Glacial lake outburst flood hazards in Hindukush, Karakoram and Himalayan Ranges of Pakistan: implications and risk analysis

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1 Geomatics, Natural Hazards and Risk ISSN: (Print) (Online) Journal homepage: Glacial lake outburst flood hazards in Hindukush, Karakoram and Himalayan Ranges of Pakistan: implications and risk analysis Arshad Ashraf, Rozina Naz & Rakhshan Roohi To cite this article: Arshad Ashraf, Rozina Naz & Rakhshan Roohi (2012) Glacial lake outburst flood hazards in Hindukush, Karakoram and Himalayan Ranges of Pakistan: implications and risk analysis, Geomatics, Natural Hazards and Risk, 3:2, , DOI: / To link to this article: Copyright Taylor and Francis Group, LLC Published online: 05 Jan Submit your article to this journal Article views: 793 View related articles Citing articles: 8 View citing articles Full Terms & Conditions of access and use can be found at Download by: [ ] Date: 20 December 2017, At: 06:13

2 Geomatics, Natural Hazards and Risk Vol. 3, No. 2, May 2012, Glacial lake outburst flood hazards in Hindukush, Karakoram and Himalayan Ranges of Pakistan: implications and risk analysis ARSHAD ASHRAF*, ROZINA NAZ and RAKHSHAN ROOHI National Agricultural Research Centre, Park Road, Islamabad, Pakistan (Received 12 July 2001; in final form 15 August 2011) One of the spectacular effects of recent atmospheric warming in the Himalayan region has been the creation of meltwater lakes on the lower sections of many glaciers. Climate change is likely to exacerbate further some of these natural hazards such as glacial lake outburst floods (GLOFs), which can cause major social and economic damage for large populations living in the Himalayan region. Thirty-five destructive outburst floods have been recorded for the Karakoram Range in the past 200 years. Systematic application of remote sensing and geographic information systems (GIS) has revealed the formation of about 2420 glacial lakes in the Hindukush-Karakoram-Himalaya (HKH) Region of Pakistan, among which 52 lakes are characterized as potentially dangerous GLOF hazards. About 62% of the GLOF lakes belong to End Moraine Dammed type and 25% to Cirque type. Due to poor livelihood conditions, lack of resources and proper management within the system the local communities have a problem in taking effective response measures for risk reduction or mitigation. There is a need to create awareness of flood hazard, coordination and capacity buildings for preparedness and risk reduction among target communities. High resolution satellite data integrated with ground information can be utilized effectively for regular monitoring of these lakes in order to mitigate flood risk hazard in future. 1. Introduction Global climate change has influenced the snow and glaciated environment of the Hindukush-Karakoram-Himalaya (HKH) region of Pakistan, which contributes more than 50% of the total flow of the Indus River system. As a result of this situation the frequency of glacial hazards has increased in this part of the Himalayan region. Sudden breach of the unstable moraine dams results in discharges of huge amounts of water and debris known as glacial lake outburst floods (GLOFs ) that often have catastrophic effects downstream. Even the small glacial lake associated with hanging glaciers poses a high potential for breaching resulting in a GLOF. At least 20 GLOF events recorded in the Himalayan region in the last seven decades resulted in heavy loss of human lives and their property, destruction of infrastructure as well as damage to agricultural land and forests. In the past 50 years, the general *Corresponding author. mashr22@yahoo.com Geomatics, Natural Hazards and Risk ISSN Print/ISSN Online ª 2012 Taylor & Francis

3 114 A. Ashraf et al. glacier recession in the area is considered to be linked to the general climatic change experienced here, as in many mountain areas in the world. The climatic changes indicate the possibility of glacial advance/retreat, which may be a precursor of an era of renewed dam burst floods. Flood risks are dominated by monsoonal storm conditions in summer. However, the larger part of summer high flows on the Indus system are due to snow and ice melting. During certain periods in the past, for example, the 1920s and 1930s, glacier dams and dam burst floods in the Indus system were a major and recurrent risk. There are indications that the return of such problems can be anticipated. Knowledge of glaciers and glacial lake activity is required not only for planning for water resources but also for management of flood hazards such as GLOFs downstream. Unfortunately, understanding of the mountainous headwater of the Indus, and especially of snow and ice conditions is extremely poor. The geomorphologists of the International Karakoram Project surveyed the Hunza valley between Gilgit and Gulmit along the Karakoram Highway in 1980 and identified traces of 339 disastrous incidents, including a wide range of short-lived mass movements as well as earthquake-related destruction (Goudie 1981, Miller 1984). Among these hazards, the destructive ones are related to the movement of glaciers when glacier advance/retreat led to outburst floods of ice-dammed lakes, damaging and burying cultivated lands, irrigation systems and infrastructure downstream. The importance of this situation has magnified over the past century due to the increased number of glacial lakes. The lakes are formed on the glacier terminus due to the recent retreating processes of glaciers (Meyer et al. 1993). Monitoring of glacier resource can be much facilitated by the effective use of satellite remote sensing technology. The technology is found to be one of the best tools for identifying such glacial lakes and offers strong advantages for rapid and qualitative hazard assessments of glacier lakes (Raj 2010). There is no doubt that people and property at considerable distances downstream from the unstable lakes are facing a serious threat to their existence. This situation, together with the realization that the risk of damage and loss of life may continue to increase in the near future, demands indepth study of the situation of GLOF hazard and response analysis in the target Himalayan area. It is quite alarming that five GLOF events had occurred in the Hunza basin of the Karakoram Range during 2007 and 2008, which severely affected the nearby communities and posed a threat for the future. The situation demands better hazard assessment, risk reduction, mitigation of GLOF hazard and adoption of a suitable early warning system. This paper describes a stepwise approach to the assessment of risk, beginning with an extensive desk study of satellite images that provided the first reconnaissance mapping of more than 2400 glacial lakes. The study attempts to describe the existing situation of glacial lakes and lakes susceptible to creating GLOF hazards in the HKH Region of Pakistan. Also the implications of recent GLOF events occurring during 2007 and 2008, communities response and risk mitigation measures in order to provide a basis for strategy development for future risk management are described. 1.1 Physiography of HKH Region Of the physical formations present in the country, the three marvellous mountain ranges in the north, namely Himalayas, Karakoram and Hindukush, are spectacular

4 Flood hazards in HKH Region 115 in their own way. They stretch like a bow in the north of Pakistan extending into India, China, Nepal and Bhutan with a total length of about 2500 km. Rapid uplift of the Himalayas to great heights and under the influence of a very cold climate with high altitude, the mountains embraced a blanket of snow and ice during the Quaternary period (Kazmi and Jan 1997). High mountains contain towering snowclad peaks with heights varying from 1000 to over 8000 metres above mean sea level (masl). The westernmost part of the High Himalayas within Pakistan is comprised of the Nanga Parbat Range. Most of the glaciers are alpine type in which maximum ablation and snowfall occurs in the summer half year. The glacial ice is of cold metamorphic type with only the lower reaches being isothermal and showing behaviour characteristic of temperate glaciers. The Karakoram Range comprises some of the highest peaks, large glaciers, deepest gorges and canyons of this region. It is the largest store of moisture in Central Asia and the single most concentrated source of runoff for the whole Upper Indus Basin. From here comes the larger part of the Indus flow at Tarbela dam. The word Karakoram comes from the Turkish term meaning black rock. The range covers 500 km from the easternmost extension of Afghanistan towards South Asia. The mountains are covered with glaciers that are the longest in this region. This splendid and magnificent collection of dark brown and black metamorphic rocks is the most unique mountain range. A combination of high ablation rates in the lower reaches (e.g. annual ablation on bare ice of 1841 mm per year for the snout of the Batura glacier was recorded during an ablation season of 315 days) and high snowfall and avalanching induces high values of mass flux, so that they can be classified as high active glaciers (Khan 1994). The snow line in this range varies from 4200 to 4500 m during summer. The temperatures are extreme and there is a large difference between the lowest and highest temperatures during a day. Monsoons do not penetrate in this area. The valleys around Gilgit and Hunza are amongst the driest areas of Central Asia. The precipitation enhancing and shadowing effects of the main mountain ranges provide dramatic contrasts that greatly complicate the hydrological picture. The Hindukush Range runs from the western edge of the Pamir Plateau, west of the Karakoram. It forms the boundary between Pakistan, Afghanistan and China. Like the other two chains, they also have snow-covered mountains and are crossed by a number of glaciers that are not as well developed as those of the other chains. The highest peaks are Noshak (7369 m) and Tirich Mir (7690 m). The Chitral, Kunar, Punjkora and Swat rivers drain the mountain range. The extent of the three mountain ranges and river basins in Northern Pakistan is shown in figure 1. There are two distinct rainy periods, one in summer and one in winter. The monsoon rainfall is extensive in the period from July to September. The winter is dominated by the westerly fronts originating from the Mediterranean region or from the area of the Caspian Sea during the winter and spring seasons (Roohi et al. 2005). In the winter however, under the prevailing influence of the Tibetan anticyclone, local conditions are dominant (Archer 2001). The high mountain region i.e. between 358 and 378 N is mostly dominated by winter rains, whereas the sub mountainous region i.e. between and 358 N is dominated by summer rains. The winter snow, glaciers and snowfields start melting from April and continue until July when the monsoon sets in. The precipitation enhancing and shadowing effects of the main mountain range provide dramatic contrasts that greatly complicate the hydrological picture.

5 116 A. Ashraf et al. Figure 1. Location of study area indicating 10 river basins in the Hindukush-Karakoram- Himalaya (HKH) Region of Pakistan. Available in colour online. 1.2 Catastrophic floods Thirty-five destructive outburst floods have been recorded for the Karakoram Range in the past 200 years (Khan 1994). Thirty glaciers are known to have advanced across major head water streams of the Indus and Yarkand Rivers. Some ice dams may have been the result of glacier surges. A surge is commonly accompanied by increased water, sediment and discharge, and is extremely hazardous to settlements, or installations in the path. At least 11 surges of exceptional scale have been recorded so far in the Upper Indus Basin. There is unambiguous evidence of large reservoirs ponded by 18 glaciers. Meanwhile, a further 37 glaciers interfered with the flow of trunk streams in a potentially dangerous way. There is geological evidence of other dams and numerous reports of glaciers across the main river channels, which they were not actually damming. During the late Pleistocene and little Ice Age, large-scale damming was more extensive than recently (Khan 1994). Indications of climatic changes likely to result in glacier advance, especially if applicable to the Karakoram Range, may herald an era of renewed dam burst floods.

6 Flood hazards in HKH Region 117 Glacier survey activity in the upper Shyok river basin in the late 1920s led to the discovery and monitoring of a large ice dam across the upper Shyok River. This was formed by the advance of the Chung Khumdan glacier, a tributary of the Shyok. The filling of the reservoir, the timing and magnitude of the resulting outburst floods in 1929 and 1932 and the movement of the flood waves down valley were well documented by Gunn (1930). Similarly in 1884 an ice dam burst in the Shimshal valley, a northern tributary of the Hunza River and led to a 3 m rise in the river level causing considerable devastation at Ganesh and Baltit. This was followed by a similar event in 1893 and then again in The latter sent a 9 m flood wave down the Hunza, causing landslips. In the following year the Shimshal caused an even bigger flood than that of 1905, raising the Hunza River by over 15 m above its normal summer flood level at Chalt. A lake formed again in the Shimshal valley and water began to flow over the top of the ice dam on 28 May and breached on 10 June. Generally detailed information on the specific GLOF events is limited and the monetary losses and death toll of the floods has been reported by various sources and sometimes there is no agreement among these figures. There have occurred numerous GLOF events in Hunza River basin of Karakoram Range probably due to climate change in recent years. Serious effects are generated by the formation of these lakes and they pose a great threat downstream in the valleys. The high sliding velocities and isothermal ice produces abundant englacial and subglacial meltwater, which leaves the glacier by sub-glacial tunnels. The positions of these exits migrate due to thermal erosion, ice-collapse and sub-glacial debris removal resulting in the shift of proglacial streams (Khan 1994). Five GLOF events have been reported on Ghulkin and Passu glaciers in 2008 and a similar event on Passu glacier in 2007 that resulted in loss of valuable lives and property downstream. 2. Material and methods In the present study 11 Landsat-7 Enhanced Thematic Mapper Plus (ETMþ) images for the period were used for the delineation of glacial lakes and supported by limited ground truth verification and other ancillary datasets, identification of potentially dangerous lakes was carried out for the HKH region. Details of the Landsat images used are shown in table 1. The database generation and spatial analysis was performed in ILWIS 3.2 software using the Transverse Mercator projection system. The Landsat-7 ETMþ sensor is a nadir-viewing, seven-band plus multi-spectral scanning radiometer that detects spectrally filtered radiation from several portions of the electromagnetic spectrum. Nominal ground sample distances or pixel sizes include 15 m for the panchromatic band, 30 m each for the six visible, near-infrared, and short-wave infrared bands and 60 m for the thermal infrared band. The digital topographic map of ARC Digitized Raster Graphics (ADRG) published in January 1996 by the National Imagery and Mapping Agency (NIMA) and Defense Mapping Agency (DMA) of the US Government at a scale of 1: , along with topographic maps of Survey of Pakistan, available at 1: scale, were also used. The methodology for mapping lakes is based on that developed by the Lanzhou Institute of Glaciology and Geocryology, the Water and Energy Commission Secretariat, and the Nepal Electricity Authority (LIGG/WECS/NEA 1988, Mool et al. 2001). Mapping has been systematically carried out for 10 major river basins of the northern glaciated area of Pakistan (figure 1). The basins

7 118 A. Ashraf et al. Table 1. Details of Landsat-7 Enhanced Thematic Mapper Plus (ETMþ) scenes ( ). Serial no. Path Row Bands Spatial resolution Date plus 15 m, 30 m, 60 m 21 July plus 15 m, 30 m, 60 m 18 May plus 15 m, 30 m, 60 m 30 September plus 15 m, 30 m, 60 m 30 September plus 15 m, 30 m, 60 m 30 September plus 15 m, 30 m, 60 m 7 October plus 15 m, 30 m, 60 m 7 October plus 15 m, 30 m, 60 m 7 October plus 15 m, 30 m, 60 m 28 September plus 15 m, 30 m, 60 m 9 September plus 15 m, 30 m, 60 m 28 September 2001 clockwise from the west are Swat, Chitral, Gilgit, Hunza, Shigar, Shyok, Indus, Shingo, Astore and Jhelum. The lakes are classified into Erosion, Valley trough, Cirque, Blocked, Moraine Dammed (Lateral Moraine and End Moraine Dammed lakes), and Supraglacial types. Clear water absorbs relatively little energy with wavelengths of less than about 0.6 mm. High transmittance typifies these wavelengths with a maximum in the bluegreen portion of the spectrum. However, as the turbidity of water changes (because of the presence of organic or inorganic materials), transmittance, and therefore reflectance, changes dramatically (Mool et al. 2001). Glacial lakes can be identified clearly in the band combinations of Pan, 7, 6b and 5, 4, 2 (Red, Green, Blue) due to their distinct true colour and contrast with the surrounding features. In the winter season image the glacial lakes can be identified on the basis of their smooth texture and varying grey tone due to their semi-frozen ice surface. In the false colour composite of 5, 4, 3 (RGB), the water bodies, like lakes in blue colour, can be differentiated from the shadow areas appearing black in this band combination. Using Digital Elevation Model (DEM) data with a remote sensing image, decision rules for integrated analysis in GIS can be assigned i.e. if the slope is not too pronounced and the texture smooth, then such areas are recognized as frozen glacial lakes. After digitization of the lake boundaries, the segments were checked and the glacial lakes were numbered using point identifiers. The numbering of the lakes starts from the outlet of the major stream/river and proceeds clockwise round the basin. Reference longitude and latitude are designated for the approximate centre of the glacial lake by creating a digital point map over the screen digitized glacial lakes. The area of the glacial lake is determined from the digital database after digitization of the lake from the image data and topographic maps. The drainage direction of the glacial lake is specified as one of eight cardinal directions (N,NE,E,SE,S,SW,WandNW).Foraclosedglaciallake,theorientationis specified according to the direction of its longer axis (Mool et al. 2001). The required attributes of the lakes were derived or entered in the attribute database in the GIS. For the identification of potentially dangerous glacial lakes, the glacial lakes associated with glaciers such as Supraglacial, Valley, Cirque and/or dammed by

8 Flood hazards in HKH Region 119 Lateral Moraine or End Moraine with an area larger than 0.02 km 2 have been considered and they have been defined as major glacial lakes. Moraine Dammed glacial lakes, which are still in contact or very near to the glaciers, are usually dangerous. These End Moraines are loose and unstable in nature. The advance and retreat of the glacier affect the hydrology between the glacier and the lake dammed by the moraines. Sudden natural phenomena, with a direct effect on a lake, like ice avalanches or rock and lateral moraine material collapsing on a lake, cause moraine breaches with subsequent lake outburst events. The physical conditions and criteria for identification of potential GLOF lakes, as mentioned by Mool et al. (2001), Bajracharya et al. (2007) and ICIMOD (2011), may include:. The rise in water level in glacial lakes dammed by moraines creates a situation that endangers the lake to reach a breaching point.. Activity of Supraglacial lakes the lakes formed over glacial surface: as time passes, groups of closely spaced Supraglacial lakes of smaller size at glacier tongues merge and form bigger lakes that may become potentially dangerous.. The potentially dangerous status of Moraine Dammed lakes can be defined by the conditions of the damming material and the nature of the mother glacier.. The valley lakes with an area bigger than 0.1 km 2 and a distance less than 0.5 km from the mother glacier of considerable size are considered to be potentially dangerous. Cirque lakes even smaller than 0.1 km 2 associated (in contact or distance less than 0.5 km) with steep hanging glaciers are considered to be potentially dangerous.. A Moraine Dammed lake, which has breached and closed subsequently in the past and has refilled again with water, can breach again.. Physical conditions of the surrounding area such as potential rockfall/ slide (mass movements) sitedaround the lake which can fall into the lake suddenly, hanging glacier in contact with the lake, snow avalanches of large size around the lake which can fall into the lake suddenly, neo-tectonic and earthquake activities around or near the lake area, presence of large mother glacier can cause the lake to be potentially dangerous. The actively retreating and steep hanging glaciers on the banks of lakes may also be a potential cause of danger. Although a standard index to define a lake as a source of potential dangerous outbursting does not exist, the main factors considered were its physical characteristics and association with its surroundings/nourishing glaciers. These factors are found critical for identification of the potential GLOF lakes using single period remote sensing image data. Later, a limited field survey was carried out on two lakes in the Shyok basin and one in the Hunza basin, which conform the susceptible conditions of the lakes. A questionnaire survey was conducted in Ghulkin, Hussaini and Passu villages of Hunza basin, Karakoram Range, which were affected by recent GLOF events during 2007 and Out of these, four occurred at Ghulkin glacier and one at Passu glacier. A similar event also occurred on Passu glacier in 2007 that resulted in loss of life and property downstream. The information collected pertained to the socioeconomic condition, understanding of national hazards, particularly glacial lake

9 120 A. Ashraf et al. outburst floods, response to such hazards, preparedness, risk assessment and mitigation. 3. Results and discussion The systematic application of remote sensing and GIS has revealed about 2420 glacial lakes covering a surface area of about 126 km 2 in the HKH Region of Pakistan (table 2). There are 1328 major lakes that have areas greater than 0.02 km 2. Among 10 river basins in the HKH region, maximum glacial lakes lie in the Gilgit basin followed by the Indus sub-basin, which lies partly in the Hindukush, Karakoram and Himalaya mountain ranges. Fifty-two glacial lakes are characterized as potentially danger of GLOF based on pre-defined criteria. Most of these lie in Indus, Astore and Gilgit river basins. Out of 52 potentially dangerous lakes, about 62% (32) belong to End Moraine Dammed type (figure 2). This type is present in almost all the river basins except Shigar basin. About 25% of lakes (13) are Cirque type, which lies in four southern basins namely Indus, Shingo, Astor and Jhelum. Most of the GLOF lakes are oriented in the northwest while a minimum amount is in the eastward direction (table 3). Generally, the northern and western aspects in the high relief region of HKH are less exposed to solar radiations as compared to the southern and eastern aspects. About 40% of glaciers (Roohi et al. 2005) and 60% of the potential GLOF lakes concentrated on relatively cooler aspects of N, NW and W may be less susceptible to climate induced hazards. However, lake characteristics i.e. position and area may vary with changes in the physical condition of the surrounding area. 3.1 Glacial lakes in HKH ranges Among the three mountain ranges, Karakoram contains a maximum of about 37% of the total glacial lakes followed by the Himalaya Range with about 34% lakes (figure 3). Similarly, major lakes are higher in the Karakoram Range as compared to other ranges. Among various types of glacial lakes, most of the lakes belong to Table 2. Summary of glacial lakes in 10 river basins of HKH Region of Pakistan. Basins Range Number of lakes Lake area (km 2 ) Major lakes GLOF lakes Swat Hindukush Chitral Hindukush Gilgit Karakoram Hunza Karakoram Shigar Karakoram Shyok Karakoram Shingo Himalaya Astor Himalaya Jhelum Himalaya Indus part Hindukush Karakoram Himalaya Total GLOF, glacial lake outburst flood.

10 Flood hazards in HKH Region 121 Figure 2. Types of glacial lake outburst flood (GLOF) lakes in the Hindukush-Karakoram- Himalaya (HKH) Region. Majority of GLOF lakes belong to End Moraine Dammed type. Available in colour online. Table 3. Summary of glacial lake outburst flood (GLOF) lakes at various aspects. Aspect Number Total area (ha) Largest (ha) Smallest (ha) E N NE NW S SE SW W Total Figure 3. Glacial lakes in the Hindukush-Karakoram-Himalaya (HKH) ranges. Glacial lakes are maximum in the Karakoram Range. Available in colour online. Erosion type the concentration of which is higher in the Himalaya Range than in the other ranges (figure 4). Similarly, Cirque type lakes are dominant in this mountain range, indicating a higher recession of glaciers due to environmental changes. The Moraine Dammed lakes are predominant in the Karakoram Range, which is evidence of the existence of more valley- type glaciers causing the development of the moraine environment and ultimately melt-water lakes behind their moraines. The occurrence of high numbers of supraglacial lakes in this mountain range also provides a clue to the presence of large size glaciers here. In addition to high relief, unstable deposits along the valley sides have made the slopes prone to mass

11 122 A. Ashraf et al. Figure 4. Various types of glacial lake in the Hindukush-Karakoram-Himalaya (HKH) ranges. Most of the lakes belong to Erosion type in the three mountain ranges. Available in colour online. movements in Karakoram. The termini of a number of glaciers lie close to the valley floors and have advanced across it in the Late Pleistocene, and probably also in the Neo-glacial (Roohi et al. 2005). Consequently, there have been a number of interruptions to the drainage of the main rivers such as Hunza, Shimshal by ice or debris dams besides landsliding and rockfall, causing frequent blocking of streams and formation of dammed lakes. Although these blocked lakes are higher in Karakoram than in other ranges but they are often short-lived and so their numbers are usually low. The potential GLOF lakes are dominant in the Himalaya Range indicating the influence of global climate change in this mountainous range. Figure 5 shows a few of the potential GLOF lakes referred to as A, B, C, D and E in the three mountain ranges. Lakes B, C and D were surveyed, which indicated evidences of cyclic refill and breach history thus making them susceptible to creating outburst flood hazards in future. Lake A, visible in the FCC of 5, 4, 3 (RGB) of the Landsat-7 ETMþ image is located in Chitral basin, Hindukush near the Afghanistan border. It has an area of about km 2 and is in contact with the glacier that has an area of 1.75 km 2. Lakes B and C, seen in a semi-frozen state, have drainage linked to Shyok River near a small town Bara in the eastern Karakoram Range. The lakes nourished by large valley glaciers were identified due to their smooth surficial texure in the panchromatic image of the winter season. Lake D, seen in FCC of 5, 4, 2 (RGB), is an End Moraine Dammed lake draining into Hunza River in central Karakoram. It was outburst several times during 2007 and 2008, probably due to the influence of global warming in this glaciated area. Lake E in the FCC of 3, 1, 2 (RGB) of the SPOT XS image is an End Moraine Dammed lake in contact with a large valley glacier in the Astore basin, western Himalaya. It has an area of about 0.16 km 2 and was found to be growing at a rate of 0.74 hectares/year (Ashraf et al. 2008). About 54% (28) of GLOF lakes lie within an elevation range of masl and 29% (15) within masl (figure 6). About 12% of lakes (6) exist within the masl range. A maximum of 14 lakes in the Himalaya Range and 7 lakes in the Hindukush and Karakoram Ranges are situated above the masl elevation range. Details of the physical characteristics of the GLOF lakes in the three ranges are given in tables 4 6. The Hindukush Range comprising of Swat River basin, Chitral River basin and part of Indus sub-basin, contains 711 glacial lakes covering a surface area of about

12 Flood hazards in HKH Region 123 Figure 5. The glimpses of potential Glacial Lake Outburst Flood (GLOF) lakes in the Hindukush-Karakoram-Himalaya (HKH) Region. A: An End Moraine Dammed lake in Chitral basin, Hindukush Range. B, C, D: These lakes in Shyok basin and Hunza basin, Karakoram have a recycle history of refill and breach. E: An expanding lake in Astore basin, Himalaya Range (Source: A D Landsat ETMþ images of 2001 and E SPOT image of 2005). Available in colour online. Figure 6. Glacial lake outburst flood (GLOF) lakes at different elevation ranges of the Hindukush-Karakoram-Himalaya (HKH) Region. Most of the potential GLOF lakes lie within the masl elevation range km 2. There are 393 major lakes, among which 11 lakes are characterized as potential danger of GLOF. In Swat River basin, major lakes possess about 94% of the total lake area of the basin. The Valley lakes are relatively high in numbers.

13 124 A. Ashraf et al. Table 4. Characteristics of potential glacial lake outburst flood (GLOF) lakes in Hindukush Range of Pakistan. Serial no. Lake no. Lake type Area (km 2 ) Associated glacier Distance to glacier (m) Situation 1 Swat_gl 28 End Moraine 0.22 Swat_gr 21 In contact with large glacier source 2 Swat_gl 189 End Moraine 0.27 Near large glacier of hanging nature 3 Chitr_gl 61 End Moraine 0.05 Chitr_gr 108 in contact with large glacier 4 Ind_gl 125 Cirque 0.14 Ind_gr 213 In contact with hanging glacier 5 Ind_gl 162 Cirque 0.27 Ind_gr 313 In contact with hanging glacier 6 Ind_gl 47 End Moraine 0.11 Ind_gr 166 Near large glacier of hanging nature 7 Ind_gl 160 End Moraine 0.12 Ind_gr 311 Near large glacier of hanging nature 8 Ind_gl 41 End Moraine 0.17 Ind_gr Near glacier of hanging nature 9 Ind_gl 135 End Moraine 0.24 Ind_gr Near large glacier of hanging nature 10 Ind_gl 147 End Moraine 0.28 Ind_gr Near large glacier of hanging nature 11 Ind_gl 130 Valley 0.11 Ind_gr Near hanging glacier

14 Flood hazards in HKH Region 125 Table 5. Characteristics of potential glacial lake outburst flood (GLOF) lakes in the Karakoram Range of Pakistan. Serial no. Lake no. Lake type Area (km 2 ) Associated glacier Distance to glacier (m) Situation 1 Gil_gl 550 End Moraine 0.10 Gil_gr Near large glacier source 2 Gil_gl 590 End Moraine 0.19 Gil_gr 366 In contact with large glacier of hanging nature 3 Gil_gl 505 End Moraine 0.21 Gil_gr Near large glacier of hanging nature 4 Gil_gl 336 End Moraine 0.21 Gil_gr Near large glacier of hanging nature 5 Gil_gl 469 End Moraine Near massive glacier 6 Gil_gl 399 End Moraine 0.73 Gil_gr 28 In contact with large glacier of hanging nature 7 Gil_gl 589 Valley Near several hanging glaciers 8 Gil_gl 611 Valley Near several hanging glaciers 9 Hunza_gl 6 End Moraine 0.12 Hunza_gr Near large glacier 10 Ind_gl 290 End Moraine 0.13 Ind_gr 470 In contact with large glacier of hanging nature 11 Shyk_gl 60 End Moraine 0.08 Shyk_gr 345 In contact with large glacier of hanging nature 12 Shyk_gl 62 End Moraine 0.09 Shyk_gr 355 In contact with large glacier 13 Shyk_gl 45 End Moraine 0.13 Shyk_gr 293 In contact with large glacier 14 Shyk_gl 65 End Moraine 0.21 Shyk_gr 361 Large glacier source 15 Shyk_gl 64 Valley 0.11 Shyk_gr Preceded by a lake and large glacier 16 Shyk_gl 51 Valley 0.17 Shyk_gr Large glacier source

15 126 A. Ashraf et al. Table 6. Characteristics of potential glacial lake outburst flood (GLOF) lakes in the Himalaya Range of Pakistan. Serial no. Lake no. Lake type Area (km 2 ) Associated glacier Distance to glacier (m) Situation 1 Shin_gl 75 Cirque 0.25 Shin_gr 85 In contact with hanging glacier 2 Shin_gl 115 End Moraine 0.13 Shin_gr Near large glacier of hanging nature 3 Shin_gl 167 End Moraine 0.72 Shin_gr 118 In contact with large glacier of hanging nature 4 Shin_gl 220 End Moraine 0.05 Shin_gr 151 Near large glacier of hanging nature 5 Shin_gl 227 Valley 0.08 Shin_gr Near hanging glacier source 6 Astor_gl 36 Cirque 0.05 Astor_gr 199 Hanging glacier source 7 Astor_gl 48 Cirque 0.07 Astor_gr 250 Snow avalanche source 8 Astor_gl 51 Cirque 0.11 Astor_gr 254 Hanging glacier source 9 Astor_gl 25 Cirque 0.14 Astor_gr 163 In contact with hanging glacier 10 Astor_gl 40 Cirque 0.16 Astor_gr 218 Hanging glacier source 11 Astor_gl 53 End Moraine 0.08 Astor_gr Close to large glacier 12 Astor_gl 121 End Moraine 0.09 Astor_gr 564 At active glacier tongue 13 Astor_gl 108 End Moraine 0.16 Astor_gr 445 In contact with large glacier 14 Astor_gl 50 Valley 0.31 Astor_gr Situated in hanging valley, dangerous glacial lake 300 m upstream 15 Jhe_gl 97 Cirque 0.20 In contact with large glacier 16 Jhe_gl 113 Cirque 0.12 Jhe_gr 200 In contact with hanging glacier 17 Jhe_gl 134 Cirque 0.24 Jhe_gr 315 Snow avalanche source 18 Jhe_gl 131 End Moraine 0.71 Jhe_gr Near large glacier of hanging nature 19 Jhe_gl 140 End Moraine 0.12 In contact with large glacier of hanging nature 20 Ind_gl 502 Cirque 0.15 Near hanging ice mass 21 Ind_gl 519 Cirque 0.17 Ind_gr 928 Large lake near hanging glacier 22 Ind_gl 394 End Moraine 0.03 Ind_gr 656 In contact with large glacier 23 Ind_gl 444 End Moraine 0.04 Ind_gr 878 In contact with large glacier of hanging nature 24 Ind_gl 457 End Moraine 0.06 Ind_gr Near large glacier of hanging nature 25 Ind_gl 351 End Moraine 0.14 Snow avalanche source

16 Flood hazards in HKH Region 127 The two End Moraine Dammed lakes classified as potentially dangerous in this basin lie in the extreme northwestern part adjacent to the Chitral River basin and are associated with large Valley type glaciers (table 4). In Chitral River basin, about 37% of lakes have been characterized as major lakes, the majority of which belong to Valley and Erosion types. Only one lake of the End Moraine Dammed type has been identified as potentially dangerous, which is in contact with a large valley glacier. In the part of Indus sub basin of Hindukush, out of 269 glacial lakes, 160 are characterized as major lakes. Eight lakes are identified as potentially dangerous, among which 5 belong to the End Moraine Dammed type. Figure 7 indicates the distribution of glacial lakes and potential GLOF lakes in the three HKH ranges of Pakistan. The Karakoram Range, comprised of Gilgit, Hunza, Shigar, Shyok River basins and part of Indus sub-basin, contains 887 glacial lakes covering a surface area of about 47.7 km 2. There are 492 major lakes in the range, among which 16 lakes are identified as potentially dangerous. In Gilgit basin, about 62% lakes have been characterized as major lakes in which dominant lakes belong to Erosion and Valley types. Among 8 glacial lakes identified as potentially danger of GLOF in this basin, 6 belong to the End Moraine Dammed type (table 5). In Hunza River basin, the majority of glacial lakes are smaller in size as about 43% of the lakes are characterized as major lakes. Due to high altitude and extensive glacial coverage, the numbers as well as the area of glacial lakes are relatively low in this basin. An End Moraine Dammed lake (Hunza_gl 6) associated with a large valley glacier is characterized as potentially hazardous of GLOF. Similarly Figure 7. Potential glacial lake outburst flood (GLOF) lakes in the glaciated Hindukush- Karakoram-Himalaya (HKH) ranges of Pakistan. Available in colour online.

17 128 A. Ashraf et al. in the Shigar River basin, due to extensive glaciated coverage i.e. about 30% of the basin, glacial lakes are less in number and size, and major lakes are only 20% of the total basin lakes. Most of the glacial lakes are of Supraglacial type. There is no lake identified as potentially danger of GLOF in this basin. In Shyok River basin, about 47% lakes are characterized as major lakes among which End Moraine Dammed type are dominant. Six lakes are identified as potentially dangerous associated mostly with large source glaciers. In the Indus sub basin part of Karakoram Range, out of 43 glacial lakes, 23 are characterized as major lakes and only one lake of End Moraine Dammed type is identified as potentially hazardous of GLOF (table 5). The Himalaya Range comprised of Shingo, Astore, Jhelum River basins and part of Indus sub-basin east and south of the Indus River contains 822 glacial lakes covering a surface area of about 40.4 km 2. There are 443 major lakes in the range, among which 25 lakes are characterized as potentially danger of GLOF. In Shingo river basin, about 58% of the glacial lakes are characterized as major lakes, among which dominant lakes belong to Erosion and Valley types. There are 5 potential GLOF lakes consisting of three End Moraine Dammed, and one each Cirque and Valley type lakes (table 6). In Astor River basin, 64 lakes are characterized as major lakes, the majority of which belong to Cirque and Valley types. Nine lakes are identified as potentially danger of GLOF consisting mainly of Cirque and End Moraine and one Valley lake. All the potentially dangerous Cirque lakes are situated at the toe of the hanging glaciers. This situation is susceptible as the ice mass of hanging glaciers can slip and plunge into the lake at any time, resulting in surging and breaching of the lake s dam causing a glacial lake outburst flood. In Jhelum River basin there are 95 major lakes, most of which belong to Erosion and Cirque types. Five lakes are identified as potentially danger of GLOF concentrated mainly in the central and northern parts of the basin. These lakes are generally in contact with hanging glaciers or a large glacial source. In the part of the Indus sub-basin of Himalaya, among 145 major lakes, 6 lakes are identified as potentially dangerous. Most of these belong to End Moraine Dammed type and are associated with large glaciers of hanging nature (table 6). 3.2 Risk assessment and mitigation Overall the northern glaciated region has a population of about 0.5 million, which is mainly concentrated in the southern Himalayan basins. A questionnaire survey was conducted in about 32 households of the three flood affected villages of Hunza basin in Karakoram Range. Nearly all villages have been affected to different degrees by natural hazards, which resulted in the loss of cultivated lands, destruction of irrigation and communication networks. Thus the resource potential of existing villages has been diminished by catastrophic events. The three affected villages Ghulkin, Hussaini and Passu have total households of about 138, 83 and 117 with a population of about 1133, 621 and 863 during 2005 (FOCUS 2008). The villages lie in Gojal the largest tehsil (sub-district) of the Northern Areas, which shares its border with China in the northeast and Afghanistan in the northwest. It has a population of about comprised of different ethnic groups of Wakhi and Burushaski. Ghulkin village is situated in the south whereas Hussaini is in the northeast of Ghulkin glacier. Hussaini spreads upward from the bank of Hunza River and reaches up to a considerable elevation along the lateral moraine of

18 Flood hazards in HKH Region 129 Ghulkin glacier. The moraine is exposed with huge boulders, gravel, pebbles, and sandy soil with a gentle slope. In the south, the snout of the glacier and the glacial stream separates Hussaini from Ghulkin. Passu village lies in the east to the northeast of Passu glacier. Passu lake separates the village from the snout of the glacier. Most of the respondents think landslides, flash floods and glacier surges are the main natural hazards. A few add earthquake and river erosion. Some of these hazards such as floods, river erosion and landslides are interlinked. The intensity of flash floods may increase the process of river erosion and in some cases cause triggering of landslides. According to the respondents in Ghulkin and Hussaini, flash floods mostly occurred during the period from spring to the end of the summer, but for the first time in January Though rainfall is not a major hazard in the area, it results in the creation of a mass movement/landslide hazard. The Karakoram Highway (KKH) is often blocked and/or damaged due to such events during the rainy season. According to most of the respondents, the villagers responses to such events were on a self-help basis. No formal coping and preparedness mechanism exists in the villages. In the case of any disaster incidence, they participate actively in providing evacuation and relief services to the victims of their village or even of their neighbouring villages. Everyone uses self-experience, knowledge, physical and mental abilities to reduce the hazard risks. Some of the people temporarily move to other towns and villages, usually to their relatives houses. Village communities help in risk reduction by pooling resources. Though local volunteers and scouts assist villagers in evacuation and provide necessary relief to the people, resources are mostly inadequate at community level to cope with such extreme flood situations. Some of the respondents informed that due to lack of resources they had a problem relocating even though most of the villagers wanted to migrate to safe places. The community members pointed towards the scanty state of medical help during emergencies and requested quick first aid and medical assistance during the emergency situations. The people of demolished households were shifted to the community s religious centres (locally Jammat Khana ) and schools for shelter and relief. Most of the respondents claim non-availability of outside support from any government agency in such hazards. The major impact of the glacial floods was on agriculture land, which ultimately affected the economy of the people. Livelihood insecurity due to agriculture losses is among the major concern for flood vulnerability. Similarly, flood damage to the infrastructure in turn influences the tourism and trade/marketing across the area. In Ghulkin, there was a heavy damage due to flood events in 2008 ( pamirtimes.net/2008/04/08). The destruction of land and property in situation such as on 6 January 2008 had caused a psychological trauma and unrest in the village community. During high flood conditions, people often face mental disturbances, health and psychological problems. The village people, especially the elderly, women and children are under great mental stress because of the shadowing disasters and risks. In Hussaini, floods damaged the main irrigation channels, which disturbed the livelihood of the village. At present, there was no functional irrigation channel in the village. The damage to the bridge had caused the KKH to be blocked for 4 days. People had to carry their goods manually, which intensified their efforts and created physical and mental fatigue. Many tours were cancelled because of the road block. The tourism office was also totally destroyed.

19 130 A. Ashraf et al. Three lives were lost in the Hussaini village, two of which were females. Two lives were lost in the Ghulkin village, which include one female under 10 years. These events mostly occurred near agricultural land away from the village settlement, which is why loss of human lives was less. In total 21 people were affected by these floods. As a result of the GLOF events, 72 kanals of land were affected out of which 29 kanals were cropland. Four hundred and sixty fruit trees worth over Pak rupees were destroyed. Seven houses and 4 livestock sheds were demolished killing 15 cattle. Nine hundred square feet of terrace walls were damaged (verbal communication). About 760 m of link road and 2 electricity poles were destroyed. Five water channels, 28 pipes and 2 water storage tanks were also damaged. The damage to KKH and a bridge cost hundreds of thousands of rupees. Similarly, loss to trade and tourism affected the livelihood and economy of the communities. In Ghulkin, the loss of livestock to a farmer ranged up to Pak rupees, which collectively reached a hundred thousand rupees. In Hussaini, the loss exceeded Pak rupees (Roohi et al. 2008). There was a loss to crops e.g. wheat, potatoes, fruit plants e.g. apricot, apple and popular trees. In Passu, loss to a farmer ranged within thousand rupees. But collectively, it reached hundreds of thousands of rupees as a whole. The crops affected include potatoes, barley, wheat, apples, cherry, grapes, apricot and plums, besides loss of popular trees. It has become increasingly recognized that the isolated nature of many of the region s communities, coupled with the Northern Areas high-altitude and fragile environment, poses special constraints and challenges in mitigating natural hazards like GLOFs. In order to lower the water level and drain the lake posing threat of GLOF hazard on Ghulkin glacier, a siphoning technique was applied by the village community. An excavation of the lateral moraine near the lake formation was undertaken to setup siphoning. Due to poor livelihood conditions, lack of resources and proper management within the system the communities have a problem in taking effective response measures for risk reduction or mitigation. Although local committees are therefore undertaking different tasks, gaps exist in their coordination and capacity buildings. Outside help is rarely available or rather unavailable in time. 4. Conclusion. Digital image analysis integrated with GIS application has revealed the formation of about 2420 glacial lakes in the Hindukush-Karakoram-Himalaya (HKH) Region of Pakistan, among which 52 lakes are characterized as potentially dangerous GLOF hazards. Among 52 potential GLOF lakes are identified in HKH region, 25 of which lie in the Himalaya Range, indicating the prevalence of global change influence on this mountainous range.. About 62% of these lakes belong to the End Moraine Dammed type and 25% to the Cirque type. About 54% of GLOF lakes lie within the elevation range of masl and 29% within masl. A maximum of 14 lakes in Himalaya and 7 each in Hindukush and Karakoram lie over the masl range.. GLOF events are becoming a threat to the livelihood of the glaciated HKH region of Pakistan, probably due to the influence of global warming in this region.

20 Flood hazards in HKH Region 131. The communities of the northern glaciated region are highly vulnerable to natural hazards as no formal coping and preparedness mechanism exists at village levels. The local communities usually respond to such events on a selfhelp basis.. There is a need to create awareness of flood hazard preparedness and risk reduction among target communities and key stakeholders, impart specialized training and capacity building in hazard mitigation and risk management.. Climate change needs to be studied more systematically in order to cope with the degree of its impact on the glacial environment, especially in GLOFsusceptible areas. Detailed investigations of hot spot GLOF lakes should be undertaken in different river basins.. In the face of the increase in global warming, there is a need to perform hazard and risk assessment analysis, and develop risk mitigation strategies to provide a comprehensive policy framework. As non-structural measures, hazard assessment and monitoring of GLOF areas are required through the utilization of techniques such as remote sensing and hydrodynamic modelling coupled with ground surveys for better risk mitigation and early warning. Acknowledgments The all out support of International Centre for Integrated Mountain Development (ICIMOD), Asia-Pacific Network for Global Change Research (APN), United Nations Environment Programme (UNEP) and the global change SysTem for Analysis, Research, and Training (START) for undertaking the glacier resource inventory and UNDP, Pakistan for community based risk assessment and the response survey is highly appreciated as without this the present work would not be possible. The database development and mapping support by members of the Water Resources Research Institute, National Agricultural Research Centre, Islamabad is also gratefully acknowledged. The authors are also grateful to two reviewers of the manuscript for rendering valuable comments and suggestions for its improvement. References ARCHER, D.R., 2001, The climate and hydrology of northern Pakistan with respect to assessment of flood risks to hydropower schemes. Report by GTZ/WAPDA. ASHRAF, A., ROOHI, R., AHMAD, B. and MUSTAFA, N., 2008, Depleting Glacier Resources of Northern Himalaya, Pakistan. In Proceedings of a National Conference on Water Shortage and Future Agricultural Challenges and Opportunities, Islamabad, August, pp BAJRACHARYA, S.R., MOOL, P.K. and SHRESTHA, B.R., 2007, Impact of Climate Change on Himalayan Glaciers and Glacial Lakes: Case studies on GLOF and associated hazards in Nepal and Bhutan. ICIMOD, Kathmandu, Nepal. FOCUS, 2008, Preliminary Assessment Report on Aerial Reconnaissance Survey of Ghulkin Glacier Lake Outburst. UNDP, Pakistan. GOUDIE, A., 1981, Fearful landscape of the Karakoram. The Geographical Magazine, 53, pp GUNN, J.P., 1930, Report of the Khumdan Dam and Shyok Flood of Government of Punjab Publication, Lahore, Pakistan. ICIMOD, 2011, Glacial Lakes and Glacial Lake Outburst Floods in Nepal. ICIMOD, Kathmandu, Nepal.