Publications
Journal Articles
2.
Sattar, Ashim; Allen, Simon; Mergili, Martin; Haeberli, Wilfried; Frey, Holger; Kulkarni, Anil V.; Haritashya, Umesh K.; Huggel, Christian; Goswami, Ajanta; Ramsankaran, R. A. A. J.
In: Journal of Geophysical Research: Earth Surface, vol. 128, iss. 3, pp. e2022JF006826, 2023, ISSN: 2169-9011.
Abstract | Links | Tags: glacial lake outburst floods, GLOF exposure, GLOF mitigation, GLOF modeling, GLOF risk reduction, lake lowering, western Himalaya
@article{Sattar2023,
title = {Modeling Potential Glacial Lake Outburst Flood Process Chains and Effects From Artificial Lake-Level Lowering at Gepang Gath Lake, Indian Himalaya},
author = {Ashim Sattar and Simon Allen and Martin Mergili and Wilfried Haeberli and Holger Frey and Anil V. Kulkarni and Umesh K. Haritashya and Christian Huggel and Ajanta Goswami and R. A. A. J. Ramsankaran},
url = {https://onlinelibrary.wiley.com/doi/full/10.1029/2022JF006826 https://onlinelibrary.wiley.com/doi/abs/10.1029/2022JF006826 https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JF006826},
doi = {10.1029/2022JF006826},
issn = {2169-9011},
year = {2023},
date = {2023-01-01},
journal = {Journal of Geophysical Research: Earth Surface},
volume = {128},
issue = {3},
pages = {e2022JF006826},
publisher = {John Wiley & Sons, Ltd},
abstract = {Glacial lake outburst floods (GLOFs) are a severe threat to communities in the Himalayas; however, GLOF mitigation strategies have been implemented for only a few lakes, and future changes in hazard are rarely considered. Here, we present a comprehensive assessment of current and future GLOF hazard for Gepang Gath Lake, Western Himalaya, considering rock and/or ice avalanches cascading into the lake. We consider ground surface temperature and topography to define avalanche source zones located in areas of potentially degrading permafrost. GLOF process chains in current and future scenarios, also considering engineered lake lowering of 10 and 30 m, were evaluated. Here, varied avalanche impact waves, erosion patterns, debris flow hydraulics, and GLOF impacts at Sissu village, under 18 different scenarios were assessed. Authors demonstrated that a larger future lake does not necessarily produce larger GLOF events in Sissu, depending, among other factors, on the location from where the triggering avalanche initiates and strikes the lake. For the largest scenarios, 10 m of lowering reduces the high-intensity zone by 54% and 63% for the current and future scenarios, respectively, but has little effect on the medium-intensity flood zone. Even with 30 m of lake lowering, the Sissu helipad falls in the high-intensity zone under all moderate-to-large scenarios, with severe implications for evacuations and other emergency response actions. The approach can be extended to other glacial lakes to demonstrate the efficiency of lake lowering as an option for GLOF mitigation and enable a robust GLOF hazard and risk assessment.},
keywords = {glacial lake outburst floods, GLOF exposure, GLOF mitigation, GLOF modeling, GLOF risk reduction, lake lowering, western Himalaya},
pubstate = {published},
tppubtype = {article}
}
Glacial lake outburst floods (GLOFs) are a severe threat to communities in the Himalayas; however, GLOF mitigation strategies have been implemented for only a few lakes, and future changes in hazard are rarely considered. Here, we present a comprehensive assessment of current and future GLOF hazard for Gepang Gath Lake, Western Himalaya, considering rock and/or ice avalanches cascading into the lake. We consider ground surface temperature and topography to define avalanche source zones located in areas of potentially degrading permafrost. GLOF process chains in current and future scenarios, also considering engineered lake lowering of 10 and 30 m, were evaluated. Here, varied avalanche impact waves, erosion patterns, debris flow hydraulics, and GLOF impacts at Sissu village, under 18 different scenarios were assessed. Authors demonstrated that a larger future lake does not necessarily produce larger GLOF events in Sissu, depending, among other factors, on the location from where the triggering avalanche initiates and strikes the lake. For the largest scenarios, 10 m of lowering reduces the high-intensity zone by 54% and 63% for the current and future scenarios, respectively, but has little effect on the medium-intensity flood zone. Even with 30 m of lake lowering, the Sissu helipad falls in the high-intensity zone under all moderate-to-large scenarios, with severe implications for evacuations and other emergency response actions. The approach can be extended to other glacial lakes to demonstrate the efficiency of lake lowering as an option for GLOF mitigation and enable a robust GLOF hazard and risk assessment.
1.
Mal, Suraj; Allen, Simon K.; Frey, Holger; Huggel, Christian; Dimri, A. P.
Sectorwise Assessment of Glacial Lake Outburst Flood Danger in the Indian Himalayan Region Journal Article
In: Mountain Research and Development, vol. 41, no. 1, pp. R1, 2021, ISSN: 0276-4741.
Abstract | Links | Tags: Exposure, glacial lake outburst floods, Hazard, hydropower, indian himalayas, transboundary threats
@article{Mal2021c,
title = {Sectorwise Assessment of Glacial Lake Outburst Flood Danger in the Indian Himalayan Region},
author = {Suraj Mal and Simon K. Allen and Holger Frey and Christian Huggel and A. P. Dimri},
url = {https://bioone.org/journals/mountain-research-and-development/volume-41/issue-1/MRD-JOURNAL-D-20-00043.1/Sectorwise-Assessment-of-Glacial-Lake-Outburst-Flood-Danger-in-the/10.1659/MRD-JOURNAL-D-20-00043.1.full https://bioone.org/journals/mountain-research-and-development/volume-41/issue-1/MRD-JOURNAL-D-20-00043.1/Sectorwise-Assessment-of-Glacial-Lake-Outburst-Flood-Danger-in-the/10.1659/MRD-JOURNAL-D-20-00043.1.short},
doi = {10.1659/MRD-JOURNAL-D-20-00043.1},
issn = {0276-4741},
year = {2021},
date = {2021-05-01},
journal = {Mountain Research and Development},
volume = {41},
number = {1},
pages = {R1},
publisher = {International Mountain Society},
abstract = {Climate change and associated glacier recession have led to the formation of new glacial lakes and the expansion of existing ones across the Himalayas. Many pose a potential glacial lake outburst flood (GLOF) threat to downstream communities and infrastructure. In this paper, 4418 glacial lakes in the Indian Himalayan Region and 636 transboundary lakes are analyzed. We consider hazard, exposure, and integrated danger levels using robust geographic information system-based automated approaches. The hazard level of lakes was estimated based on the potential for avalanches to strike the lake, size of the lake and its upstream watershed, and distal slope of its dam. Exposure levels were calculated by intersecting cropland, roads, hydropower projects, and the human population with potential GLOF trajectories. Then, GLOF danger was determined as a function of hazard and exposure. The study demonstrates that Jammu and Kashmir (JK) is potentially the most threatened region in terms of total number of very high and high danger lakes (n = 556), followed by Arunachal Pradesh (AP) (n = 388) and Sikkim (SK) (n = 219). Sectorwise, JK faces the greatest GLOF threat to roads and population, whereas the threat to cropland and hydropower is greatest in AP and SK, respectively. Transboundary lakes primarily threaten AP and, to a lesser extent, Himachal Pradesh (HP). For Uttarakhand (UK), the impacts of potential future glacial lakes, expected to form during rapid ongoing glacier recession because of climate change, are explored. Finally, a comparison of current results with previous studies suggests that 13 lakes in SK, 5 in HP, 4 in JK, 2 in UK, and 1 in AP are of highest priority for local investigation and potential risk reduction measures. Current results are of vital importance to policymakers, disaster management authorities, and the scientific community.},
keywords = {Exposure, glacial lake outburst floods, Hazard, hydropower, indian himalayas, transboundary threats},
pubstate = {published},
tppubtype = {article}
}
Climate change and associated glacier recession have led to the formation of new glacial lakes and the expansion of existing ones across the Himalayas. Many pose a potential glacial lake outburst flood (GLOF) threat to downstream communities and infrastructure. In this paper, 4418 glacial lakes in the Indian Himalayan Region and 636 transboundary lakes are analyzed. We consider hazard, exposure, and integrated danger levels using robust geographic information system-based automated approaches. The hazard level of lakes was estimated based on the potential for avalanches to strike the lake, size of the lake and its upstream watershed, and distal slope of its dam. Exposure levels were calculated by intersecting cropland, roads, hydropower projects, and the human population with potential GLOF trajectories. Then, GLOF danger was determined as a function of hazard and exposure. The study demonstrates that Jammu and Kashmir (JK) is potentially the most threatened region in terms of total number of very high and high danger lakes (n = 556), followed by Arunachal Pradesh (AP) (n = 388) and Sikkim (SK) (n = 219). Sectorwise, JK faces the greatest GLOF threat to roads and population, whereas the threat to cropland and hydropower is greatest in AP and SK, respectively. Transboundary lakes primarily threaten AP and, to a lesser extent, Himachal Pradesh (HP). For Uttarakhand (UK), the impacts of potential future glacial lakes, expected to form during rapid ongoing glacier recession because of climate change, are explored. Finally, a comparison of current results with previous studies suggests that 13 lakes in SK, 5 in HP, 4 in JK, 2 in UK, and 1 in AP are of highest priority for local investigation and potential risk reduction measures. Current results are of vital importance to policymakers, disaster management authorities, and the scientific community.