Glacial lakes and glacial lake outburst flood in a Himalayan basin using remote sensing and GIS

In past Nepal has encountered a number of glacial lake outburst flood (GLOF) events causing loss of billions of rupees. Still there are a number of glacial lakes forming and there are chances of new glacial lake formation. Hence there is intense need to monitor glaciers and glacial lakes. The development on remote sensing technology has eased the researches on glacier and glacial lakes. Identification of locations of potential glacial lakes through the use of remote sensing technology has been proven and hence is opted for identification of locations of potential glacial lake in Khumbu Valley of Sagarmatha Zone, Nepal. The probable sites for glacial lake formation are at Ngojumpa, Lobuche, Khumbu, Bhotekoshi, Inkhu, Kyasar, Lumsumna, etc. As per study, the biggest glacial lake could form at Ngozumpa glacier. Even in other glaciers potential supra-glacial lakes could merge together to form lakes that occupy significant area. Nepalese Journal on Geoinformatics -12, 2070 (2013AD): 10-16

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Cryosphere hazards in Ladakh: the 2014 Gya glacial lake outburst flood and its implications for risk assessment

Natural Hazards ◽

10.1007/s11069-020-04262-8 ◽

2020 ◽

Vol 104 (3) ◽

pp. 2071-2095 ◽

Cited By ~ 1

Author(s):

Susanne Schmidt ◽

Marcus Nüsser ◽

Ravi Baghel ◽

Juliane Dame

Keyword(s):

Remote Sensing ◽

Risk Assessment ◽

Integrated Approach ◽

Glacial Lake ◽

Glacial Lakes ◽

Outburst Flood ◽

Field Surveys ◽

Depth Analysis ◽

Glacial Lake Outburst Flood

Abstract This article attempts to reconstruct the causes and consequences of the 2014 glacial lake outburst flood (GLOF) event in Gya, Ladakh. We analyse the evolution of the Gya glacial lake using a high temporal and high spatial resolution remote sensing approach. In order to frame the case study in a larger picture, we produce a comprehensive inventory of glacial lakes for the entire Trans-Himalayan region of Ladakh. Changes in the extent and number of glacial lakes have been detected for the years 1969, 1993, 2000/02 and 2018 in order to assess the potential risk of future GLOFs in the region. The remote sensing approach was supported by field surveys between 2014 and 2019. The case study of the Gya GLOF illustrates the problem of potentially hazardous lakes being overlooked in inventories. The broader analysis of the Ladakh region and in-depth analysis of one GLOF lead us to propose an integrated approach for detecting undocumented GLOFs. This article demonstrates the necessity for using multiple methods to ensure robustness of risk assessment. The improved understanding can lead to a more accurate evaluation of exposure to cryosphere hazards and identification of alternative mechanisms and spatial patterns of GLOFs in the Himalaya.

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Glacial lake outburst flood risk assessment using combined approaches of remote sensing, GIS and dam break modelling

Geomatics Natural Hazards and Risk ◽

10.1080/19475705.2013.862573 ◽

2013 ◽

Vol 7 (1) ◽

pp. 18-36 ◽

Cited By ~ 15

Author(s):

Arpit Aggarwal ◽

Sanjay K. Jain ◽

Anil K. Lohani ◽

Neha Jain

Keyword(s):

Remote Sensing ◽

Risk Assessment ◽

Flood Risk ◽

Dam Break ◽

Glacial Lake ◽

Flood Risk Assessment ◽

Outburst Flood ◽

Glacial Lake Outburst Flood

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UAV-based remote sensing of immediate changes in geomorphology following a glacial lake outburst flood at the Zackenberg river, northeast Greenland

Journal of Maps ◽

10.1080/17445647.2020.1749146 ◽

2020 ◽

Vol 16 (1) ◽

pp. 86-100 ◽

Cited By ~ 2

Author(s):

Aleksandra M. Tomczyk ◽

Marek W. Ewertowski

Keyword(s):

Remote Sensing ◽

Glacial Lake ◽

Outburst Flood ◽

Glacial Lake Outburst Flood

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Temporal monitoring of Ghamu bar glacial lakes using remote sensing and GIS

International Journal of Advanced Geosciences ◽

10.14419/ijag.v7i1.20308 ◽

2019 ◽

Vol 7 (1) ◽

pp. 18

Author(s):

Alamgeer Hussain ◽

Dilshad Bano

Keyword(s):

Climate Change ◽

Remote Sensing ◽

Remote Sensing Data ◽

Remote Sensing And Gis ◽

Glacial Lake ◽

Lake Area ◽

Glacial Lakes ◽

Landsat Images ◽

Water Index ◽

Normalized Difference Water Index

The trends of glacial lakes formation and glacial lake outburst flooding events have been increased across Himalayan Karakorum Hindu Kush (HKH) ranges during last decade due to increase in global warming. This research is addressing the temporal monitoring of ghamu bar glacial lakes using remote sensing and GIS. Landsat images of 1990, 2000, 2010 and 2015 were used to map temporal glacial lakes using normalized difference water index (NDWI) index. The results of normalized difference water index were validated through modified normalized difference water index and field photographs. Temporal variability shows that, glacier lake area has been increase from 1990 to 2015. In 1990 total area of lake was 0.052 sq, which further increased 0.0423 in 1995 than it decreases to 0.314 in 2000 due to detached of debris cover moraine from glacier tongue and it reach 0.0846 sq.km in 2005. The area gradually increased up to 0.1296 sq.km in 2010 and it goes up to 0.157 sq.km 2015. The overall increase in area are expanding at an accelerated rate in past two decades, indicating that Darkut glacier is more vulnerable toward climate change through increase in size and volume ofghamu bar glacial lakes. There is need for vigilance in monitoring of ghamu bar glacial lake through high resolution remote sensing data and development of Geo-database enabling more details about past and future lakes behaviors toward climate change impacts.

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Simulation and Assessment of Future Glacial Lake Outburst Floods in the Poiqu River Basin, Central Himalayas

Water ◽

10.3390/w13101376 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1376

Author(s):

Taigang Zhang ◽

Weicai Wang ◽

Tanguang Gao ◽

Baosheng An

Keyword(s):

River Basin ◽

Hazard Assessment ◽

Glacial Lake ◽

High Mountain ◽

Glacial Lakes ◽

Central Himalayas ◽

Outburst Floods ◽

Glacial Lake Outburst Floods ◽

Social And Economic Development ◽

Glacial Lake Outburst Flood

A glacial lake outburst flood (GLOF) is a typical glacier-related hazard in high mountain regions. In recent decades, glacial lakes in the Himalayas have expanded rapidly due to climate warming and glacial retreat. Some of these lakes are unstable, and may suddenly burst under different triggering factors, thus draining large amounts of water and impacting downstream social and economic development. Glacial lakes in the Poiqu River basin, Central Himalayas, have attracted great attention since GLOFs originating there could have a transboundary impact on both China and Nepal, as occurred during the Cirenmaco GLOF in 1981 and the Gongbatongshaco GLOF in 2016. Based on previous studies of this basin, we selected seven very high-risk moraine-dammed lakes (Gangxico, Galongco, Jialongco, Cirenmaco, Taraco, Beihu, and Cawuqudenco) to simulate GLOF propagation at different drainage percentage scenarios (i.e., 25%, 50%, 75%, and 100%), and to conduct hazard assessment. The results show that, when any glacial lake is drained completely or partly, most of the floods will enter Nepal after raging in China, and will continue to cause damage. In summary, 57.5 km of roads, 754 buildings, 3.3 km2 of farmland, and 25 bridges are at risk of damage due to GLOFs. The potentially inundated area within the Chinese part of the Poiqu River basin exceeds 45 km2. Due to the destructive impacts of GLOFs on downstream areas, appropriate and effective measures should be implemented to adapt to GLOF risk. We finally present a paradigm for conducting hazard assessment and risk management. It uses only freely available data and thus is easy to apply.

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Sustained Impact of a Glacial Lake Outburst Flood on Winter Turbidity Regimes across the Land-Ocean Aquatic Continuum

10.5194/egusphere-egu21-16594 ◽

2021 ◽

Author(s):

Ian Giesbrecht ◽

Suzanne Tank ◽

Justin Del Bel Belluz ◽

Jennifer Jackson

Keyword(s):

Freshwater Ecosystems ◽

Glacial Lake ◽

Mass Wasting ◽

Outburst Flood ◽

Fisheries Resources ◽

Carbon Burial ◽

Source To Sink ◽

Creek Watershed ◽

Glacial Lake Outburst Flood ◽

The Impact

Rainforest rivers export large quantities of terrestrial materials from watersheds to the coastal ocean, with important implications for local ecosystems and global biogeochemical cycles. However, the impact of episodic disturbance on this process is a critical knowledge gap in our understanding of land-sea connections. Fjords represent a global hotspot for terrestrial carbon burial in marine sediments, yet the relative importance of typical riverine fluxes vs. mass wasting fluxes is uncertain and dynamic. Similarly, mass wasting events can generate both an instantaneous pulse and a sustained shift in the material export regime. Riverine sediment regimes also have important implications for freshwater ecosystems and fisheries resources. A recent mass wasting event in Bute Inlet &#8211; Homalco First Nation traditional territory and British Columbia, Canada &#8211; presents an important opportunity to quantify the sustained impact of such an infrequent large disturbance on the source-to-sink linkages between glacierized mountains, rivers, and fjords.On November 28, 2020, a landslide in the headwaters of the Elliot Creek watershed (118 km2) triggered a glacial lake outburst flood (GLOF) that eroded 3 km2 of forested land and exported large volumes of water and terrestrial materials to the lower reaches of the Southgate River watershed (1986 km2) and ultimately to the head of Bute Inlet. Here we assess river and ocean surface turbidity over four winter months following the event, in comparison to pre-event measurements taken across all seasons in recent years. River turbidity was measured on the Southgate River above and below the confluence of Elliot Creek, beginning in December 2020, and at the mouth of the Southgate and nearby Homathko Rivers prior to November 2020. Bute Inlet turbidity was measured (every month to two months) starting in May 2017.Prior to the GLOF event, Southgate River turbidity ranged from a low of 3.3 &#177; 0.4&#160;FNU in the winter to a high of 71.4 FNU in the summer meltwater period. Since the event, Southgate River turbidity has been consistently elevated &#8805;6 times background levels recorded above Elliot Creek. At the extreme, on January 13, 2021, seven weeks after the GLOF, Southgate River mean turbidity (105.2 &#177; 3.3&#160;FNU) was 32 times the background (3.3 &#177; 0.4&#160;FNU), equating to a sustained increase in wintertime turbidity that sometimes exceeds the historical summertime peak. Given the typical coupling of turbidity with discharge, we expect further increases in turbidity with the coming freshet of 2021; the first meltwater season following the GLOF. These results suggest the potential for a sustained shift in the seasonal turbidity regime of the Southgate River and the estuarine waters of Bute Inlet. The elevated turbidity signals broader changes to: sediment export and carbon burial, the depth and seasonality of light penetration, river water quality, and spawning habitat quality for anadromous fish. Ongoing monitoring will be used to characterize the duration, dynamics, and potential recovery of elevated turbidity regimes across the land-to-ocean aquatic continuum in Bute Inlet.

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The 2020 glacial lake outburst flood at Jinwuco, Tibet: causes, impacts, and implications for hazard and risk assessment

10.5194/tc-2020-379 ◽

2021 ◽

Author(s):

Guoxiong Zheng ◽

Martin Mergili ◽

Adam Emmer ◽

Simon Allen ◽

Anming Bao ◽

...

Keyword(s):

Time Lag ◽

Peak Discharge ◽

Glacial Lake ◽

Lateral Moraine ◽

Process Chain ◽

Outburst Flood ◽

Impact Wave ◽

Debris Landslide ◽

Property Losses ◽

Glacial Lake Outburst Flood

Abstract. We analyze and reconstruct a recent Glacial Lake Outburst Flood (GLOF) process chain on 26 June 2020, involving the moraine-dammed proglacial lake Jinwuco (30.356° N, 93.631° E) in eastern Nyainqentanglha, Tibet, China. Satellite images reveal that from 1965 to 2020, the surface area of Jinwuco has expanded by 0.2 km2 (+56 %) to 0.56 km2, and subsequently decreased to 0.26 km2 (‒54 %) after the GLOF. Estimates based on topographic reconstruction and sets of published empirical relationships indicate that the GLOF had a volume of 10 million m3, an average breach time of 0.62 hours, and an average peak discharge of 5,390 m3/s at the dam. Based on pre- and post-event high-resolution satellite scenes, we identified a large progressive debris landslide originating from western lateral moraine, having occurred 5–17 days before the GLOF. This landslide was most likely triggered by extremely heavy, south Asian monsoon-associated rainfall in June. The time lag between the landslide and the GLOF suggests that pre-weakening of the dam due to landslide-induced outflow pushed the system towards a tipping point, that was finally exceeded following subsequent rainfall, snowmelt, a secondary landslide, or calving of ice into the lake. We back-calculate part of the GLOF process chain, using the GIS-based open source numerical simulation tool r.avaflow. Two scenarios are considered, assuming a debris landslide-induced impact wave with overtopping and resulting retrogressive erosion of the moraine dam (Scenario A), and retrogressive erosion due to pre-weakening of the dam without a major impact wave (Scenario B). Both scenarios yield plausible results which are in line with empirically derived ranges of peak discharge and breach time. The breaching process is characterized by a slower onset and a resulting delay in Scenario B, compared to Scenario A. Evidence, however, points towards Scenario B as a more realistic possibility. There were no casualties from this GLOF but it caused severe destruction of infrastructure (e.g. roads and bridges) and property losses in downstream areas. Given the clear role of continued glacial retreat in destabilizing the adjacent lateral moraine slopes, and directly enabling the landslide to deposit into the expanding lake body, the GLOF process chain under Scenario B can be robustly attributable to anthropogenic climate change, while downstream consequences have been enhanced by the development of infrastructure on exposed flood plains. Such process chains could become more frequent under a warmer and wetter future climate, calling for comprehensive and forward-looking risk reduction planning.

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