scholarly journals Dynamics of Lower-Barun Glacier and Glacial Lake and its GLOF Susceptibility Using Geospatial Analysis and Modelling

Jalawaayu ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 57-77
Author(s):  
Nabin Gurung ◽  
Sudeep Thakuri ◽  
Raju Chauhan ◽  
Narayan Prasad Ghimire ◽  
Motilal Ghimire
Keyword(s):  
Failure Time ◽  
Peak Discharge ◽  
Mitigation Measures ◽  
Glacial Lake ◽  
Water Volume ◽  
Glacial Lakes ◽  
Water Index ◽  
Outburst Floods ◽  
Normalized Difference Water Index ◽  
Multi Temporal

Shrinkage of some of the glaciers has direct impacts on the formation and expansion of glacial lakes. Sudden glacial lake outburst floods (GLOFs) are a major threat to lives and livelihoods downstream as they can cause catastrophic damage. In this study, we present the dynamics of the Lower-Barun glacier and glacial lakes and their GLOF susceptibility. We used multi temporal Landsat and Sentinel satellite imagery and extracted the lake outlines using the Normalized Difference Water Index (NDWI) with manual post-correction while the glacier outline was digitized manually. Multi-criteria decision-based method was used to assess the GLOF susceptibility. For the estimation of peak discharge and failure time, an empirical model developed by Froelich (1995) was used. The surface area of the Lower-Barun glacial lake was increased by 86% in the last 40 yrs (from 1979 to 2018), with a mean increase of 0.0432 km2/yr. The shrinkage in the glacier area is around 0.49 km2/yr and has shrunk by 8% in the last four decades. The retreat of the Lower-Barun glacier was 0.20% per year in the last four decades. The susceptibility index was 0.94, which suggests that the lake is very highly susceptible to the GLOF. The peak discharge of 5768 m3/s is produced when the breach depth is 20 m and the entire water volume is released. Likewise, in the case of 15 m breach depth, the peak discharge of 4038 m3/s is formed. Breach depth scenario of 10 m, peak discharge of 2442 m3/s is produced and in case of breach depth of 5 m produces the peak discharge of 1034 m3/s. If GLOF occurs, it can exert disastrous impacts on the livelihood and infrastructure in the downstream. So, it is necessary to examine such lakes regularly and mitigation measures to lower the GLOF susceptibility should be emphasized.

scholarly journals Glacial Lake Inventory Derived from Landsat 8 OLI in 2016–2018 in China–Pakistan Economic Corridor

2020 ◽  
Vol 9 (5) ◽  
pp. 294
Author(s):  
Da Li ◽  
Donghui Shangguan ◽  
Muhammad Naveed Anjum
Keyword(s):  
Indus Basin ◽  
Glacial Lake ◽  
Formation Mechanisms ◽  
Landsat 8 ◽  
Lateral Moraine ◽  
Glacial Lakes ◽  
Threshold Method ◽  
Water Index ◽  
Supraglacial Lakes ◽  
Normalized Difference Water Index

The China–Pakistan Economic Corridor (CPEC), a key hub for trade, is susceptible to glacial lake outburst floods. The distributions and types of glacial lakes in the CPEC are not well documented. In this study, cloud-free imagery acquired using the Landsat 8 Operational Land Imager during 2016–2018 was used to delineate the extent of glacial lakes in the mountainous terrain of the CPEC. In the study domain, 1341 glacial lakes (size ≥ 0.01 km2) with a total area of 109.76 ± 9.82 km2 were delineated through the normalized difference water index threshold method, slope analysis, and a manual rectification process. On the basis of the formation mechanisms and characteristics of glacial lakes, four major classes and eight subclasses of lakes were identified. In all, 492 blocked lakes (162 end moraine-dammed lakes, 17 lateral moraine-dammed lakes, 312 other moraine-dammed lakes, and 1 ice-blocked lake), 723 erosion lakes (123 cirque lakes and 600 other erosion lakes), 86 supraglacial lakes, and 40 other glacial lakes were identified. All lakes were distributed between 2220 and 5119 m a.s.l. At higher latitudes, the predominate lake type changed from moraine-related to erosion. From among the Gez, Taxkorgan, Hunza, Gilgit, and Indus basins, most glacial lakes were located in the Indus Basin. The number and area of glacial lakes were larger on the southern slopes of the Karakoram range.

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

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.    

scholarly journals Glacial Lake Outburst Floods Simulation in the Yi’ong Zangbo River Basin Based on One-Dimensional Hydrodynamic Model

2021 ◽  
Author(s):  
Qi Wang ◽  
Hongyu Duan ◽  
Na Liu ◽  
Zhishui Du ◽  
Pan Wang ◽  
...  
Keyword(s):  
River Basin ◽  
Hydrodynamic Model ◽  
Peak Discharge ◽  
Glacial Lake ◽  
Glacial Lakes ◽  
Potential Threat ◽  
One Dimensional ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
The One

Abstract Glacial lake outburst floods (GLOFs) are a serious potential threat to the safety of life and property in downstream areas. In this study, moraine-dammed glacial lakes in the Yi’ong Zangbo River basin were recognized based on Landsat ETM+/TM/OLI images in 2000 and 2019. And the GLOFs for the Jionglaco, the largest glacial lake in this basin, was simulated using the one-dimensional hydrodynamic model. The results show that the total number and area of moraine-dammed glacial lakes in this basin increased by 10 (10.52%) and 5.49 km2 (48.24%) from 2000 to 2019, in which the area of the Jionglaco increased by 3.22 km2. The peak discharge at the breach outlet for five scenarios with different combinations of breach width (80 m and 120 m), depth (2.5 m and 5 m) and flood time (1.5 h and 3 h) are 489 m3/s, 1327.43 m3/s, 444.32 m3/s, 617.47 m3/s and 1570.61 m3/s. With the addition of baseflow in river, the peak discharge at bridge site 15 138.93 km from Jionglaco are 1040.89 m3/s, 1724.00 m3/s, 1024.85 m3/s, 1162.25 m3/s and 1990.52 m3/s. The combination of baseflow in river and the GLOFs discharge results in the increasing peak discharge in the further downstream region. However, the arrival of peak discharge in downstream areas is delayed, which increases the chances of people escaping. This study aims to provide some references for the prevention of GLOFs in this region.

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.

Identifying key predictors for the susceptibility of Himalayan glacial lakes to sudden outburst floods

2020 ◽  
Author(s):  
Melanie Fischer ◽  
Georg Veh ◽  
Oliver Korup ◽  
Ariane Walz
Keyword(s):  
Logistic Regression ◽  
Binary Logistic Regression ◽  
Glacial Lake ◽  
Occurrence Rate ◽  
Past Century ◽  
Glacial Lakes ◽  
Mountain Areas ◽  
Logistic Regression Models ◽  
The Past ◽  
Outburst Floods

<p>Despite being a rather rare phenomenon when compared to the occurrence rates of other alpine hazards (e.g. landslides, avalanches), glacial lake outburst floods (GLOFs) pose a significant threat to downvalley communities in glaciated mountain areas. Characteristically high peak discharge rates and flood volumes, documented to have reached 30,000 m³/s and > 50 million m³ in the past century, not only provide GLOFs with a landscape-forming potential but also killed a reported global total of > 12,000 people and caused severe damage to infrastructures. Extensive glacial covers and steep topographic gradients, coupled with rapidly changing socio-economical implications, make the Hindu-Kush-Himalaya (HKH) a high priority region for GLOF research, even though recent studies suggest an annual occurrence rate of 1.3 GLOFs per year across this range during the past three decades. So far, GLOF research in the greater HKH region has been predominantly focused on the classification of potentially dangerous glacial lakes derived from analysing a limited number of glacial lakes and even fewer reportedly GLOF-generating glacial lakes. Moreover, subjectively set thresholds are commonly used to produce GLOF hazard classification matrices. Contrastingly, our study is aimed at an unbiased, statistical robust and reproducible assessment of GLOF susceptibility. It is based on the currently most complete inventory of GLOFs in the HKH since the 1980’s, which comprises 38 events. In order to identify key predictors for GLOF susceptibility, a total of 104 potential predictors are tested in logistic regression models. These parameters cover four predictor categories, which describe each glacial lake’s a) topography, b) catchment glaciers, c) geology and seismicity in its surroundings, and c) local climatic variables. Both classical binary logistic regression as well as hierarchical logistic regression approaches are implemented in order to assess which factors drive susceptibility of HKH glacial lakes to sudden outbursts and whether these are regionally distinct.</p>

Evolving hazards from Himalayan glacier lake outburst floods

2020 ◽  
Author(s):  
Georg Veh ◽  
Daniel Garcia-Castellano ◽  
Oliver Korup
Keyword(s):  
Western Himalaya ◽  
Peak Discharge ◽  
Lake Area ◽  
Landsat Images ◽  
The Past ◽  
Himalayan Glacier ◽  
Outburst Floods ◽  
Multi Temporal ◽  
Extreme Value Model ◽  
Lake Size

<p>The ongoing retreat of glaciers has formed several thousands of meltwater lakes in the Himalayas. Hundreds of these lakes have grown rapidly in area and volume in past decades, raising widely publicised concerns of an increasing hazard from sudden glacier lake outburst floods (GLOFs). Some 40 catastrophic lake outbursts have claimed thousands of fatalities and high losses in the Himalayas, mostly as a consequence of moraine-dam failures. Human and public safety along densely populated river reaches may thus be prone to changes in the lake size-distribution and the frequency of outburst floods. Yet multi-temporal inventories of Himalayan glacier lakes and associated outburst floods that we need for hazard appraisals have been collated only for selected basins with few standardised rules. Objectively tracing changes in regional GLOF hazard through time has thus remained elusive.</p><p>Here we meet this urgent demand for an improved GLOF hazard assessment. We estimate changes in the 100-year GLOF peak discharge from the late 1980s towards a scenario of completely ice-free Himalayas. We use a Random Forest model to predict land cover from seasonal Landsat images, and automatically extract glacier lakes for four time intervals. We obtain credible lake depths and volumes for each interval from a linear model learned from published bathymetric surveys. We further project possible sites for future Himalayan meltwater lakes from three published models of subglacial topography. We assume that these presently ice-covered depressions could fill completely with water though sediment and debris could decrease the storage space for future lakes. We simulate distributions of peak discharge for historic, present, and future lakes, accounting for different combinations of lake area, breach depth, and dam lithology. Most barrier types are unknown and could range from intact metamorphic bedrock to unconsolidated moraine debris. These two end members help to constrain the physically possible boundaries of GLOF peak discharges, which is supported by data from 82 natural dam breaks with known values of erodibility. To estimate the return periods of outburst floods, we used an extreme-value model to couple our simulations of peak discharge with mean annual rates of outburst floods, which remained unchanged in the Himalayas in the past three decades.</p><p>Given this constant rate of outburst floods, we report how hazard—expressed as the 100-year GLOF discharge—varied with regionally changing lake-size distributions in the past decades. We show that the southern Himalayas of Nepal and Bhutan had the largest increase of lake area, feeding notions of a rising GLOF hazard in this region. Hazard in the Western Himalaya, Karakoram, and Hindu Kush increased marginally, in line with the smallest historic abundance of glacier lakes and outburst floods. Future lake abundance and volumes may increase at least six-fold, with the largest lakes appearing in regions that have large glaciers today such as the Western Himalaya and the Karakoram. All other controls held constant, we find that hazard from these future lakes will largely rest on the erodibility of the barrier type, which needs to be acknowledged better in hazard appraisals.</p>

The formation of new glacial lakes at the Jostedalsbreen ice cap in southwest Norway and their future implications

2020 ◽  
Author(s):  
Katja Laute ◽  
Achim A. Beylich
Keyword(s):  
Current Trend ◽  
Glacial Lake ◽  
Glacier Area ◽  
Glacial Lakes ◽  
Economic Implications ◽  
Ice Cap ◽  
Western Norway ◽  
Outburst Floods ◽  
Glacier Length ◽  
Length Changes

<p>In recent years, the number and size of glacial lakes in mountain regions have increased worldwide associated to the climate-induced glacier retreat and thinning. Glacial lakes can cause glacial lake outburst floods (GLOFs) which can pose a significant natural hazard in mountainous areas and can cause loss of human life as well as damage to infrastructure and property.</p><p>The glacial landscape of the Jostedalsbreen ice cap in south-western Norway is currently undergoing significant changes reflected by progressing glacier length changes of the outlet glaciers and the formation of new glacial lakes within the recently exposed glacier forefields. We present a new glacier area outline for the entire Jostedalsbreen ice cap and the first detailed inventory of glacial lakes which were formed within the newly exposed ice-free area at the Jostedalsbreen ice cap. In detail, we explore (i) the glacial lake characteristics and types and (ii) analyse their spatial distribution and hazard potential.</p><p>For the period from 1952-1985 to 2017/2018 the entire glacier area of the Jostdalsbreen ice cap experienced a loss of 79 km<sup>2</sup>. A glacier area reduction of 10 km<sup>2</sup> occurred since 1999-2006. Two percent of the recently exposed surface area (since 1952-1985) is currently covered with newly developed glacial lakes corresponding to a total number of 57 lakes. In addition, eleven lakes that already existed have enlarged in size. Four types of glacial lakes are identified including bedrock-dammed, bedrock- and moraine-dammed, moraine-dammed and ice-dammed lakes. Especially ice- or moraine-dammed glacial lakes can be the source of potentially catastrophic glacier lake outburst floods. According to the inventory of glacier-related hazardous events in Norway GLOFs represent the most common hazardous events besides ice avalanches and incidents related to glacier length changes. Around the Jostedalsbreen ice cap several historical but also recent events are documented. The majority of the events caused partly severe damage to farmland and infrastructure but fortunately no people have been harmed by today.</p><p>Due to the predicted increase in summer temperatures for western Norway until the end of this century, it is very likely that the current trend of an accelerated mass loss of Norwegian glaciers will continue. As one consequence of this development, further new lakes will emerge within the newly exposed terrain. The development of new glacial lakes has diverse regional and global socio-economic implications. Especially in mainland Norway, where glaciers and glacier-fed streams have a high importance for hydropower production, tourism and climate research it is essential to gain a better understanding of the possible impacts of glacial lakes for being prepared for risks but also advantages arising from these newly emerging landscape elements.</p>

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 Periodic Glacial Lake Outburst Floods threatening the oldest Buddhist monastery in north-west Nepal

2014 ◽  
Vol 2 (11) ◽  
pp. 6937-6971 ◽  
Author(s):  
J. Kropáček ◽  
N. Neckel ◽  
B. Tyrna ◽  
N. Holzer ◽  
A. Hovden ◽  
...  
Keyword(s):  
Satellite Images ◽  
Empirical Relation ◽  
Mitigation Measures ◽  
Glacial Lake ◽  
Lake Basin ◽  
North West ◽  
Outburst Floods ◽  
Glacial Lake Outburst Floods ◽  
Geodetic Mass Balance ◽  
Flooded Area

Abstract. Since 2004 Halji Village, home of the oldest Buddhist Monastery in north-west Nepal has suffered from recurrent Glacial Lake Outburst Floods (GLOFs). Studies of recent satellite images identified a supra-glacial lake, located at a distance of 6.5 km from the village, as a possible source of the flood. During a field survey in 2013, the finding was confirmed and several entrances to en-glacial conduits which are draining the lake were found. The topography of the lake basin was then mapped by combining Differential Global Positioning System (DGPS) measurements with a Structure From Motion (SFM) approach from terrestrial photographs. From this model the maximum filling capacity of the lake has been estimated as 1.06 × 106 m3 with a maximum discharge of 77.8 m3 s−1 calculated using an empirical relation. The flooded area in the valley has been estimated by employing a raster-based hydraulic model considering six scenarios of discharge volume and surface roughness. To understand the changes in glacier geometry in the last decade the thinning and retreat of Halji Glacier have been analysed by geodetic mass balance measurements and a time series of satellite images respectively. The GLOF occurrences have further been correlated with cumulative temperature and cumulative liquid precipitation calculated from the High Asia Reanalysis (HAR) dataset. Finally, effective mitigation measures and adaption strategies for Halji village have been discussed.

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