Glacial lake outburst floods (GLOFs) are a great concern for the Himalaya, as they can severely d... more Glacial lake outburst floods (GLOFs) are a great concern for the Himalaya, as they can severely damage downstream populations and infrastructures. These floods originate at high altitudes and can flow down with enormous energy and change the terrain’s existing morphology. One such devastating event occurred on the night of 5 July 2016, from the inconspicuous Gongbatongsha Lake, located in the Poiqu basin, Eastern Himalaya. The Poiqu basin in the Tibetan Autonomous Region currently contains numerous big glacial lakes; however, this event originated from a small lake. The GLOF was triggered following heavy precipitation that led to a slope failure above the lake and deposition of debris into the lake, which breached the moraine dam and rapidly drained the entire lake. The flood damaged several downstream infrastructures, including the Arniko highway, the Upper Bhotekoshi hydropower plant, and several buildings as it made its way into the Bhotekoshi basin in Nepal. This study adopts a ...
It is a robust study where the causes, impacts, and implications are well presented. The authors ... more It is a robust study where the causes, impacts, and implications are well presented. The authors also point out that heavy precipitation can be an important trigger of GLOF. Meteorological conditions, especially extreme rain events, may partly melt ice in the moraine dam and weaken the moraine, or cause overfill and thermal and physical erosion of the moraine, or induce a mass movement into the lake.
The existence of numerous lakes at the higher reaches of the Himalaya makes it a potential natura... more The existence of numerous lakes at the higher reaches of the Himalaya makes it a potential natural hazard, as it imposes a risk of glacial lake outburst flood (GLOF). A GLOF event may cause great loss of life and infrastructure in the low-lying areas. Hydrodynamic modeling of a natural earth dam failure helps us to understand the flow behavior of the sudden water discharge along a given river channel. Further, flood forecasting along the river channel would determine the water discharge of the dam failure event at a particular downstream point. In the present study, moraine failure using hydrodynamic modeling of the Satopanth Tal located in the Alaknanda basin, Central Himalaya is performed to estimate peak discharge at a point just downstream of the lake. Further, unsteady flow routing of the dam-break outflow discharge is performed along the river channel to estimate the peak discharge at a hydropower dam site located 21 km downstream of the lake. The simulation of the glacial lak...
The Hindu-Kush-Himalayan region is home to numerous glacial lakes. Some of these lakes could fail... more The Hindu-Kush-Himalayan region is home to numerous glacial lakes. Some of these lakes could fail and produce hazardous Glacial Lake Outburst Floods (GLOF). GLOFs are primarily triggered by an avalanche or a rockfall entering the lake that generates an overtopping displacement waves. In the present study, we investigate the susceptibility of all lakes present in the Hindu-KushKarakorum (HKH) region (Randolph Glacier inventory region 14 and 15) to the dynamic mass movement (avalanche and rockfall). Avalanche and rockfall trajectories are developed considering various depths and “Minimum Look-Up Angle” (MLUA: a term used to define the avalanche runout distance). These trajectories are also validated against the results obtained from the Rapid Mass Movement Simulation (RAMMS) model. The mass movement of avalanche or rockfall along the major axis may enhance the wave run-up leading to a higher impact on the damming structure. Therefore, each susceptible lake is critically assessed for t...
Abstract Climate change-driven retreat of glaciers is producing thousands of glacial lakes across... more Abstract Climate change-driven retreat of glaciers is producing thousands of glacial lakes across mountain regions. These lakes generally grow, coalesce into larger lakes that may produce increased downstream hazards and risks due to glacial lake outburst floods (GLOFs). This study assesses such hazards of Lower Barun Lake located near Mount Everest, Nepal. We model a series of scenarios, including two potential avalanches that enter the lake from the surrounding slope and eight potential GLOFs from the lake. To evaluate the susceptibility of the frontal moraine to overtopping, we characterize the initial avalanche-induced surge of water over the moraine caused by the kinetic energy of arriving masses and possible tsunami-like events. Further, we present physical hydrodynamic models that reveal the hazard from the potential overtopping and GLOF events along the Barun-Arun river valley. Special attention is given to analyze the flow hydraulics at six downstream settlements. To estimate potential impacts at each location, two extreme-magnitude, two high-magnitude, two moderate-magnitude, and two low-magnitude GLOFs were hydraulically evaluated for the present lake dimension and the modeled future growth of the lake. As with most hydrological processes, the magnitude and frequency of GLOFs from Lower Barun Lake have an inverse, albeit uncertain, relationship, but the potential impacts on people and infrastructure are extremely sensitive to the events’ magnitude. The flow dynamics results indicate that an overtopping flood without erosion of the damming moraine causes minimal impact in the valley. The extreme-magnitude and high-magnitude GLOF cases, where the moraine is incised, have a larger impact but differ greatly in magnitude at each of the downstream settlements. The moderate-magnitude and low-magnitude GLOFs, while the most frequent type, have limited volume and peak discharge, causing less impact downstream. Our calculations only portray the part of the hydrograph representing lake overfill due to a volume of ice or rock entering the lake, and the volume of the lake that could drain from a breach of the damming moraine down to specified depths over specified time periods.
Climate change has led to the formation of numerous high-altitude lakes of glacial origin in the ... more Climate change has led to the formation of numerous high-altitude lakes of glacial origin in the Himalaya. Safed Lake is one of the largest glacial lakes, located at an elevation 4882 m a.s.l. in the state of Uttarakhand, central Himalaya, India. A temporal analysis of the lake surface using satellite imagery shows that the lake has grown more than double its size from 0.10 km2 to 0.23 km2 over the past 50 years. In this study, we performed a hazard assessment of the lake using 1D and 2D hydrodynamic modeling. We identified the potential glacial lake outburst flood (GLOF) triggering factors and evaluated the impact of a moraine breach event of the lake on the nearest village located 16.2 km downstream of the lake. A series of dynamic simulations were performed for different scenario-models based on varied breach depths, breach widths and time of moraine failure. In a worst-case GLOF scenario where breach depth reached up to 60 m, hydrodynamic routing of the breach hydrograph along t...
Glacial lake outburst floods (GLOFs) are a great concern for the Himalaya, as they can severely d... more Glacial lake outburst floods (GLOFs) are a great concern for the Himalaya, as they can severely damage downstream populations and infrastructures. These floods originate at high altitudes and can flow down with enormous energy and change the terrain’s existing morphology. One such devastating event occurred on the night of 5 July 2016, from the inconspicuous Gongbatongsha Lake, located in the Poiqu basin, Eastern Himalaya. The Poiqu basin in the Tibetan Autonomous Region currently contains numerous big glacial lakes; however, this event originated from a small lake. The GLOF was triggered following heavy precipitation that led to a slope failure above the lake and deposition of debris into the lake, which breached the moraine dam and rapidly drained the entire lake. The flood damaged several downstream infrastructures, including the Arniko highway, the Upper Bhotekoshi hydropower plant, and several buildings as it made its way into the Bhotekoshi basin in Nepal. This study adopts a ...
It is a robust study where the causes, impacts, and implications are well presented. The authors ... more It is a robust study where the causes, impacts, and implications are well presented. The authors also point out that heavy precipitation can be an important trigger of GLOF. Meteorological conditions, especially extreme rain events, may partly melt ice in the moraine dam and weaken the moraine, or cause overfill and thermal and physical erosion of the moraine, or induce a mass movement into the lake.
The existence of numerous lakes at the higher reaches of the Himalaya makes it a potential natura... more The existence of numerous lakes at the higher reaches of the Himalaya makes it a potential natural hazard, as it imposes a risk of glacial lake outburst flood (GLOF). A GLOF event may cause great loss of life and infrastructure in the low-lying areas. Hydrodynamic modeling of a natural earth dam failure helps us to understand the flow behavior of the sudden water discharge along a given river channel. Further, flood forecasting along the river channel would determine the water discharge of the dam failure event at a particular downstream point. In the present study, moraine failure using hydrodynamic modeling of the Satopanth Tal located in the Alaknanda basin, Central Himalaya is performed to estimate peak discharge at a point just downstream of the lake. Further, unsteady flow routing of the dam-break outflow discharge is performed along the river channel to estimate the peak discharge at a hydropower dam site located 21 km downstream of the lake. The simulation of the glacial lak...
The Hindu-Kush-Himalayan region is home to numerous glacial lakes. Some of these lakes could fail... more The Hindu-Kush-Himalayan region is home to numerous glacial lakes. Some of these lakes could fail and produce hazardous Glacial Lake Outburst Floods (GLOF). GLOFs are primarily triggered by an avalanche or a rockfall entering the lake that generates an overtopping displacement waves. In the present study, we investigate the susceptibility of all lakes present in the Hindu-KushKarakorum (HKH) region (Randolph Glacier inventory region 14 and 15) to the dynamic mass movement (avalanche and rockfall). Avalanche and rockfall trajectories are developed considering various depths and “Minimum Look-Up Angle” (MLUA: a term used to define the avalanche runout distance). These trajectories are also validated against the results obtained from the Rapid Mass Movement Simulation (RAMMS) model. The mass movement of avalanche or rockfall along the major axis may enhance the wave run-up leading to a higher impact on the damming structure. Therefore, each susceptible lake is critically assessed for t...
Abstract Climate change-driven retreat of glaciers is producing thousands of glacial lakes across... more Abstract Climate change-driven retreat of glaciers is producing thousands of glacial lakes across mountain regions. These lakes generally grow, coalesce into larger lakes that may produce increased downstream hazards and risks due to glacial lake outburst floods (GLOFs). This study assesses such hazards of Lower Barun Lake located near Mount Everest, Nepal. We model a series of scenarios, including two potential avalanches that enter the lake from the surrounding slope and eight potential GLOFs from the lake. To evaluate the susceptibility of the frontal moraine to overtopping, we characterize the initial avalanche-induced surge of water over the moraine caused by the kinetic energy of arriving masses and possible tsunami-like events. Further, we present physical hydrodynamic models that reveal the hazard from the potential overtopping and GLOF events along the Barun-Arun river valley. Special attention is given to analyze the flow hydraulics at six downstream settlements. To estimate potential impacts at each location, two extreme-magnitude, two high-magnitude, two moderate-magnitude, and two low-magnitude GLOFs were hydraulically evaluated for the present lake dimension and the modeled future growth of the lake. As with most hydrological processes, the magnitude and frequency of GLOFs from Lower Barun Lake have an inverse, albeit uncertain, relationship, but the potential impacts on people and infrastructure are extremely sensitive to the events’ magnitude. The flow dynamics results indicate that an overtopping flood without erosion of the damming moraine causes minimal impact in the valley. The extreme-magnitude and high-magnitude GLOF cases, where the moraine is incised, have a larger impact but differ greatly in magnitude at each of the downstream settlements. The moderate-magnitude and low-magnitude GLOFs, while the most frequent type, have limited volume and peak discharge, causing less impact downstream. Our calculations only portray the part of the hydrograph representing lake overfill due to a volume of ice or rock entering the lake, and the volume of the lake that could drain from a breach of the damming moraine down to specified depths over specified time periods.
Climate change has led to the formation of numerous high-altitude lakes of glacial origin in the ... more Climate change has led to the formation of numerous high-altitude lakes of glacial origin in the Himalaya. Safed Lake is one of the largest glacial lakes, located at an elevation 4882 m a.s.l. in the state of Uttarakhand, central Himalaya, India. A temporal analysis of the lake surface using satellite imagery shows that the lake has grown more than double its size from 0.10 km2 to 0.23 km2 over the past 50 years. In this study, we performed a hazard assessment of the lake using 1D and 2D hydrodynamic modeling. We identified the potential glacial lake outburst flood (GLOF) triggering factors and evaluated the impact of a moraine breach event of the lake on the nearest village located 16.2 km downstream of the lake. A series of dynamic simulations were performed for different scenario-models based on varied breach depths, breach widths and time of moraine failure. In a worst-case GLOF scenario where breach depth reached up to 60 m, hydrodynamic routing of the breach hydrograph along t...
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