallel flow model. The depth was used to estimate the bed topography and potential lake sites. The model is applied to Samudra Tapu and Drang Drung glaciers using satellite data between the years 1999 and 2001, where eight potential lake sites were identified. The analysis predicts an over-deepening near the snout of Samudra Tapu, in close proximity to an existing moraine dammed lake. A portion of the predicted site has already evolved into a lake between the years 2000 and 2015, which upon further deglaciation could lead to an expansion of the existing lake by an area of 14 ±2 ha. The present study demonstrates the utility of the model to predict maximum expansion of the existing lakes and possible formation of new lakes due to glacier retreat. Systematic application of this technique can provide information crucial to policy makers and planners dealing with the security of people living in the mountains.