Author(s): Null
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Keywords: GLOFs; Lateral moraine; InSAR; HEC-RAS
Abstract: The exacerbation of glacier mass loss due to global warming leads to the accelerating expansion of glacial lakes globally. The destabilization of lateral moraines and the following landslide into a glacial lake may trigger the outburst floods greater than before, which has become an increasing threat to the residents and infrastructure downstream of the glacier lake. However, due to the remote and inaccessible of glacial lakes and the absence of insite monitoring data, accurately assessing the risk of GLOFs remains challenging. This study aims to quantitatively assess the potential impacts of the GLOFs induced by the collapse of varying volume of lateral moraines on the settlements and infrastructure downstream based on a comprehensive approach integrating multi-source remote sensing and hydraulic modeling techniques. This study delineated the water surface areas of the Qiangzongkeco using optical remote sensing images and estimated the lake volumes based on the empirical relationship. The cumulative deformation and deformation rate of the lateral moraines and the glacial tongue were assessed by analyzing a long-time series of Interferometric Synthetic Aperture Radar (InSAR) data. The potential landslide volume range into the lake was estimated based on the deformative lateral moraines. The Froehlich equation was employed to predict the breach hydrological process curve of the GLOFs accordingly, serving as inputs for the hydraulic modeling of downstream flood routing in HEC-RAS software. The distributions of flood depth and flow velocity along the channel and in the settlements and infrastructure downstream were visualized to analyze the inundation risk by the floods. The results show that the deformation of lateral moraines were significant and keeps accelerating since 2010s. Variations in landslide scale and outburst flood volume lead to significant differences in the GLOFs peak discharge. Besides, Gonglema and Chentang Town’s infrastructure will be severely damaged. Our results highlight the necessity on continuous monitoring of the deformative lateral moraines around rapidly expanding glacial lakes to mitigate the hazards of GLOFs in high-altitude mountainous areas.
Year: 2024