Status: this discussion paper is a preprint. It has been under review for the journal The Cryosphere (TC). The manuscript was not accepted for further review after discussion.
Geospatial Analysis and Simulation of Glacial Lake Outburst Flood
Hazard in Hunza and Shyok Basins of Upper Indus Basin
Syed Naseem Abbas Gilany,Javed Iqbal,and Ejaz Hussain
Abstract. The UIB (Upper Indus Basin) is prone to GLOFs (Glacial Lake Outburst Floods). Physical monitoring of such a large area on regular basis is a challenging task especially when the temporal and spatial extent of the hazard is highly variable. The purpose of this study was to map the potentially dangerous glacial lakes and simulate the associated hazard in the downward settlements using HEC-RAS in the GIS environment using Landsat 7 remote sensing data. The study was conducted in Hunza and Shyok sub-basins of UIB where there are several human settlements which are endangered due to the GLOF hazard. Sudden breaches in the unstable moraine dams adjoining receding glaciers may occur because of rapid and huge accumulation of turbulent water in the glacial lakes. The ASTER DEM (Digital Elevation Model) is utilized to detect flow accumulation of glacial hazard involving slope, elevation, and orientation of the mountain glaciers. The study results revealed that settlements of Hunza and Shyok basins are threatened by the GLOFs hazard. Keeping in view the seasonal growth of the potentially dangerous glacial lakes of Hunza basin, a low discharge of 3500 m3/s from potentially dangerous glacial lake can affect 40 %, whereas, a moderate discharge of 5000 m3/s can affect 60% and a high discharge of 7000 m3/s can affect 80 % of the Shimshal village habitat. In Shyok basin, a low discharge of 100 m3/s from both lakes can affect 20 %, whereas, a moderate discharge of 300 m3/s can affect 30 % and a high discharge of 500 m3/s can affect 40 % of the Barah village habitat. The results of the study can provide a platform for the establishment of an early warning and monitoring system to minimize the impact of future GLOFs. Accurate and comprehensive knowledge of potentially dangerous GLOFs is of utmost importance for risk management. A digital repository of GLOFs can enhance the ability to inform policy makers on the vulnerability, risk mitigation and action/adaptation measures.
Received: 27 Nov 2019 – Discussion started: 06 Feb 2020
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
The Shyok and Hunza basin are prone to glacial lake outburst floods hazard based on the proximity of glacial lake with respect to infrastructure, geomorphology of underneath surface, geo-cover of the vicinity, crevasses, ice melt, and anthropogenic activities. Therefore, continuous monitoring through physical gauge stations and satellite images is very vital of the streams nearing settlements of these basins. HEC-RAS simulated extents of damages can help in adoption of mitigation measures.
The Shyok and Hunza basin are prone to glacial lake outburst floods hazard based on the...
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