Glacial lake outburst floods as drivers of fluvial erosion in the Himalaya

Science ◽  
2018 ◽  
Vol 362 (6410) ◽  
pp. 53-57 ◽  
Author(s):  
Kristen L. Cook ◽  
Christoff Andermann ◽  
Florent Gimbert ◽  
Basanta Raj Adhikari ◽  
Niels Hovius
Keyword(s):  
Glacial Lake ◽  
Outburst Flood ◽  
Fluvial Erosion ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Seismic Records ◽  
Glacial Lake Outburst Flood ◽  
The Himalaya ◽  
Annual Summer

Himalayan rivers are frequently hit by catastrophic floods that are caused by the failure of glacial lake and landslide dams; however, the dynamics and long-term impacts of such floods remain poorly understood. We present a comprehensive set of observations that capture the July 2016 glacial lake outburst flood (GLOF) in the Bhotekoshi/Sunkoshi River of Nepal. Seismic records of the flood provide new insights into GLOF mechanics and their ability to mobilize large boulders that otherwise prevent channel erosion. Because of this boulder mobilization, GLOF impacts far exceed those of the annual summer monsoon, and GLOFs may dominate fluvial erosion and channel-hillslope coupling many tens of kilometers downstream of glaciated areas. Long-term valley evolution in these regions may therefore be driven by GLOF frequency and magnitude, rather than by precipitation.

Neoglacial increase in high-magnitude Glacial Lake Outburst Flood frequency (Baker River, Patagonia, 47°S)

2021 ◽  
Author(s):  
Sebastien Bertrand ◽  
Elke Vandekerkhove ◽  
Dmitri Mauquoy ◽  
Dave McWethy ◽  
Brian Reid ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Flood Frequency ◽  
Glacial Lake ◽  
Fine Grained ◽  
High Magnitude ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
History Of ◽  
Glacial Lake Outburst Flood

<p>Glacial Lake Outburst Floods (GLOFs) constitute a major hazard in periglacial environments. Despite a recent increase in the size and number of glacial lakes worldwide, there is only limited evidence that climate change is affecting GLOF frequency. In Patagonia, GLOFs are particularly common in the Baker River watershed (47°S), where 21 GLOFs occurred between 2008 and 2017 due to the drainage of Cachet 2 Lake into the Colonia River, a tributary of the Baker River. During these GLOFs, the increased discharge from the Colonia River blocks the regular flow of the Baker River, resulting in the inundation of the Valle Grande floodplain, which is located approximately 4 km upstream of the confluence. To assess the possible long-term relationship between GLOF frequency, glacier behavior, and climate variability, four sediment cores collected in the Valle Grande floodplain were analyzed. Their geophysical and sedimentological properties were examined, and radiocarbon-based age-depth models were constructed. All cores consist of dense, fine-grained, organic-poor material alternating with low-density organic-rich deposits. The percentage of lithogenic particles, which were most likely deposited during high-magnitude GLOFs, was used to reconstruct the flood history of the last 2.75 kyr. Results show increased flood activity between 2.57 and 2.17 cal kyr BP, and between 0.75 and 0 cal kyr BP. These two periods coincide with glacier advances during the Neoglaciation. Our results suggest that GLOFs are not a new phenomenon in the region. Although rapid glacier retreat is likely responsible for high GLOF frequency in the 21<sup>st</sup> century, high-magnitude GLOFs seem to occur more frequently when glaciers are larger and thicker.</p>

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

Water ◽  
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.

Unchanged frequency of moraine-dammed glacial lake outburst floods in the Himalaya

2019 ◽  
Vol 9 (5) ◽  
pp. 379-383 ◽  
Author(s):  
Georg Veh ◽  
Oliver Korup ◽  
Sebastian von Specht ◽  
Sigrid Roessner ◽  
Ariane Walz
Keyword(s):  
Glacial Lake ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
The Himalaya

scholarly journals New method for assessing the potential hazardousness of glacial lakes in the Cordillera Blanca, Peru

2014 ◽  
Vol 11 (2) ◽  
pp. 2391-2439 ◽  
Author(s):  
A. Emmer ◽  
V. Vilímek
Keyword(s):  
Slope Movement ◽  
Dam Failure ◽  
Glacial Lake ◽  
Flood Wave ◽  
Glacial Lakes ◽  
Cordillera Blanca ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Glacial Lake Outburst Flood ◽  
Dam Overtopping

Abstract. This paper presents a new and easily repeatable objective method for assessing the potential hazardousness of glacial lakes within the Peruvian region of Cordillera Blanca (excluding ice-dammed lakes, which do not reach significant volumes in this region). The presented method was designed to meet four basic principles, which we considered as being crucial. These are: (a) principle of regional focus; (b) principle of objectivity; (c) principle of repeatability; and (d) principle of multiple results. Potential hazardousness is assessed based on a combination of decision trees for clarity and numerical calculation for objectivity. A total of seventeen assessed characteristics are used, of which seven have yet to be used in this context before. Also, several ratios and calculations are defined for the first time. We assume that it is not relevant to represent the overall potential hazardousness of a particular lake by one result (number), thus the potential hazardousness is described in the presented method by five separate results (representing five different glacial lake outburst flood scenarios). These are potentials for: (a) dam overtopping resulting from a dynamic slope movement into the lake; (b) dam overtopping following the flood wave originating in a lake situated upstream; (c) dam failure resulting from a dynamic slope movement into the lake; (d) dam failure following the flood wave originating in a lake situated upstream; and (e) dam failure following a heavy earthquake. All of these potentials theoretically range from 0 to 1. The presented method was verified on the basis of assessing the pre-flood conditions of seven lakes which have produced ten glacial lake outburst floods in the past and ten lakes which have not. A comparison of these results showed that the presented method successfully identifies the potentially hazardous lakes.

scholarly journals Glacial Lake Outburst Flood in Nepal: A Challenging Environmental Hazard and Disaster

2015 ◽  
Vol 4 ◽  
pp. 56-67
Author(s):  
Shiva Kant Dube
Keyword(s):  
Flash Flood ◽  
Global Climate ◽  
Glacial Lake ◽  
Central Himalayas ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Hindu Kush ◽  
Glacial Lake Outburst Flood ◽  
Basic Infrastructure ◽  
Percent Area

Geographically, Nepal is situated on the lap of the Himalayas occupying 0.3 percent area of Asia and 0.03 percent of the world. Recently, global climate change has invited enormous environmental hazards and disasters in the Hindu-Kush Himalayan region. Catastrophic floods originating from the outburst of glacial lakes have been recognized as one of the primary natural hazards in Nepal, making downstream areas vulnerable. Frequent severe floodscaused by glacier outburst in the Nepal Himalayas, occur once every three years. Nine potentially dangerous glaciers were identified in the Eastern and Central Himalayas during pre- and post-monsoon seasons. At national and international level, Glacial Lake Outburst Floods (GLOF) in Nepal, are receiving considerable attention. Such floods endanger thousands of people, hundreds of villages and basic infrastructure causing disasters. This paper incorporates a case of flash-flood caused by GLOF and torrential rain in India which can be taken as a lesson to mitigate/minimize massive loss of lives and property in the Nepalese context.DOI: http://dx.doi.org/10.3126/av.v4i0.12360Academic Voices Vol.4 2014: 56-67

scholarly journals Glacial lake outburst floods enhance benthic microbial productivity in perennially ice-covered Lake Untersee (East Antarctica)

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Benoit Faucher ◽  
Denis Lacelle ◽  
Nicole Britney Marsh ◽  
Liam Jasperse ◽  
Ian Douglas Clark ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Microbial Mats ◽  
Dissolved Inorganic Carbon ◽  
Glacial Lake ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Glacial Lake Outburst Flood ◽  
Microbial Productivity ◽  
Benthic Ecosystems ◽  
Flooding Events

AbstractBenthic ecosystems of perennially ice-covered lakes in Antarctica are highly sensitive to climate-driven changes. Lake Untersee has been in hydrological steady-state for several hundred years with a high pH water column and extremely low levels of dissolved inorganic carbon. Here, we show that glacial lake outburst floods can replenish carbon dioxide-depleted lakes with carbon, enhancing phototrophic activity of the benthic ecosystem. In 2019, a glacial lake outburst flood brought 17.5 million m3 of water to Lake Untersee, the most substantial reported increase for any surface lake in Antarctica. High-resolution grain-size and carbon isotope analyses of microbial mats suggest that glacial lake outburst floods have occurred periodically over the Holocene and help explain the complex patterns of carbon cycling and sequestration observed in the lake. Our findings suggest that periodic flooding events may provide biological stimuli to other carbon dioxide-depleted Antarctic ecosystems and perhaps even icy lakes on early Mars.

Hydropower in the Himalayan hazardscape

2021 ◽  
Author(s):  
Wolfgang Schwanghart ◽  
Ugur Öztürk ◽  
Sumit Sen ◽  
Ankit Agarwal ◽  
Oliver Korup
Keyword(s):  
Heavy Rain ◽  
High Energy ◽  
Glacial Lake ◽  
Indian States ◽  
Ground Shaking ◽  
Energy Demands ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Hydropower Potential ◽  
Glacial Lake Outburst Flood

<p>The 7 February Chamoli flood once again unveiled the vulnerability of Himalayan hydropower. On its destructive path downstream, the flood inflicted the loss of two nearby hydropower projects and damaged at least two more projects further downstream.</p><p>The flood is the third in a series of events with severe impact on the Himalayan hydropower sector. Uttarakhand was among the Indian states affected most by the 2013 Indian floods. Heavy rain, snow melt, and a glacial lake outburst flood damaged and partly destroyed more than 20 hydropower projects. The Gorkha Earthquake in 2015 led to damages to >30 projects, leading to a temporary loss of 34% of the hydropower generated in Nepal.</p><p>Analysis of these events reveals that neither flood discharge nor ground shaking were the primary processes responsible for the losses. Instead, the majority of damage was caused by geomorphological processes including landslides and rockfall, debris flows and extreme sediment discharges.</p><p>Only 20% of the ~500-GW hydropower potential is currently tapped in the Himalayas. This share is likely to increase given the high energy demands in the rapidly growing economies of the Himalayan countries.</p><p>With many opportune sites along large rivers being already occupied, there is a trend towards developing hydropower further upstream at higher elevations and closer to glaciated areas.</p><p>We argue that these developments and the past events highlight the need for a reappraisal of the Himalayan hazardscape. Risk analysis should increasingly incorporate processes such as glacial lake outburst floods and extreme sediment discharge events, and particularly aim to better understand hazard cascades which originate in glaciated and steep headwater catchments.</p>

scholarly journals Reason Analysis of the Jiwenco Glacial Lake Outburst Flood (GLOF) and Potential Hazard on the Qinghai-Tibetan Plateau

2021 ◽  
Vol 13 (16) ◽  
pp. 3114
Author(s):  
Shijin Wang ◽  
Yuande Yang ◽  
Wenyu Gong ◽  
Yanjun Che ◽  
Xinggang Ma ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Image Data ◽  
Heavy Precipitation ◽  
Glacial Lake ◽  
Precipitation Process ◽  
Potential Hazard ◽  
Outburst Flood ◽  
Outburst Floods ◽  
Before And After ◽  
Glacial Lake Outburst Flood

Glacial lake outburst flood (GLOF) is one of the major natural disasters in the Qinghai-Tibetan Plateau (QTP). On 25 June 2020, the outburst of the Jiwenco Glacial Lake (JGL) in the upper reaches of Nidu river in Jiari County of the QTP reached the downstream Niwu Township on 26 June, causing damage to many bridges, roads, houses, and other infrastructure, and disrupting telecommunications for several days. Based on radar and optical image data, the evolution of the JGL before and after the outburst was analyzed. The results showed that the area and storage capacity of the JGL were 0.58 square kilometers and 0.071 cubic kilometers, respectively, before the outburst (29 May), and only 0.26 square kilometers and 0.017 cubic kilometers remained after the outburst (27 July). The outburst reservoir capacity was as high as 5.4 million cubic meters. The main cause of the JGL outburst was the heavy precipitation process before outburst and the ice/snow/landslides entering the lake was the direct inducement. The outburst flood/debris flow disaster also led to many sections of the river and buildings in Niwu Township at high risk. Therefore, it is urgent to pay more attention to glacial lake outburst floods and other low-probability disasters, and early real-time engineering measures should be taken to minimize their potential impacts.

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