Pakistan Agricultural Research CouncilAsia-Pacific Network for Global Change Research

global change SysTem for Analysis, Research and TrainingInternational Centre for Integrated Mountain Development

United Nations Environment Programme/Regional Resource Centre for Asia and The Pacific

Asia Pacific Network for Global Change Research

Indus BasinPakistan HimalayaInventory of Glaciers and Glacial Lakes andthe Identification of Potential Glacial Lake Outburst Floods (GLOFs) Affected by Global Warming in the Mountains of Himalayan Region

Indus Basin

Inventory of Glaciers and Glacial Lakes and Identification of Potential Glacial Lake Outburst Floods (GLOFs) Affected by Global Warming in the Mountains of Himalayan Region

Pakistan Agricultural Research Council (PARC) International Centre for Integrated Mountain Development (ICIMOD) Asia-Pacific Network for Global Change Research (APN) Global Change System for Analysis, Research, and Training (START) United Nations Environment Programme (UNEP)

2005

ICIMOD Pradeep Kumar Mool Samjwal Ratna Bajracharya Basanta Shrestha Sharad Prasad Joshi

WRRI/PARC Rakhshan Roohi (Ph.D) Arshad Ashraf Rozina Naz Syed Amjad Hussain M. Hamid Chaudhry

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Foreword

The glaciers of the Hindu Kush-Karakoram-Himalayan (HKH) region are nature’s valuable source of fresh water for present and future needs of millions of people living in this region as well as down stream. These frozen reservoirs release large amounts of ice melt water to many of the major rivers of the region including Indus River in Pakistan. The glaciers, few of which consist of a huge amount of perpetual snow and ice, are found to create many glacial lakes over centuries. However, these glaciers are retreating in the face of accelerating global warming. Rapid accumulation of water in these glacial lakes, particularly in those adjacent to receding glaciers, can lead to a sudden breach of their unstable moraine ‘dams’. The resultant discharge of huge amounts of water and debris – a Glacial Lake Outburst Flood or GLOF – often cause catastrophic effects downstream.

In Pakistan, numerous glaciers and glacial lakes are found in the high mountain ranges of HKH region. These glaciers and glacial lakes contribute more than 50% of the total flow of the lndus system and are the major source of water supply for agricultural, industrial, and hydropower development in the country. These valuable resources have never been systematically harnessed in the past. Knowledge of this resource seems to be an outstanding requirement for future planning of water resources and flood hazard monitoring in the entire lndus Basin System. Many GLOFs have been recorded in the last few decades that resulted in heavy loss of human lives and their property, destruction of infrastructure, and damage to crop fields and forests.

Major parts of snow and ice mass are concentrated in the watershed of the Indus River. Under a collaborative programme with ICIMOD a study was carried out in the ten sub basins of Indus River System namely Swat, Chitral, Gilgit, Hunza, Shigar, Shyok, Upper Indus, Shingo, Astor and Jhelum, covering the HKH region of Pakistan. In the period of three years, a systematic study on the inventory of glaciers and glacial lakes of this part was completed using Remote sensing satellite and topographic data and a comprehensive database was developed. The results generated from this study will provide baseline data and information for future planning and investigation of these resources and monitoring of GLOF in the area. The project has provided an opportunity for professionals of Water Resources Research Institute (WRRI) of Pakistan Agricultural Research Council (PARC) to learn more about the methodology and related activities to build up their confidence for the future work. Furthermore, a semi-automatic methodology for inventory of glaciers and glacial lakes was developed for future glacial monitoring. One of the major objectives of this study was to identify areas where GLOF events could pose a potential threat in the near future. Based on the detailed criteria the potentially dangerous lakes were identified which needs to be monitored in future.

The total geographic area of the river basins studied is about 128,730.8 sq. km. Altogether 5,218 glaciers are identified in the ten basins which cover a total glaciated area of about 15,040 sq. km (About 11.7% of the total geographic area of the ten basins). The total ice reserves in HKH region of Pakistan are about 2,738.5 km3. The Shyok, Hunza and Shigar basins contain the major part (about 83%) of these ice reserves. There are altogether

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2,420 glacial lakes in the study area. The highest number of lakes is in Gilgit basin (614) and minimum in Shigar basin (54). The total area covered by these lakes is around 126 sq. km. The major types of glacial lakes identified in the study, include; Erosion, Valley, End Moraine Dammed and Cirque types. Based on the detailed characteristics of each lake, 52 lakes are identified as potentially dangerous lakes which include Cirque (13), End Moraine dammed (31) and Valley lakes (8). The erosion lakes are generally stable and are therefore less susceptible to GLOF, if it is not associated with the mother glaciers.

These results provide the basis for the development of a monitoring and early warning system, planning and prioritization of disaster mitigation efforts that could save many lives and properties situated downstream, and a guideline for infrastructure planning and development. In addition, it is anticipated that this study will provide useful information for many of those concerned with water resources and land-use planning. Coupled with the information on climate change and future monitoring of glaciers, this database can provide the basis for estimation of future available water resources and their planning and management.

This document not only presents the description of methods used to identify glaciers, glacial lakes, and potentially dangerous glacial lakes but also includes an inventory of these glaciers and glacial lakes for future monitoring of GLOFs in the HKH region of Pakistan. We are thus confident that this comprehensive report and digital database will be of service to scientists, planners, and decision-makers in many areas. We further hope that their informed actions, will contribute to improve the lives of those living in the mountains as well as downstream and help safeguard future investments.

This project has enabled further strengthening of the collaboration between APN, UNEP, START, PARC, and ICIMOD to continue to assist in developing regional capacities and co-operation.

J. G. Campbell (Ph. D) Baduruddin Soomro (Ph. D)

Director General, ICIMOD Chairman, PARC

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Acknowledgement and Credits

The support of Abdul Hafeez Randhawa, ex-Secretary (MINFAL), Government of Pakistan and former Board Member of ICIMOD needs special thanks in initiating this project. We would like to extend our deepest gratitude to Dr. Baduruddin Soomro, Chairman, PARC, Dr Naeem Hashmi, ex- Director General NARC and Dr. Muhammad Ashraf, Director General, NARC for their kind support and encouragement throughout the project period.

Thanks are also due to Dr. Zahid Hussain (CSO, WRRI) and Dr. Shahid Ahmad (CSO, NRD) for their valuable input and advice while implementing the project.

We would like to specially thank Mr. Riaz Hussain and Mr. Waqas Kareem Awan M.Sc final year students of Punjab University for working for this project. Without their support, the extensive work would not have been possible to complete within due time.

We would like to thank Dr. J. Gabriel Campbell, Director General of ICIMOD for overall coordination, supervision and timely supports during the implementation of the project.

Other ICIMOD staff members who have assisted in the study include Ms. Monica Moktan, Mr. Rajan Bajracharya, Mr. Lokap Rajbhandari, Mr. Sushil Pandey, Mr. Birendra Bajracharya, Mr. Sushil Pradhan, Mr. Saisab Pradhan, Ms. Mandakini Bhatta, and, Mr. Govinda Joshi, and from WRRI, Mr. Arbab Ahmad, Mr. Azhar Shafiq Butt, Mr. Muhammad Afzal, Mr. Suhail Ahmad, Mr. Khalid Mehmood and Mr. Liaqat Ali. We would like to thank them all for their contributions

We would like to express appreciation and sincere thanks to Mr. Surendra Shrestha, Regional Director and Representative for Asia and the Pacific - UNEP and Director of UNEP/RRC-AP, Mr. Mylvakanam Iyngararasan, Ms. May Ann Mamicpic and Ms. Kitiya Gajesani of UNEP/RRC-AP for their strong support and advise.

Thanks are due to Mr. Sombo T. Yamamura, Director, Mr. Yukihiro Imanari, Executive Manager, Ms. Jody Chambers, Programme Manager, Mr. Martin Rice, former Programme Manager, Communications and Development, Dr. Linda Anne Stevenson, Programme Manager, Ms. Sirijit Sangunurai, Programme Fellow, Mr. Tomoya Motoda, Technical Assistant, Mr. Toshiaki Mitani, Administrative Manager, Ms. Kanako Taguchi, Administrative Assistant, of Asia-Pacific Network for Global Change Research (APN) for their continuous support in the implementation of the project.

Last but not least we would like to express our sincere thanks to Prof. Roland Fuchs, Director, Dr. Hassan Virji, Deputy Director, Ms. Kathleen Landauer, Programme Associate Ms. Alix Cotumaccio, Programme Associate and Dr. Yna Calimon, former Programme Associate of International global change SysTem for Analysis, Research, and Training (START) Secretariat for their timely and strong support and advice while implementing the project. Development Team ICIMOD Pradeep Kumar Mool, Samjwal Ratna Bajracharya, Basanta Shrestha, Sharad P. Joshi, Kiran Shakya and Gauri S. Dangol

PARC Rakhshan Roohi (Ph.D), Arshad Ashraf, Syed Amjnd Hussain, Rozina Naz, Hamid Chaudhary, Tariq Mustafa and Shakeel Ahmad

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Acronyms ADB Asian Development Bank

ADRG ARC Digitized Raster Graphics AP Aerial Photograph AP Asia and the Pacific APN Asia-Pacific Network for Global Change Research

APT Automatic Picture Transmission

BCM Billion Cubic Meter

°C Degree Centigrade CIDA Canadian International Development Agency CSO Chief Scientific Officer

DEM Digital Elevation Model DHM Department of Hydrology and Meteorology

D.I. Khan Dera Ismail Khan DMA Defense Mapping Agency

EESL Electrowatt Engineering Service Ltd. ERTS Earth Resources Technology Satellite ETH Swiss Federal Institute of Technology ETM Enhanced Thematic Mapper FATA Federally Administered Tribal Areas FCC False Color Composite FFC Federal Flood Commission FFD Flood Forecasting Division FFS Flood Forecasting System FPSP Flood Protection Sector Project FWC Flood Warning Centre

GDP Gross Domestic Product GIS Geographic Information System gl Glacial Lake GLOF Glacial Lake Outburst Flood GOP Government of Pakistan gr Glacier

Ha. Hectares H.F High Frequency HKH Hindu Kush-Himalaya HRPT High Resolution Picture Transmission HRV High Resolution Visible (SPOT) HYCOS Hydrological Observing System

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IBIS Indus Basin Irrigation System ICIMOD International Centre for Integrated Mountain Development ILWIS Integrated Land and Water Information Systems IR Infrared IIR First infrared IRS Indian Remote Sensing Satellite series IRS1D Indian Remote Sensing Satellite series 1D IUCN International Union for Conservation of Natural Resources

KKH Karakoram Highway

LANDSAT Land Resources Satellite Lat/Lon Latitude/Longitude LIGG Lanzhou Institute of Glaciology and Geocryology LISS Linear Imaging and Self Scanning Sensor (IRS)

M Million masl metre above sea level MENRIS Mountain Environment and Natural Resources’ Information System Met Meteorology mg L –1 miligram/litre MINFAL Ministry of Food, Agriculture and Livestock MSS Multi Spectral Scanner

N.A. Not Available NACS Northern Area Conservation Strategy NARC National Agricultural Research Centre NEA Nepal Electricity Authority NESPAK National Engineering Services of Pakistan NFFB National Flood Forecasting Bureau NIR Near infrared NIMA National Imagery and Mapping Agency NOAA National Oceanic and Atmospheric Administration NRD Natural Resources Division NWFP North West Frontier Province

PAN Panchromatic Mode Sensor System PARC Pakistan Agricultural Research Council PMD Pakistan Meteorological Department

RECA Rapid Environmental Change Assessment RGB Red Green Blue RRC Regional Resources Centre RS Remote Sensing

SPOT Système Probatoire d’ Observation de la Terre / Satellite Pour l’Observation de la Terre SoP Survey of Pakistan START global change SysTem for Analysis, Research, and Training SWIR Short Wave Infra Red (JERS)

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TM Thematic Mapper (LANDSAT) TDS Total Dissolved Solids THIR Thermal infrared TPC Tactical Pilotage Chart TTS Temporary Technical Secretary

UNDP United Nations Development Programme UNEP United Nations Environment Programme

VNIR Visible and Near Infra Red instrument

WAA Water Apportionment Accord

WAPDA Water and Power Development Authority WECS Water and Energy Commission Secretariat

WGI World Glacier Inventory WGS World Geographic System WGMS World Glacier Monitoring Service WHYCOS World Hydrological Observing System WMO World Meteorological Organization WRRI Water Resources Research Institute

XS Multispectral Mode Sensor System (SPOT)

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Contents Foreword..........................................................................................................................i Acknowledgement and Credits............................................................................. iii Acronyms........................................................................................................................v Contents...................................................................................................................... viii Chapter 1 Introduction to Inventory of Glaciers and Glacial Lakes ...... 1

1.1 INTRODUCTION .................................................................................................................. 1 1.2 OBJECTIVES ....................................................................................................................... 3

Main Objectives............................................................................................................... 3 Long-Term Objective ...................................................................................................... 3

1.3 OUTPUTS .................................................................................................................3 1.4 ACTIVITIES ...............................................................................................................3 1.5 FLOWCHART.............................................................................................................5

Chapter 2 General Characteristics of the Country .................................. 7 2.1 INTRODUCTION.........................................................................................................7 2.2 PHYSIOGRAPHY........................................................................................................7 2.3 GEOLOGY AND GEOMORPHOLOGY..........................................................................11 2.4 SEISMICITY .............................................................................................................17 2.5 CLIMATE ................................................................................................................17

Agro-Climatic Zones ................................................................................................. 18 Water Resources....................................................................................................... 20 Rivers ....................................................................................................................... 20 Mineral Resources .................................................................................................... 20 Soils ......................................................................................................................... 21 Forests...................................................................................................................... 22 Wildlife ..................................................................................................................... 23

2.7 LAND USE ..............................................................................................................23 2.8 AGRICULTURE ........................................................................................................23

Chapter 3 Hydro-Meteorology ............................................................. 27 3.1 RIVER BASINS .................................................................................................................. 27

3.1.1 Swat River Basin.................................................................................................. 28 3.1.1 Swat River Basin.................................................................................................. 28 3.1.2 Chitral River Basin............................................................................................... 31 3.1.3 Gilgit River Basin................................................................................................. 32 3.1.4 Hunza River Basin ............................................................................................... 33 3.1.5 Shigar River Basin ............................................................................................... 35 3.1.6 Shyok River Basin ............................................................................................... 35 3.1.7 Indus River Basin................................................................................................. 37 3.1.8 Shingo River Basin .............................................................................................. 38 3.1.9 Astor River Basin ................................................................................................. 39 3.1.10 Jhelum River Basin............................................................................................ 42

3.2 CLIMATE...................................................................................................... 43 3.2.1 Altitudinal Zones In The Northern Mountain Region ............................................ 46

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3.2.2 Glacier’s Velocity And Fluctuations...................................................................... 47 3.2.3 Surges And Climate Change ................................................................................ 47

3.3 HYDROLOGY................................................................................................ 48 3.3.1 Runoff ................................................................................................................. 48 3.3.2 Sediment Yield .................................................................................................... 49

Chapter 4 Materials and Methodology ..................................................51 4.1 TOPOGRAPHIC MAPS ………………………………………………………………….53 4.2 SATELLITE IMAGE ...................................................................................................53 4.3 INVENTORY METHOD ..............................................................................................54

4.3.1 Inventory of Glaciers............................................................................................ 54 Numbering of Glaciers.............................................................................................. 55 Registration of snow and ice masses ......................................................................... 55 SnowLine ................................................................................................................. 55 Accuracy Rating Table.............................................................................................. 55 Mean Glacier Thickness and Ice Reserves ................................................................. 56 Area of the Glacier ................................................................................................... 57 Length of the glacier ................................................................................................. 57 Mean width .............................................................................................................. 57 Orientation of the glacier .......................................................................................... 57 Elevation of the Glacier ............................................................................................ 57 Morphological Classification ..................................................................................... 57

4.3.2 Inventory of Glacial Lakes ................................................................................... 63 Numbering of Glacial Lakes...................................................................................... 63 Longitude and Latitude ............................................................................................ 63 Area ......................................................................................................................... 63 Length...................................................................................................................... 63 Width ....................................................................................................................... 64 Depth ....................................................................................................................... 64 Orientation ............................................................................................................... 64 Altitude..................................................................................................................... 64 Classification of lakes................................................................................................ 64 Activity ..................................................................................................................... 64 Types of Water Drainage .......................................................................................... 65 Chemical Properties ................................................................................................. 65 Other Indices ............................................................................................................ 65

Chapter 5 Spatial Data Input and Attribute Data Handling ................ 67

Chapter 6 Application of Remote Sensing ............................................. 71 Chapter 7 Inventory of Glaciers ............................................................ 93

7.2 BRIEF DESCRIPTION OF GLACIER INVENTORY ..........................................................93 7.2 TYPES OF GLACIER........................................................................................ 93 7.3 GENERAL CHARACTERISTICS OF GLACIATION .................................................... 94 7.4 GLACIERS OF PAKISTAN IN HKH REGION .......................................................... 96

7.4.1 Swat River Basin.................................................................................................. 97 7.4.3 Gilgit River Basin............................................................................................... 111 7.4.4 Hunza River Basin ............................................................................................. 119 7.4.5 Shigar River Basin ............................................................................................. 126 7.4.6 Shyok River Basin ............................................................................................. 133

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7.4.7 Indus River Basin............................................................................................... 140 7.4.8 Shingo River Basin ............................................................................................ 148 7.4.9. Astor River Basin .............................................................................................. 154 7.4.10. Jhelum River Basin......................................................................................... 161

Chapter 8 Inventory of Glacial Lakes ................................................. 175 8.2 BRIEF DESCRIPTION OF GLACIAL LAKE INVENTORY..................................................... 175 8.2 GLACIAL LAKES—THEIR NUMBERING, TYPE AND CHARACTERISTICS ......................... 175

Erosion lakes .......................................................................................................... 175 Supraglacial lakes ................................................................................................... 176 Moraine Dammed lakes.......................................................................................... 177 Blocking lakes......................................................................................................... 177 Ice-dammed lakes................................................................................................... 177

8.3 GLACIAL LAKES OF RIVER BASINS OF HKH REGION OF PAKISTAN ............................ 178 8.3.1 Glacial Lakes of Swat River basin ...................................................................... 178 8.3.2 Glacial Lakes of Chitral River basin.................................................................... 181 8.3.3 Glacial Lakes of Gilgit River basin...................................................................... 185 8.3.4 Glacial Lakes of Hunza River basin.................................................................... 188 8.3.5: Glacial Lakes of Shigar River basin ................................................................... 190 8.3.6: Glacial Lakes of Shyok River basin ................................................................... 194 8.3.7 Glacial Lakes of Indus River basin ..................................................................... 197 8.3.8 Glacial Lakes of Shingo River basin ................................................................... 201 8.3.9 Glacial Lakes of Astor River Basin ..................................................................... 204 8.3.10 Glacial Lakes of Jhelum River basin................................................................. 207 8.3.11 Summary......................................................................................................... 211

Chapter 9 Glacial Lake Outburst Floods and Damages in the Country 215 9.1 INTRODUCTION ........................................................................................... 215 9.2 CAUSES OF LAKE CREATION ......................................................................... 215

Global Warming ..................................................................................................... 215 Glacier Retreat........................................................................................................ 215 Causes of Glacial Lake Water Level Rise ................................................................ 216

9.3 BURSTING MECHANISMS ............................................................................................... 216 Mechanism of Ice Core-dammed Lake Failure........................................................ 217 Mechanism of moraine-dammed lake failure .......................................................... 217 Melting Ice-core ...................................................................................................... 218 Overtopping by Displacement Waves ..................................................................... 218 Settlement and/or Piping ........................................................................................ 219 Sub-glacial Drainage .............................................................................................. 219 Engineering Works ................................................................................................. 219

9.4 SURGE PROPAGATION.................................................................................. 219 9.5 SEDIMENT PROCESSES DURING A GLACIAL LAKE OUTBURST FLOOD.................... 223 9.6 SOCIOECONOMIC EFFECTS OF GLACIAL LAKE OUTBURST FLOODS ...................... 224 9.7 BRIEF REVIEW OF GLACIAL LAKE OUTBURST FLOOD EVENTS AND DAMAGES CAUSED

IN PAKISTAN .................................................................................................... 225 9.8 SOME EXAMPLES OF GLOF EVENTS................................................................ 226 9.9 LAKE OUTBURST FLOOD HAZARDS................................................................. 236 Chapter 10 Potentially Dangerous Glacial Lakes ............................237 10.1 CRITERIA FOR IDENTIFICATION ............................................................................... 237

Rise in Lake Water Level ........................................................................................ 237

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Activity of Supraglacial lakes................................................................................... 238 Position of Lakes .................................................................................................... 238 Dam Conditions ..................................................................................................... 238 Conditions of Associated Mother Glacier ................................................................ 239 Physical Conditions of the Surrounding Area.......................................................... 239

10.2 Major Glacial Lakes Associated with the Glaciers and Potentially Dangerous Glacial Lakes of Ten River Basins In Hkh Region Of Pakistan ...................................... 240

10.2.1 Swat River basin........................................................................................................240 10.2.2 Chitral River basin.....................................................................................................246 10.2.3 Gilgit River basin .......................................................................................................250 10.2.4 Hunza River basin .....................................................................................................262 10.2.5 Shigar River basin .....................................................................................................265 10.2.6 Shyok River Basin .....................................................................................................266 10.2.7 Indus River basin.......................................................................................................270 10.2.8 Shingo River basin ....................................................................................................281 10.2.9 Astor River basin .......................................................................................................287 10.2.10 Jhelum River basin .................................................................................................292 10.2.11 Summary .................................................................................................................298

Chapter 11 Glacial Lake Outburst Flood Mitigation Measures, Monitoring and Early Warning Systems ........................... 303

11.1 REDUCING THE VOLUME OF LAKE WATER ...........................................................303 Pumping or siphoning the water out from the lake .......................................................304 Making a tunnel through the moraine dam....................................................................304

11.2 PREVENTATIVE MEASURES AROUND THE LAKE AREA ...........................................305 11.3 PROTECTING INFRASTRUCTURE AGAINST THE DESTRUCTIVE FORCES OF THE SURGE

..................................................................................................................................305 11.4 MONITORING AND EARLY WARNING SYSTEMS .....................................................305 11.5: EARLY WARNING AND FLOOD FORECASTING SYSTEMS IN PAKISTAN ....................306

Existing facilities for the flood forecasting system ..........................................................308 Efficiency of flood forecasting system .............................................................................309 Future developments........................................................................................................309 Needs within the HKH regional framework....................................................................310

Chapter 12 Conclusions ....................................................................... 311 References..................................................................................................................315

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Chapter 1

Introduction to Inventory of Glaciers and Glacial Lakes 1.1 INTRODUCTION The glaciers are nature's renewable storehouse of fresh water that benefits hundreds of millions of people downstream. The glaciers of the Hindu Kush - Himalayan (HKH) region, however, are retreating in the face of accelerated global warming since the second half of the 20th century and have contributed to the formation of many glacial lakes on the recent glacier terminus. A majority of these glacial lakes are formed due to damming by unstable moraines. Rapid accumulation of water in these lakes can lead to sudden breaching of the unstable moraine dams discharging huge amounts of water and debris - known as a Glacial Lake Outburst Floods, or GLOFs causing loss of life, property and the destruction of valuable forest and pasture resources, farmlands, and costly mountain infrastructures. Some GLOFs are reported to have created long-term secondary environmental degradation physically and socio-economically, both locally and in neighboring downstream countries. GLOF is recognized to be a common problem in the Hindu Kush - Himalayan countries such as Bhutan, China, India, Nepal and Pakistan. The study of glaciers and glacial lakes in Nepal and Bhutan carried out by the International Centre for Integrated Mountain Development (ICIMOD) and United Nation Environment Programme/Regional Resources Centre, Asia and The Pacific (UNEP/RRC-AP) from 1999 to 2001 inventoried 3,252 glaciers and 2,323 glacial lakes in Nepal and 677 glaciers and 2,674 glacial lakes in Bhutan. The study also identified 20 glacial lakes in Nepal and 24 glacial lakes in Bhutan as potentially dangerous. Many GLOF events in Nepal and some in Bhutan, reported and unreported, were documented from the study of satellite images, aerial photographs, and available topographic maps of different years. The reported GLOF events are highly destructive downstream and lead to long-term secondary environmental degradation in the valleys, both physically and socio-economically. A major part of the snow and ice mass of the Pakistan’s HKH is concentrated in the watershed of the Indus basin. This watershed can be divided into distinct ten river basins. A study was carried out in these ten river basins of HKH region of the country. This study was carried out in three phases. In the first phase the inventory work of Astor River basin was completed while in the second phase inventory of five more basins namely Upper Indus, Jhelum, Shingo, Shyok and Shigar was completed. Finally in the third year the inventory of remaining four basins namely Swat, Chitral, Gilgit and Hunza was completed and the entire database of Pakistan was compiled.

The total geographic area of all these ten river basins studied is about 128,730.8 sq. km. Altogether 5,218 glaciers were identified which cover a total glaciated area of about 15,040 sq. km (about 11.7% of the total geographic area of the basins). These glaciers contribute total ice reserves of about 2,738.5 km3. The Shyok, Hunza and Shigar basins contain the major part (about 83%) of these ice reserves.

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There are altogether 2,420 glacial lakes in the study area. The highest number of lakes is in Gilgit basin (614) and minimum in Shigar basin (54). The total area covered by these lakes is around 126 sq. km. Based on the detailed characteristics of each lake, 52 lakes are identified as potentially dangerous lakes which include Cirque (13), End Moraine dammed (31) and Valley lakes (8). The erosion lakes are generally stable and are therefore less susceptible to GLOF, if it is not associated with the mother glaciers.

Most of these potentially dangerous glacial lakes are situated at the headwater of the river basins, settlements, agricultural fields, and infrastructure which are mostly concentrated along the river valley downstream of glaciers and glacial lakes. Therefore, accurate and comprehensive knowledge of glaciers and glacial lakes are of utmost importance. A digital repository of valuable knowledge on glaciers, glacial lakes, and GLOF events will enhance the ability to inform policy makers on the vulnerability, risk mitigation and action/adaptation measures. Specifically for Pakistan where irrigation network of the country is heavily dependent on the snow melt in summer, this information on one hand can serve to plan the agricultural activities downstream according to the ice reserves available and the prevailing climate and on the other it can provide a basis for future climate change/global warming studies. Since the total number of glaciers and potential GLOF hazards in the region is still unknown, this study will add greatly to sustainable development as well as regional and global database. The northern sector of Pakistan is a mountainous region, where all the land is in the form of rugged terrain including mountains and hills. The central and northern mountain sectors are steeper than the southern sector. The region is vulnerable to landslide and river erosion due to great elevation differences, steep sloping terrain, and fragile geological conditions. In addition, the watersheds of the region are covered by some major glaciers and glacial lakes, which are quite susceptible to disastrous hazards due to GLOFs. In general, snow clad line is found above 5,300 meters above mean sea level (masl). The glaciers, some of which consist of a huge amount of perpetual snow and ice, are found to create many glacial lakes. The glaciers and glacial lakes of the HKH region are nature's renewable storehouse of fresh water that benefits hundreds of millions of people downstream. Lakes at an elevation that is higher than 4,000 masl are considered as glacial lakes. Most of these lakes are located in the down valleys close to the glaciers. They are formed by the accumulation of vast amounts of water from the melting snow and ice cover and by blockage of End Moraines. The sudden break of a moraine dam may generate the discharge of large volumes of water and debris causing disastrous floods. In Pakistan these glaciers as well as glacial lakes are the sources of the headwaters of Indus River. For the inventory of glaciers and glacial lakes, the methodology in this study is used similar to Nepal and Bhutan (Mool et al. 2001a and Mool et al. 2001b), which is based on the research study of the Temporary Technical Secretary (TTS) for the World Glacier Inventory (WGI) of the Swiss Federal Institute of Technology (ETH), Zurich (Muller et al. 1977; World Glacier Monitoring Service [WGMS] 1989).

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1.2 OBJECTIVES Main Objectives The main objectives of the present study is to assure that mountain inhabitants in the HKH region enjoy safe and sustainable livelihoods through a better understanding of environmental hazards associated with Mountain Glaciers and glacial lakes, with which to address environmental policy, planning and impact/risk mitigation. Long-Term Objective The long-term objective of the study is to establish an inventory of and digital database on mountain glaciers/glacial lakes and change due to global warming affecting potential glacial lake outburst floods (GLOFs) and associated hazards. The database, methodologies and information will be analyzed, synthesized, and shared nationally and regionally among the collaborating national organizations and agencies to form the foundations for both policy and planning (and, later, in a second phase under other funding, to establish GLOF hazard monitoring and early warning systems for environmental risk mitigation). 1.3 OUTPUTS The major outputs of this study are:

1. Documentation of glaciers, glacial lakes, and potential GLOFs and associated hazards.

2. Inventory of hot-spots and hazards using GIS and RS technologies 3. Strengthened institutional capacities of collaborating institutions and agencies,

with special attention to training female participants. 4. Policy products for use in source and downstream countries. 5. Implementation of comprehensive communication and dissemination plans based

on the results and outputs of database analysis, strengthening policy and planning within relevant agencies, and informed research institutions and the public, nationally and regionally.

1.4 ACTIVITIES The major activities of the study will be as follow:

1. Inventory of glaciers and glacial lakes and establishment of an easily-accessible digital database using GIS and RS technologies

2. Establish analytical protocols and systems to identify 'hot-spots' (existing and potentially dangerous glacial lake hazards) and to regularize GLOF hazard studies

3. Analyse and synthesize the database to determine the existence of hot-spots and potential GLOF circumstances, and to network the results among concerned agencies

4. Conduct Rapid Environmental Change Assessment (RECA) studies on GLOF hazard risks and potential impacts

5. Enhance the capacities of participating institutions to manage and regularly update the database through technology transfer to collaborating organizations and agencies

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6. Prepare analytical studies and briefing papers for policy- makers/planners to be presented at regional/international workshops and conferences and publications on potential GLOF hazards and risks and their potential impacts and mitigation, through the participating country organizations

7. Help create wider awareness, locally/regionally/internationally, among governments, development agencies, and the public about GLOF phenomena and hazards through a variety of communication channels (e.g., published reports/documents in appropriate languages, Internet applications including information portals, seminars, workshops, and conferences, TV and radio documentaries, and other professional learning, capacity building and public awareness strategies).

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1.5 FLOWCHART

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Chapter 2 General Characteristics of the Country 2.1 INTRODUCTION

Pakistan is situated in the heart of the South Asian sub-continent; it is a country with its own fascinating history and cultural heritage. Pakistan was the site for one of the world's earliest human settlements, the great prehistoric Indus Valley Civilization, the crucible of ancient empires, religions and cultures. It extends between the latitudes 24° to 37° north and longitudes 61° to 78° east. Iran lies to the west, Afghanistan to the northwest, China to the north and India to the east (Figure 2.1). The landscape of the country ranges from lofty mountains in the north through dissected plateaus to the rich alluvial plains of the Punjab. This landscape follows desolate barrenness of Balochistan and the hot dry deserts of Sindh blending into miles and miles of golden beaches of the coastal area covering a total area of about 79.6 M ha. There are four provinces; Balochistan covering area of 34.72 M ha in the western part of the country, North-West Frontier Province (NWFP) is stretching over 7.45 M ha in the northwestern part, Punjab covering 20.53 M ha in the middle and Sindh covering 14.09 M ha in the southeastern part (Figure 2.2). There is Federally Administered Tribal Areas (FATA) covering area of 2.72 M ha and Capital territory stretching over 0.09 M ha. About 47.59 M ha in the north, northwest and west of Pakistan form a highly differentiated mountainous terrain, while the remaining 32.02 M ha present a flat and gradational surface.

2.2 PHYSIOGRAPHY High mountains of Pakistan comprise of the western end of 2,400 km long Himalayan range and some parts in the Hindu-Kush and Karakoram ranges stretching over NWFP and the Northern Areas. Northern areas spread over 72,496 sq. Km. with amidst towering snow-clad peaks with heights varying from 1,000 meters above sea level (masl) to over 8,000 masl. Of the 14 over 8,000 masl peaks on earth, 4 occupy an amphitheater at the head of Baltoro glacier in the Karakoram Range. These are: K-2 (Mount Godwin Austen) which is 8,611 masl and is world second highest peak, Gasherbrum-I (8,068 masl), Broad Peak (8,047 masl) and Gasherbrum II (8,035 masl). There is yet another which is equally great, that is, Nanga Parbat (8,126 masl) at the western most end of the Himalayas and is rated as worlds’ 8th highest peak (Figure 2.3). In addition to these, there are 68 peaks over 7,000 masl (Table 2.1) and hundreds which are over 6,000 masl. Generally because of their rugged topography and the rigors of the climate, the northern highlands and the Himalayas to the east have been formidable barriers to movement into Pakistan throughout history. There are though several famous passes like Khyber, Kurrum, Tochi, Gomal, Lowari and Khunjrab, which have been used historically as trade routes.

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Figure 2.1: Index map of Hindu Kush - Himalayan region showing mountains of Pakistan at the western end of the HKH region.

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The Northern Pakistan has some of the longest glaciers outside Polar Region like Siachen (76 km), Hispar (61 km.), Biafo (60 km.), Baltoro (60 km.), Batura (64 km.), Yenguta (35 km), Chiantar (34 km), Trich (29 km) and Atrak (28 km). The lower Himalayan valleys of Swat, Kaghan and Chitral in the Hindukush range equally share the beauty and diverse culture of the Northern Pakistan. The HKH region in Pakistan house many gorgeous lakes especially like Saif-ul-Maluk, Satpara and Kachura. Northern Area is connected with air and road with other cities of Pakistan including Islamabad the Capital. There are daily flights to Skardu and Gilgit, subject to weather. It is also linked with the road - Karakoram Highway which is passing through the Indus valley. The Karakoram Highway, or KKH, is the greatest wonder of modern Pakistan and is highest mettle border crossing in the world. Connecting Pakistan to China, it twists through three great mountain ranges - the Himalayas, Karakoram and Pamir - following one of the ancient silk routes along the valleys of the Indus, Gilgit and Hunza rivers to Chinese border at the Khunjerab Pass. For much of its 1,284 km the KKH is overshadowed by towering, barren mountains, a high altitude desert enjoying less than 100 millimeters of rain a year. In many of the gorges through which it passes, it rides a shelf cut into a sheer cliff face as high as 500 meters above the river. The KKH has opened up remote villages where little has changed in hundreds of years, where farmers irrigate tiny terraces to grow small patches of wheat, barely or maize that stand out like emeralds against the gray stony mountains. The KKH hugs the banks of the Indus for 310 km of its climb north, winding around the foot of Nanga Parbat, the western anchor of the Himalayas. The highway then leaves the Indus for the Gilgit, Hunza and Khunjerab rivers to take on the Karakoram Range, which boat 12 of the 30 highest mountains in the world. (www.mountainleaders.com).

Figure 2.2: Administrative boundaries of Pakistan.

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Table 2.1: Mountain Peaks of interest in Pakistan exceeding 7,000 metres in height.

Peaks Ht. (Metres)

Lat. ( º , ′ )

Long. ( º , ′ ) Peaks Ht.

(Metres) Lat.

( º , ′ ) Long. ( º , ′ )

K-2 8611 35-88 76-50 Peak* 7407 35-16 77-22 Nanga Parbat 8126 35-25 74-60 Haramos 7397 35-50 74-54 Gasharbrum I 8068 35-43 76-42 Istoro Nal 7389 36-23 71-54 Broad Peak 8047 35-48 76-34 Teram Kangri III 7382 35-36 77-02 Gasharbrum II 8035 35-46 76-37 Sad Ishtrag 7367 35-23 77-07 Gasharbrum III 7952 35-46 76-39 Peak* 7345 36-07 75-12 Peak* 7930 35-52 76-34 Momhil 7343 36-20 75-03 Gashabrum IV 7925 35-46 76-37 Sad Ishtrag 7340 36-23 72-07 Peak* 7884 36-21 75-02 Sad Ishtrag II 7336 36-33 72-07 Distaghil Sar 7884 36-20 75-11 Hunza Kungi IV 7329 36-24 74-42 Peak* 7852 36-12 75-12 Peak* 7324 36-19 75-14 Mashebrum E 7821 35-39 76-19 Peak* 7303 35-28 76-47 North Peak 7809 35-15 74-36 Sad Ishtrag III 7300 36-32 72-07 Mashebrum W 7806 35-38 76-18 Peak* 7298 36-33 72-08 Raka Poshi 7788 36-09 74-31 Baintha Brakk 7285 35-57 75-45 Hunza Kunji I 7785 36-31 74-31 Peak 7282 36-26 71-52 Kanjut Sar 7760 36-13 75-25 Long Hill 7280 36-36 71-52 Double East Peak 7750 36-15 71-50 Apsarasa I 7245 35-32 72-09 Peak* 7745 35-16 74-35 Apsarasa II 7239 35-32 72-10 Dong Dong-Gl 7705 35-24 76-51 Peak* 7239 36-13 75-23 Tirich Mir 7690 36-15 71-51 Tirich Mir III 7238 36-24 71-54 Bride Peak 7654 35-37 76-34 Peak* 7236 35-31 77-12 Hunza Kunji 7611 36-27 74-41 Peak* 7233 35-19 77-23 Peak* 7577 36-18 75-05 Peak* 7203 35-35 77-59 Masostang Kangri 7526 35-19 77-38 Peak* 7169 35-26 77-23 Rakhiot I 7510 35-15 74-37 Peak* 7144 35-50 75-49 Naushan 7501 35-26 71-50 Peak* 7143 36-37 74-19 Pumarikish 7492 36-12 75-15 Tuin Peak 7122 36-32 71-59 Pointed Hill 7484 36-25 71-50 Rakhiot II 7074 35-15 74-39 Peak* 7468 35-18 77-08 Peak* 7071 35-11 37-35 Skillbrum 7468 35-35 75-50 Sad Ishtrag I 7053 36-35 72-07 Tirich Mir II 7468 36-16 71-50 Chanishehish 7027 36-03 74-58 Teram Kangri I 7464 35-34 77-05 Peak* 7018 36-39 72-09 Malubating 7458 36-00 74-53 Peak* 7016 35-55 76-34 Peak* 7428 35-17 77-01 Peak* 7004 35-12 77-32 Peak* 7422 35-36 76-45 Taram Kangri II 7407 35-34 77-05

Peak* 7000 36-40 72-14

* Unnamed peaks

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Pakistan shows a great diversity of bio-climates, vegetation types and fauna. There are thick forests of Pines, Poplars, Conifers and Junipers. Major habitats consist of: a) flood and arid plains, sand and piedmont deserts and a variety of forests; b) grassy tundra and cold deserts; and c) lakes, rivers, swamps, and coastal marine habitats (GOP, 1992). The major physiographic regions in the country include; Dry and wet mountains in the north, dry mountains and plateau in the west, Indus irrigated plain and Indus delta in the east and south respectively. The northern dry and wet mountains comprise high mountain ranges of Himalayas, Karakoram, and Hindu Kush with 50 peaks of over 6,700 m. Some of the lower mountain ranges in the northeast receive high monsoon rainfall in summer and snow precipitation during winter. The forest cover is dense in this mountain region. The high northern and northwestern areas are out of monsoon reach so the climate is dry and precipitation occurs only due to depressions moving in from the west during spring and summer. Western dry mountains are lower and more arid with highest peak of 3,374 m. The Balochistan Plateau comprises of arid land in the west of the Sulaiman-Kirthar Mountains. The land mainly consists of dispersed rangelands, rugged terrain and some desert areas. Indus irrigated plain stretches from the foothills of Himalayas in the north to the coastal plains near Karachi in the south of the country. It is the main agricultural production area of the country. The Indus River forms a large delta before entering into Arabian Sea in the south. Mangrove forests are the significant feature of this area. In addition, there is barani land (rainfed) in the northwest of Indus plain comprises of Pothwar plateau and Salt range with elevations ranging from 450 to 600 m. The plateau has topography dissected badly by water and wind erosion. In the eastern parts of Punjab and Sindh provinces, there is sandy desert consisting of sand dunes and rare vegetation. 2.3 GEOLOGY AND GEOMORPHOLOGY The land of Pakistan provides a fascinating exhibition of geological evolution. It is a bonanza of different lithospheric plates, which have been accreted together in such a way that has a rare parallel in the world with respect to its structure, relief, rock types and landscape. The geo-history of Pakistan, as a part of the Indo-Pak Plate, is rooted in the dismemberment of a super-continent the "Gondwanaland" in about Late Jurassic period. Since 55 million years ago, India has steadily rotated counterclockwise. Coupled with Arabia’s separation from Africa about 20 million years ago, this rotation caused convergence in Balochistan, collision of various crustal blocks in Iran-Afghanistan region and formation of Balochistan fold and fault belt. The India-Eurasia collision produced the spectacular Himalayas along uplifted and deformed 2,500 km long Indo-Pakistan plate margin. The collision between these segments resulted in the formation of new relief and topography, which consists of series of mountain ranges located in the north, northwest and southwest of Pakistan, commonly known as the Himalayan Mountain System. Rapid uplift of the Himalayas to great heights and under the influence of very cold climate of high altitude embraced a blanket of snow and ice during the Quaternary period. Huge amount of detritus carried by the streams emerging from the glaciated Himalayas during the warm interglacial periods, deposited in the Indo-Gangetic Synclinorium gradually, built the Indus Basin with new drainage pattern and new landforms.

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Of the physical formations present in the country, none is as impressive as the huge mountain ranges in the north. The three marvelous ranges namely Himalayas, Karakoram and Hindukush, are spectacular in its own way. These stretch like a bow in the north of Pakistan extending into the India, China, Nepal and Bhutan with a total length of 2,500 km. The Himalayas are classified as the youngest mountains of the world. The principal uplift occurred during the middle or late Tertiary period, 12 to 65 million years ago. The Himalayas serve as the divide between Central Asia and South Asia. In Pakistan, they stretch uninterruptedly from the Nanga Parbat (8,126 meters) to the Namch Barwa in Tibet (7,756 meters). The Western Himalayas is situated between Kashmir valley in the East to Indus River in the North and West, and is dominated by Nanga Parbat. Nanga Parbat complex has numerous routes but the prominent base camps are Rupal (Eastern face), Raikot / Fairy Meadows (North Western face), Diamer (the Western face) and the long West Mazeno ridge (www.hussaini.20m.com). The Himalayas have four sub-regions; Sub-Himalayas or Siwaliks, The lesser Himalayas, The Central or High Himalayas and the Trans Himalayas. The Sub-Himalayas or Siwaliks is a range of low hills with average height varying from 600-1,200 m. The rocks are folded and faulted to produce a most rugged landscape. The Lesser Himalayas lie north of the Siwaliks and rise to 1,800-4,600 m. The rocks in these ranges are metasedimentary and have some granitic intrusions, which are folded, faulted and over thrust. Rawalpindi, Mansehra and Abbotabad Districts form part of this range. The inner ranges are higher and parallel to the High Himalayas and comprise the north west trending Pir Panjal range, which links up with the southwest trending Hazara mountains. The Central or High Himalayas are located north of the lesser Himalayas. The central Himalayas have an average height of about 6,000 m and remain covered by snow throughout the year. The western most part of the High Himalayas within Pakistan is comprised of the Nanga Parbat range. To the north, this range is bounded by the Indus River and to the south by the Kishenganga River (Kaszmi, A. H. and Qasim, M. 1997). The highest mountain of this range in Pakistan is the Nanga Parbat. The Trans-Himalayas including the Karakoram Range are also very high which comprises some of the highest peaks, large glaciers, deepest gorges and canyons of this region.

The word 'Karakoram' comes from the Turkish term meaning 'black rock', for where the snow does not cover the mountains, they emerge as dark patches of rock. The Karakoram covers 500 km from the eastern most extension of Afghanistan towards South Asia. The mountains are covered with glaciers that are the longest in this region. Passes at various altitudes cross the mountains. The more commonly used passes are included in Table 2.1. This splendid and magnificent collection of dark brown and black metamorphic rocks is the most unique mountain range. It has the largest concentration of lofty pinnacles and mountains in the world. It is bounded by Shyok River in the East and Karamber, Ishkuman and Gilgit Rivers in the West. In the North East it is bounded by Shaksgam River and in the South West by Shyok and the Indus Rivers. Karakoram is specially

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characterised by its fissured rocks, gendarme like vertical features and steep slopes presenting great challenge to climbers and adventure seekers. The Karakoram Range has an average height of 6,100 masl north. The range boasts of the greatest concentration of high mountains in the world including K-2 (8,611m) which is the second highest peak in the world. Gasherbrum 1 (8,068m), Broad peak (8,047m) and Rakaposhi (7,788m) are other prominent peaks of this range (Figure 2.3). Four peaks above eight thousand metres i.e., K-2, Gasherbrum I and II and Broad Peak are situated in Karakoram in a radius of just 20 km around the famous glacial junction-Concordia.

Table 2.2: The important passes, their location and elevation. S.No. Passes Linking Towns masl

1 Babusar Pass Abbotabad-Gilgit 4,386 2 Lowari Pass Peshawer-Chitral 3,118 3 Shandur Pass Chitral-Gilgit Valley 3,720 4 Mustagh Pass Gilgit-Sinkiang (China) 5,800

The sub regions of the Karakoram are Boltoro, Soltoro, Lupghar, Ghujerab, Panmah, Aghil, Masherbrum, Saser, Hispar, Siachen, Rimo, Batura, Rakaposhi/Bagrot, and Haramosh. The snow line in this range varies from 4,200 to 4,500 metres during summer. The temperatures in the area are extreme and there is large difference between lowest and highest temperatures during a day. Monsoons do not penetrate in this area.

The glaciated area of this region contains some of the world's longest glaciers, such as Siachen glacier. It is said to be the highest battlefield in the world. The other glaciers include Baltoro, Batura, Biafo and Hisper. Karakoram is extremely inaccessible. Mountain passes situated at various altitudes are only open for five to six months during summer (www.hussaini.20m.com). The Hindukush range runs from the western edge of the Pamir Plateau, west of the Karakoram. These form 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 which are not as well developed as those of the other chains. The highest peaks are Noshak (7,369 meters) and Tirich Mir (7,690 meters). A number of passes cross the mountains, which are Baroghil, Dorah, Shul, Shera Shing and Shingara. They are located in remote and tough dangerous areas and it has been historically impossible to patrol them. The Chitral, Kunar, Punjkora and Swat rivers cross the mountains. In addition to the above three chains, lesser chains of mountains cross the country. The Kabul River separates the northern mountains from the Koh-e-Safaid ranges, which are inclined on an east-west axis.

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The Koh-e-Safaid Ranges have an east-west trend and rise to an average height of 3,600 m. They are commonly covered with snow. Sikeram, the highest peak in Koh-e-Safaid Ranges rises to 4,760 m. Similarly, the elevation of Waziristan hills ranges from 1,500 and 3,000 m. Among these, the Khyber Pass is the most important that connects Peshawar in Pakistan to Kabul in Afghanistan.

a. The magnificent view of K2

b. Broad Peak at Sunrise

c. Base Camp Gasherbrum I

d. Gasherbrum II from Gasherbrum I

e. Gondoro Peak Ridge

f. Nanga Parbat from Fairy Meadows

Figure 2.3: Some of the important peaks of HKH region of Pakistan. Source: (www.geocities.com/Pentagon/Barracks/9722/Mountains/index.htm)

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The Sulaiman-Kirthar Mountain Ranges extending from south of Gomal River lie between Balochistan Plateau and the Indus Plains. On reaching the Mari-Bugti Hills, they turn northward and extend up to Quetta. Further south, they meet the Kirthar Mountains, which merge into the Kohistan area of Sindh. The Indus Plains begins at the southern end of the Himalayas and the Salt Range and stretches to the Arabian Sea. It covers an area of nearly 21 M ha. The flat plain is largely made of alluvium, over 300 m deep, deposited by the river Indus and its tributaries, which flow over 1,000 km through the provinces of Punjab and Sindh to the Arabian Sea near Karachi. The Indus Plain comprises the main agricultural areas of the country. Rolling Sandy Plains and Dunes: An extensive area in the southwest of the country is covered with these plains. It is separated from the Indus valley by the dry channels of Ghaggar River. This extensive desert is called Cholistan in the Punjab and Thar in Sindh, which is not drained by any perennial stream. The wind action is dominant in the formation of its topography. A vast expanse of sand plains with dunes dominates the scene. Agriculturally the area has a limited potential. In the south of Pakistan, there are coastal plains stretched along 700 km shoreline from east to west. The Makran coast is comprised of 16-32 km wide coastal plain dotted with several hills and ridges, and is extensively covered with sand dunes. Numerous small streams drain the coastal ranges and transverse the plain. Valleys Of the trans-Indus Basin, there are valleys; Peshawer, Kohat and Bannu in the northwest of Pakistan, among which, Peshawar drained by the Kabul River is the biggest one. In the northern part of the country, Swat, Kaghan, Hunza, Gilgit and Chitral are strikingly beautiful valleys (Figure 2.4). The valley of Swat is linked by road to Islamabad (257 km) as well as by air through the divisional capital at Saidu Sharif. Sparkling streams are abundant amongst thick forests of pine and conifers. The Kaghan valley lies at the northern tip of the Hazara district which is home to the exquisitely beautiful lakes like Saif-ul-Maluk and Lulusar. The valley of Hangu nestles in a sub-range of three prominent hills. The valley of Gilgit lies in a bowl shaped depression and is reached both by air and road. Early accounts of Gilgit and its surroundings have been found in the memoirs of the famous Chinese traveller Fa Hien (399 AD). In Gilgit, there are other famous valleys like Yasin, Ishkuman and Hunza. The Chitral Valley in the northwest is better known for the Kalash tribe, rivers and sulphur springs. In the northeast the Kashmir valley bounded by Pakistan, China and Afghanistan and separated by a strip of Indian land has many interspersed lakes and woodlands.

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(a) Shimshal Valley under winter snow

(b) The lush green Lalazar, Kaghan valley

(c) The Haramosh Valley

(d) Indus Valley, descending from Thalle La

(e) Chitral Valley and Trich Mir

(f) Village in beautiful Swat Valley

Figure 2.4: Panoramic views of valleys in the northern areas of Pakistan. Source: (www.geocities.com/Pentagon/Barracks/9722/Mountains/index)

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2.4 SEISMICITY Pakistan is characterized by extensive zones of high seismicity and contains several seismotectonic features generated by an integrated network of active faults. The earliest indication of an active fault associated with earthquakes came in 1892, when the town of Chamen was destroyed and the great Chamen fault was noted for the first time. High seismicity is observed in the collisional mountain ranges where the active faults are common whereas the more sTable Indus platform zone is characterized by relatively low seismicity. Paleo magnetic data show that Indian Eurasia collision was accompanied by a counter clockwise rotation so that the Pamir arc was probably the site of first continent-continent contact. As the western end has been in contact for a longer time, it has wedged deeper into Eurasia, with steeper subduction and much more intense seismicity (Kaszmi et al. 1984).

2.5 CLIMATE Pakistan is basically a dry country of the warm Temperate Zone. The climate of the area is transitional between that of Central Asia and the monsoonal lands of South Asia, which, varies considerably with latitude, altitude, aspect and localized relief. There is not only high spatial variability but temporal variability is quite high as well. Except for a small strip of sub-tropical terrain in Punjab and the wet zone on the southern slopes of the Himalayan and Karakoram mountain ranges, most of the country is arid or semi-arid steppe land (GOP et al. 1992). In general more than three-fourth of the country has less than 250 mm rainfall (Figure 2.5). There are two distinct rainy periods, one in summer and one in winter. The monsoon rainfall is extensive in period from July to September. The winter is dominated by the westerly fronts originating from Mediterranean region. In the north of the country, most of the precipitation is not only derived from the Indian monsoon but from depressions moving in from the west during the spring and summer as well. The winter snow, glaciers and snowfields start melting from April and continue till July when monsoon sets in.

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Figure 2.5: Mean annual rainfall of Pakistan.

Agro-climatic Zones The country experiences two distinct seasons namely winter (Rabi) and summer (Kharif). The seasonal aridity and crop growth indices were used to characterize and classify the agro-environments. The aridity index refers to the ratio of 50% probability of rainfall and actual crop evapo-transpiration. The aridity classes ranged from humid to hyper-arid. Based on the seasonal aridity classes, 18 zones were delineated. The crop growth index reflects the temperature availability for crop growth and is estimated as a ratio of growing degree-days available to those required by a particular crop. The crop growth classes defined ranged from deficit to excess. A total of 9 zones were defined by superimposing the seasonal crop growth maps. The annual aridity classes and crop growth classes are shown in Figures 2.6 and 2.7. These two indices contributed to 57 agro-climatic zones in Pakistan. These agro-climatic zones show variability in terms of aridity and crop growth for both the Kharif and Rabi seasons. About 0.117 million sq. km area is characterized as arid zone both in Kharif and Rabi seasons. Generally in this zone the temperature availability is adequate or excess accept for a small portion where it is deficit. A vast tract of 0.27 million sq. km has an arid climate in Kharif with a combination of hyper-arid Rabi. Another belt of 0.14 million sq. km is characterized as hyper-arid in Kharif season with a range of semi-arid to arid Rabi.

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Figure 2.6: Annual aridity classes of Pakistan.

Figure 2.7: Annual crop growth classes of Pakistan.

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2.6 NATURAL RESOURCES Water Resources The snowmelt run-off constitutes a substantial part of water resources of the rivers of Pakistan. The Indus River, primarily supplied by glaciers in its upper reaches, and subject to the least seasonal variation, still has a maximum flow more than fifty times its minimum. The Indus basin irrigation network in Pakistan stretches over an area of 14 M ha (Asim et. al. 2002). The network has three major reservoirs (Tarbela, Mangla and Chashma), 19 barrages or headworks, 12 link canals and 43 canal commands presented in (Figure 2.8). Hydrogeologically whole of the Indus alluvial complex can be treated as a huge, single unconfined aquifer, which is high yielding aquifer with substantial storage capacity (Rathur, 1987). As reported by Gazdar (1987), the aquifer is believed to extend 300 m in depth over most of the area. Rain, rivers and seepage from surface storage reservoirs, canals, watercourses and fields, recharge the aquifer. Zones of saline groundwater are found in the central and lower parts of inter fluvial regions. In the lower Indus Plain particularly in Sind province groundwater quality is poor and in large areas TDS values are greater than 3000 mg L -1 (Ahmad and Chaudhry, 1990). Water logging and salinity are severe problems due to a massive network of irrigation canals, especially, in between the rivers in Punjab. Other methods of irrigation are wells (Persian wheels) in central Punjab and Kareezes in Balochistan. There were 18 small and 97 mini dams until 1991 in the rain-fed areas of Punjab. In addition there are 272,962 private and 15,491 public sector tube wells, which irrigate 3.97 million hectares of land besides supplementing some canal-fed areas in the country.

Rivers Five main rivers, namely, the Indus, Jhelum, Chenab, Ravi and Sutlej flow through the country’s plains. Aided by a number of smaller tributary rivers and streams, these rivers supply water to the entire Indus Basin Irrigation System (IBIS), which forms the world's largest contiguous irrigation system. The Indus River is about 2,800 km long and 62% of its catchment lies in Pakistan (Shafique and Skogerboe, 1984). Indus system receives a number of tributaries from the west: Kabul, Kurram, Tochi and the Gomal river. The eastern tributaries are Jhelum, Ravi and Sutlej. The five major rivers combine at Panjnad. The swelling of Indus and its tributaries during summer causes floods.

Mineral Resources The main economic minerals in Pakistan include Barite, chromite, copper, coal, gypsum, iron ore, limestone, marble, quartz, rock salts, fire clay, etc. Some mediums in small deposits include antimony, asbestos, china clay, gemstones, rock phosphate, manganese, sulphur, gold and silver (Kaszmi et. al. 1984). The large iron ore deposits are found in

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Kalabagh beside Pezu, Langrial, etc. Gold and silver occurs in association with other minerals in the northern part of the Indus platforms, the Himalayan crystalline zone, Bela ophiolite, Kohistan magmatic arc, Karakoram block and the Chagai magmetic arc. Placer

Figure 2.8: Irrigation system of Pakistan.

deposits occur extensively in the upper reaches of the Chitral, Gilgit, Hunza and Indus rivers. These placers are largely thin pockets of heavy minerals concentration that are removed by floods every summer season and redepositted as the floods recede. Mining of the gold-silver bearing Saindak copper deposits were started 1995 and it is expected that processing of this ore would produce 1.47 tones of gold and 2.76 tones of silver annually. The silver bearing Duddar Lead-Zinc ore is expected to be mined in the near future and a small production of silver is likely. Other minerals of economic importance are limestone, dolomite, marble, silica sand, magnesite and china clay. The first National Mineral Policy was announced on 23rd September, 1995. It aimed at increasing the share of mineral sector in the national economy and reducing the cost of mineral exploration.

Soils Pakistan possesses different types of soils, which are varied in composition, color, texture and organic content. These soils can be classified into three major categories as; a) Soils of the Indus Basin, b) Mountain-soils, and c) Sandy desert soils. Soils of the Indus basin include Bangar Soil (Old alluvium), Khaddar Soil (new alluvium) and Indus Delta Soils. Bangar soils are found over a large area of the scalloped interfluves, occupying the central parts of the land between major rivers of the Punjab, the

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Vale of Peshawar and the Bannu Plains. Khaddar soils are relatively younger and low in organic contents. Delta soils are formed of sub-recent alluvium and estuarine deposits. Mountain-Soils are found over high land areas of northern and western mountains and also the Salt Range. These soils are transported as well as residual. These soils have a light content of organic matter and are humified to deeper depths. Sandy Desert Soils extend over some parts of western Balochistan, Cholistan and Thar Desert. Desert soils include rolling to hilly sandy soils and clayey flood plain soils (Survey of Pakistan, 1997). Forests Pakistan’s extremes of climate and physiography provide conditions for a rich variety of forest covers. The main types of forest which are recognized under the prevailing ecological conditions include:

1) Alpine Forests 2) Coniferous Forests 3) Sub-Tropical Forests 4) Tropical Thorn Forests 5) Irrigated Plantations 6) Riverain Forests 7) Mangrove/Coastal Forests

The Alpine Forests occur in the northern districts of Chitral, Swat, Dir and Kohistan. Because of long severe winters, dwarfed and stunted trees of Silver Fir (Abies webbiana), and Juniper (Juniperus spp.) are present. The Coniferous Forests occur from 1,000 to 4,000 m altitudes. Swat, Dir, Malakand, Mansehra and Abbottabad districts of NWFP, and Rawalpindi districts of the Punjab are the main areas covered with coniferous forests. Fir (Abies spp.) and Spruce (Picea smithiana) occupy the highest altitudes, Deodar (Cedrus deodara) and Blue Pine (Pinus wallichiana), the intermediate heights, and Chir Pine (Pinus roxburghii), the lower areas. The Coniferous forests also present in Balochistan hills. The Sub-Tropical Dry Forests are found in Attock, Rawalpindi, Jhelum and Gujrat districts of the Punjab, and in Mansehra, Abbottabad, Mardan, Peshawar and Kohat districts of NWFP up to a height of 1,000 m. In Balochistan, they are confined to the Sulaiman Mountains and other hilly areas. The Tropical Thorn Forests are dominated by xerophytic scrubs which are most widespread in the Punjab plains. They also occupy small areas in southern Sindh and western Balochistan. The Irrigated Plantations were first initiated in 1866 at Changa Manga (Punjab). Today they occupy an area of about 226,000 ha. Shisham (Dalbergia sissoo), Mulberry (Morus alba), Babul (Acacia nilotica), Eucalyptus and Populus spp. are the common tree species grown in these areas.

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The Riverain Forests grow in narrow belts along the banks of Indus and its tributaries. They are more commonly found in Sindh and to some extent in the Punjab. Babul (Acacia nilotica), Shisham (Dalbergia sissoo) and Tamarax dioica are the most common species. The Mangrove Forests are located in the Indus delta. However, lack of fresh water has resulted in their stunted growth. Avecennia officanilis is the main species. Wildlife The wildlife is mostly conserved through declaring special protected areas and hot spots in the country. There are three types of protected areas in the country; a) National parks, b) Wildlife Sanctuaries, and c) Game Reserves. National Parks are only meant for recreational purposes where no other activity can take place. In Wildlife Sanctuaries, no hunting is allowed as they have the endangered wildlife species. Game Reserves are areas where hunting is allowed but only in certain months in a year and after obtaining a hunting permit from the Wildlife Department. Although wildlife is fast disappearing from the country but still there are areas especially in the northern mountains inhabited by ibex, brown bear, snow leopard, mountain sheep and musk deer. In the plains and westerly mountainous areas there are found variety of game birds and animals like partridge, jungle fowl, gazelle, hog deer, stag and black buck etc. 2.7 LAND USE The main land uses in the country include forest area in the north and northwest, irrigated agriculture, rain fed agriculture, rangeland and sandy plains. Cultivable area is 24.6 million ha. Another about 12 million ha are under forage and forests (GOP, 1998). In the cropped area, food grains (wheat, rice, sorghum, maize, millets and barley) claim 56% of the area, cash crops (sugarcane, cotton, tobacco, sugar beet and jute) occupy 18%, while the remaining 26% is shared by other crops like pulses, oil seeds, vegetables, condiments etc. The entire country was classified into major land covers by using NOAA Imagery (Figure 2.9 and 2.10). The rangelands including low rangeland of rock outcrops are dominant in the north and western part of the country. Agriculture mainly lies in the irrigated plains of Punjab and Sindh provinces. In the north, the land is mainly under dense forests, some rangeland and snow and glacial covers. 2.8 AGRICULTURE Agriculture in Pakistan dates back to Neolithic times. It formed the base of the well-known Indus Valley Civilization. Its contribution to the Gross Domestic Product (GDP) has decreased from 52% in 1950-51 to just 24% in 1993-94. This is primarily because of higher growth rates registered by other sectors, particularly, the manufacturing and mining. In spite of the contribution of 25% in GDP the agricultural sector provides job opportunities for 55% of the labor force. It also accounts for 80% of the total export earnings of the country. Livestock sub sector accounts for 34.1 percent of the agricultural value added and 8.3 percent to the GDP (GOP, 1998; Survey of Pakistan, 1997).

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Within the agriculture sector, irrigation plays a predominant role as it provides 90% of the total wheat production of the country and almost 100% of cotton, sugarcane, rice, fruits and vegetables mainly within 16.4 M. ha of the Indus basin.

Figure 2.9: Landcover of Pakistan.

2%5%1%

26%

16%

15%

35% Water bodies and snow

Forest (Coniferous, Scrub andMangrove)Forest (Riverine and plantation)

Agriculture (Irrigated and Rainfed)

Rangeland

Sandy desert

Barrenlands (Rockoutcrops and Tidalflats)

Figure 2.10: Graph indicating distribution of major land covers in Pakistan. The agricultural calendar has two main cropping seasons: a) Rabi and b) Kharif. Rabi crops which include wheat, barely, grams, tobacco and oilseeds, are sown in October-December and harvested in April-May. These have a 55 percent share in the sown area. Kharif crops are sown in April-June and harvested in October-December. They include cotton, sugarcane, rice, maize, jawar, bajra and comprise 45 percent of the sown area. The minor crops include pulses, potatoes, onions, chili and garlic, etc.

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2.9 Population

According to 1998 census results the total population of Pakistan is 130.58 million as against 84.254 millions in 1981 showing an overall percentage increase of 54.9 or an average growth rate of 2.61 percent. The Punjab province has the largest population of 72.58 millions with population density of 353 persons /sq.km. The second largest population lies in Sindh province (29.99 millions) with density of 213 persons /sq.km. The NWFP and Balochistan provinces have population of 17.55 M and 6.51 M with population densities of 236 and 19 persons /sq.km respectively. There are federally administered areas in the country which include capital territory and tribal areas with having an overall population of 3.93 millions (GOP, 2001)

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Chapter 3

Hydro-Meteorology 3.1 RIVER BASINS

Out of the six major key basins in Asia and Pacific namely Indus, Brahmaputra, Ganges, Yellow River, Yangtze and Mekong River, the first three falls within the HKH Region. Pakistan lies within the Indus River basin. The Indus River has its farthest sources behind the Himalayan escarpment of the Tibetan Tableland and rises in the north side of the Kailas range in 31° 20' N, 82° E near the sources of the Sutlej and San Pro and within 60 miles of the Karnali, farthest head stream of the Ganges. On emerging from the Himalayas, it collects all the southern drainage of the Hindu Kush through the Kabul River, which joins its right bank at Attock. Lower down, it receives the waters of Sulaiman uplands mainly through the Kurram and Gomal Rivers. The chief accession to its volume is from the united waters of Jhelum, Chenab, Ravi and Sutlej all flowing from the western Himalayas and through Panjnad (means five streams) join the mainstream at Mithan Kot. Beyond Panjnad, the united stream receives no further affluent. The rivers descend south towards the Arabian Sea with a combined annual average volume of 178 BCM (for all major rivers) discharged into the Indus Plains. The Indus System Rivers form a link between two great natural reservoirs, the snow and glaciers in the mountains and the groundwater contained by the alluvium in the Indus Plains of the Punjab and Sindh provinces of Pakistan (www.waterinfo.net.pk/fsmd.htm).

The tributary rivers also have their origin in the Himalayas and derive their flows mainly from snowmelt and monsoon rains. The Jhelum River rises in Kashmir at a much lower elevation than the source of the Indus River and falls much less rapidly after entering into Pakistani territory. The Chenab River originates in Himachal Pradesh in India at an elevation of over 4,900 masl. It flows through Jammu in Indian-held Kashmir and enters into Pakistani territory upstream of the Marala Barrage. The Jhelum River joins the Chenab River at Trimmu Barrage.

Snowfall at higher altitudes (above 2,500 m) accounts for most of the river runoff. The active hydrological zone lies between 2,500 and 5,500 masl, and snowfall in the mountains accounts for a large portion of the total runoff into the river (PSIHP, 1991). Within this zone, snow and glacial melt contribute towards river runoff from March to September. In the upper Indus catchments, the snow line is at an elevation of 5,500 masl; above this elevation it’s the process of snow accumulation that dominates rather than melting of snow even during the summer months. (www.waterinfo.net.pk/fsmd.htm)

The snow and ice melt from the glacial area of the upper Indus catchments supply approximately 80% of the total flow of the Indus River in the summer season. The annual flows in the Kabul River are less than one-third of that in the Indus River. However, the Kabul River starts to rise approximately a month earlier than the Indus River (Trunk River), its flows are of significance for fulfilling the late-Rabi and early-Kharif (March to May) irrigation requirements of the canals. Snowmelt accounts for more than 50% of the flow in the Jhelum River but it is much more dependent than the Indus River for variable

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monsoon runoff. Both, the Jhelum and Chenab River catchments can simultaneously be influenced by the monsoons. Since the Chenab River rises at higher altitudes, snowmelt accounts for a considerable proportion of its runoff (www.waterinfo.net.pk/fsmd.htm)

For hydrological studies, Pakistan’s northern area is divided into 10 major river basins (Figure 3.1). Clockwise from west, these basins are of the Swat River, Chitral River, Gilgit River, Hunza River, Shigar River, Shyok River, Indus River, Shingo River, Astor River, and the Jhelum River. Most of the snow and ice reserves are concentrated in the mountain ranges lying in these basins. These river basins contain the glaciated part of northern Pakistan, which forms the headwaters of the main Indus basin.

3.1.1 SWAT RIVER BASIN

The Swat river network drains parts of the Hindu Kush, Dir, Swat, and Kohistan ranges in the western territory of Pakistan (Figure 3.2). The Swat River contributed by the Panjkora River in the northwest joins the Kabul River near Nowshera in the NWFP. The Swat range has an altitude of about 4,500 to 5,500 masl in the north, which reduces to about 2,000 masl near its southern end, west of Mingora. The upper reaches of the Kohistan-Swat ranges are mostly covered with snow and glaciers.

Historically Swat is the most interesting valley of Pakistan. It is also one of the most beautiful, as it lies in the monsoon belt and is greener and more fertile than the valleys further north. The valley is the land of waterfalls, lakes, Lush green hills and other gifts bestowed upon it by the nature.

3.1.1 SWAT RIVER BASIN

The Swat river network drains parts of the Hindu Kush, Dir, Swat, and Kohistan ranges in the western territory of Pakistan (Figure 3.2). The Swat River contributed by the Panjkora River in the northwest joins the Kabul River near Nowshera in the NWFP. The Swat range has an altitude of about 4,500 to 5,500 masl in the north, which reduces to about 2,000 masl near its southern end, west of Mingora. The upper reaches of the Kohistan-Swat ranges are mostly covered with snow and glaciers.

Historically Swat is the most interesting valley of Pakistan. It is also one of the most beautiful, as it lies in the monsoon belt and is greener and more fertile than the valleys further north. The valley is the land of waterfalls, lakes, Lush green hills and other gifts bestowed upon it by the nature.

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Figure 3.1: The Glaciated River basins of Northern Pakistan.

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(a) Utrot Valley

(b) Malam Jabba under clouds

(c) Swat River near Kalam Valley

(d) Village in beautiful Swat Valley

Figure 3.2: Valleys and rivers of Swat River basin.

In lower Swat the valley is wide and the fields on either side of the river are full of wheat and Lucerne surrounded by fruit orchards; the villages here are prosperous. In upper Swat the narrow river tumbles through pine forests hemmed in by snowcapped mountains. Swat offers some of the best walking trails in Pakistan, as well as excellent fishing and climbing. The excavated archaeological sites here range from prehistoric caves through Aryan graveyards to Buddhist monasteries.

Saidu Sharif and Mingora are twin towns. Saidu Sharif is the administrative capital of Swat Division, and Mingora is the district headquarter and main bazar area. Both are located at an elevation of 990 masl. Mingora has been an important trading center for last 2,000 years. Its bazars are worth exploring for semi-precious stones, locally woven and embroidered cloth and tribal jewelry. At Saidu Sharif there is the Swat Museum where one can find the remains of Butkara Stupa, the Wali of Swat's palace, and the tome of the Akund of Swat. Marghazar is a small village at the top of Saidu Valley, 1,287 masl and 13 kilometers from Saidu Sharif. The Saidu stream cascades down off Mount Ilam.

At Manglaur, the first town north of Mingora, a metalled road leads off to the right (east), three kilometers to the Jahanabad Buddha and 30 kilometers to Malam Jabba. Miandam is a small summer resort ten kilometers up a steep side valley, and 56 kilometers from Saidu Sharif. Madyan and Bahrain are the popular tourist resort on the Swat River. Bahrain is located at ten kilometers north of Madyan at about 1,400 masl. The bazars of Bahrain, like those of Mingora, Khwazakhela and Madyan, are worth exploring for handicrafts.

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At Kalam, 29 kilometers from Bahrain, at about 2,000 masl, the valley opens out into a fertile little plain that was probably once the basin of an ancient lake. Just beyond Kalam is the junction of the Ushu and Utrot rivers, which together form the Swat. It is 16 kilometers up the Utrot River to Utrot village, which is about 2,200 masl. The Gabral Valley enters Utrot from the northwest. The Ushu Valley runs northeast from Kalam and offers magnificent views of Mount Falaksir. Lake Mahodand or the Lake of the Fish is about ten kilometers to the north.

The Swat valley is blocked by snow above Bahrain in winter, but in summer one can drive up beyond Kalam and from there trek north to either Chitral or Gilgit valley. Swat becomes more and more beautiful as one goes at the higher altitudes. From Khwazakhela the road across the Shangla Pass to the Karakoram Highway (www.geocities.com/swat_pakistan, www.travel-culture.com/pakistan/swat).

3.1.2 Chitral River Basin The river network drains the northwest Hindu Kush-mountains including the main Chitral Valley in the NWFP province of Pakistan. The Chitral River tributaries include Arkari River, Rich Gor River, Yar Khan River, and Mastuj River. The basin is bordered in the north and northwest by Afghanistan and in the east by the Gilgit River basin. The upper reaches of the river basin comprising the Hindu Kush-mountains are mainly covered with perennial snow and glaciers. The Chitral region of the Hindu Kush in Pakistan is one of the most isolated areas of the western end of the Himalayas, and is surrounded by high mountain passes. It is also one of extreme beauty. The remote human communities, which include the Kalash, live in narrow valleys dominated by mountain rivers and natural hazards, and prehistoric sites abound. Chitral's biodiversity is unique, and many of the passes are migration routes between central Asia and the Indian subcontinent. The main Chitral valley starts in the north east at an altitude of 3000 masl, and over a distance of 300 km it runs down to 2,000 masl in the SW. The valley is flanked by the High Hindu Kush in the northwest, with altitudes between 5,500 and 7,500 masl and in the southeast by the Hindu Raj, with altitudes up to 7,000 masl. North of Chitral town stands Tirich Mir - at 7,706 masl the highest peak in the Hindu Kush. About 34 % of the Chitral basin lies above 4500 masl (Kamp, 1999).

The Yarkhun River in the northeast joins the Laspur River further south near Mastuj to form the Mastuj River. The latter flows south to join the Lutkho River from the west. The Lutkho River is fed by the Tirich Mir glacier. The Mastuj and Lutkho rivers combine to form the Chitral River, which flows, through Chitral Town. At this stage the plain of the Chitral River is 4km wide with cultivated alluvial fans. As the Chitral River flows further south it becomes the Kunhar River and is joined by the Ayun River from the west, which in turn is fed by the narrow rivers of Rumbur, Bumburet and Birir valleys. The Ayun valley is famous for its fertile land and lush green vegetation. The Kunhar River winds its way west into Afghanistan where it joins the Kabul River and eventually re-enters Pakistan and joins the Indus River at the historic city of Attock.

The sediments of Chitral reflect a variety of sedimentation environments: glacial, glacio-fluvial, fluvial, lacustrine, Aeolian and gravitational. After accumulation, the erosion

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processes formed six types of terraces: morainic, glacio-fluvial, fluvial, lacustrine, debris and fan terraces. The most frequent type in Chitral is the alluvial fan terrace. A similar classification was also given by Owen (1988a, 1989) for the Karakoram in the east (Kamp, 1999). Huge morainic terraces can be found in Upper Chitral and upper Middle Chitral, testifying to former intense valley glaciations.

Agriculture is the main occupation of the Chitralis and irrigation is highly developed with gravity flow channels, sometimes referred to as "siphon irrigation". The winter crops are wheat and barley and the summer crops are maize and rice, with fruit and vegetable. Terracing on steep slopes is normally practiced with small water channels for irrigation. Any land which has less than 45 degrees angle is termed as level land in Chitral, and there is a major problem of soil erosion because of the steep slopes. Water also plays a vital role in the lives of the locals for example water grinding mills, Hydal power generators such as the new Reshun Hydro Power station and the number of mini-hydel power stations (www.gla.ac.uk/ibls/Biosed/linprnov).

3.1.3 Gilgit River Basin

The Gilgit River drains the parts of Hindu Kush and the Karakoram ranges in the northern territory of Pakistan. The river basin in the north is bordered with Afghanistan and China. The Gilgit River network comprises of the Ghizar, Yasin, Ishkuman and Hunza River and joins the Indus River near Jaglot (Figure 3.3). The upper reaches of the basin are mostly glaciated and covered with permanent snow.

(a) Yasin Valley in the Gilgit River basin (b) Naltar Lake, Naltar Valley

(c) Shandur Lake, Shandur Pass

(d) Naltar River, Naltar Valley

Figure 3.3: Lake and valleys of Gilgit River Basin.

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Gilgit has been inhabited for thousands of years by various invaders. From the 1st century Gilgit was like Kashgar, the trade center from all places as its now. From 4th century to 11th century AD, It was under Buddhism influence of Sogdiana dynasty, Kushans Hindu Shahis and later Islam introduce in this area. (www.hgp.com.pk/northpakistan)

3.1.4 Hunza River Basin

The Hunza River basin actually forms the sub basin of the Gilgit River but due to its considerable size and importance it is considered as a separate basin. The river drains the Karakoram Mountains comprising of large glaciated area in the north. The Karakoram highway linking Pakistan to China passes across this basin. Part of the road runs along Hunza River and ends near Kunjurab Pass (Figure 3.4).

The tributaries joining the Hunza River are Chabursan, Khunjerab, Ghujerab, and Shunsha River. The basin comprises of major valleys and hanging glaciers on the high Karakoram Range. Karimabad, the capital of the Hunza valley, is stretched over miles and miles of terraced fields and fruit orchards. It offers a panoramic view of the Rakaposhi, Ultar and Balimo peaks (www28.brinkster.com/pakistan4ever).

Nagar, the large kingdom across the river from Hunza, was possibly first settled by people from Baltistan who arrived over the mountains by walking along the Biafo and Hispar glaciers. It was settled again in about the 14th century by Hunzakuts who crossed the river. A man called Borosh from Hunza supposedly founded the first village of Boroshal, and married a Balti girl he found there. The legend says the girl and her grandmother were the sole survivors of a landslide that killed all the early Balti settlers.

Gulmit is shining white and deeply crevassed - just as you would expect a glacier to look. Above the glacier to the left is the jagged line of the Passu and Batura peaks, seven of which are over 7,500 masl. On the opposite side of the river, which can be crossed over a terrifying footbridge, the valley is hemmed in by a half-circle of saw-toothed summits, down the flanks of which slide gray alluvial fans. Passu is a village of farmers and mountain guides 15 kilometers beyond Gulmit. This is the setting-off point for climbing expeditions up the Batura, Passu, Kurk and Lupgar groups of peaks, and for trekking trips up the Shimshal Valley and Batura Glacier. The Passu village is the meeting place for mountaineers and guides (www.mountainleaders.com).

Today Hunza is progressing in education, agriculture, orchard, business, small industries automobile, wooden work, building construction, banking, women development programs, health programs, health units as well as first aid posts. In every village, embroidery, handicrafts, carpet industries, mining precious stones etc. has been promoted.

The actual changes started after 1978, when the Karakorum highway opened between China and Pakistan. The joint efforts of Aga Khan Network and Government of Pakistan, brought fruitful result to the lives of people of Hunza (www.hgp.com.pk/northpakistan).

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(a) Hunza River near Pasu from KKH

(b) Karimabad,Hunza Valley

(c) Suspension foot bridge on Hunza River

(d) Khunjerab Pass from Pakistan

(e) The beautiful Hunza Valley from HKH

Figure 3.4: Valleys of Hunza River Basin.

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3.1.5 Shigar River Basin

Shigar River is a small right bank tributary of the Indus River. This river rises from the Hispar glacier at the base of the Haramosh and Kanjut Sar peaks in Shigar valley. Thereafter it flows towards the southeast and joins the Indus at Skardu. The Shigar River drains parts of Haramosh range and Masherbrum range in the northeast of the country. The river fed by melting water of large glaciers, joins the main Indus River near Skardu. In the east of the basin there is a tributary named Bro River entering into the Shigar River.

An important tributary of the Shigar River rises from the Baltoro glacier at the base of the Masherbrum peak and flows westwards to join the main channel of the Shigar in its middle course. Thus the Shigar system drains the melt-waters of two of the most important glaciers of the Karakoram Range. This river descends along a very steep gradient. Its entire catchment has been influenced by the action of glaciers. The valley is deep in its upper reaches but widens near its mouth. A small river island has formed at the junction of the main stream with the tributary draining the Baltoro glacier. The catchment area of this river is virtually devoid of a vegetative cover due to its high altitude and scarcity of rainfall. Human habitation is sparse (www.mountainleaders.com).

Shigar Valley, 32 km from Skardu is watered by the Shigar River. It forms the gateway to the great mountain peaks of the Karakoram, including K-2. The valley has an extremely picturesque landscape, and abounds in fruit such as grapes, peaches, pears, walnuts and apricots. (www.mountainleaders.com). The valley is surrounded by snow-clad peaks and runs down from the north to join the Indus just above Skardu. Raja Fort, Mosque of Amburik and Khanqah-e-Shigar are the famous historical sites in Shigar. (www.baltistantours.com) The inhabitants of Shigar are the decedents of Kirgis, who migrated from China in the region of Yarkand, when it was possible to travel from Baltistan to the North of China as a Karavan via Sinkiang and Kashmir as a trade route. 3.1.6 Shyok River Basin

The Shyok River network drains large parts of glacier and snow covered mountains of the Karakoram Range in the northeast of the country. The river basin consists of some of the high mountain peaks of the Karakoram. This river crosses through parts of Laddak and the Karakoram ranges.

Shyok River is an important tributary of the Indus River in Ladakh (Figure 3.5). The main stream rises from the snowy wastes on the Despang plains in northern Ladakh, north of the Karakoram Range. The river flows westwards its initial stages, then turns southeast and makes a U-turn near Shyok to flow towards the northwest. It flows into the Indus about 40 km upstream of Skardu. Many tributaries join the Shyok River. Important amongst these are Chang Celmo, Chipshap, Galiwan, Chus, Nubra and Saltoro River. The Saltoro River is a tributary of the Hughe River which, in turn drains into the Shyok. It rises as two main streams from glaciers at the base of the Saltoro Kangri peak in Baltistan. The northwestern main stream flows southeast and then turns southwest to merge with the

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northeastern main stream flowing towards the northwest. The two main streams join together in the middle course of the river and the Saltoro flows for a short distance before draining into the Hushe River. The entire valley of the Saltoro River has been carved by the action of glaciers. Deposits of moraines brought down by ancient glaciers are found all along the river right from its origin to the mouth. Small tributary snow-fed streams empty themselves into the main river, usually from hanging valleys at different places. The discharge of this river increases in late summer when the snow on the high mountains melts at a very fast rate. The entire catchment area is devoid of a vegetative cover. Human habitation is virtually absent and the tract is bleak and desolate. (www.littletibet.org/rivers.htm) The beautiful Khaplu Valley of the Shyok River is 103 km from Skardu. This valley with lush green corn fields, located at 2,700 masl. There is a sprawling village perched on the slopes of the steep mountains that hem in the river. Khaplu is the gateway to Masharbrum Peak, K7, K6, Namika, Chogolisa for mountaineers and Gondogoro La, Gondogoro Peak, Saraksa glacier, Amin Peak Kanday, Thaley La, Daholi Lake, Kharfaq Lake, Ghangche Lake and Bara Lake for trekkers. Chaqchan Mosque Khaplu is a unique and beautiful historical mosque; founded by Syed Ali Shah Hamdani some 800 years back (www.mountainleaders.com).

(a) A Sunset on Chogoliza in Concordia

Figure 3. 5: Panoramic view of marvelous Concordia and Shyok River.

(b) Boating in Shyok River

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3.1.7 Indus River Basin

The river basin consists of part of the upper Indus basin other than the adjoining river basins mentioned above. The river system drains parts of Kohistan, Karakoram, and Central/High Himalayan ranges including Laddak and Deosai mountains. The river basin lies between Swat River on the west, Gilgit, Hunza on the north, Shigar, and Shyok River on the east and Shingo, Astor, and Jhelum River basins on the southeast side. The basin can be divided into sub-basins-Indus East and Indus West.

The major river of this basin-the Indus called “Senghe Chhu” (the Lion River) in Balti language. The main tributaries of this river in the Ladakh region are Hanle, Gurtang, Shingo and Shigar River. The Indus River flows northwest, dividing the Himalayas from the Karakoram, before being knocked south by the Hindu Kush. The KKH hugs the banks of the Indus for 310 kilometres of its climb north, winding around the foot of Nanga Parbat the western anchor of the Himalayas.

The Basin extends over an area of 11, 65,500 km2 and lies in Tibet (China), India, Pakistan and Afghanistan. The drainage area lying in India is 321,289 km2, which is nearly 9.8% of the total of the total geographical area of the country. The basin lies in the states of Jammu & Kashmir (193,762 km2), Himachal Pradesh (51,356 km2), Punjab (50,304 km2), Rajasthan (15,814km2), Haryana (9,939 km2) and Union Territory of Chandigarh (114 km2). The upper part of basin lying in Jammu and Kashmir and Himachal Pradesh is mostly comprised of mountain ranges and narrow valleys. In Punjab, Haryana and Rajasthan the basin consists of vast plains, which are fertile belt of the country. The principal soil types found in the basin are sub-montane, brown hill and alluvial soils (www.wrmin.nic.in/riverbasin/Indus)

Amidst landscape of towering mountains, deep gorges, crashing waterfalls and quiet lakes, Skardu, is situated on the banks of the mighty river Indus, just 8 km above its confluence with the river Shigar (Figure 3.6). Perched at a height of 2,286 masl, Skardu offers a cool and bracing climate. During the summer, Skardu attracts a large number of trekkers and mountaineers from all parts of the world. In fact, the entire region is known as a mountaineers' paradise. Hilal Bagh and Chahar Bagh-the royal garden covered the areas from Mindoq Khan to the present bazaar at Skardu where the newly constructed road crosses the channel. A palace built in marble with towers also stood in the middle of the garden, above the Polo Ground which is called Ghudi Changra. There is only one surviving Buddhist Rock with rock carvings in the Skardu Valley located on Satpara road. Probably the rock carvings and images of Buddha date back to the period of Great Tibetan Empire (www28.brinkster.com/pakistan4ever). About 8 km south of Skardu, lies the Satpara Lake. Surrounded by high glacial mountains, this lake has an island in the middle of its clear waters, which can be reached by boat. The lake is considered ideal for fishing (www.baltistantours.com).

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About 32 km from Skardu, lie the shimmering waters of the Kachura Lake. In the springtime its banks are adorned by a multitude of colorful flowers, while the trees are laden with peach, apricot and apple blossoms. The lake offers great opportunities for trout fishing.

(a) Indus River in Skardu

(b) Rope above Indus River for crossing

(c) Aerial view of Satpara Lake (d) Clear waters of Shingrela Lake

Figure 3.6: The mighty Indus River and gorgeous lakes of Indus River basin.

The total length of River Indus in Pakistan is 2,682 Km. The area of the drainage basin of the Indus is of the order of 9.7 x 105 km2 making it the 12th largest among the rivers of the world. Its deltaic area is 3 x 104 km2, ranking it 7th in the world. The annual water runoff is a little under 2 x 1011 m3 per year – placing it 10th, and its annual sediment discharge is 2 x 1011 kg per year – placing it 6th in the world (www.waterinfo.net.pk/pdf/indusbasin). The Indus originates in a spring called Singikahad near Mansarwar Lake. The spring is located on the northern side of Himalayan range in Kailas Parbat, Tibet. 3.1.8 Shingo River Basin

The Shingo River drains parts of High Himalayan range, including Laddakh - Deosai Mountains. There are small tributaries such as Sagad, Barwahi, Karapchu and Panultukish, Nullah joining the main Shingo River. The basin consists of Deosai plains

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stretched over a large area and numerous glacial lakes scattered at various places. Deosai Plateau, a treeless wilderness at 4,000 meters lies south of Satpara Lake. The Deosai Plains are 32 km south of Skardu. This plateau is the habitat of the greatly threatened Himalayan Brown Bear and many other wild animals. At an average elevation of 3,500 masl, Deosai is now a National Park and protected area for wildlife. The rolling grassland here supports no trees or shrubs and the area is snow covered for seven months of the year. Spring comes to Deosai in August when millions of wild flowers begin to bloom all over the lush green grassland. This is a time when Deosai looks like a paradise with a landscape full of wild flowers on green rolling hills and crystal clear water streams with snow covered peaks in the background.

3.1.9 Astor River Basin

The Astor River basin lies in the eastern side of the Nanga Parbat Mountain. The Astor River drains the snow and glacier covered mountains of Laddakh - Deosai and the High Himalayan range. The elevation of this basin ranges from 2,104 masl to 5,993 masl. Generally the western parts have higher elevation ranges than the eastern parts. Adjacent to the valleys, the slopes are steeper ranging from 20º to 60º (Figure 3.7). Furthermore, the steeper slopes are towards the northwestern part of the basin. The more prevalent slope ranges from <5º to 20º. The direction of surface slopes is shown in aspect map in Figure 3.8.

Astor River rises in a glacier on the north-facing slopes of the great Himalayan range near the Burzil Pass in the Laddakh region of Jammu and Kashmir. It flows in a northwesterly direction and joins the Indus River soon after it emerges from the main Himalayan gorge a little downstream of Bunji. This river drains the area lying to the east of Nanga Parbat. Many small snow-fed streams originating from different depressions on the great Himalayan range join the Astor River in its short course. Its catchment area consists of U-shaped valleys, glacial moraines, cirques and steep slopes. It is largely devoid of a vegetative cover (www.littletibet.org/rivers.) Astor Valley is situated at the back of Tatupani near Nanga Parbat peak and is prone to quakes. On Wednesday Nov 21, 2002, at 2.31am a strong earthquake, measuring 5.5 on the Richter scale, struck Astor Valley, 120 km south of Gilgit, killing 23 people, including 18 children. The quake also damaged about 60 houses in Mushkin, Hurcho and Dashkin areas of Astor valley, besides injuring over 100 people. The quake also caused landslides along the Karakoram Highway (KKH) at Tatupani. The damages to the glacial lakes, if any, are not reported. Rama Lake is a short walk from Astor and is fed by the Sachen Glacier. Surrounded by green meadows and snowcapped mountains, the lake offers superb reflections of cloud and surrounding peaks (www.geocities.com/altafjasminetours/itineries_for_jeep_safaris).

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Figure 3.7: Slope Map of Astor River basin.

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Figure 3.8: Aspect Map of Astor River basin.

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3.1.10 Jhelum River Basin

The Jhelum River basin lies on the south and south west of the Astor River basin which is in the south of Nanga Parbat range. The Jhelum is a large eastern tributary of the Indus. The River network drains parts of the Himalayan range extending into Kashmir valley towards the south. The main tributaries of the Jhelum River are Kunhar and Kishan Ganga rivers. It drains about 2,300 square miles of alluvial lands in the Kashmir Valley and gets water from various important sources including glaciers located in the north of the valley.

The river first flows through Dal Lake and then an even bigger lake - Wular Lake, into which it drops coarse grades of sediment. On emergence from the Wular Lake near Baramula at Domel, near Muzaffarabad, the river is joined by its largest tributary, Neelum (earlier called the Kishan Ganga), which drains hilly area lying on the eastern side of the Nanga Parbat. The Neelum drains Himalayan ranges that are perpetually covered by snow and glaciers. In the lower reaches the river flows through mountainous country covered by forests.

Five miles below the Domel, the Kunhar, another tributary, joins the River Jhelum, draining the famous Kaghan Valley. One of Kunar's tributaries also flows through the famous Saif-ul-Molook Lake (Figure 3.9).

From Domel to Mangla two streams, the Kanshi and Poonch join the River Jhelum. The Kanshi is a floodwater stream draining eroded areas of the Jhelum and Rawalpindi districts. This stream carries mainly monsoon rain or seepage water. The Poonch is an important stream joining the Jhelum at Tangrot, about seven miles above Mangla. The site where the two rivers meet used to be a famous fishing spot but now lies within the storage area of the Mangla Dam.

The Poonch drains the southern sides of Pir Panjal, which stays snow bound during winter. Its catchment area is partly covered by forests. The river flows through hilly country for its entire length and drains the areas of Poonch, Kotli and Mirpur. The discharge and sediment load of various tributaries of Jhelum River are presented in Table 3.1.

The Mangla Dam has been constructed near the head regulator of Upper Jhelum Canal. From Mangla down to Rasul, several floodwater streams drain into the Jhelum. The Jhelum River Basin comprises of some dense forest covers mainly due to the monsoonal effect in this area. The mountains, dales, lakes, water-falls, streams and glaciers of Kaghan Valley are still in unbelievable pristine state, and unspoiled paradise. The valley extends for 155 km. rising from an elevation of 2,134 masl to its highest point, the Babusar Pass, at 4,173 masl. Kaghan is at its best in the summer months (May to September). In May the maximum and minimum temperatures are 11 °C and the 3 °C respectively. From the middle of July up to the end of September, the road beyond Naran, snow-bound throughout the winter, is open right up to Babusar Pass. (www.littletibet.org/rivers.htm).

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Figure 3.9: View of Saiful Maluk lake and Kaghan valley.

Table 3.1: Important tributaries, their discharge and sediment load.

Tributary Discharge (MAF) Sediments (Acre-ft/year)

Neelum 6.1 5,224 Kunhar 2.0 2,861 Kanshi 0.36 293 Poonch 2.0 5,678 Kahan 0.037 425

3.2 CLIMATE

The Karakoram-Himalayan region lies in an environment that is glaciological complex with high altitude source areas (above 4,500 masl) having permafrost and annual precipitation in excess of 2,000 mm. Some of the large glacier snouts extend down to semi-arid valley floors (2,700 masl) with an annual precipitation of less than 100-200 mm. Table 3.2 indicates the monthly and annual rainfall recorded at various stations in the northern areas (NACS 2001). The maximum annual rainfall is received in Astor basin followed by Skardu. The areas towards the north receive less rain. In a study to see the correlation among climatic parameters and the potential for the floods (Awan 2002) it was concluded that at an elevation of about 3,000 m, solid and liquid precipitation are about equal over a year. Seasonal proportion of rainfall differs from Outer to Greater Himalayas, with 60% during the monsoon season on the windward outer Himalayas and 35% on the Greater Himalayas (windward). For the outer Himalayas, more rainfall is received on the leeward side, except during the Monsoon season, while on the windward side the precipitation decreases at elevations over 600 masl. In the middle Himalayas rainfall on the windward side increases with elevation up to a certain altitude (varying from 1600 masl to 2200 masl depending on season) and then decreases. Rainfall on the

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leeward side is lower and has a maximum at about the same elevation range as the windward side. Snowfall increases linearly with elevation on the windward side to a maximum of 950 mm at 2,500 masl, but on the leeward side it first increases and then

Table 3.2: Mean rainfall of selected locations of the Northern Areas (average of 1960-90).

Mean Rainfall (mm) Months

Astor Bunji Chilas Gilgit Gupis Skardu January 35.2 4.2 8.4 4.0 5.2 21.0 February 49.4 6.1 12.7 6.0 6.7 24.3 March 82.6 16.2 30.0 12.6 9.2 40.3 April 87.1 22.9 31.9 23.0 20.4 26.3 May 71.2 28.7 27.7 25.3 24.0 26.4 June 19.8 7.2 7.6 6.1 8.2 8.8 July 21.0 14.5 11.6 15.6 11.4 9.1 August 23.5 18.4 12.4 15.5 15.8 10.5 September 18.5 8.8 3.0 6.5 8.5 7.1 October 30.0 10.7 12.8 8.4 3.8 10.4 November 13.6 2.6 4.0 1.8 1.3 6.4 December 25.8 4.0 11.1 4.1 4.4 13.7 Annual 477.7 144.4 173.2 129.0 118.9 204.2

Source: Northern Area Conservation Strategy (NACS), 2001. decreases. Total precipitation is significantly less on the leeward side. Monthly, seasonal and annual totals and seasonal distribution at Gilgit, Gupis and Bunji are very similar. These stations also receive amounts very similar to Skardu and Chilas during the period from April to September, but Skardu and Chilas receive significantly greater rainfall during the winter months.

The Karakoram alpine glaciers are amongst the steepest in the world and they extend through a wide range of climatic environments. In this semi-arid environment, the summer temperature is frequently in excess of 25°C. Most of the precipitation is not derived from the Indian monsoon but from depressions moving in from the west during the spring and summer. However, occasional monsoon disturbances do succeed in extending sufficiently far north so as to enter the area. Under such circumstances the precipitation levels increases substantially.

The maximum normal temperature of 33.2 ° C is at Chilas whereas a temperature of 20.8 ° C is found at Astor (Table 3.3). The minimum normal temperatures at Astor and its nearby station Bunji is 2.8 ° C and 4.5 ° C respectively. The Gupis has the lowest

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minimum temperature of 0.91° C. The mean temperature in the Northern glacieated area of the country is shown in Figure 3.10.

Table 3.3: The minimum and maximum temperature of selected stations in northern areas of Pakistan

Temperature (°C) Location Minimum Maximum Gupis 0.91 22.55 Gilgit 6.00 27.30 Chilas 5.80 33.25 Bunji 4.55 30.75 Astore 2.83 20.88 Skardu 2.22

Figure 3.10: Mean Temperature of January in Northern Areas of Pakistan. Source: Pakistan Germany Technical Cooperation WAPDA/GTZ Kiel March 1996

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3.2.1 Altitudinal Zones in the Northern Mountain Region

The spectacular vertical relief of the Karakoram-high Himalayan range has resulted in well-defined altitudinal zones each with its characteristic microclimate, geological processes, geomorphic features, and landforms. Hewitt (1989) has delineated four altitudinal zones in this region.

Zone: I

This zone lies above 5,500 masl altitude with 90% of its area under snow. It contains active glaciers. Erosion and land degradation is mainly due to rock fracture from frost action and extreme variation in diurnal temperature. There are frequent avalanches and rock falls. The summits form the glacial divide with sharp ridges, horns, spires, and pinnacles.

Zone: II

This zone lies between 4,500 masl and 5,500 masl altitude. It comprises of high, alpine, humid tundra and includes the upper and middle ablation zones. It has a heavy snowfall period of 6-10 months and a shorter summer. Abundant mechanical weathering and rock fragmentation occur resulting in avalanches, rock falls, and debris flow.

Zone: III

This zone extends between 3,000 and 4,000 masl altitude and has sub alpine features with seasonal droughts, cold sub-humid winters, warm summers, rare grassy meadows, and clumps of alpine trees. Mechanical rock weathering and per glacial processes are common features with glacial ablation, snow melt runoff, glacial lakes, glacial debris, talus cones, rock falls, and land slides. Glaciers are located in this zone and they are covered with thick rock debris. Sharp narrow and transverse ridges and intervening valleys having wide U-shaped sections characterise this zone.

Zone: IV

It covers an area between 1,000 to 3,000 masl altitudes and is climatically arid to semi arid, with hot summers and frequent droughts. It is comprised of mountain valleys and basins, which are in a continuous state of degradation resulting from Para glacial, fluvial, and lakebed deposits. These deposits have formed along the wider stretches of valley flanks. The upper parts of the valleys exhibit U-shaped glaciated valley floor and glaciers descending from tributary valleys often have their snouts close to the confluence with main streams. In the lower reaches this zone contains abundant defiles, gorges, and canyons.

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3.2.2 Glacier’s Velocity and Fluctuations

Due to great thickness of ice, the deeper parts of the glaciers are at or close to 0° C and they behave like temperate glaciers. Owing to relatively high activity indices, these glaciers have a relatively high flow rates ranging from 100 to 1,000 m/yr (Goudie et al. 1984).Velocities of some of the selected glaciers of Karakoram are shown in Table 3.4. Historical record of glacier fluctuations in the Himalayas and the Karakoram indicate that in the late nineteenth and early twentieth centuries the glaciers were generally advancing followed by predominant retreat during 1910-1960 (Mason 1930 and 1935 and Goudie et al. 1984).

In the study of glacier behavior since 1812 A.D., Mayewski et al. (1980) found that the advancing glaciers flow most commonly eastward, southeastward, northeastward, and northward and that advance is rare in glaciers flowing south and west. High summer radiation and steep barren slopes control the glacier ablation patterns. The maximum radiation balance measured on Batura glacier was over 27.9 MWm-2 (Zhang Jinhua et al., 1980). It is estimated that melting accounts for 80% of the heat loss whereas only 20% is due to evaporation and convection (Goudie et al. 1984).

Table 3.4: Velocities of selected Karakoram glaciers.

Glaciers Velocity (m/yr) Glaciers Velocity (m/yr) Baltoro 300 Hasanabad 329-449 Batura 1,000 Kutiah 80-216 Biafo 19 Minapin 350-645 Chogglungma 296-366 Pasu 157 Fedehenko 169 Ghulkm 117

Zemu 84

Source: Wadia 1957 and Goudie et al. 1984

In a study, Hewitt (1998) observed in detail the behavior of glacier surges of Chiring glacier of Karakoram. Between 1994 and 1996 catastrophic movement of 16-km-long Chiring Glacier transferred 1-1.5 km3 of ice from its upper two thirds to its lower third, and into the main Panmah Glacier of which it is a tributary. By October 1996, a lobe of Chiring ice some 3.2 km2 in area had entered and compressed the main glacier, which was severely disturbed for 3 km above and 5 km below the junction of the glaciers. Ice streams and medial moraines were pushed into a series of looped or "tear-drop" forms, well-known in surging glaciers. Despite an observational record back to 1856, this type of glacier surge was not previously recognized. In the last 100 years, 26 sudden, rapid advances have been reported involving 17 glaciers (Hewitt, 1969).

3.2.3 Surges and Climate Change Five confirmed and three other possible tributary surges in Karakoram have occurred in the past decade. Whether this number is really exceptional or an artifact of improved observation, it raises important questions of interpreting glacier fluctuations and their normally sensitive response to climate change. The Karakoram is of unusual interest and perhaps sensitive to climate change, since its glaciers lie within the variable influence of

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three major weather systems: the sub-Mediterranean regime of mainly winter, westerly storms; the summer monsoon; and the Tibetan anticyclone. Winter storms dominate glacier nourishment at present. However, nearly one third of the high-elevation snow accumulation which has been measured occurs in summer (Hewitt, 1990). It has been argued that general patterns of advance and retreat in the region relate to changing vigor of the summer monsoon (Mayewski et al., 1980). The possibility of such large shifts in the atmospheric sources, regime, and seasonal occurrence of glacier nourishment, does not seem to be a factor in other regions with surging glaciers. This seems to be a further reason to give more attention to surging glaciers in a relatively neglected region. 3.3 HYDROLOGY

The Karakoram and Himalayan mountains form the main source of snow and ice melt runoff to the Indus River System. The precipitation enhancing and shadowing effects of the main mountain ranges provide dramatic contrasts that greatly complicate the hydrological picture. Snowmelt predominates the south of the Himalayan crest. The Indus and its tributaries form the main drainage in the Karakoram-High Himalayan region. East to west, its main tributaries are Shyok, Shigar, Hunza, Astor, Gilgit, Ishkuman, Yasin, Ghizer, Yarkhun, Rich Gol, Arkari, Kunar, Panjkora, and Swat rivers. The Astor River flows in the northwest direction and joins Indus River just north of Nanga Parbat range.

3.3.1 Runoff

The Pakistan Water and Power Development Authority (WAPDA) have gauged the flow of the upper Indus since the early 1960s, at a string of flood monitoring stations upstream of Terbela. The gauging station on the Indus River at Partab Bridge just below the confluence of the Gilgit River covers the runoff of 142,700 km2 catchment including the whole of the Karakoram mountains except for their NE slopes draining to the interior basins in western China. WAPDA also operates gauging stations on the upper Indus at Kachura near Skardu south of the central Karakoram; on the Shyok River, which drains the eastern Karakoram; on the Hunza River at Dainyor Bridge near Gilgit in the western Karakoram; and on the Gilgit River just downstream of its confluence with the Hunza.

The data of Table 3.5 show a marked spatial variation in the annual runoff and sediment yield. The Batura is the first of a series of large glacier-fed tributaries of the Hunza River, which increase its annual runoff from 320 mm above the Batura confluence of 5,000 km2

to a mean of 910 mm during 1966-79 near Gilgit (catchment 13,200 km2). The other gauged catchments in the Karakoram region have lesser percentages of permanent snow and ice cover and correspondingly lower annual runoff depths (Goudie et al. 1984). The monthly stream regimes throughout the Karakoram show very strong summer peaks attributing to glacier melt. Discharge decreases progressively throughout autumn and winter to a minimum in March, begins to rise with April snowmelt, but does not peak until July or August. A clear but considerably lagged diurnal cycle is interrupted by sharp recessions when snowfall or prolonged cloud cover halts glacier ablation. The general 20th century movements of the Karakoram glaciers must also have affected runoff but no attempt has been made to quantify this. The river flow is affected by the creation of major natural dams as a consequence of either glacial, mudflow or landslide blocking (Goudie et al. 1984).

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3.3.2 Sediment Yield

A considerable amount of the sediments carried by the Indus River is derived from glaciers or debris flow in the catchment. During the winter months, the Himalayan Rivers transport relatively fine suspended load. During this period there is little deposition of sediments on the flood plains. During the monsoon floods, large quantities of sediments are deposited on the flooded areas of the plain and vast tracts of land along the riverbeds. There are number of factors, which ensure that large quantities of material are delivered to the trunk stream for evacuation from the area. These include: (a) the glaciated nature of the catchment (b) the limited vegetation cover, (c) the steep relief, (d) the fractured and distorted nature of the bedrock, (e) the efficacy of frost and salt weathering, (f) the presence of an easily eroded store of Pleistocene debris, (g) the frequency and magnitude of landslides, mudflows, avalanches, etc. (Goudie et al. 1984).

Table 3.5: Annual runoff and suspended sediment load from Rivers of Karakoram Range.

Runoff Sediment load/yr S. No. River and site of

measurement RecordPeriod

Catchment area (km2) m3s-1 mm a-1 Mt t.km-2

1 Hunza (Dainvor Bridge) 1966-75 13,200 380 910 63 4800

2 Gi1git (Gilgit Town) 1963-72 12,100 280 740 14 1100

3 Gilgit (Alam Bridge) 1966-75 26,200 700 840 70 2700

4 Shyok (Yugo) 1973-75 3,3700 310 290 34 1000

5 Indus (Kachura) 1970-75 112,700 960 270 87 770

6 Indus (Partab Bridge) 1963-75 142,700 1760 390 160 1100Source: WAPDA 1976; converted to SI units

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Chapter 4 Materials and Methodology

The basic materials required for the compilation of an inventory of glaciers and glacial lakes are high quality topographic maps and remote-sensing data. The remote sensing data of land observation satellite Landsat-7 Enhanced Thematic Mapper Plus (ETM+) are used for the inventory of glaciers and glacial lakes and the identification of potentially dangerous glacial lakes. The combination of digital satellite data and the Digital Elevation Model (DEM) of the area are also used for better and more accurate results for the inventory of glaciers and glacial lakes (Figure 4.1).

Figure 4.1: Three dimensional view of the northern glaciated area of Pakistan. 4.1 TOPOGRAPHIC MAPS

The glaciers and glacial lakes are mostly concentrated in the north. The river basin boundary and spatial distribution of glaciers and glacial lakes were identified from the satellite images and supplemented with the available topographic maps at scales of 1:500,000, 1:250,000 and 1:50,000. The sheet numbers of topographic maps used for analysis of all the ten river basins are given in Table 4.1. The topographic maps are the map series of the 1960s published by the Survey of Pakistan. These topographic maps are based on aerial photographs, field surveys at various times, and verification through large-scale top sheets.

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The detail projection parameter of the map is not available and, on the other hand, the digital topographic map (ARC digitized Raster Graphics (ADRG) published in January 1996 by the National Imagery and Mapping Agency (NIMA) and Defense Mapping Agency (DMA) of the U.S. Government at the scale of 1:500,000 with detail projection parameter are used in the geo-reference of the satellite images (Figure 4.2).

Figure 4.2: Sub-set of a digital topographic map (ARC Digitized Raster Graphics) of the basins under

investigation published in January 1996 by NIMA and DMA of the U.S. Government.

Table 4.1: List of Topographic Maps used in the Study. Grid Map (NIMA)

1:500,000 scale

Longitude (Degree)

Latitude (Degree)

Map Sheet 1:250,000 scale

Map Sheet 1:50,000 scale

Go7a 74- 81 36-40 42L, P -

Go7d 74-81 32-36 43I, J, M, N; 52A, E 43 I/1, 5, 9

Go6b 67-74 36-40 42D, H 42D/4, 7, 8, 10, 11, 12, 14, 15, 16;

Go6c 67-74 32-36 38M, N; 43A, B, E,F

38 M/13, 14, 15, 16; 37 P/16; 38 N/11, 12, 14, 15, 16; 43 A/1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16; 43 B/1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16; 43 F/1, 2, 3, 4, 5, 6, 9, 10, 12, 13, 14;

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4.2 SATELLITE IMAGE

The remote sensing data of Landsat-7 ETM+ have been used for the inventory of glaciers and glacial lakes. The image data are in digital format and have a pixel size of 15m and 30m. Thirteen full or partial scenes of Landsat-7 ETM+ are required to cover the glaciated part of Northern Pakistan (Figure 4.3). For analysis of all the ten river basins, eleven scenes of Landsat-7 of period 2000 - 2001 were used in the ILWIS software (Table 4.2). The mosaic of Landsat-7 images covering the glaciated region of Pakistan is shown in Figure 4.4.

Figure 4.3: Index map of Landsat-7+ ETM scenes of northern Pakistan.

Table 4.2: The Details of Landsat-7 ETM+ Scenes (2000-2001). S. No. Path Row Date

1 148 035 21-07-2001 2 148 036 18-05-2001 3 149 034 30-09-2001 4 149 035 30-09-2001 5 149 036 30-09-2001 6 150 034 07-10-2001 7 150 035 07-10-2001 8 150 036 07-10-2001 9 151 034 28-09-2001

10 151 035 09-09-2000 11 151 036 28-09-2001

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4.3 INVENTORY METHOD

The methodology for mapping and inventory of the glaciers is based on instructions for compilation and assemblage of data for the World Glacier Inventory (WGI), developed by the Temporary Technical Secretary (TTS) at the Swiss Federal Institute of Technology, Zurich (Muller et al. 1977). The methodology for the inventory of glacial 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). The inventory of glaciers and glacial lakes has been systematically carried out for the drainage basins on the basis of topographic maps and satellite images. The following sections describe details of the methodologies used for inventory of both glaciers and glacial lakes.

4.3.1 Inventory of Glaciers

The glacier margins are delineated on the geo-referenced Landsat-7 ETM+ of panchromatic mode and compared with other individual bands as well as in different color composite bands, and the exact boundaries between glaciers and seasonal snow cover are delineated. The coding system is based on the subordinate relation and direction of river progression according to the World Glacier Inventory. The descriptions of attributes for the inventory of glaciers are given below.

Figure 4.4: Mosaic of Landsat-7 ETM+ images of the northern glaciated region of Pakistan.

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Numbering of Glaciers

The lettering and numbering start from the mouth of the major stream and proceed clockwise round the basin. The inventory of glaciers is carried out throughout the ten basins separately.

Registration of snow and ice masses

All perennial snow and ice masses are registered in the inventory. Measurements of glacier dimensions are made with respect to carefully delineated drainage area for each ‘ice stream’. Tributaries are included in main streams when they are not differentiated from one another. If no flow takes place between separate parts of a continuous ice mass, they are treated as separate units.

Delineation of visible ice, firn, and snow from rock and debris surfaces for an individual glacier does affect various inventory measurements. Marginal and terminal moraines are also included if they contain ice. The ‘inactive’ Ice apron, which is frequently found above the head of the Valley Glacier, is regarded as part of the Valley Glacier. Perennial snow patches of large enough size are also included in the inventory. Rock glaciers are included if there is evidence of large ice content.

SnowLine

In the present study, the snow line specially refers to the firn line of a glacier, not the equilibrium line. The elevation of the firn line of most glaciers was not measured directly but estimated by indirect methods. For the regular Valley and Cirque glaciers, from the topographical maps, Hoss’s method (i.e., studying changes in the shape of the contour lines from convex in the ablation area to concave in the accumulation area) was used to assess the snow line.

Accuracy Rating Table

The accuracy rating Table proposed by Muller et al. 1977 on the basis of actual measurements (Table 4.3) is used in the present study. For the snow line an error range of 50–100m in altitude is entered as an accuracy rating of ‘3’. In the glacier inventory, different methods or a combination of methods are usually chosen for comparison with satellite images in order to assess the elevation of the firn line for different forms of glacier.

Table 4.3: Accuracy rating adopted from Muller et al. 1977.

Index Area/length (%) Altitude (m) Depth (%) 1 2 3 4 5

0–5 5–10 10–15 15–25 >25

0–25 25–50

50–100 100–200

>200

0–5 5–10

10–20 20–30 >30

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Mean Glacier Thickness and Ice Reserves

The data based on different geophysical techniques available for the measurement of glacial ice thickness in the northern parts of Pakistan are available for only selected glaciers. Such information is not available for most of the glaciers in these areas. Measurements of glacial ice thickness in the Tianshan Mountains, China, show that the glacial thickness increases with the increase of its area (LIGG/WECS/NEA 1988). The relationship between ice thickness (H) and glacial area (F) was obtained there as:

H = –11.32 + 53.21 F0.3

This formula has been used to estimate the mean ice thickness of the glaciers. The ice reserves are estimated by mean ice thickness multiplied by the glacial area. Muller et al. 1977 roughly estimated the ice thickness values for Khumbu Valley using the relationship between glacier type, form, and area (Table 4.4). The same method was used by WECS to calculate the thickness values for Rolwaling Valley.

Table 4.4: Relationship between glacier type, form, area, and depth given by Muller et al. 1977.

Glacier type Form Area (km2) Depth (m) 1–10 50

10–20 70 20–50 100 Compound basin

50–100 120 1–5 30

5–10 60 10–20 80 20–50 120

Compound basins

50–100 120 1–5 40

5–10 75

Valley Glacier

Simple basins 10–20 100

0–1 20 1–2 30 2–5 50

5–10 90

Mountain Glacier

Cirque

10–20 120

According to Muller et al. 1977, the mean depth can be estimated with the appropriate model developed for each area by local investigators.

For example, the following model was used for the Swiss Alps:

where h is the mean depth, F is the total surface area, and a and b are arbitrary parameters that are empirically determined. The measured depth is shown on the data sheet only if

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the depths of large parts of the glacier bed are known from literature and field measurements. Area of the Glacier The area of the glacier is divided into accumulation area and ablation area (the area below the firn line). The area is given in square kilometers. The delineated glacier area is digitized in the ‘Integrated Land and Water Information Systems’ (ILWIS) format and the database is used to calculate the total area. Length of the glacier The length of the glacier is divided into three columns: total length, length of ablation, and the mean length. The total (maximum) length refers to the longest distance of the glacier along the centerline. The mean value of maximum lengths of glacier tributaries (or firn basins) is the mean length. Mean width The mean width is calculated by dividing the total area (km2) by the mean length (km). Orientation of the glacier The orientation of accumulation and ablation areas is represented in eight cardinal directions (N, NE, E, SE, S, SW, W, and NW). Some of the glaciers are capping just in the form of an apron on the peak, which is inert and sloping in all directions, and is represented as ‘open’. The orientations of both the areas (accumulation and ablation) are the same for most of the glaciers. Elevation of the Glacier Glacier elevation can be divided into highest elevation (the highest elevation of the crown of the glacier), mean elevation (the arithmetic mean value of the highest glacier elevation and the lowest glacier elevation), and lowest elevation. The glaciers identified and mapped in the satellite images are not mapped in the available topographic map and hence in this study the elevation of the glaciers is not considered. Morphological Classification The morphological matrix-type classification and description is used in the study. It was proposed by Muller et al. 1977 for the TTS to the WGI. Each glacier is coded as a six-digit number; the six digits being the vertical columns of Table 4.5. The individual numbers for each digit (horizontal row numbers) must be read on the left-hand side. This scheme is a simple key for the classification of all types of glaciers all over the world. Each glacier can be written as a six-digit number following Table 4.5. For example, ‘520110’ represents ‘5’ for a Valley Glacier in the primary classification, ‘2’ for compound basins in Digit 2, ‘0’ for normal or miscellaneous in frontal characteristics in Digit 3, ‘1’ for even or regular in longitudinal profile in Digit 4, ‘1’ for snow and/or drift

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snow in the major source of nourishment in Digit 5, and ‘0’ for uncertain tongue activity in Digit 6.

Table 4.5: Classification and description of glaciers.

Digit 1 Digit 2 Digit 3 Digit 4 Digit 5 Digit 6 Primary

classification Form Frontal characteristic

Longitudinal profile

Major source of nourishment

Activity of tongue

0 Uncertain or miscellaneous

Uncertain or miscellaneous

Normal or miscellaneous

Uncertain or miscellaneous

Uncertain or miscellaneous

Uncertain

1 Continental ice sheet

Compound basins

Piedmont Even: regular Snow and/or drift snow

Marked retreat

2 Ice field Compound basin

Expanded foot Hanging Avalanche and/or snow

Slight retreat

3 Ice cap Simple basin Lobed Cascading Superimposed ice

Stationary

4 Outlet glacier Cirque Calving Ice fall Slight advance

5 Valley Glacier Niche Confluent Interrupted Marked advance

6 Mountain Glacier Crater Possible surge

7 Glacieret and snow field

Ice apron Known surge

8 Ice shelf Group Oscillating 9 Rock glacier Remnant

The details for the glacier morphological code values according to TTS are explained below:

Digit 1. Primary Classification

0 Miscellaneous: Any not listed.

1 Continental ice sheet: Inundates areas of continental size.

2 Ice field: More or less horizontal ice mass of sheet or blanket type of a thickness not sufficient to obscure the sub-surface topography. It varies in size from features just larger than glacierets to those of continental size.

3 Ice cap: Dome-shaped ice mass with radial flow.

4 Outlet glacier: Drains an ice field or icecap, usually of Valley Glacier form; the catchment area may not be clearly delineated (Figure 4.5a).

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5 Valley Glacier: Flows down a valley; the catchment area is in most cases well defined.

6 Mountain Glacier: Any shape, sometimes similar to a Valley Glacier, but much smaller; frequently located in a Cirque or Niche.

7 Glacieret and snowfield: A glacieret is a small ice mass of indefinite shape in hollows, river beds, and on protected slopes developed from snow drifting, avalanching and/or especially heavy accumulation in certain years; usually no marked flow pattern is visible, no clear distinction from the snowfield is possible, and it exists for at least two consecutive summers.

8 Ice shelf: A floating ice sheet of considerable thickness attached to a coast, nourished by glacier(s), with snow accumulation on its surface or bottom freezing (Figure 4.5b).

9 Rock glacier: A glacier-shaped mass of angular rock either with interstitial ice, firn, and snow or covering the remnants of a glacier, moving slowly downslope. If in doubt about the ice content, the frequently present surface firn fields should be classified as ‘glacieret and snowfield’.

Fig. 4.5a: Outlet Figure 4.5b: Ice shelf

Figure 4.5: Primary Classification of glaciers.

Digit 2 Form

1 Compound basins: Two or more tributaries of a Valley Glacier, coalescing (Figure 4.6a)

2 Compound basin: Two or more accumulation basins feeding one glacier (Figure 4.6b)

3 Simple basin: Single accumulation area (Figure 4.6c).

4 Cirque: Occupies a separate, rounded, steep-walled recess on a mountain (Figure 4.6d)

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5 Niche: Small glacier formed in initially a V-shaped gully or depression on a mountain slope (Figure 4.6e)

6 Crater: Occurring in and /or on a volcanic crater

7 Ice apron: An irregular, usually thin ice mass plastered along a mountain slope

8 Group: A number of similar ice masses occurring in close proximity and too small to be assessed individually

9 Remnant: An inactive, usually small ice mass left by a receding glacier

Figure 4.6a: Compound basins Figure 4.6b Compound basin Figure 4.6c Simple basin

Figure 4.6d: Cirque Figure 4.6e: Niche

Figure 4.6: Different forms of glaciers.

Digit 3 Frontal Characteristics

1 Piedmont: Ice field formed on low land with the Lateral Moraine expansion of one or the coalescence of several glaciers (Figures 4.7a and b)

2 Expanded foot: Lobe or fan of ice formed where the lower portion of the glacier leaves the confining wall of a valley and extends on

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to a less restricted and more level surface. Lateral Moraine expansion markedly less than for Piedmont (Figure 4.7c)

3 Lobed: Tongue-like form of an ice field or Ice cap (see Figure 4.7d)

4 Calving: Terminus of glacier sufficiently extending into sea or occasionally lake water to produce icebergs

5 Confluent: Glaciers whose tongues come together and flow in parallel without coalescing (Figure 4.7e)

Figure 4.7a: Piedmont Figure 4.7b: Piedmont Figure 4.7c: Expanded

Figure 4.7d Lobed Figure 4.7e Confluent

Figure 4.7: Different frontal characteristics of glaciers.

Digit 4 Longitudinal Profile

1 Even /regular: Includes the regular or slightly irregular and stepped longitudinal profile.

2 Hanging: Perched on a steep mountain slope, or in some cases issuing from a steep hanging valley.

3 Cascading: Descending in a series of marked steps with some crevasses and seracs.

4 Ice fall: A glacier with a considerable drop in the longitudinal profile at one point causing a heavily broken surface.

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5 Interrupted: Glacier that breaks off over a cliff and reconstitutes below.

Digit 5 Major Source of Nourishment The sources of nourishment could be uncertain or miscellaneous (0), snow and/or drift snow (1), avalanche and/or snow (2), or superimposed ice (3) as indicated in Table 4.4. Digit 6 Activity of Tongue A simple-point qualitative statement regarding advance or retreat of the glacier tongue in recent years, if made for all glaciers on earth, would provide the most useful information. The assessment of an individual glacier (strongly or slightly advancing or retreating etc.) should be made in terms of the world picture and not just that of the local area. However, it seems very difficult to establish the quantitative basis for the assessment of the tongue activity. A change of frontal position of up to 20m per year might be classed as ‘slight’ advance or retreat. If the frontal change takes place at a greater rate it would be called ‘marked’. Very strong advances or surges might shift the glacier front by more than 500m per year. Digit 6 expresses qualitatively the annual tongue activity. If observations are not available on an annual basis then an average annual activity is given. Moraines: Two digits to be given. Digit 1: moraines in contact with present-day glacier. Digit 2: moraines further downstream.

0 no moraines 1 terminal moraine 2 Lateral Moraine and/or medial moraine 3 push moraine 4 combination of 1 and 2 5 combination of 1 and 3 6 combination of 2 and 3 7 combination of 1, 2, and 3 8 debris, uncertain if morainic 9 moraines, type uncertain or not listed.

Remarks: The remarks can, for instance, consist of the following information:

• Critical comments on any of the parameters listed on the data sheet (e.g., how close is the snow line to the firn line, comparison of the year concerned with other years).

• Special glacier types and glacier characteristics which, because of the nature of the classification scheme, are not described in sufficient detail (e.g., ‘melt structures’, glacier-dammed lakes).

• Additional parameters of special interest to the basins concerned (e.g., area of altitudinal zones, inclination, etc).

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• It is often useful to divide the snow line into several sections (because of different exposition or nourishment). In such cases, the snow line data of each section can be recorded separately.

• Literature on the glacier concerned. • Any other remarks

The inventory database form (see Annex) used for compilation of the inventory of glaciers includes map/satellite codes, aerial photographs, and basin numbers, as well as the glacier parameters described above. 4.3.2 Inventory of Glacial Lakes The glacial lakes on satellite image of Landsat-7ETM+ of panchromatic mode, other individual bands and different colour combinations are delineated and compared with other satellite images and data sources. The descriptions of attributes for the inventory of glacial lakes based on LIGG/WECS/NEA. 1988 and Mool et al. (2001a) are given below: Numbering of Glacial Lakes The glacial lakes in the river basin are identified and demarcated using the spectral and spatial characteristics of the image data supplemented with the topographic maps. The global climatic change during the first half of the twentieth century had a tremendous impact on the high mountainous glacial environment. Many of the big glaciers melted rapidly and gave birth to a large number of glacial lakes. Due to the faster rate of ice and snow melting, possibly caused by global warming, the accumulation of water in these lakes has been increasing rapidly. The isolated lakes above 3,500m are assumed to be the remnants of the glaciers left due to the retreat of the glaciers. The attributes used for the present inventory are similar to the lake inventories that were carried out in the Pumqu (Arun) and Poiqu (Bhote-SunKoshi) basins in Tibet-China (LIGG/WECS/NEA. 1988), Nepal, and Bhutan by ICIMOD in 2001. The numbering of the lakes starts from the outlet of the major stream and proceeds clockwise round the basin. Longitude and Latitude 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. Area The area of the glacial lake is determined from the digital database after digitization of the lake from the image data and topographic maps. Length The length is measured along the long axis of the lake, and represented in meter units.

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Width The width is normally calculated by dividing the area by the length of the lake, down to one decimal place in km units (100 m). Depth The depth is measured along the axis of the cross section of the lake. On the basis of the depth along the cross section, the average depth and maximum depth are estimated. The data are collected from literature, if available. Orientation The drainage direction of the glacial lake is specified as one of eight cardinal directions (N, NE, E, SE, S, SW, W, and NW). For a closed glacial lake, the orientation is specified according to the direction of its longer axis. Altitude The altitude is registered by the water surface level of the lake in masl. Classification of lakes Genetically glacial lakes can be divided into the following:

• Glacial erosion lakes, including Cirque lakes, Trough Valley lakes, and Erosion lakes

• Moraine Dammed lakes (also divided into neo End Moraine and paleo End Moraine lakes), including End Moraine lakes and Lateral Moraine lakes

• Blocking lakes formed through glaciers and other factors, including the main glacier blocking the branch valley, the glacier branch blocking the main valley, and the lakes formed through snow avalanche, collapse, and debris flow blockade

• Ice Surface and Sub-Glacial lakes

In the glacial lake inventory, End Moraine Dammed lakes, Lateral Moraine lakes, Trough Valley lakes, Glacial Erosion lakes, and Cirque lakes are represented by the letters M, L, V, E, and C respectively; B and S represent Blocking and Supraglacier lakes. Activity According to their stability, the glacial lakes are divided into three types: STable, Potentially Dangerus, and Outburst (when there have been previous bursts). The letters S, D, and O represent these types respectively.

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Types of Water Drainage Glacial lakes are divided into drained lakes and closed lakes according to the drainage condition. The former refers to lakes from which water flows to the river and joins the river system while in the latter, water does not flow into the river. Ds and Cs represent those two kinds of glacial lakes respectively. Chemical Properties This attribute is represented by the degree of mineralization of the water, mg l–1. Other Indices One important index for evaluating the stability of a glacial lake is its contact relation with the glacier. So an item of distance from the upper edge of the lake to the terminus of the glacier has been added and the code of the corresponding glacier registered. Since an End Moraine Dammed lake is related to its originating glacier, this index is only referred to End Moraine lakes. As not enough field data exist, the average depth of glacial lakes is difficult to establish in most cases. Based on field data, and as an indication only, the average depth of a glacial lake formed by different causes can be roughly estimated as follows: Cirque Lake, 10m; End Moraine Lake, 30m; Trough Valley Lake, 25m; Blocking lake and Glacier Erosion Lake, 40m; and Lateral Moraine Lake, 20m. The water reserves of different types of glacial lakes can be obtained by multiplying their average depth by their area (LIGG/WECS/NEA. 1988).

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Chapter 5 Spatial Data Input and Attribute Data Handling

One of the main objectives of the present study is to develop a digital database of glaciers and glacial lakes using GIS. A digital database is necessary for monitoring of glaciers and glacial lakes and to identify the potentially dangerous lakes. GIS is the most appropriate tool for spatial data input and attributes data handling. It is a computer-based system that provides the following four sets of capabilities to handle geo-referenced data (Arnoff 1989):

• data input, • data management (data storage and retrieval), • data manipulation and analysis, and • data output

Any spatial features of the earth’s surface are represented in GIS by the following:

• Area/polygons: features which occupy a certain area, e.g. glacier units, lake units, land-use units, geological units etc;

• Lines/segments: linear features, e.g. drainage lines, contour lines, boundaries of glaciers and lakes etc;

• Points: points define the discrete locations of geographic features, the areas of which are too small to illustrate as lines or polygons, e.g. mountain peaks or discrete elevation points, sampling points for field observations, identification points for polygon features, centers of glaciers and lakes etc. and attribute data refer to the properties of spatial entities.

The spatial entities described above can be represented in digital form by two data models: vector or raster models. In a vector model the position of each spatial feature is defined by a series of X and Y coordinates. Besides the location, the meaning of the feature is given by a ‘code’. In a raster model, spatial data are organized in grid cells or pixels, a term derived for a picture element. Pixels are the basic units for which information is explicitly recorded. Each pixel is assigned only one value. For the present study, Integrated Land and Water Information System (ILWIS) 3.1 for Windows is used for the spatial and attribute database development and analysis. ILWIS for Windows is an object oriented image processing and GIS setup. Analysis and modeling in a GIS requires input of relevant data. Delineation of all the glaciers and glacial lakes was done on the satellite images supplemented by the available topographic maps of scale 1:63,360 (one inch to one mile) and 1: 250,000 published by the Survey of Pakistan in 1960s to 70s. The detail projection parameter of the topographic maps published by the Survey of Pakistan is not available. The digital topographic map named ARC digitized Raster Graphics (ADRG) at the scale of 1:500,000 published in 1996 by

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NIMA and DMA of the U.S. Government has the projection parameter, which is shown in the Table 5.1.

Table 5.1: Coordinate system and map parameters of NIMA and DMA of the U.S. Government.

Name of the map ARC Digitized Raster Graphics (ADRG) Tactical Pilotage Chart (TPC)

Series ARC2

Item TPC XXG06B TPC XXG06C TPC XXG07A TPC XXG07D

Edition number 001 Publication date Tuesday January 09, 1996 Geographical area coverage:

Latitude

Longitude

32° 00’ N to 36° 00’ N 74° 00’ E to 81° 00’ E

Projection Geographical Lat/Lon Spheroid WGS84 Datum WGS84 Unit Degree decimal Pixel size 0.00051714 (1.86 sec)

For the uniformity with other regions and precise digitization, the projection parameter of NIMA map is converted to Transverse Mercator. The details of projection parameter given in Table 5.2 are used to geo-reference the satellite image. The digitization of the glaciers and glacial lakes was performed on geo-referenced satellite images. The details of the methodology for the delineation and attributes are given in Chapter 4.

This map projection defines the relationship between the map coordinates and the geographic coordinates (latitude and longitude). The most common method of entering spatial data is by manual digitization using a digitizer. For the current study, the data was entered mainly by on-screen digitization.

Table 5.2: Coordinate system used for the maps and satellite images. S No. Coordinate system

1 Projection Transverse Mercator 2 Ellipsoid WGS84 3 Datum WGS84 4 False easting 0 5 False northing 0 6 Central meridian 60° E 7 Central parallel 0° N 8 Scale factor 0.9996 metre

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It is always necessary to maintain the details, smoothness, and accuracy of the input spatial data of all the required information as in the maps of the given map scale. They are defined by the snap and tunnel tolerances in the system. The snap and tunnel tolerances in the system are defined by the extent of the minimum and maximum X and Y values. To increase the detail and accuracy, the coordinate systems with the required X and Y extents for each one degree area were created to digitize all the topographic maps. These sub-coordinate systems were very useful and made easy the input and handling of the data.

The segment code values are necessary for data retrieval and analysis in GIS. Therefore, after the delineation of the glaciers, glacial lakes, and ridges on the maps, the segments were digitized using the following codes:

1 = lake boundary 2 = glacier boundary 3 = ridge line 5 = basin or international boundary 10 = dry lake 11 = drainage line 12 = lake attached to glacier – common boundary 20 = rock glacier boundary only 23 = glacier attached to ridge line – common boundary 25 = glacier attached to basin boundary – common boundary

100 = tic points reference lines

All the polygons representing glaciers and glacial lakes are numbered as mentioned in Chapter 4. Points showing the location of glaciers and glacial lakes were digitized. They were used later for identification of the polygons of the glaciers and glacial lakes. After digitization, the segments were checked and the glaciers and glacial lakes were numbered using point identifiers.

In an object oriented GIS, polygon maps with identifier domains of the objects have a related attribute Table with the same domain. The domain defines the possible contents of a map, a Table, or a column in a Table (attribute). Some examples of ‘domain’ are class domain (a list of class names), value domain (measured, calculated, or interpolated values), image domain (reflectance values in a satellite image or scanned aerial photograph), identifier domain (a unique code for each item in the map), string domain (columns in a Table that contain text), bit domain (value 0 and 1), bool domain (yes or no) etc. An attribute Table is linked to a map through its domain. An attribute Table can only be linked to maps with a class or identifier domain. An attribute Table may contain several columns.

The required attributes of the glaciers and glacial lakes as explained in Chapter 4 were derived or entered in the attribute database in the GIS. Most of the attributes were derived from the topographic maps, satellite images, reports, etc. Attributes such as area, location (latitude, longitude), etc. were derived from the spatial database. If other necessary digital spatial data layers, such as digital elevation models (DEM), are available, it is possible to

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generate terrain parameters such as elevation, slope, length, etc. as measuring units for glaciers and glacial lakes. Other attributes, such as aspect, mean length, elevation, map code, name, etc. were manually entered in the attribute database. Additional attributes, such as mean elevation, volume, etc. were derived using logical calculations. For each basin, attribute Tables were developed for glaciers and glacial lakes. Some of the attributes were also derived from the results of an aggregation in the same Table or from another Table using the Table joining operations, such as glaciers associated with the glacial lakes, etc. The attribute database for glaciers and glacial lakes is given in the annexes.

The criteria for the identification of potentially dangerous glacial lakes are explained in Chapter 10. Using the logical calculation in the GIS, the potentially dangerous glacial lakes were determined. Traditionally to study the geomorphic characteristics of these potentially dangerous lakes, time-series’ of satellite image and topographic maps are used for the identification of potentially dangerous lakes. In the case of current study the time series data is not available so based on the available data the potentially dangerous lakes are identified.

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Chapter 6

Application of Remote Sensing Glaciers and glacial lakes are generally located in remote areas mainly in the high mountains, where access is through tough and difficult terrain. The study of glaciers and glacial lakes, as well as carrying out inventories and field investigations of glacial lake outburst floods (GLOFs) using conventional methods, require extensive time and resources together with undergoing hardship in the field. Creating inventories and monitoring of the glaciers, glacial lakes, and extent of GLOF impact downstream can be done quickly and correctly using satellite images and aerial photographs. Use of these images and photographs for an evaluation of the physical conditions of the area provides greater accuracy. The multistage-approach using remotely sensed data and field investigation increase the ability and accuracy of the work. Visual and digital image analysis techniques integrated with techniques of GIS are very useful for the study of glaciers, glacial lakes, and GLOFs. For the present inventory, satellite images of Landsat-7 ETM+ supplemented with relevant topographic maps were used to identify and demark the glaciers and glacial lakes. Remote sensing is the science and art of acquiring information (spectral, spatial, and temporal) about material objects, areas, or phenomena through the analysis of data acquired by a device from measurements made at a distance, without coming into physical contact with the objects, area, or phenomena under investigation. There are different types of commercial satellite data available. Generally high and medium digital data sets like of the Land Observation Satellite (Landsat)-5 Thematic Mapper (TM), Landsat-7 Enhanced Thematic Mapper (ETM +), Système Probatoire Pour l’Observation de la Terre (SPOT) Multi-Spectral (XS) and SPOT Panchromatic (PAN) are used for such studies. Some other data sets like the Indian Remote Sensing Satellite Series 1D (IRS 1D), (LISS)-3 can also be used. The Landsat-7 ETM+ 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 30 meters each for the six visible, near-infrared, and short-wave infrared bands, 60 meters for the thermal infrared band, and 15 meters for the panchromatic band (Table 6.1). The list of the Landsat-7 ETM+ images covering the study area is given in Chapter 4. A scene of a Landsat-7 data gives a synoptic view of an area of 183 km by 170 km of the earth’s surface sensed by the American Landsat satellite from an altitude of 705 km, sun-synchronous orbit at an inclination of 98.2 degrees, imaging the same 183 km swath of the earth's surface every 16 days. The Landsat-7 satellite carries the ETM+ sensor. The bandwidth of TM and ETM+ are slightly different ranging from the blue to far infrared wavelength (Table 6.1). The individual bands are Band 1 (0.45–0.52µm), Band 2 (0.53–0.60µm), Band 3 (0.62 –0.69µm), Band 4 (0.78–0.90µm), Band 5 (1.57–1.78µm), and Band 7 (2.10–2.35 µm) with the spatial resolution of 30m in the visible, near infrared and middle infrared bands, and Band 6 (10.45–11.66 µm) in the far infrared with low gain and

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high gain bands with 60m resolution. Band 1, 3, 5, and 6 are same in TM and ETM+. Band 2, 4, and 7 are slightly different and the visible panchromatic mode is only available in ETM+. Some of the potential applications of different spectral bands of Landsat TM and ETM+ are given in Table 6.2. Table 6.1: Some optical sensor system characteristics of Earth Resources’ Satellites

Satellite system Optical sensor system (Launch dates)

Landsat 4/5 MSS (1982 Landsat-4) (1985 Landsat-5)

Landsat 4/5 TM (1982 Landsat-4) (1984 Landsat-5) (1999 Landsat-7)

Landsat 7 ETM+

IRS-1C LISS-III (1995 IRS-1C) (1997 IRS-1D)

Sensor altitude Landsat 1,2,3 = 900 km Landsat 4, 5 = 705 km

705 km 705 km 817 km

Spatial resolution 80m 30m 15 m (pan) 30m 60m

24m

Temporal resolution (Revisit cycle in days)

16 16 16 24 (nadir)

Radiometric resolution (Bits per pixel)

6-bit (scaled to 7 or 8-bit during ground processing)

8-bit 8-bit 7-bit

Swath width 185 km Scene area = 185*170

185 km Scene area = 185*170

183 km 141 km 124*141 133*148

Off-nadir viewing capability for PAN mode for stereo image data acquisition (±26° off-nadir viewing)

IRS-1C PAN (6m resolution) (70 km swath) 0.50–0.70 µm (6-bit) 3 days revisit

Spectral resolution (Number of bands)

4

7

7 plus

4

The TM and ETM+ sensors greatly facilitate the multi-temporal data availability (repeated coverage of 16 days) for studying the temporal changes of glaciers, lakes, and other features. The Landsat-7 ETM+ sensor is a nadir-viewing, eight-band multi-spectral scanning radiometer that detects spectrally filtered radiation from several portions of the electromagnetic spectrum. The list of the Landsat-7 ETM images covering the study area is given in Chapter 4. The individual bands and sample of colour composite in Pan(R), 7(G) and 2(B) of subset of Landsat-7 ETM+ of a part of study area is shown in the Figure 6.1. The SPOT series of French satellites and recent series of IRS satellites have more advantages for the study of glaciers, glacial lakes, and GLOFs due to their stereo data acquisition capacity (±26° off-nadir viewing capability of the system) and higher spatial resolutions of 6 (IRS1C/IRSID PAN data) to 10m (SPOT PAN data). LISS3 sensors on board IRS1C/D satellites provide multi-spectral data collected in four bands of VNIR (visible and the near infrared) and SWIR (short wave infrared) regions

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(Tables 6.2 and 6.3). LISS3 images cover an area of 124 by 141 km for the VNIR bands (B2, B3, and B4) and 133 by 148 km for the SWIR band (B5) sensed from an altitude of 817 km (IRS1C) to 780 km (IRS1D) with repetitive coverage of 25 days. The spatial resolution of VNIR bands is 24m and that of SWIR is 71m. The spatial resolution of LISS3 of the IRS satellite series and XS of the SPOT satellite series are greater than that of Landsat TM. With a greater number of spectral bands and spatial resolution of 30 by 30m close to the former two data types, cloud free Landsat TM data are equally good for the inventory and evaluation of glaciers, glacial lakes, and GLOFs in the medium scale (1:100,000 to 1:25,000). One can compare the amount of detail in different images covering the same area. Table 6.2: Spectral band ranges (µm) used in TM on board Landsat-7 ETM+ sensor

system and their potential applications Band

number Band range (µm) Potential applications

1 0.45–0.52 Coastal water mapping; soil/vegetation differentiation; deciduous/coniferous differentiation (sensitive to chlorophyll concentration), etc

2 0.53–0.61 Green reflectance by healthy vegetation, etc 3 0.63–0.69 Chlorophyll absorption for plant species’ differentiation 4 0.78–0.90 Biomass surveys; water body delineation 5 1.55–1.75 Vegetation moisture measurement; snow/cloud differentiation; snow/ice

quality study 6 10.4–12.5 Plant heat stress management; other thermal mapping; soil moisture

discrimination 7 2.09–2.35 Hydro-thermal mapping; discrimination of mineral and rock types;

snow/cloud differentiation; snow/ice quality study Pan 0.52 – 0.90 General picture in gray scale

When electro-magnetic energy is incident on any given earth surface feature, three fundamental energy interactions with the feature are possible. Various fractions of energy incident on the element are reflected, absorbed, and/or transmitted. All components of incident, reflected, absorbed, and/or transmitted energy are a function of the wavelength. The proportions of energy reflected, absorbed, and transmitted vary for different earth features, depending on their material types and conditions. These differences permit us to distinguish different features on an image. Thus, two features may be distinguishable in one spectral range and may be very different on another wavelength band. Within the visible portion of the spectrum, these spectral variations result in the visual effect called colour. For example, blue objects reflect highly in the blue portion of the spectrum, likewise green reflects highly in the ‘green’ spectral region, and so on. Thus, the eye uses spectral variations in the magnitude of reflected energy to discriminate between various objects.

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Figure 6.1.a: Band 1 (0.45 – 0.52 µm)

Figure 6.1.b: Band 2 (0.53 – 0.61 µm)

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Figure 6.1.c: Band 3 (0.63 – 0.69 µm)

Figure 6.1.d: Band 4 (0.78 – 0.90 µm)

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Figure 6.1.e: Band 5 (1.55 – 1.75 µm)

Figure 6.1.f: Band 6a (10.4 – 12.5 µm) high gain

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Figure 6.1.g: Band 6b (10.4 – 12.5 µm) low gain

Figure 6.1.h: Band 7 (2.509– 2.35 µm)

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Figure 6.1.i: Panchromatic (0.52 – 0.90µm) band

Figure 6.1.j: Panchromatic (0.52-0.90 µm) band of Landsat-7 ETM+ images of 2001 showing a tributary glacier of complex valley glacier in Shigar basin

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Figure 6.1.k.: Panchromatic (0.52-0.90 µm) band of Landsat-7 ETM+ images of 2001 showing a portion of complex valley glacier in Shyok basin

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Table 6.3: Wavelength ranges of the optical sensor system of earth resources’

satellites Satellites systems

Optical sensor

system

Landsat 4/5

MSS

Landsat 4/5

TM

Landsat-7

ETM+

IRS-1C/1D

LISS-III

Blue 0.45–0.52 µm (B1) 0.45–0.52 µm (B1)

Green 0.50–0.60 µm (Ch1 or B4) 0.53–0.61 µm (B2) 0.53–0.61 µm

(B2) 0.52–0.59 µm (B2)

Red 0.60–0.70 µm (Ch2 or B5) 0.62–0.69 µm (B3) 0.63–0.69 µm

(B3) 0.62–0.68 µm (B3)

NIR 0.70–0.80 µm (Ch3 or B6) 0.78–0.90 µm (B4) 0.78–0.90 µm

(B4) 0.77–0.86 µm (B4)

NIR 0.80–1.10 µm (Ch4 or B7)

IIR 1.57–1.78 µm (B5) 1.55–1.75 µm (B5)

1.55–1.75 µm (B5)

IIR 2.10–2.35 µm (B7) 2.09–2.35 µm (B7)

IIR (MIR)

ThIR 10.45–11.66 µm (B6)

10.4–12.5 µm (B6)

Pan 0.52 – 0.90µm (panchromatic)

Figure 6.1.l: Subset and colour composite of bands Pan (R), 7(G), and 2(B) of Landsat-7 ETM+ image of the study area

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Satellite data are digital records of the spectral reflectance of the earth’s surface features. These digital values of spectral reflectance are used for image processing and image interpretations. A graph of the spectral reflectance of an object as a function of wavelength is called a spectral reflectance curve. The configuration of spectral reflectance curves provides insight into the characteristics of an object and has a strong influence on the choice of wavelength region(s) in which remote-sensing data are acquired for a particular application. Figure 6.2 shows the typical spectral reflectance curves for three basic types of earth feature: green vegetation, soil, and water. The lines in this figure represent average reflectance curves compiled by measuring large sample features. It should be noted how distinctive the curves are for each feature. In general, the configuration of these curves is an indicator of the type and condition of the features to which they apply. Although the reflectance of individual features may vary considerably above and below the average, these curves demonstrate some fundamental points concerning spectral reflectance. When more than two wavelengths are involved, the plots in multi-dimensional space tend to increase the separability among different materials.

Spectral reflectance curves for vegetation almost always manifest the ‘peak-and-valley’ configuration (Figure 6.2). Valleys in the different parts of the spectral reflectance curve are the result of the absorption of energy due to plants, leaves, pigments, and chlorophyll content at 0.45 and 0.67 µm wavelength bands and water content at 1.4, 1.9, and 2.7 µm wavelength bands. In near infrared spectrum wavelength bands ranging from about 0.7–1.3 µm, plants reflect 40–50% of energy incident upon them. Different plant species reflect differently in different portions of wavelength. The soil curve in Figure 6.2 shows considerably less peak-and-valley variation in reflectance. This is because the factors that influence soil reflectance act over less specific spectral bands. Some of the factors affecting soil reflectance are moisture content, soil texture (proportion of sand, silt, and clay), surface roughness, presence of iron oxide, and

Figure 6.2: Typical spectral reflectance curves for vegetation, soil, and water (after Swain and Davis 1979)

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organic matter content. These factors are complex, variable, and inter-related. For example, the presence of moisture in soil will decrease its reflectance. As with vegetation, this effect is greatest in the water absorption bands at about 1.4, 1.9, and 2.7 µm. When considering the spectral reflectance of water, probably the most distinctive characteristic is the energy absorption at near infrared wavelengths. Water absorbs energy in these wavelengths, whether considering water features per se (such as lakes and streams) or water contained in vegetation or soil. Locating and delineating water bodies with remote-sensing data are carried out easily in near infrared wavelengths because of this absorption property. However, various conditions of water bodies manifest themselves primarily in visible wavelengths. Clear water absorbs relatively little energy with wavelengths of less than about 0.6 µm. High transmittance typifies these wavelengths with a maximum in the blue-green 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. This is true in the case of water bodies in the same geographic area. Spectral reflectance increases as the turbidity of water increases. Likewise, the reflectance of water depends on the concentration of chlorophyll. Increases in chlorophyll concentration tend to decrease water reflectance in blue wavelengths and increase it in green wavelengths. Many important water characteristics, such as dissolved oxygen concentration, pH, and salt concentration, cannot be observed directly through changes in water reflectance. However, such parameters sometimes correlate with observed reflectance. In short, there are many complex inter-relationships between the spectral reflectance of water and its particular characteristics. One must use appropriate reference data to correctly interpret reflectance measurements made over water. Snow and ice are the frozen state of water. Early work with satellite data indicated that snow and ice could not be reliably mapped because of the similarity in spectral response between snow and clouds due to limitations in the then available data set. Today satellite remote sensing systems’ data are available in more spectral bands (e.g., Landsat bands). It is now possible to differentiate snow and cloud easily in the middle infrared portion of the spectrum, particularly in the 1.55–1.75 µm and 2.10–2.35 µm wavelength bands (bands 5 and band 7). The reflectance of snow is generally very high in the visible portions and decreases throughout the reflective infrared portions of the spectrum. The reflectance of old snow and ice is always lower than that of fresh snow and clean/fresh glacier in all the visible and reflective infrared portions of the spectrum. Compared to clean glacier and snow (fresh as well as old), debris covered glacier and very old/dirty snow have much lower reflectance in the visible portions of the spectrum and higher in the middle infrared portions of spectrum (Figure 6.3).

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The technique of digital image analysis facilitates image enhancement and spectral classification of the ground features and, hence, greatly helps in the study of glaciers and glacial lakes. Monitoring of the lakes and glaciers can be done visually as well as digitally. In both the visual interpretation and digital feature extraction techniques, the analyst’s experience and adequate field knowledge are necessary. The satellite images have to be geometrically rectified based on the appropriate geo-reference system and cell sizes. The same geo-reference system is required for the integration and analysis of the remote sensing satellite data in the GIS database.

Figure 6.3: Spectral reflectance characteristics of snow/ice, clean glaciers, debris-covered glaciers, clouds, and water bodies. Reflectance in terms of pixel value based on a September 22, 1992, Landsat TM seven-band data set of the Tama Koshi and Dudh Koshi areas of Nepal. Red lines—clean glaciers and fresh snow (A); black lines—clouds (B); green lines—recent debris from GLOFs (C); maroon lines—debris covered glacier (D); blue lines—clean/melted (E) and silty and/or partly frozen water (lake) (F)

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To identify the individual glaciers and glacial lakes, different image enhancement techniques are useful. However, complemented by the visual interpretation method (visual pattern recognition), with the knowledge and experience of the terrain conditions, glacier and glacial lake inventories and monitoring can be done. For glacier and glacial lake identification from satellite images, the images should be with least snow cover and cloud free. Least snow cover in the Himalayas occurs generally in the summer season (May–September). But during this season, monsoon clouds will block the views. If snow precipitation is late in the year, winter images are also suitable except for the problem of long relief shadows in the high mountain regions. For the present study, most of the images are of the winter season under conditions of least seasonal snow cover and cloud free. With different spectral band combinations in False Colour Composite (FCC) and in individual spectral bands, glaciers and glacial lakes can be identified and studied using the knowledge of image interpretation keys: colour, tone, texture, pattern, association, shape, shadow, etc. Combinations of different bands can be used to prepare FCC. Different colour composite images highlight different land-cover features. Colours in the colour composite images and tones in the individual band images are the outcome of the reflectance values. Glaciers appear white (in individual bands and colour composite) to light blue (in colour composite only) of variable sizes, with linear and regular shape having fine to medium texture, whereas, in the thermal band, they appear gray to black (Figure 6.1 f and g).

Figure 6.4: False Colour Composite (FCC) of Red(4) Green(3) Blue(2) Indicating; Fresh Snow (A), Glacier Ice (B), and Glacier Ice Covered with Debris (C). Subset of Landsat-7 ETM+ Images of the of the study area

A

C

B

FCC R4G3B2

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The distinct linear and dendritic pattern associated with slopes and valley floors of the high mountains covered with seasonal snow can be distinguished in the river basin. Bands 5 and band 8 show drainage pattern and topographic features distinctly. Band 1 shows the clear demarcation between fresh snow and the surroundings. In false color composite of 4(R)3(G)2(B) the fresh snow appearing in white (A) can be differentiated from the glacier ice (B) in light blue. The glacier ice mixed with debris (C) is appearing dark due to low radiation reflectance of the debris material (Figure 6.4). The glacial lake is not prominent in this FCC 432 while in FCC 543 the lake can be identified easily in dark blue color and some of the glacial types can even be demarked (Figure 6.5).

The Valley Glacier with mixed ice and debris (Figure 6.5 C) resembles in color with the surrounding rocks and soil. The debris cover of the glacier can be differentiated on the basis of its coarse texture and presence of supraglacial lakes over it.

The reddish color in the FCC 543 represents the non-glaciated area i.e. indicating portions of rocks, bare ground and vegetation cover in reddish green as shown in figure 6.5 D. The water bodies like lakes in blue color can be differentiated from the shadow areas appearing black in this band combination. The mountain peaks/ ridges like Ghur and tango towers can be identified on the basis of associated shadow pattern giving idea of the elevation from the ground surface.

The physical features of the glaciated area and types of glacier can be displayed distinctly using the suitable band combination. In figure 6.6, the valley and mountain glaciers appearing in light blue color can be differentiated on the basis of their physical characteristics and association with their surrounding. The eroded surface developed from the retreat of the glacier is shown in parallel pattern (Figure 6.6 C) of left over moraine/debris material by the glacier. The glacial lake like the end moraine dammed lake, developed at the terminus of the glacier Ind_gr 707 can be seen in dark blue color (Figure 6.6 D).

The Galcial lakes can be easily identified in the band combination of RGB Pan,7,6b due to their better contrast with the surrounding features (Figure 6.7). In this FCC, the fresh snow and ice of the glaciers appear in light to dark red color. The lake Shin_gl 75 shown in figure 6.7 is a large cirque type lake having closed drainage. In the image of winter season the glacial lakes can be identified on the basis of their smooth texture and varying gray tone due to their semi frozen ice surface (Figure 6.8).

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Figure 6.5: Image in false color composite of Red (5),Green (4), and Blue (3) Indicating; Fresh Snow (A),

Glacier Ice and snow mixed with debris (B), Glacial lakes (C) and Pastures (D).

Figure 6.6: FCC of R5G4B3 Image Indicating Valley Glacier (A), Hanging Glacier (B), Eroded surface

containing rock debris (C) and Glacial Lake (D). Subset of Landsat-7 ETM+ Image of the Indus River basin (30th September 2001)

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Figure 6.7: Glacial lake Shin_gl 75 in False Color Composite of R(Pan) G(7) B(6b). Landsat-7 ETM+ Image of the Shingo River basin (30th September 2001)

In panchromatic image, the glaciers can be well identified by increasing the reflectance values of the image. This is especially helpful when one is using the image of winter season for the inventory of glaciers and glacial lakes.

Figure 6.8: Panchromatic band of Landsat-7 ETM+ image of 30th September 2001 showing

the Lake Shin_gl 75 under snow cover.

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The technique of integrating remote sensing data with GIS does help a lot with identification and monitoring of lakes and glaciers. The DEM of an area can be generated by using stereo satellite images, aerial photographs, or digitization of topographic map data. It can play a major role in deciding the rules for discrimination of features and land cover types in GIS techniques and help in better perspective viewing and presentations. DEM itself can be used to create various data sets of the area like slope and aspect as indicated in Chapter 3. For example, even though glacial lakes are covered by snow, the lake surfaces are flat, and glaciers, snow, and ice create slope angles. In this case, decision rules for integrated analysis in GIS can be assigned, that is, if the slope is not too pronounced and the texture smooth, then such areas are recognized as frozen glacial lakes. DEM generated from satellite images, aerial photographs, or topographic maps should be compatible with and of reliable quality to other data sets.

Figure 6.9: FCC of R5G4B3 Image Indicating Valley Glacier (A), Hanging Glacier (B), and Glacial Lake (C)

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Figure 6.10: Image in false color composite of Red (Pan),Green (7), and Blue (6b)

Figure 6.11: False Color Composite of Red (5) Green (4) Blue (2)

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Figure 6.12: Landsat ETM+ Image of 30 September 2001 of Part of the of the study area in False Colour Composite of Red(Pan) Green(7) Blue(6b)

Figure 6.13: False Colour Composite of Red(Pan) Green(7) Blue(6b) Indicating; (A) Supraglacial Lakes, (B) Blocked Lake, (C) Valley Glacier with Debris Cover, and (D) Fresh Snow

FCC R(Pan)G(7)B(6b)

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Figure 6.14: DEM based on SRTM3 and GTPO of Northern Pakistan and surrounding area

Figure 6.15: GeoCover Landsat TM draped over DEM based on SRTM3 and GTPO of Northern Pakistan and surrounding area

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Chapter 7 Inventory of Glaciers

7.1 BRIEF DESCRIPTION OF GLACIER INVENTORY

The inventory of glaciers based on topographic maps and satellite images. As the scale of the topographic maps is 1: 250,000 and not all topographic maps are available for the northern areas, for the identification, classification, and characterization of glaciers, satellite images were studied closely. The source of the topographic maps is the Survey of Pakistan. The images of Landsat-7 ETM+ were geo-referenced using digital topographic maps at a scale of 1: 500,000 published by NIMA and DMA of the US Government in January 1996. All the projection parameters of the topographic maps were incorporated to make the image compatible with the topographic maps.

For the inventory of glaciers, the northern area is divided into 10 river basins, (Figure 3.1). The aerial extension of the glaciers is determined by using remote sensing satellite image and Geographic Information System (GIS). To estimate the ice reserves, it is of an utmost necessity to have the mean thickness of the glaciers. Since the mean glacier thickness data are not available, it has been estimated using the equation developed for the Tianshan Mountains (Chaohai Liu and Liangfu Ding 1986) and applied in Nepal and Bhutan (Mool et al., 2001).

H = –11.32 + 53.21F 0.3

Where, H = mean ice thickness in meter and F = area of glacier in square kilometer The ice reserves were estimated by multiplying the mean thickness by the area of the glacier. 7.2 TYPES OF GLACIER The classification of glaciers is adopted from the morphological classification of glaciers by the World Glacier Monitoring Service (WGMS) defined by Muller et al. 1977. Details of the classification parameters are mentioned in Chapter 4. The glaciers are divided into different classes, combining Digit 1 of ‘primary classification’ and Digit 2 of ‘form’. Generally, six types of glacier are observed in HKH region of Pakistan namely Mountain, Valley, Cirque, Niche, Ice caps, and Ice aprons. Mountain glaciers are the dominant ones and by profile due to steepness of the slope, they are of hanging nature. Other glaciers, except for Valley glaciers, generally fall into the category of Mountain glaciers but the thickness of ice is comparatively low. The number of Valley glaciers is comparatively low but the corresponding area and ice reserves are higher than those of Mountain glaciers. The area and ice reserves of the Valley glaciers are generally large owing to the fact that the ice thickness increases with increase in the area of the glacier.

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The Mountain glaciers are uncertain or miscellaneous, compound basins, compound basin, or simple basin in the form of a hanging glacier. The Mountain glaciers sometimes join with the Valley glaciers and make a big mass of ice (Figure 7.1 and 7.2). The major source of nourishment is snow and/or drift snow. Ice caps, Cirque, Niche, and Ice apron type glaciers are other types of hanging Mountain glaciers, but they are considered to be of a different type due to their significance in size, shape, form, and ice thickness.

The most significant Valley type glaciers are fewer in number and are characterized by compound basins, compound basin, and simple basin. They are mainly nourished by snow and drift snow at the headwater and by snow and ice avalanches at the lower valley. The adjoining part of the Valley glacier at the headwater is characteristically a Mountain glacier, but due to its continuation into a Valley glacier, the whole ice mass will be considered as a Valley glacier. This is the reason for higher area of Valley glaciers than that of the Mountain glaciers. The longitudinal profile of the Valley glacier from crown to toe shows an even or regular shape. As the headwater is steeper and has a gentle slope in the lower reaches, the profile makes the curve concave upward. Due to the gentle slope at the lower reaches and the accumulation of debris derived from the headwater, the glacial lakes develop in the form of supra glacial or moraine dammed. Generally, the stability of glacial lakes is poor and there is always the chance of avalanches from Mountain glaciers, which may break the damming material and cause GLOFs.

7.3 GENERAL CHARACTERISTICS OF GLACIATION The occurrence of glaciers has always been linked to climatic conditions. Climate is of fundamental importance to the inception and growth of glaciers. The form of the landscape dictates the threshold conditions for glacier occurrence and determines glacier morphology. Under certain climatic conditions for glaciation, glaciers of different shapes

Figure 7.1: An example of Mountain glaciers entering into Valley glaciers in Shimshal valley of Hunza River basin (FCC 7(R)4(G)2(B)).

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and sizes are formed depending on the landscape. Mountain glaciated regions are associated with climatic fronts and zones of maximum precipitation. The Central Himalayas receive moisture from the summer monsoons and the western Himalayas from winter and summer fronts.

(a) Bazhin Glacier, Nanga Parbat (b) Ghondogoro Glacier

(c) A beautiful Lake in the middle of Biafo Glacier (d) Hopper Glacier Valley

(e) Passu Glacier (f) Out of this world, Baltoro Glacier

Figure 7.2: Few glimpses of huge glaciers of Pakistan. Source: (www.geocities.com/Pentagon/Barracks/9722/Mountains/index.htm)

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7.4 GLACIERS OF PAKISTAN IN HKH REGION

The glacier area of northern Pakistan forms the single most concentrated source of runoff for the whole Indus basin. Since this frozen precipitation contributes more than 50% of the total flow of the Indus River System and a larger part of the future supplies upon which Pakistan can depend, knowledge of this resource would seem an outstanding requirement for water resource and flood hazard monitoring on the Indus basin. Wissman (1959) has estimated that 33,200 km2 of the Himalayan range and 16,000 km2 of the Karakoram Range are covered with ice, which constitutes 17% of the Himalayas and 37% of the Karakoram respectively. In the 1940s estimates were made for the Sutlej River basin and a total ice cover of 6,390 km2 was computed. This area is roughly 11% of the total area of the Sutlej River basin (Khan 1994).

Crests of the high ranges in the Karakoram–Himalayan region are largely snow bound. The Karakoram has greater ice and snow cover (27 to 37%) than any other mountain system outside the polar region (Wissman 1959). In Hindu Kush, western Karakoram and High Himalaya, ice and snow cover is relatively less extensive, and in other ranges west of Nanga Parbat only the highest peaks are snow bound. Snow line is at about 5,200 masl to 5,800 masl along the northern aspects of the High Himalaya. It is at 5,100 masl to 5,600 masl in southern Karakoram and 4,700 masl to 5,300 masl in the northern part of the Karakoram (Kick 1964).

The glaciers in Karakoram region are high activity glaciers and have some of the steepest gradients in the world. According to their movement patterns, Mercer (1975) has grouped Karakoram and Himalayan glaciers into the following three categories:

• Glaciers with steady movement (these are also the longer ones) • Glaciers having cyclic advances (these have short steep crevasses) • Surging glaciers characterized by catastrophic advances

During most of the summer season, high flows in the Indus River system are due to snow and ice melt. Evidence over the past 150 years indicates that the snow and ice cover of the upper Indus River basin undergoes large spatial as well as temporal variations. Many minor ice masses are important to village water supplies in the region and the threat to these masses is creating acute water shortages. Knowledge of glacier storage and transfer of ice down slope and area altitude relations of ice cover are integral parts of the water balance. Knowledge of glacier activity is also required, in relation to glacier hazards such as ice dams and surges. To systematically identify and make an inventory of different types of glaciers and to estimate the ice reserves in the HKH region of Pakistan, the northern area is divided into 10 river basins. As a first step, the Astor River basin was selected and a detailed inventory was carried out. In the second phase of the project Indus, Jhelum, Shingo, Shyok, and Shigar River basins were selected and the inventory of glaciers was completed. In the final phase of the phase of the project, inventory the remaining four basins namely Swat, Chitral, Gilgit and Hunza was completed. The basin-wise outcome of this inventory is summarized here.

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7.4.1 Swat River basin Swat River with many other major tributaries like Panjkora River joins Kabul River which is the western tributary of Indus River. The northern and north eastern part of basin has the glaciated area. The Basin is located in the northern areas with the latitude and longitude range of 34º 06' to 35º 53' and 71º to 72º 48' respectively (Figure 7.4.1.1). This basin is bounded in southwest by Afghanistan, northwest by Chitral River basin, north by Gilgit River basins and east and southeast by Indus River basin. In the south of the basin, Peshawar Valley is located. The northern part of the basin has mountainous terrain with an elevation range of about 750 masl to more than 5,800 masl. The basin occupies an area of 14,656.2 sq. km out of which the glacier area is about 223.55 sq. km (Table 7.4.1.1). The distribution of different types of glaciers is presented in Figure 7.4.1.2 and 7.4.1.3. Most of the glaciers (about 90%) are classified as Mountain glaciers including the Cirque, Ice cap, Niche, and Ice apron (sub types). These sub-types are based on the characteristics of position, thickness of the ice, topographical locations, etc. Among these sub types the maximum number is of Mountain type (47%) followed by Cirque and Niche (21.5% each), and Ice apron (8%). Only about two percent of glaciers are classified as Ice caps. Generally the Valley glaciers are large in size and length. In spite of having only about 10 percent share in total number, they cover an area of about 71 sq. km, which is about 32% of the total glacier area. The largest and smallest glacier of this category has an area of about 8 and 0.44 sq. km respectively. The Mountain glaciers are generally small in size even though some of these glaciers are of large size. These glaciers altogether contribute 47 % of the total glacier area. Among the specialized Mountain glaciers, the Niche glaciers are relatively larger in size and cover an area of 25.53 sq. km. The Ice caps are the smallest glaciers and contribute only 0.48% of the area. Clips of some of the typical Mountain and Valley glaciers of this basin are presented in Figure 7.4.1.4.

Table 7.4.1.1: Details of various types of glaciers of Swat River basin

Number Area (km2) Length (m) Ice reserve (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total %

Cirque 45 19.3 0.06 1.25 14.78 6.6 278 1806 34855 0.455 3.7 Ice apron 16 6.9 0.09 0.89 5.86 2.6 532 2109 15776 0.176 1.4 Ice cap 5 2.1 0.15 0.28 1.07 0.5 301 640 2408 0.024 0.2 Mountain 99 42.5 0.12 5.69 105.32 47.1 326 3873 141689 5.45 44.6 Niche 45 19.3 0.10 4.99 25.53 11.4 487 3347 57274 1.118 9.1 Valley 23 9.9 0.44 8.02 70.99 31.8 948 6731 77834 4.998 40.9

Total 233 223.55 12.221

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Figure 7.4.1.1: Location map of the Swat River basin.

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The total 233 glaciers of the Swat River basin contribute 12.22 km3 of ice reserves. The Mountain glaciers contribute about 45% to the ice reserves followed by about 41 percent contribution by Valley glaciers. Rest 14 percent ice reserves are contributed by Mountain sub-type glaciers (Figure 7.4.1.5). Most of the Valley glaciers are concentrated only in the northern aspects of this basin. There are altogether 23 Valley glaciers and the largest (Swat_gr 216) and smallest (Swat_gr 30) glaciers have the area of 8.02 and 0.44 sq. km respectively. There are eight Valley glaciers which have area of more than 4 sq. km. Six of this type of glaciers has area less than 1 sq. km out of which three are less than half a sq. kilometer in size. Among the Niche glaciers there is high variability in size ranging from about 5 sq. km (Swat_gr 108) to about 0.1 sq. km (Swat_gr 161). Out of 99 Mountain glaciers, 66 have area less than 1 sq. km while only two glaciers are more than 5 sq. km in size. All the Ice apron type Mountain glaciers have area less than 1 sq. km. There is only one Cirque glacier (Swat_gr 169) which has area more than 1 sq. km. The details of each glacier of Swat River basin are given in the Annex_gr_7.1.

Ice cap 2%

Ice apron 7%

Cirque 19%

Valley 10%

Niche 19%

Mountain 43%

Niche 11%

Mountain 47%

Ice apron 3%

Cirque 7%Valley

32%

(a) Number percentage (b) Area percentage

Figure 7.4.1.2: Distribution of different types of glaciers in Swat River basin.

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Figure 7.4.1.3: The glacier distribution in the Swat River basin.

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(a) Few of the Mountain glaciers in FCC Pan(R)7(G)6b(B)

(b) Few scattered glaciers and lakes in the basin

(c) A Valley glacier (Swat_gr 54) draining into the lakes Figure 7.4.1.4: Typical glaciers in the Swat River basin.

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The glaciers in Swat River basin are classified into various ordinal directions. Table 7.4.1.2 includes the details of the distribution of glaciers in different ordinal directions. Aspect-wise, generally the glaciers are distributed evenly in all the different directions except east. About 16% glaciers are oriented towards NW and 15% in SW. The distribution in W, SE and S is about the same (12%) while in N and NE directions the glacier number is also same (about 13%). The glacier area follows the same pattern i.e. maximum in NW and minimum in E. The smallest and largest glacier does not follow the pattern of glacier number and total glacier area while the total length of the glaciers and ice reserves follow the pattern.

Table 7.4.1.3 and Figure 7.4.1.5 show the distribution of various types of glaciers in different ordinal directions. The Mountain glaciers are more on northern and western aspects while the southern and eastern aspects have the minimum number. Out of 23 Valley glaciers there are 8 glaciers on N and 4 each on NE and NW aspects followed by 2 each on SE and W. There are no glaciers present on S and E aspects. The Ice cap glaciers are present only on S and SW aspects. Similarly the Ice apron glaciers are missing on southern aspect. Out of total 16 glaciers of this type 4 are present on NW, 3 each on NE and SW and 2 each on N and W. Maximum Cirque glaciers (12) are oriented towards SE while the minimum (2 each) are orientated towards E and NW. The Niche glaciers are mostly oriented toward NE, SW and NW.

Table 7.4.1.2: Distribution of glaciers under different aspects in Swat River basin

Number Area (Km2) Length (m) Ice reserve (Km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 32 13.7 0.06 5.7 26.82 12.00 278 4097 42255 1.39 11.4 NE 31 13.3 0.09 8.02 33.90 15.2 300 5439 51131 1.922 15.7 E 13 5.6 0.08 1.76 6.01 2.7 403 1816 14004 0.223 1.8 SE 28 12.0 0.08 7.55 28.99 13.0 316 6731 42614 1.744 14.3 S 27 11.6 0.08 5.69 24.69 11.0 301 3509 33346 1.365 11.2 SW 35 15.0 0.09 4.69 33.87 15.2 326 4895 51029 1.803 14.7 W 29 12.4 0.17 3.67 26.99 12.1 552 3926 41852 1.341 11.0 NW 38 16.31 0.12 5.15 42.28 19.0 344 4290 53605 2.433 19.9 Total 233 223.55 12.221

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Table 7.4.1.3 : Distribution of glacier types on different aspects in Swat River basin

Glacier Types Aspect Mountai

n Valley Ice cap Ice apron Cirque Niche Total

N 13 8 - 2 5 4 32 NE 12 4 - 3 4 8 31 E 5 - - 1 2 5 13 SE 11 2 - 1 12 2 28 S 8 - 3 - 9 7 27 SW 14 3 2 3 5 8 35 W 16 2 - 2 6 3 29 NW 20 4 - 4 2 8 38 Total 99 23 5 16 45 45 233

Valley 41%

Niche 9%

Ice apron 1%

Cirque 4%

Mountain 45%

Figure 7.4.1.5: Ice reserves of different types of glaciers in Swat River basin.

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7.4.2 Chitral River basin

The major tributaries of Chitral River are Lutkha, Rich Gor, Yar Khan and Mastuj. Rich Gor and Mastuj join at Kosht and flows down to Birmogh Lasht town where it joins Lutkha to form Chitral River. The Chitral River first flow southwards and then turns southwest near Darosh and enters into Afghanistan near Arandu. Most of the northern and northeastern part of the basin is glaciated. The Basin is located in the northern areas with the latitude and longitude range of 35º 13' to 36º 54' and 71º 12' to 73º 53' respectively (Figure 7.4.2.1). The basin is bounded in west and north by Afghanistan, in the east by Gilgit River basin and southeast by Swat River basin. The major part of the basin consists of mountainous terrain with an elevation range of about 1,300 masl to more than 7,500 masl close to Tirich Mir the highest peak of the basin in the northwest.

(a) Mountain glacier (b) Valley Glacier

S8%

SW14%

W16%

SE11%

E5%

NE12%

N13%

NW21%

NW17% W

9%

SW13% SE

9%

N35%

NE17%

(c) Ice cap glaciers (d) Ice apron glaciers

SW40%

S60%

SW19%

W13%

NW24%

N13% NE

19%

E6% SE

6%

(e) Cirque glaciers (f) Niche glaciers

S20%

SW11%

W13%

NW4%

N11% NE

9%

E4%

SE28%

SW18%

W7%

NW18%

N9%

NE17%

E11% SE

4% S

16%

Figure 7.4.1.6: Distribution of different types of glaciers with respect to aspect in Swat River basin.

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Figure 7.4.2.1: Location map of Chitral River basin.

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The basin occupies an area of 15,322.4 sq. km out of which the glacier area is about 1,903.7 sq. km (Table 7.4.2.1). The distribution of different types of glaciers is presented in Figure 7.4.2.2 and 7.4.2.3. Most of the glaciers (77%) are classified as Mountain glaciers including the sub types like Ice cap, Cirque, Niche, and Ice apron. Among these sub types the maximum number is of Niche type (36%) followed by Mountain (31%) and Cirque (29%). There are only 2 Ice apron glaciers. Out of 542 glaciers, 125 are classified as Valley glaciers. The inventory of glaciers is given in the Annex_gr_7.2.

Generally the Valley glaciers are large in size and length and contribute about 81% to the glacier area of the basin owing to the fact that the smallest and largest glaciers of this category are of largest size among all the categories. The largest (Chiantar--Chitr_gr 316) and smallest (Chitr_gr 20) Valley glacier have an area of 231.6 and 0.09 sq. km respectively. There are quite a few large size Valley glaciers e.g. three glaciers (Chitr_gr 316, 129 and 140) have area more than 120 sq. km while two (Chitr_gr 177 and 169) have area more than 50 sq. km (Annex_gr_7.2). There are 22 Valley glaciers having less than one sq. km area.

Table 7.4.2.1: Details of various types of glaciers of Chitral River basin

Number Area (km2) Length (m) Ice reserve (km3)Type

Total % Smallest Largest Total % Min. Max. Total Total %

Cirque 123 22.7 0.04 1.96 49.48 2.6 144 3665 127432 1.728 0.67 Ice apron 2 0.4 0.30 0.63 0.93 0.0 760 1282 2042 0.030 0.01 Ice cap 12 2.2 0.07 1.24 3.87 0.2 349 1943 8203 0.124 0.05 Mountain 130 24.0 0.10 26.56 224.84 11.8 316 8079 268662 15.368 5.94 Niche 150 27.7 0.07 2.26 77.02 4.0 512 3451 233997 2.819 1.09 Valley 125 23.1 0.09 231.57 1547.53 81.3 570 33755 775724 238.748 92.25

Total 542 1903.67 258.817

Mountain 24%

Ice cap 2%

Cirque 23%

Niche 28%

Valley 23%

Cirque 3%

Mountain 12%

Niche 4%

Valley 81%

(a) Number percentage (b) Area percentage

Figure 7.4.2.2: Distribution of different types of glaciers in Chitral River basin.

107

Figure 7.4.2.3: The glacier distribution in Chitral River basin.

108

Generally the Mountain glaciers are smaller in size and altogether contribute 19% of the total glacier area. Among these glaciers 28% Niche, 24% Mountain and 23% Cirque contribute to total glacier area only 4, 11 and 3 percent respectively. Mostly the Niche glaciers are small in size since out of total of 150 glaciers of this type only 18 have an area of more than one sq. km. The largest Niche glacier (Chitr_gr 468) has an area of 2.26 sq. km while the smallest is 0.074 sq. km in size. The Mountain glaciers are relatively larger in size since the largest (Chitr_gr 209) and smallest (Chitr_gr 76) glaciers have area of more than 26.56 and 0.1 sq. km respectively. Some of the image clips of Mountain and Valley glaciers are presented in Figure 7.4.2.4. The one Ice cap glacier (Chitr_gr 324) is large in size having an area of 1.24 sq. km. The two Ice apron glaciers contribute less than one sq. km of the glacier area. A total of 123 Cirque glaciers contribute 2.6% of the total glacier area. Among these 11 glaciers have an area more than 1 sq. km.

(a) A big Valley glacier “Chiantar” (Chitr_gr 316) covering an area of 231.5 sq. km, draining into Yarkhun River.

(b) Two valley glaciers Risht (Upper) and Madit (Lower side).

(c) Most of large valley glaciers have their snouts close to the Yarkhun River

Figure 7.4.2.4: Typical large size glaciers in Chitral River basin, in FCC Pan(R)7(G)6b(B).

109

The total 542 glaciers of Chitral River basin are the good source of ice reserves of about 259 km3. The Valley glaciers contribute more than 92% to the ice reserves of the basin while rest is contributed by the Mountain type glaciers (Figure 7.4.2.5). Out of 8% remaining ice reserves, the subtypes of Mountain glaciers contribute very little (less than 2%).

Cirque 1%

Niche 1%

Mountain 6%

Valley 92%

Figure 7.4.2.5: Ice reserves of different types of glaciers in Chitral River basin.

Table 7.4.2.2 includes the details of glaciers in different ordinal directions. Aspect-wise, most of the glaciers are oriented towards N and NW (20% each) followed by NE and SW (15 and 11% respectively). The eastern aspect has the lowest number (5%) of glaciers. More than 57 percent of the glaciated area is concentrated on the northern aspects due to large size glaciers. The W, SW and S aspects have the lowest glacier area due to high sunshine hours while SE aspect has 20% contribution to the glacier area of the basin. The total length of the glaciers is highest on NW, N and SE aspects.

Table 7.4.2.2: Distribution of glaciers under different aspects in Chitral River basin

Number Area (Km2) Length (m) Ice reserve (Km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total %

N 111 20.5 0.04 53.64 349.71 18.4 317 16210 265604 32.871 12.7NE 84 15.5 0.05 56.59 179.79 9.4 344 15649 167944 39.923 15.4E 28 5.2 0.06 134.85 179.42 9.4 409 21753 87000 20.981 8.1SE 66 12.2 0.1 120.50 377.25 19.8 144 22336 232937 93.269 36.0S 42 7.7 0.11 26.56 120.20 6.3 448 8079 109042 10.695 4.1SW 59 10.9 0.05 16.46 75.80 4.0 306 10176 106003 52.375 20.2W 44 8.1 0.18 16.44 49.59 2.6 703 6824 81913 5.380 2.1NW 108 19.9 0.06 231.57 571.91 30.0 197 33755 365617 3.323 1.3Total 542 1903.67 258.817

110

The major ice reserves are on SE (36%) followed by SW (20%), NE (15%) and N (13%). The lowest ice reserves are on W and NW (2 and 1% respectively).

Table 7.4.2.3 shows the distribution of various types of glaciers in different ordinal directions. The Mountain glaciers are more (22 each) on SE and SW aspects while the W and E have the minimum number. Out of 125 Valley glaciers there are 47 glaciers on NW and 35 on N followed by 14 on SE. The E and SW have only 4 and 3 Valley glaciers respectively. The Ice cap type Mountain glaciers are missing on E and W. Out of total of 12 glaciers of this type 4 are oriented towards S, 2 each on NE, SE and SW (Figure 7.4.2.6). There is only one glacier each on N and NW. There are only 2 Ice apron type glaciers one oriented towards N and one towards SE. Out of 123 Cirque type glaciers maximum (71) are oriented towards northern aspects followed by southern aspects (32). Niche glaciers follow the distribution pattern of Cirque glaciers.

Table 7.4.2.3: Distribution of glacier types on different aspects in Chitral River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 19 35 1 1 29 26 111 NE 18 8 2 - 28 28 84 E 6 4 - - 9 9 28 SE 22 14 2 1 12 15 66 S 15 8 4 - 9 6 42 SW 22 3 2 - 11 21 59 W 8 6 - - 11 19 44 NW 20 47 1 - 14 26 108 Total 130 125 12 2 123 150 542

111

7.4.3 Gilgit River basin In this basin, Ghizar River in the west flows eastwards and joins Yasin River coming from the north near Gupis. Further in the east Ishkuman and Hunza Rivers join this river and form Gilgit River which flow southeast wards and join Indus River near Jaglot. In the west of the basin is Chitral River basin. A small portion in the northern boarder with Afghanistan, in the east by Hunza River basin and south by Indus and Swat River basins. The Basin is located in the northern areas with the latitude and longitude range of 35º 49' to 36º 54' and 72º 30' to 74º 45' respectively (Figure 7.4.3.1). The mountainous terrain is dominant with an elevation range of about 1,500 masl to more than 6,500 masl. The basin occupies an area of 14,082.4 sq. km out of which the glacier area is about 968 sq. km

(a) Mountain glacier (b) Valley Glacier

NW15%

N15%

NE14%

E5% SE

16%

W6%

SW17% S

12%

NW39%

SW2%

W5%

S6%

SE11%

E3%

NE6%

N28%

(c) Ice cap glaciers (d) Ice apronglaciers

S33%

SE17%

NE17%

N8%

NW8% SW

17%

SE50%

N50%

(e) Cirque glaciers (f) Niche glaciers

S7%

SW9%

W9%

NW11%

N24%

NE23% E

7% SE

10%

SW14%

W13%

NW17%

N17%

NE19%

E6% SE

10% S

4%

Figure 7.4.2.6: Distribution of different types of glaciers with respect to aspect in Chitral River basin.

112

Figure 7.4.3.1: Location map of the Gilgit River basin.

113

(Table 7.4.3.1). The distribution of different types of glaciers is presented in Figure 7.4.3.2 and 7.4.3.3. In this basin a total of 585 glaciers are identified covering an area of about 968 sq. km. Most of the glaciers (93%) are classified as Mountain glaciers including the Ice cap, Cirque, Niche, and Ice apron (sub types). Among these sub types the maximum number is of Mountain type (47%) followed by Niche (24%), Cirque (12%) and Ice apron(9%). Only 6 glaciers are classified as Ice caps.

Generally the Valley glaciers are large in size and length. In spite of having only about 7 percent share in total number, they cover an area of about 454 sq. km, which is about 47% of the total glacier area. The largest glacier (Karambar- Gil_gr 529) and smallest glacier (Gil_gr 172) of this category has an area of 63.32 and 0.97 sq. km respectively. Few of the important glaciers are shown in Figure 7.4.3.4. Except the smallest glacier of this category, all have the area more than one sq. km.There are total of 12 Valley glaciers having area more than 10 sq. km (Annex_gr_7.3). Some of the important large size Valley glaciers of this basin include Hinacna (Gil_gr 578), Salili (Gil_gr 581), Chhateboi (Gil_gr 487), Pekin (Gil_gr 479), etc. The Mountain glaciers are smaller in size and altogether contribute 53% of the total glacier area. Among these Mountain glaciers have the maximum coverage (41%) followed by Niche (7%). The Ice caps are the smallest glaciers and contribute only 1.26 sq. km to the glacier area. The largest Mountain glacier (Gil_gr 304) and smallest (Gil_gr 50) have area of 13 and 0.067 sq. km respectively. Some of the important Mountain glaciers of this basin are Kerum Bar (Gil_gr 294), Dadaril (Gil_gr 137), Ghasho Bar (Gil_gr 277), Thish Bar (Gil_gr 114), Ochhono (Gil_gr 155), etc. The largest Niche glacier (Chllinji_Gil_gr 515) has an area of 7.56 sq. km. There are 97 glaciers of this type which have area ranging from 0.1 to 0.5. Generally Ice capand Ice apron glaciers are small in size. There are only two Ice apron type glaciers ((Gil_gr 554 and Gil_gr 546) which have an area of more than one sq. km. Out of total 68 Cirque glaciers only five have the area exceeding one sq. km.

Table 7.4.3.1 : Details of various types of glaciers of Gilgit River basin

Number Area (km2) Length (m) Ice reserve (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total %

Cirque 68 11.6 0.06 2.81 27.71 2.9 270 3386 71572 1.022 1.23Ice apron 55 9.4 0.05 1.46 15.99 1.6 187 2542 48867 0.480 0.58Ice cap 6 1.0 0.11 0.40 1.26 0.1 271 883 3300 0.031 0.04Mountain 276 47.2 0.07 12.98 399.42 41.3 126 6806 543284 23.673 28.40Niche 140 23.9 0.08 7.56 69.56 7.2 147 9228 232329 2.944 3.53Valley 40 6.8 0.97 63.32 454.16 46.9 2055 19231 286098 55.195 66.22

Total 585 968.10 83.345

114

Due to high number of Mountain glaciers the total length is also higher for this category. The Valley glaciers are generally longer glaciers having total length of 286 km with a minimum and maximum length of 2.1 and 19 km respectively. Mountain glaciers have a total length of about 543 km followed by Niche having total length of 232 km. The other subtypes of Mountain glaciers are relatively smaller in length.

The total ice reserves of 83 km3 of Gilgit River basin are contributed by 585 glaciers of

the basin. The Valley glaciers contribute about 66% to the ice reserves of the basin while rest is contributed by the Mountain type glaciers (Figure 7.4.3.5). Following the Valley glaciers, Mountain glaciers contribute the maximum ice reserves (28%) due to their higher number as well as area. The contribution of Ice apron and Ice cap glaciers in the total Ice reserves is very low.

Valley 7%Niche

24%

Mountain 47%

Cirque 12% Ice apron

9%Ice cap

1%

Valley 47%

Cirque 3%

Ice apron 2%

Mountain 41%

Niche 7%

(a) Number percentage (b) Area percentage

Figure 7.4.3.2: Distribution of different types of glaciers in Gilgit River basin.

Table 7.4.3.2: Distribution of glaciers under different aspects in Gilgit River basin

Number Area (Km2) Length (m) Ice reserve (km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 74 12.6 0.1 38.1 158.28 16.3 270 15507 173882 13.807 16.6NE 127 21.7 0.07 5.49 95.85 9.9 147 6291 196843 4.547 5.4E 77 13.2 0.07 12.46 104.82 10.8 271 11116 152137 7.382 8.9SE 52 8.9 0.06 12.98 50.33 5.2 328 5463 85559 3.079 3.7S 62 10.6 0.1 51.26 153.82 15.9 301 16833 151462 15.47 18.5SW 63 10.8 0.08 41.9 100.88 10.4 241 14446 132536 9.727 11.7W 48 8.2 0.08 63.32 180.86 18.7 400 19231 146961 21.183 25.4NW 82 14.0 0.05 13.19 123.26 12.7 126 8325 146070 8.15 9.8Total 585 968.1 83.345

115

Figure 7.4.3.3: The glacier distribution in the Gilgit River basin.

116

(a) Ochhono glacier (Gil_gr 155) draining into a large glacial lake

(b) Large size Mountain glacier (Gil_gr 289) entering into a Valley glacier (Gil_gr 288)

(c) Valley glaciers (Mushk Bar Gil_gr 283 and Ghalsapar Gil_gr 284)

(d) Karambar a large size Valley glacier having an area of 63.3 sq. km.

Figure 7.4.3.4: Clips of various large size Valley and Mountain glaciers in Gilgit River basin.

Table 7.4.3.2 includes the details of the glaciers in different ordinal directions. Aspect-wise, most of the glaciers are oriented towards NE (22%) and NW (14%) followed by E and N (13 % each). The other aspects have more or less uniform distribution. Most of the

Cirque 1%

Mountain 28%

Ice apron 1%

Niche 4%

Valley 66%

Figure 7.4.3.5: Ice reserves of different types of glaciers in Gilgit River basin.

117

glaciated area is concentrated on the western aspects (W-19%, NW-12.73 and SW-10%) followed by northern aspects. The total length of the glaciers is maximum on the northern aspects followed by E and S. The minimum length of glaciers is on SE due to minimum number of glaciers. Out of total of 83.35 km3 ice reserves of the basin, maximum are on W (25%) followed by S (19%), N (17%) and SW (12%). The minimum ice reserves of 4% are on SE aspect.

Table 7.4.3.3: Distribution of glacier types on different aspects in Gilgit River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 40 11 - 8 5 10 74 NE 62 4 1 18 16 26 127 E 29 3 1 8 11 25 77 SE 25 - - 1 10 16 52 S 29 7 1 - 8 17 62 SW 26 4 1 5 5 22 63 W 17 9 - 5 2 15 48 NW 48 2 2 10 11 9 82 Total 276 40 6 55 68 140 585

Table 7.4.3.3 shows the distribution of various types of glaciers in different ordinal directions. Out of total of 585 glaciers in the basin maximum (127) are oriented towards NE mainly of Mountain type. Minimum representation of the glaciers is on the W. Out of 276 Mountain glaciers, 150 are distributed on northern aspects. The eastern aspects also have the higher number of Mountain glaciers. Valley glaciers are mainly distributed on northern and western aspects (Figure 7.4.3.6). No Valley glacier was found on SE. Two Ice cap glaciers are oriented towards NW while the NE, E, S and SW aspects have one each of this type of glaciers. Since the Ice apron glaciers are small in size so they are missing on S while northern aspects have maximum number of this type. Generally Cirque and Niche glaciers are maximum on eastern aspects.

118

(a) Mountain glacier (b) Valley Glacier

S11%

SW9%

W6%

SE9%

E11%

NE23%

N14%

NW17%

W22%

NW5%

SW10% S

18% E

8%

NE10%

N27%

(c) Ice cap glaciers (d) Ice apron glaciers

NW32%

NE17%

E17%S

17%

SW17%

E

15%

SW9%

W9%

NW19%

NE33%

N15%

(e) Cirque glaciers (f) Niche glaciers

S12%

SW7%

W3%

NW16%

N7%

NE24%

E16%

SE15%

SW16%

W11%

NW6%

N7%

NE19%

E18%

SE11%

S12%

Figure 7.4.3.6: Distribution of different types of glaciers with respect to aspect in Gilgit River basin.

119

7.4.4 Hunza River basin In this basin the two tributaries each in the west (Chapursan and Kilik) and east (Khunjerab along with Ghujerab) join near Kudabad. After joining the river flows southwards and joins the Shimshal River. It flows further south and near Atabad turns westward and a small tributary originating from Hispar glacier joins at Aliabad. Further flowing westwards it takes a turn near Chalt towards south and another tributary Bola Das joins near Nomal and forms the Hunza River. The Basin is located in the high Karakoram Range and the latitude and longitude range from 35º 54' to 37º 05' and 74º 02' to 73º 03' respectively (Figure 7.4.4.1). In the west of the basin is Gilgit River basin and in the north partly bordered with Afghanistan. In the north and northeast the basin is boarded with China and in the south by Shigar and Indus river basins. The small portion in the northeast of this basin drains in the Chinese territory and does not contribute to the Hunza River flow. Most of the terrain of the basin falls in the high mountains of Karakoram with an elevation range of about 1,500 masl to more than 7,500 masl. The basin occupies an area of 16,389.4 sq. km out of which 87.5% contributes to Hunza River flow. The glacier area of the basin is about 4,677.3 sq. km (Table 7.4.4.1). The distribution of different types of glaciers is presented in Figure 7.4.4.2 and 7.4.4.3. In the Hunza River basin a total of 1050 glaciers are identified out of which more than 80% are classified as various types of Mountain glaciers. The maximum number is of Mountain type followed by Niche glaciers. There are 201 Valley glaciers. About 14 percent glaciers are classified as Cirque glaciers while the Ice cap and Ice apron are quite low in number.

The total 1,050 glaciers of this basin contribute an area of more than 4,677 sq. km and length of about 2,915 km. Due to higher elevation; generally the Valley glaciers are large in size and length. They contribute more than 83% to the total glacier area. Among 201 Valley glaciers there are quite a few important and well known glaciers like Hispar, Batura, Gulmit, Khunjarab, etc. (Annex_gr_7.4). Figure 7.4.4.4 shows the clips of some of the important large size Valley glaciers. The largest glacier is Hispar (Hunza_gr 830) which is more than 521 sq. km in size and is about 52.8 km long. There are 10 Valley glaciers which have an area of more than 100 km. Another 7 glaciers of this category

Table 7.4.4.1: Details of various types of glaciers of Hunza River basin

Number Area (km2) Length (m) Ice reserve (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total % Cirque 149 14.2 0.07 3.10 82.03 1.7 223 4029 193382 3.251 0.40Ice apron 31 2.9 0.08 1.08 9.48 0.2 239 2028 24805 0.282 0.03Ice cap 27 2.6 0.10 0.71 7.29 0.2 236 1852 18391 0.199 0.02Mountain 407 38.8 0.06 31.92 520.83 11.2 300 11052 723300 31.469 3.89Niche 235 22.4 0.05 5.43 153.50 3.3 215 7076 431008 6.497 0.80

Valley 201 19.1 0.23 521.15 3904.21 83.4 414 65560 1523924 767.096 94.84Total 1050 4677.34 2914810 808.794

120

Figure 7.4.4.1: Location map of the Hunza River basin.

121

contribute area of more than 50 sq. km each. There are only 10 glaciers of this type which have area less than one sq. km. The Mountain glaciers are though highest in number but they contribute only 11% of the glacier area. The largest Mountain glacier (Hunza_gr 177) is about 32 sq. km in size while it is only about 4 km long. More than half (147) of these glaciers have an area ranging between 0.1 to 0.98 sq. km. There are only three small size Mountain glaciers Hunza_gr 612, 801 and 628 having area of 0.085, 0.08 and 0.064 sq. km. The Cirque glaciers contribute only 1.7% of the glacier area and the smallest (Hunza_gr 874) and the largest (Hunza_gr 49) glacier of this type have an area of 0.07 and 3.1 sq. km respectively. The area contribution of Ice cap as well as Ice apron glaciers is very low due to small size and low number. The total 1050 glaciers of this river basin are the highest source of ice reserves in the entire HKH region of Pakistan. A total of about 809 km3 ice reserves are there in the basin. About 95% of these reserves are contributed by the Valley glaciers (Figure 7.4.4.5). The contribution of Mountain glaciers to the total ice reserves of the basin is generally low especially of those of subtypes of the Mountain glaciers.

Valley 19%Niche

22%

Mountain 39%

Cirque 14%

Ice apron 3%Ice cap

3%

Cirque 2%

Mountain

11%

Niche 3%

Valley 84%

(a) Number percentage (b) Area percentage Figure 7.4.4.2: Distribution of number and area percentage of different types of glaciers in

Hunza River basin.

122

Figure 7.4.4.3: The glacier distribution in Hunza River basin.

123

(a) Barldu glacier (Hunza_gr 937) draining into Braldu River

(b) Large glaciers (from top down); Batura, Pasu, Ghulkin and Gulmit

(c) Virjerab glacier (Hunza_gr 744) draining into Shimshal River

(d) Hispar glacier (Hunza_gr 830) draining into Hispar River

(e) Batura glacier (Hunza_gr 120) (f) Yazgil glacier (Hunza_gr 771) in Shimshal

valley Figure 7.4.4.4: Typical large size Valley glaciers in Hunza River basin.

124

Mountain 4%

Valley 95%

Niche 1%

Figure 7.4.4.5: Ice reserves of different types of glaciers in Hunza River basin.

Based on the ordinal directions the glaciers are distributed more or less uniformly in all directions except NW and W (Table 7.4.4.2). On contrary the glaciated area is higher on NW, N, E and NE. The other aspects have relatively few smaller glaciers. The ice reserves of various ordinal directions follow the pattern of total glaciated area i.e. maximum on the aspects having highest glacier coverage and vice versa.

Table 7.4.4.3 shows the distribution of various types of glaciers in different ordinal directions. Generally all types of glaciers on western aspect are low in number. Out of 407 Mountain glaciers maximum (22%) are located on S followed by E and SE (15% each). Only 6% of this type of glaciers is oriented towards W (Figure 7.4.4.6). The Valley glaciers are mostly oriented towards northern aspects. Among these N, NW and NE have 54, 38 and 32 glaciers respectively out of a total of 201. In the NW the Ice cap and Ice apron glaciers are not found. The Ice cap are maximum (13) on S while Ice apron are maximum (6 each) on N and E. Cirque glaciers are mainly concentrated on eastern and northern aspects. The Niche glaciers also follow the pattern of Cirque glaciers.

Table 7.4.4.2: Distribution of glaciers under different aspects in Hunza River basin

Number Area (Km2) Length (m) Ice reserve (km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 159 15.1 0.10 186.59 1116.92 23.9 457 34998 614348 175.071 21.6NE 173 16.5 0.0 5 134.27 513.44 11.0 357 29270 446334 63.369 7.8E 152 14.5 0.07 336.72 827.82 17.7 350 58800 420654 165.422 20.4SE 118 11.2 0.06 106.93 291.45 6.2 292 22018 267067 34.029 4.2S 176 16.8 0.09 85.06 331.04 7.1 236 65560 369004 34.230 4.2SW 117 11.1 0.08 93.45 265.74 5.7 321 20422 276348 30.456 3.8W 56 5.3 0.08 31.92 104.44 2.2 215 7430 107233 9.274 1.1NW 99 9.4 0.07 521.15 1226.49 26.2 414 52774 413822 296.943 36.7Total 1050 4677.34 2914810 808.794

125

Table7.4.4.3: Distribution of glacier types on different aspects in Hunza River basin

Glacier Types Aspect

Mountain Valley Ice Cap Ice Apron Cirque Niche Total

N 40 54 1 6 20 38 159 NE 52 32 2 3 33 51 173 E 61 24 1 6 35 25 152 SE 60 12 3 3 15 25 118 S 91 16 13 5 19 32 176 SW 44 18 6 5 4 40 117 W 26 7 1 3 6 13 56 NW 33 38 - - 17 11 99 Total 407 201 27 31 149 235 1050

(a) Mountain glacier (b) Valley Glacier

NW8%

N10% NE

13%

E15%

SE15%

W6%

SW11%

S22%

S8%

SW9%

W3%

SE6% E

12%

NE16%

N27%

NW19%

(c) Ice cap glaciers (d) Ice apronglaciers

S48%

SW22%

N4%

NE7%

E4%

SE11%

W4%

N19%

NE10%

W10% SW

16%

S16% SE

10%

E19%

126

(d) Cirque glaciers (e) Niche glaciers

SE10%

E24%

NE22%

N13%

NW11%

W4%

SW3%

S13%

S14% SE

11% E

11%

NE21%

N16%

NW5%

W6%

SW16%

Figure 7.4.4.6: Distribution of different types of glaciers with respect to aspect in Hunza River basin. 7.4.5 Shigar River Basin The Shigar River basin has the latitude and longitude range of 35º 19' to 36º 07' and 74º 53' to 76º 45' respectively (Figure 7.4.5.1). This basin is located in the northern areas bordering with China and Shyok River basin in the east, Hunza River basin in the north and Indus River basin in the south and west. The elevation range varies from about 2,500 masl to more than 8,600 masl.

127

Figure 7.4.5.1: Location map of the Shigar River basin.

128

The basin stretches over an area of 7,382 sq. km out of which, glacier area is about 2,240 sq. km (Table 7.4.5.1). The distribution of different types of the glaciers is presented in Figure 7.4.5.2 and 7.4.5.3. The basin has a total of 194 glaciers out of which around 30 % are Mountain glaciers, 25% Niche, 24 % Valley and 18% Cirque glaciers. The Ice apronand Ice cap glaciers are 2% each. These 194 glaciers cover about 30.34 % of the total basin area. Some of the Valley glaciers in this basin are also of extensive size. The large size glaciers are mainly concentrated on the N, NE and NW aspects.

Ice cap2%

Ice apron2%

Mountain29%

Niche25%

Cirque18%

Valley24%

Valley93%

Cirque1%Niche

1%

Mountain5%

(a) Number percentage (b) Area percentage

Figure 7.4.5.2: Distribution of number and area percentage of different types of glaciers in Shigar River basin.

Table 7.4.5.1: Details of various types of glaciers of Shigar River basin

Number Area (km2) Length (m) Ice Reserves (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total %

Cirque 34 17.5 0.06 2.88 25.69 1.1 250 6460 62848 1.146 0.197Ice apron 4 2.1 0.08 0.37 0.92 0.0 380 1215 2936 0.022 0.004Ice cap 3 1.5 0.15 0.23 0.56 0.0 392 754 1661 0.012 0.002Mountain 58 29.9 0.08 7.4 102.36 4.6 290 6354 142938 6.257 1.076Niche 49 25.3 0.08 1.74 29.01 1.3 344 3850 88970 1.121 0.193Valley 46 23.7 0.99 641.21 2081.54 92.9 2670 62624 500915 572.71 98.528

Total 194 2240.08 581.27

129

The 24% Valley glaciers contribute 93% of the total glacier area followed by Mountain glaciers (30%) contributing 5% to the glacier area. The contribution of other types of glaciers like Niche and Cirque is 1% each. The largest Valley glaciers are Baltoro (Shig_gr129), Biafo (Shig-gr105), Panmah (Shig_gr 113) and Chogo lungma (Shig_gr 52) few of which presented in Figure 7.4.5.4. The details of all the glaciers of the basins are presented in Annex_gr_7.5. The Baltoro glacier with a length of 59 km has the maximum area of about 641 sq. km. The Biafo glacier has the maximum length of 62.6 km covering an area of 426 sq. km. The smallest valley glacier (Shig_gr 163) has an area of 0.99 sq. km.

Figure 7.4.5.3: The glacier distribution in the Shigar River basin.

130

(a) Numerous Valley glaciers entering into gigantic Baltoro glacier (Shig_gr 129)

(b) Panmah glacier (Shig_gr 113) in FCC 5(R)4(G)2(B)

(c) Chogo Lungma (mean ‘Big valley’) glacier (Shig_gr 52)

(d) Sosbun glacier (Shig_gr _95) in FCC Pan(R)4(G)2(B)

Figure 7.4.5.4: Typical large size and complex Valley glaciers in Shigar River basin

The Mountain glaciers altogether have the maximum total length of about 143 km. The minimum and maximum length of this category is 0.29 and 6.3 km respectively. The total length of Valley glaciers is 501 km. The Niche and Cirque glaciers contribute 89 km and 63 km to the total length of the glaciers.

The total ice reserves of this basin are 581 km3. The two types of glaciers namely Valley and Mountain contribute to these ice reserves (Figure 7.4.5.5). The share of Valley glaciers to this reserve is 98.5% while about 1% is contributed by the Mountain glaciers. Less than half percent of the ice reserves is contributed by Niche, Cirque, Ice cap and ice apron type glaciers.

131

Valley98.5%

Mountain1.1%

Niche0.2%

Cirque0.2%

Figure 7.4.5.5: Ice reserves of different types of glaciers in Shigar River basin. The details of the distribution of glaciers on different aspects are presented in Table 7.4.5.2. Overall the glaciers are distributed uniformly in all directions. The maximum number of glaciers (38) is on the NE aspect while minimum number (16) is on the western aspect. The maximum glacier area (49.6%) is on the SE aspect followed by 31% on the western aspect. Rest of the area is distributed on all other directions. The extensive area on SE is due to the fact that most of the large Valley and Mountain glaciers are oriented towards this aspect. The total length of the glaciers follows almost the same pattern as that of the area.

More than 50% ice reserves are on SE followed by 40% on the western aspect. Rest of the aspects contributes very little to the ice reserves. The distribution of Mountain glaciers is higher on NE, E and SE directions (Figure 7.4.5.6). The Valley glaciers are mostly concentrated on northern, north eastern and western aspects. Table 7.4.5.3 represents the orientation of various types of glaciers. Generally in this basin the glaciers are oriented towards northern and eastern aspects. The Mountain glaciers are more oriented towards eastern aspects followed by northern aspects. Out of 46 Valley glaciers, 18% are oriented towards N and 15% each towards NE and W (Figure 7.4.5.6). The southern aspects have the equal distribution of this type of glaciers. The Ice

Table 7.4.5.2: Distribution of glaciers under different aspects in Shigar River basin

Number Area (km2) Length (m) Ice Reserves (km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 26 13.40 0.08 27.74 97.64 4.36 290 13123 89716 9.98 1.72NE 38 19.59 0.09 11.19 79.97 3.57 469 8559 113071 5.81 1.00E 27 13.92 0.06 10.47 36.70 1.64 250 6460 51590 2.42 0.42SE 32 16.49 0.11 426.09 1111.14 49.60 344 62624 230256 304.69 52.42S 17 8.76 0.26 53.27 124.54 5.56 724 15324 74293 16.67 2.87SW 17 8.76 0.23 7.40 41.60 1.86 392 6675 60337 2.85 0.49W 16 8.25 0.08 641.21 693.86 30.97 355 58970 107300 234.79 40.39NW 21 10.82 0.13 11.97 54.63 2.44 604 8233 66950 4.07 0.70Total 194 2240.08 793513 581.27

132

cap and Ice apron glaciers are predominantly present on SE. The Cirque type glaciers distribution is low on southern aspects. Niche glaciers follow the same pattern.

Table 7.4.5.3: Distribution of glacier types in different aspects in Shigar River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 3 8 - - 5 10 26 NE 14 7 1 - 6 10 38 E 10 2 - 1 7 7 27 SE 10 6 2 2 2 10 32 S 4 6 - 1 3 3 17 SW 6 6 1 - 2 2 17 W 2 7 - - 4 3 16 NW 9 4 - - 5 3 21

Total 58 46 4 4 34 48

133

7.4.6 Shyok River basin The Shyok River basin stretches over a latitudinal and longitudinal range of 34º 39' to 35º 42' and 75º 56' to 77º 27' respectively (Figure 7.4.6.1). This river basin is bounded with Jammu and Kashmir disputed Territory in south, China in northeast and Shigar and Indus River basins in the west. The elevation in the basin varies from more than 2,500 masl to more than 7,700 masl.

(a) Mountain glaciers (b) Valley glaciers

NW16% S

7%

SW10%

W3%

N5%

NE25%

SE17% E

17%

N18%

NE15%

SW13%

E4%

SE13%

S13%

NW9%

W15%

(c) Ice cap glaciers (d) Ice apron glaciers

SE50%

NE25%

SW25%

SE50%

E25%

S25%

(e) Cirque glaciers (f) Niche glaciers

SE6%

S9%

SW6%

W12%

NW15% E

20% N15%

NE17%

SE21%

NW6%

W6%

SW4% S

6%

N21% NE

21% E

15%

Figure 7.4.5.6: Distribution of different types of glaciers with respect to aspect in Shigar River basin.

134

Figure 7.4.6.1: Location map of the Shyok River basin.

135

This basin has high peaks with the elevation of more than 7,000 masl. The total area of the basin is about 10,235 sq. km out of which 34.67% is under the glacier cover. The huge size glaciers are concentrated on NE and SE side of the basin. There are 372 glaciers in the basin out of which 86% can be classified as mountain type glacier while only 14% are the Valley glaciers (Table 7.4.6.1). Among the Mountain glaciers 19 % are Niche, 16 % Cirque, 9 % Ice cap and 4 % Ice apron while the rest are categorized as Mountain glaciers (Figure 7.4.6.2).

The 372 glaciers contribute to a vast glacier area of about 3,548 sq. km (Figure 7.4.6.3). Though the Valley glaciers are only 14 % of the total number, they contribute more than 82 % to the glacier area. This high contribution is mainly due to larger area of the individual glaciers. Some of the important Valley glaciers shown in Figure 7.4.6.4 include Siachen (Shyk_gr 202), Kondus (Shyk_gr 69), Bilafond (Shyk_gr 98), Chogolisa (Shyk_gr 36), Ghandogoro (Shyk_gr 34) and Masherbrum (Shyk_gr 33).

Table 7.4.6.1: Details of various types of glaciers of Shyok River basin

Number Area (km2) Length (m) Ice Reserves ( km3) Type

Total % Smallest Largest Total % Min. Max. Total Total %

Cirque 61 16.4 0.11 4.06 54.69 1.5 265 4888 89449 2.57 0.29Ice apron 13 3.5 0.25 1.59 9.14 0.3 398 1437 11204 0.35 0.04Ice cap 32 8.6 0.17 3.18 26.11 0.7 368 2835 31770 1.18 0.13Mountain 143 38.4 0.22 32.68 471.06 13.3 353 11311 322917 38.16 4.28Niche 71 19.1 0.08 4.42 72.69 2.1 288 5014 137296 3.56 0.40Valley 52 14.0 1.10 1112.03 2914.15 82.1 540 76641 500844 845.98 94.86Total 372 3547.84 1093480 891.80

Cirque 16%Ice apron

3%

Valley 14%

Niche 19%

Mountain 39%

Ice cap 9%

Valley 82%

Mountain 13%

Cirque 2%

Ice apron 0%

Niche 2%

Ice cap 1%

(a) Number percentage (b) Area percentage

Figure 7.4.6.2: Distribution of different types of glaciers in Shyok River basin.

136

Figure 7.4.6.3: The glacier distribution in the Shyok River basin

137

The Siachen is the biggest valley glacier of this basin (Figure 7.4.6.4) having an area of 1,112 sq. km followed by Shyk_gr 218 having an area of more than 323 sq. km (Annex_gr_7.6). The Bilafond glacier is a large size Valley glacier having several supra glacial lakes (Figure 7.4.6.4). The smallest Valley glacier (Shyk_gr 18) has an area of 1.1 sq km.

The Mountain glaciers are also of large size. The largest Mountain glacier (Shyk_gr 122) has an area of more than 32.67 sq. km while the smallest one (Shyk_gr 249) stretches over an area of 0.22 sq. km. The contribution of Mountain glaciers in the total glacier area is more than 13 %. The Niche and Cirque glaciers contribute almost 2% each to the total glacier area. The Cirque glaciers are larger in size as the largest glacier of this category (Shyk_gr 95) has an area of more than 4 sq. km and the smallest one has (Shyk_gr 319) an area of 0.11 sq. km. Ice cap and Ice apron types of glacier are also of reasonable size. As mentioned earlier the Valley glaciers are of huge size and it is reflected in the total length of these glaciers as well. The total length covered by the Valley glaciers is more than 500 km. The maximum length recorded for the Siachen glacier is 76.6 km. The minimum length recorded for the Valley glacier (Shyk_gr 18) is more than 2.6 km. The

(a) A complex valley glacier - Siachen (Shyk_gr 202)

(b) Bilafond glacier (Shyk_gr 98)

(c) Ghandogoro (Left) and Chogolisa (Right) glaciers

(d) A Large Valley Glacier Masherbrum (Shyk_gr 33)

Figure 7.4.6.4: Some of the important Valley glaciers in Shyok River basin in FCC 5(R)4(G)2(B)

138

total length of Mountain glaciers is about 323 km followed by Niche glaciers (137 km). Ice apron has the minimum length of about 11 km. Among the Mountain glaciers, the

longest one is Shyk_gr 122 and the smallest one is Shyk_gr 249.

The glacier area of the basin contributes to about 892 km3 of the total ice reserves of the basin. Again the major source of this huge ice reserve is the Valley glaciers which contribute more than 94% (Figure 7.4.6.5). The Mountain glaciers contribute 4.3% while the Niche and Cirque glaciers contribute 0.4 and 0.3 % respectively. Aspect wise the basin has been divided into various ordinal directions. Distribution of glaciers with respect to different aspects is presented is Table 7.4.6.2. Cirque glaciers are oriented towards NE (29%), NW (24%) and E (18%) but are absent on the western aspects. Niche glaciers are common on S, E and SE aspects. Aspect wise generally the glaciers distributed uniformly except the W and SW. The SE and S aspects have the maximum glacier area of about 1,657 and 501 sq. km respectively owing to the fact that the larger glaciers like Siachen, Kondus, Bilafond, Ghandogoro, Masherbrum, etc. are facing to these aspects. The E and NE also have higher percentage of total glacier area. Generally the total length of the glaciers is more than 100 km except for W and N. The glaciers on southeastern aspect have a total length of 254.3 km while the west facing glaciers have a length of more than 22 km. In the total ice reserve, the glaciers on SE have a share of about 65%. About 12 % is contributed from the eastern aspect followed by southern (10 %) aspect. The contribution from western and the northern aspects is relatively low. The distribution of various types of glaciers in different ordinal direction is presented in Table 7.4.6.3 and Figure 7.4.6.6. Out of 143 Mountain glaciers, the distribution on western aspect is low while on the other aspects they are more or less uniformly distributed in the glaciated part of the basin. The

Table 7.4.6.2: Distribution of glaciers under different aspects in Shyok River basin

Number Area (km2) Length (m) Ice Reserves (km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 48 12.9 0.23 13.65 111.63 3.15 390 5348 90014 7.802 0.87 NE 70 18.82 0.17 140.15 311.35 8.78 552 15085 154196 44.975 5.04 E 57 15.32 0.08 322.78 471.04 13.28 288 30587 152962 107.603 12.07 SE 48 12.9 0.21 1112.03 1656.52 46.69 540 76641 254334 576.934 64.69 S 57 15.32 0.18 177.69 500.74 14.11 533 21362 186446 87.127 9.77 SW 30 8.06 0.28 81.63 198.98 5.61 548 18219 109754 25.507 2.86 W 9 2.42 0.36 9.43 23.63 0.67 1135 5353 22387 1.658 0.19 NW 53 14.25 0.11 84.51 273.95 7.72 265 19948 123387 40.195 4.51 Total 372 3547.84 1093480 891.801

139

Valley glaciers are mostly oriented towards SE and NE. On the western aspects the distribution of Ice cap is poor while on northern aspect they are more in number. The Ice apron glaciers are only present on the NW, N, and NE aspects.

Table 7.4.6.3: Distribution of glacier types in different aspects in Shyok River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 18 4 8 5 7 6 48 NE 24 11 9 1 18 7 70 E 20 6 5 0 11 15 57 SE 18 12 3 0 4 11 48 S 23 10 3 0 4 17 57 SW 16 4 0 0 2 8 30 W 4 2 1 0 0 2 9 NW 20 3 3 7 15 5 53

Total 143 52 32 13 61 71 372

Valley 94.9%

Cirque 0.3%

Ice apron 0.0%

Ice cap 0.1%

Niche 0.4%

Mountain 4.3%

Figure 7.4.6.5: Ice reserves of different types of glaciers in Shyok River basin.

140

7.4.7 Indus River basin The Indus River is the trunk river of Pakistan with many other major tributaries. The northern part of the basin with mostly glaciated area is considered as the upper Indus River. The Basin is located in the northern areas with the latitude and longitude range of 33º 55' to 36º 02' and 72º 11' to 76º 36' respectively (Figure 7.4.7.1). It is the largest river basin of Pakistan bounded in west by Swat River basin, in the north by Gilgit and Hunza River basins, in the northeast by Shigar River basin and in the east by Shyok River basin. In the south the Shingo, Astor and Jhelum River basins are located. The major portion of the basin consists of mountainous terrain with an elevation range of about 1,000 masl to more than 7,500 masl close to the Nanga Parbat in the west. The basin occupies an area of 32,571.2 sq. km out of which the glacier area is about 688 sq. km (Table 7.4.7.1). The distribution of different types of glaciers is presented in Figure 7.4.7.2 and 7.4.7.3.

(a) Mountain glacier (b) Valley Glacier

SE13%

NE16%

N13%

E14%

S16%

SW11%

W3%

NW14%

W4%

NW6%

NE21%SE

22% E

12%

SW8%

N8%

S19%

(c) Ice cap glaciers (d) Ice apronglaciers

S9%

W3%

NW9%

SE9%

E16%

NE29% N

25%

NE8%

N38%

NW54%

(e) Cirque glaciers (f) Niche glaciers

SE7%

S7%

SW3%

NW25%

N11%

E18%

NE29%

S25%

SW11%

N8%

NW7%

W3%

NE10%

E21%

SE15%

Figure 7.4.6.6: Distribution of different types of glaciers with respect to aspect in Shyok River basin.

141

Most of the glaciers (97%) are classified as Mountain glaciers including the Ice cap, Cirque, Niche, and Ice apron (sub types). These sub-types are based on the characteristics of position, thickness of the ice, topographical locations, etc. Among these sub types the maximum number is of Cirque type (43%) followed by Mountain (23%), Niche (19%) and Ice apron (9%). Only about three percent of glaciers are classified as Ice caps. Generally the Valley glaciers are large in size and length (Figure 7.4.7.4). In spite of having only about 3 percent share in total number, they cover an area of 291 sq. km, which is about 42% of the total glacier area. The largest and smallest glacier of this category has an area of 41 and 1 sq. km respectively. The Mountain glaciers are smaller in size and altogether contribute 58% of the total glacier area. Among the specialized Mountain glaciers, the Cirque glaciers are relatively larger in size and cover an area of 106 sq. km. The Ice caps are the smallest glaciers and contribute only 1.4% of the area.

Table 7.4.7.1: Details of various types of glaciers of Indus River basin

Number Area (km2) Length (m) Ice reserve (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total %

Cirque 471 42.9 0.02 4.45 105.91 15.4 136 3737 278847 2.62 5.65

Ice apron 103 9.4 0.04 2.15 23.34 3.4 122 2519 56769 0.53 1.14

Ice cap 33 3.0 0.04 1.32 9.63 1.4 121 2716 19172 0.28 0.60

Mountain 254 23.1 0.04 5.29 216.67 31.5 132 4989 304650 10.53 22.70

Niche 205 18.7 0.05 1.13 41.75 6.1 136 3224 169074 0.90 1.94

Valley 32 2.9 1.02 40.74 290.70 42.2 2215 18284 213861 31.52 67.96

Total 1098 688.00 1042373 46.38

142

Figure 7.4.7.1: Location map of the Indus River basin.

143

The total 1,098 glaciers of the Indus River basin are the good source of ice reserves of about 46 km3. The Valley glaciers contribute more than 67% to the ice reserves of the basin while rest is contributed by the Mountain glaciers and their subtypes (Figure 7.4.7.5). Most of the Valley glaciers are concentrated only in the northern aspects of this basin. There are altogether 32 Valley glaciers and the largest (40.7 sq. km) glacier is Kotha Lungma (Ind_gr 378). Other major Valley glaciers are Mani (Ind_gr 350), Rakhiot (Ind_gr 811), Phuparash (Ind_gr 342), Diamir (Ind_gr 824), Baskai (Ind_gr 347) and Goropha (Ind_gr 386). The Valley glaciers are mostly fed by snow avalanches and adjacent ice masses. The inventory of glaciers is given in the Annex_gr_7.7. The extensive coverage of Valley glaciers is because of the fact that the Mountain glaciers join the Valley glaciers and so the whole ice mass is classified as a Valley Glacier. Some of the important and well known Mountain glaciers include Chambar (Ind_gr 1086), Saigal (Ind_gr 1083) and Patro (Ind_gr 819).

Ice cap 3%

Mountain 23%

Niche 19%

Valley 3%

Cirque 43%

Ice apron 9%

Niche 6%

Mountain 32%

Ice apron 3%

Ice cap 1%

Cirque 15%

Valley 43%

(a) Number percentage (b) Area percentage

Figure 7.4.6.2: Distribution of different types of glaciers in Indus River basin.

144

Figure 7.4.7.3: The glacier distribution in the Indus River basin.

145

(a) Buldar (Ind_gr 803) covering an area of 11.2 sq. km.

(b) Diamir (Ind_gr 824) covering an area of 18.3 sq. km.

(c) Rakhiot (Ind_gr 811) covering an area of 23.5 sq. km.

Figure 7.4.7.4: Typical large size Valley glaciers in the Indus River basin.

146

This river basin is divided into various classes based on the aspect. Table 7.4.7.2 includes the details of the various types of glaciers in different ordinal directions. Aspect-wise, most of the glaciers are oriented towards N (21%) and NE ((20%) followed by the E aspect (13 %). On the southern aspects like S, SW and SE the glacier percentage (9, 8 and 8 respectively) is low. Similarly the total glacier area on N and NE aspects is highest. The minimum area under snow is on W, E and SW aspects.

The major ice reserves are on N, SE, S, NE and NW aspects for being 21, 19, 18, 12 and 11 percent respectively. The E, W and SW aspect have the minimum ice reserves probably due to the reason that most of the Mountain glaciers dominate on these aspects.

Table 7.4.7.3 shows the distribution of various types of glaciers in different ordinal directions. The Mountain glaciers are more on northern and eastern aspects while the south western and south eastern aspects have the minimum number. Out of 32 Valley glaciers there are 7 glaciers facing towards N and 6 towards S followed by 5 on NE. The E, SE and SW have 3 Valley glaciers each. There is only one glacier of this type on NW. The specialized type of Mountain glaciers - Ice apron are mostly concentrated on northern aspect while Cirque and Niche type glaciers are predominant on north eastern and northern aspects (Figure 7.4.7.6).

Cirque 6%

Ice cap 1%

Mountain 23%

Niche 2%

Ice apron 1%

Valley 67%

Figure 7.4.7.5: Ice reserves of different types of glaciers in Indus River basin.

Table 7.4.7.2: Distribution of glaciers under different aspects in Indus River basin

Number Area (Km2) Length (m) Ice reserve (km3) Aspect

Total % Smallest

Largest Total % Min. Max. Total Total %

N 231 21.0 0.041 23.81 146.61 21.31 122 12165 197131 9.64 20.78NE 218 19.8 0.031 11.20 105.32 15.31 132 9306 198489 5.46 11.77E 142 12.9 0.032 4.34 57.24 8.32 136 4989 117766 2.31 4.98SE 83 7.6 0.022 40.74 85.37 12.41 154 18284 88064 9.00 19.40S 98 8.9 0.033 23.10 99.33 14.44 226 15171 115096 8.26 17.81SW 89 8.1 0.034 17.35 61.84 8.99 136 12056 102189 4.22 9.10W 118 10.7 0.040 4.98 56.83 8.26 171 5195 116764 2.48 5.35NW 119 10.8 0.059 23.48 75.44 10.97 121 13725 106874 5.01 10.80Total 1098 688.00 1042373 46.38

147

Table 7.4.7.3: Distribution of glacier types on different aspects in Indus River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 62 7 3 36 85 38 231 NE 40 5 10 11 96 56 218 E 41 3 2 11 56 29 142 SE 16 3 5 6 40 13 83 S 25 6 4 12 45 6 98 SW 14 3 3 6 45 18 89 W 17 4 3 8 58 28 118 NW 39 1 3 13 46 17 119 Total 254 32 33 103 471 205 1098

(a) Mountain glacier (b) Valley Glacier

NW15%

W7%

SW6%

S10%

SE6%

E16%

NE16%

N24%

N22%

NE16% E

9% SE9%

S19%

SW9%

W13%

NW3%

(c) Ice cap glaciers (d) Ice apronglaciers

SE15%

E6%

NE31%

N9%

NW9%

W9%

SW9%

S12%

N34%

NE11% E

11% SE6%

S12%

SW6%

W8%

NW12%

(e) Cirque glaciers (f) Niche glaciers

NE20%

W12%

NW10%

N18%

SW10%

S10%

E12%

SE8%

N19% NW

8%

W14% SW

9% S3%

SE6%

E14%

NE27%

Figure 7.4.7.4: Distribution of different types of glaciers with respect to aspect in Indus River basin.

148

7.4.8 Shingo River basin

The latitude and longitude range of Shingo River basin is 34º 40' to 35º 11' and 75º 06' to 76º 15' respectively (Figure 7.4.8.1). It is bounded in west by Jhelum and Astor River basins, in the north and east by eastern part of Indus River. In the basin, elevation ranges from 3,800 masl to about 6,000 masl. The basin occupies an area of 4,679.5 sq. km out of which the glacier area is about 36.9 sq. km (Table 7.4.8.1). Generally the glaciers in this river basin are small which are distributed along the basin boundary and along the drainage. The distribution of different type of glaciers is presented in Figure 7.4.8.2 and 7.4.8.3.

Generally the glaciers in this basin are small in size and of Cirque and Mountain type (Figure 7.4.8.4). There are total of 172 glaciers identified in the basin. The Cirque type glaciers dominate the basin and contribute more than 45% of the total glacier number. These are followed by Mountain glaciers, which are 28% of the total glaciers in this basin. The Ice apron and Niche glaciers contribute about 16 and 8% respectively. There are only 5 glaciers classified as Ice cap and only one Valley glacier. The detailed attribute data of all the glaciers is included in the Annex_gr_7.8.

Out of the total glacier area of 36.9 sq. km, the Mountain glaciers contribute maximum (44.9%) followed by Cirque glaciers (37.9%). The largest Cirque glacier (Shin_gr 92) has an area of about 0.77 sq. km while the smallest glacier (Shin_gr 84) has an area of 0.046 sq. km. In this class there are 9 glaciers having an area of more than 0.3 sq. km, 24 more than 0.2 sq. km and 52 more than 0.1 sq. km. The largest Mountain glacier (Shin_gr 15) has an area of about 1.38 sq. km while the smallest one (Shin_gr 32) has an area of only 0.047 sq. km.

Table 7.4.8.1: Details of various types of glaciers of Shingo River basin

Number Area (km2) Length (m) Ice Reserves (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total % Cirque 77 44.8 0.05 0.77 13.98 37.9 162 1397 43225 0.331 32.8Ice apron 27 15.7 0.03 0.23 2.71 7.3 166 586 10109 0.049 4.86Ice cap 5 2.9 0.05 0.17 0.46 1.2 277 718 1916 0.008 0.79Mountain 49 28.5 0.05 1.37 16.58 44.9 158 1617 31743 0.532 52.73Niche 13 7.6 0.05 0.75 2.56 6.9 381 1972 10981 0.067 6.64Valley 1 0.6 - - 0.62 1.7 1683 1683 1683 0.022 2.18Total 172 36.91 99657 1.009

149

Figure 7.4.8.1: Location map of the Shingo River basin.

150

Mountain 28%

Ice Cap 3% Ice Apron

16%

Niche 8%

Valley 1%

Cirque 44%

Ice Apron 7%

Ice Cap 1%

Valley 2%

Niche 7%

Cirque 38%

Mountain 45%

(a) Number percentage (b) Area percentage

Figure 7.4.8.2: Distribution of number and area percentage of different types of glaciers in Shingo River basin. The Ice apron and Niche type glaciers contribute about 7% each in the glacier area of the basin. The Ice cap glaciers are of smaller in size and because of less number they contribute only 1.25 % in the total glacier area. Generally the glaciers of this basin are not very long. The total length of Cirque and Mountain glacier is 43.22 and 31.74 km respectively followed by Niche and Ice apron type of glacier. The longest glacier (1.97 km) is of Niche type. The 172 glaciers of this basin contribute only about 1.01 km3 of the ice reserves. Due to the fact that there is only one Valley glacier in this basin, the ice reserves are very low. Out of 1.01 km3 of ice reserves, about 53 % is contributed by Mountain and 33 % by Cirque glaciers (Figure 7.4.8.5). The Niche, Ice apron, Valley and Ice cap contribute altogether about 14% to total ice reserves. The distribution of glaciers according to various ordinal directions is presented in Table 7.4.8.2. The maximum number of glaciers is oriented towards NE and NW (21 % each) followed by N (20 %). The glaciers on SE and SW aspects are 10 each in number. The minimum number of glaciers (7) is on S aspect. The pattern of number of glaciers on various aspects is also reflected in the area covered under glaciers i.e. maximum area of 8.2, 7.55 and 7.0 sq. km on N, NW and NE respectively. These aspects have the maximum number of Cirque and Mountain glaciers. The total length of the glaciers follows the same pattern i.e. maximum length of 22.06, 18.94 and 18.84 km on NE, N and NW respectively. The minimum length of 4.2 km is on the southern aspect.

151

Figure 7.4.8.3: The glacier distribution in the Shingo River basin.

152

(a) Small size Mountain glaciers (b) Mountain glaciers with scattered glacial lakes

Figure 7.4.8.4: Typical small size Mountain glaciers and lakes distributed in Shingo River basin.

Cirque 33%

Mountain 52%

Valley 2%

Ice Cap 1%

Niche 7%

Ice Apron 5%

Figure 7.4.8.5: Ice reserves of different types of glaciers in Shingo River basin.

Table 7.4.8.2: Distribution of glaciers under different aspects in Shingo River basin

Number Area (km2) Length (m) Ice Reserves (km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 34 19.77 0.06 1.37 8.22 22.27 174 1348 18940 0.245 24.28NE 36 20.93 0.04 0.77 7.00 18.97 158 1972 22059 0.191 18.93E 26 15.12 0.03 0.54 4.80 13.00 241 1397 15153 0.117 11.6SE 10 5.81 0.05 0.86 3.07 8.32 234 1451 6886 0.093 9.22S 7 4.07 0.09 0.72 2.10 5.69 336 1148 4204 0.061 6.05SW 10 5.81 0.09 0.42 2.07 5.61 296 866 4873 0.047 4.66W 13 7.56 0.05 0.29 2.10 5.69 162 1058 8696 0.045 4.46NW 36 20.93 0.04 0.98 7.55 20.46 166 1683 18846 0.21 20.81Total 172 36.91 99657 1.009

153

The maximum ice reserve (0.245 km3) is on N followed by NW (0.21 km3) and NE (0.19 km3). Due to small size of fewer glaciers on SW, S and W the ice reserves are low as well. The distribution of various types of glaciers with respect to aspect is presented in Table 7.4.8.3 and Figure 7.4.8.6. Out of 172 glaciers, 36 each are oriented towards NE and NW followed by 34 towards N. The minimum number of glaciers i.e. 7 is present on southern aspect. Maximum Mountain glaciers are oriented towards N (12) followed by 9 each on NE, E and NW.

The Ice cap glaciers are predominantly oriented towards northern aspects. The Cirque glaciers are distributed on various aspects but predominantly on NW, N and NE aspects followed by E, W and SW aspects. Niche type glaciers in this basin are dominated on northeastern aspect.

Table 7.4.8.3: Distribution of glacier types on different aspects in Shingo River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 12 0 2 2 16 2 34 NE 9 0 0 10 13 4 36 E 9 0 1 3 10 3 26 SE 5 0 1 0 3 1 10 S 3 0 0 2 2 0 7 SW 1 0 0 2 7 0 10 W 1 0 0 1 8 3 13 NW 9 1 1 7 18 0 36 Total 49 1 5 27 77 13 172

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7.4.9. Astor River basin The Astor River basin is located in the northern areas with latitude and longitude range of 34º-45' to 35º-38' and 74º-24' to 75º-14' respectively (Figure 7.4.9.1). The major portion of the basin consists of mountainous terrain with an elevation range of 1,200 masl to more than 7,500 masl close to the Nanga Parbat range in the west. The basin occupies an area of about 4,214 Km2 and possesses glaciated area of about 607 Km2 (Table 7.4.9.1).

(a) Ice cap glaciers (b) Ice apron glaciers

E20%

SE20%

N40%

NW20%

NW26%

SW7% W

4%

S7%

E11%

NE38% N

7%

(c) Mountain glacier

SW2% S

6% SE10%

W2%

E18%

NW18%

N25%

NE19%

(d) Cirque glaciers (e) Niche glaciers

W10%

SW9%

S3%

SE4%

E13%

NE17%

N21%

NW23%

W23%

SE8% E

23%

NE31%

N15%

Figure 7.4.8.6: Distribution of different types of glaciers with respect to aspect in Shingo River basin.

155

Figure 7.4.9.1: Location map of the Astor River basin.

156

The distribution of different types of the glaciers is presented in Figure 7.4.9.2. Figure 7.4.9.3 shows the glaciated area distribution in the Astor River basin.

Most of the glaciers (97%) are classified as Mountain glaciers including the sub-types. These sub-types are based on their characteristics like the position, thickness of the ice, topographical locations etc. Rest of the glaciers (3%) is classified as Valley glaciers covering an area of about 242 km2. Though the number of Valley glaciers is low but the total area coverage, maximum and minimum area, length and ice reserves are of higher magnitude compared to rest of the glaciers. Some of the glimpses of the Valley glaciers like Bazhin (Astor_gr 566), and Sachen (Astor_gr 575) which have lengths greater than 12 km each and the distribution of glaciated cover in the basin, are shown in Figure 7.4.9.4. These valley glaciers are mostly fed by snow avalanches and adjacent ice masses. A 3D view of the basin is presented in Figure 7.4.9.5.

The inventory of the glaciers (Annex_gr_7.9) shows total of six glaciers having lengths greater than 10 km whereas six have lengths ranging from 0 to 5 km. The extensive coverage of Valley glaciers is because of the fact that sometime the Mountain glaciers are

Table 7.4.8.1: Details of various types of glaciers of Astor River basin

Number Area (km2) Length (m) Ice Reserves (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total % Cirque 33 5.6 0.03 2.68 14.34 2.4 175 2800 22865 0.560 1.168Ice apron 64 10.9 0.04 1.12 17.21 2.8 165 1230 34530 0.430 0.897Ice cap 15 2.5 0.08 0.79 2.91 0.5 215 790 6280 0.050 0.104Mountain 439 74.7 0.03 8.34 328.75 54.2 175 5745 359430 15.970 33.319Niche 19 3.2 0.04 0.20 2.03 0.3 165 885 8925 0.001 0.002Valley 18 3.1 0.65 56.80 241.79 39.8 410 16665 117025 30.920 64.509

Total 588 607.03 54905 5 47.931

Mountain74%

Ice cap3% Ice apron

11%

Niche3%

Valley3%

Cirque6%

Ice apron3%

Cirque2%

Mountain55%

Valley40%

(a) Number percentage (b) Area percentage

Figure 7.4.9.2: Distribution of different types of glaciers in Astor River basin.

157

Figure 7.4.9.3: The glacier distribution in the Astor River basin.

158

joining the Valley glaciers and so whole ice mass is classified as valley glacier. The glaciers classified as Ice cap are minimum in number (15) and since these cover only the top of the mountains, the area coverage is also low (0.48%). All the glaciers in this category have less than 1 km2 area. The contribution of Niche and Ice cap glaciers is very low and both types collectively contribute about 0.05 km3 of ice reserves to the total. The contribution to the total ice reserves is highest of Valley glaciers (Figure 7.4.9.6).

(a) Bahzin glacier (Astor_gr 566) (b) Sachen glacier (Astor_gr 575)

(c) Glaciers in FCC Pan(R)7(G)2(B) (d) Glaciers draining into River network of the basin Figure 7.4.9.4: Glimpses of typical Valley glaciers and distribution of glaciated cover in Astor River basin

159

Figure 7.4.9.5: 3-Dimentional view of the glaciated cover in Astor River basin. The number of Ice apron type of glaciers is though higher than Valley glaciers but the area coverage is quite low (2.84%). Since these glaciers have very low thickness and they do not extend over large areas, their total ice reserves are only 0.43 km3.

Table 7.4.9.2 includes the details of the various characteristics of the glaciers in different ordinal directions. Aspect-wise, most of the glaciers (26%) are oriented towards north followed by NW (18.9 %) and NE (17.2%). On the SW and W 9.9 and 8.5 percent of glaciers are found respectively. The S, SE and E aspects have the minimum number of glaciers (34, 37 and 41 respectively).

Cirque1%

Ice apron1%

Valley65%

Mountain33%

Figure 7.4.9.6: Ice reserves of different types of glaciers in Astor River basin.

160

The SE aspect possesses the highest accumulative area of glaciers (129.33 km2) due to higher number of Valley glaciers. The lowest accumulative glaciated area is on the southern aspect (27.86 km2). Similarly the ice reserves of glaciers facing SE are maximum (13.77 km3) followed by NE facing glaciers (12.31 km3). The minimum ice reserves of 1.213 km3 and 1.534 km3 are found on the W and S respectively.

Generally the glaciers are concentrated in the northern, northwestern and northeastern aspects which is due to the fact of the orientation of the basin towards the north (Table 7.4.9.3). The glaciers facing S and SE are fewer in number probably because of the higher temperatures on these aspects. Major glaciers are found along the boundary of the basin. In the center of the basin the glaciers are small and scattered. The orientation of the various types of glaciers is presented in Figure 7.4.9.7. More than 44 percent of the Valley glaciers are oriented towards southeast. The other Valley glaciers are oriented towards northeast (16.7%), east, southwest, and northwest (11.1% each). Very few of these glaciers are oriented towards south.

Table 7.4.9.2: Distribution of glaciers under different aspects in Astor River basin

Number Area (km2) Length (m) Ice reserve (km3) Aspect

Total % Smallest Largest Total % Min Max Total Total % N 156 26.5 0.04 4.21 81.95 13.5 165 3175 108040 3.36 7.01 NE 101 17.2 0.04 56.8 118.29 19.5 175 16665 98340 12.313 25.69 E 41 6.9 0.03 24.17 68.04 11.2 175 10765 48365 6.787 14.16 SE 37 6.3 0.08 33.72 129.33 21.3 250 12930 85080 13.775 28.74 S 34 5.8 0.04 7.33 27.86 4.6 185 2510 23208 1.534 3.2 SW 58 9.9 0.09 8.34 51.43 8.5 185 5745 53812 2.809 5.86 W 50 8.5 0.03 3.03 28.85 4.7 195 1785 35190 1.213 2.53 NW 111 18.9 0.04 15.7 101.28 16.7 215 6355 97020 6.14 12.81 Total 588 607.03 549055 47.931

Table 7.4.9.3: Distribution of glacier types on different aspects in Astor River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 122 - - 19 9 6 156 NE 82 3 4 6 3 3 101 E 26 2 1 7 3 2 41 SE 22 8 1 6 0 - 37 S 24 1 3 2 3 1 34 SW 41 2 3 5 1 6 58 W 38 - 1 5 5 1 50 NW 84 2 2 14 9 - 111

Total 439 18 15 64 33 19 588

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7.4.10. Jhelum River basin The Jhelum River basin is located in the northern areas with the latitude and longitude range of 34º 04' to 35º 08' and 73º 17' to 75º 16' respectively (Figure 7.4.10.1). This river basin is bounded in the west by southwestern part of Indus River basin, in the north by Indus and Astor River basins and in the east by Shingo River basins. The basin stretches over an elevation range of 1,200 masl to more than 4,700 masl. The basin occupies an area of 9,198.4 sq. km out of which about 148 sq. km is the glacier area (Table 7.4.10.1). The distribution of different types of glaciers is presented in Figure 7.4.10.2 and 7.4.10.3.

(a) Mountain glacier (b) Valley Glacier

NW19%

N28%

W9%

NE19%

E6%

S5% SW

9%

SE5%

NW11% SW

11% S

6% SE

44%

E11%

NE17%

(c) Ice cap glaciers (d) Ice apron glaciers

NE26%

E7%

SE7%

S20%

SW20%

W7%

NW13%

SE9%

SW8%

S3% E

11%

NE9%

W8%

N30%

NW22%

(e) Cirque glaciers (f) Niche glaciers

N28% NW

28%

NE9%

E9%

SW3% W

15%

S9%

S5%

W5%

SW32%

E11% NE

16%

N32%

Figure 7.4.9.7: Distribution of different types of glaciers with respect to aspect in Astor River basin.

162

Figure 7.4.10.1: Location map of Jhelum River basin.

163

Out of 384 glaciers of this basin most of them (98%) are classified as Mountain type glaciers. Among the Mountain glaciers maximum number (176) is of Cirque glaciers followed by Ice apron (79). Ice cap and Niche type glaciers are fewer in number. There are only 8 Valley glaciers in the basin. These glaciers are large in size since the largest glacier (Shonthar, Jhe_gr 286) and smallest glacier (Jhe-gr 94) of this class have area of 8.53 sq. km and 0.96 sq. km (Annex_gr_7.10).

The eight Valley glaciers all together contribute more than 21 percent of the total glacier area. Various band combinations are used to highlight the features of the glaciers and the snow and ice. Figure 7.4.10.4 shows the two large size Valley glaciers namely Shonthar and Sarawali in various FCCs.

Table 7.4.10.1: Details of various types of glaciers of Jhelum River basin

Number Area (km2) Length (m) Ice Reserves (km3) Type

Total % Smallest Largest Total % Min. Max. Total Total % Cirque 176 45.8 0.02 1.20 36.15 24.0 115 2345 92361 1.003 14.45Ice apron 79 20.6 0.02 0.37 10.03 6.8 105 929 29415 0.197 2.84Ice cap 11 2.9 0.07 0.37 1.48 1.0 203 537 3948 0.029 0.42Mountain 63 16.4 0.06 6.14 59.05 39.8 158 4198 65241 3.012 43.38Niche 47 12.2 0.03 0.90 9.58 6.5 150 2434 29383 0.258 3.72Valley 8 2.1 0.96 8.53 31.89 21.5 158 11129 38085 2.444 35.20Total 384 148.18 258433 6.943

Niche 12%

Mountain 16%

Ice cap 3%

Ice apron 21%

Valley 2%

Cirque 46%

Mountain 40% Ice cap

1%Ice apron

7%

Cirque 24%

Valley 22%

Niche 6%

(a) Number percentage (b) Area percentage

Figure 7.4.10.2: Distribution of different types of glaciers in Jhelum River basin.

164

Figure 7.4.10.3: Glacier distribution in the Jhelum River basin.

165

(a) FCC R(Pan)G(4)B(2)

(b) FCC R(4)G(3)B(2)

(c) FCC R(Pan)G(7)B(6b)

Figure 7.4.10.4: Large size Valley glaciers (Jhe_gr 274 and Jhe_gr 286) in Jhelum River basin.

166

Few of the Cirque glaciers are also of large size and due to their higher number as well they contribute 24% to the glacier area. Out of total of 176 Cirque glaciers, two of them have an area of more than 1 sq. km and 15 more than 0.5 sq. km. The largest Cirque glacier (Jhe_gr 159) has an area of about 1.2 sq. km while the smallest (Jhe_gr 34) has 0.02 sq. km. Some of the Mountain glaciers of this valley are of large size too. They all together contribute more than 39 % of the glacier area. The largest Mountain glacier (Jhe_gr 306) has an area of more than 6 sq. km. There are 2 glaciers having an area of more than 3 sq. km, five more than two sq. km and 13 more than one sq. km. The smallest Mountain glacier (Jhe_gr 174) has an area of 0.06 sq. km. The Niche and Ice apron type of glaciers contribute about 6% each followed by Ice cap glaciers (1%). The total length of Cirque, Mountain and Ice apron glaciers is more than 92, 65 and 29 km respectively. The total length of Valley glaciers is only about 38 km. The Ice caps are small glaciers and have a total length of about 4 km. The total ice reserves of the basin are 6.94 km3. The Mountain, Valley and Cirque glaciers are the major source of this ice reserves for being having 43, 35 and 14 percent share in a total reserve respectively (Figure 7.4.10.5). The Ice aprons have only 3 percent ice reserves of the basin. The Ice cap glaciers are small and contribute only 0.42 percent to the ice reserves of the basin.

Niche 3.7%

Mountain 43.3%

Ice apron 2.8%

Ice cap 0.5%

Cirque 14.4%

Valley 35.2%

Figure 7.4.10.5: Ice reserves of different types of glaciers in Jhelum River basin. The distribution of the glaciers in various ordinal directions is presented in Table 7.4.10.2. Maximum glaciers (23%) are present on the northern aspect followed by western aspects (about 18%). The E has 12.5 %, SW and NE about 11% each. The minimum number of glaciers is on SE and S aspects being 7.8 and 8.3 percent respectively.

The maximum glacier area is on W and N aspect (19.6 and 19% respectively). This is probably due to the fact that on the western aspect the Cirque and Mountain glaciers are highest in number (Table 7.4.10.3 and Figure 7.4.10.6). As mentioned earlier that in this basin some of these types of glaciers are of large size therefore, they contribute to the higher glaciated cover. The higher coverage on western (29 km2) and northern (28 km2) aspect is contributed to the higher number of these glaciers; and a large size Valley glaciers. The number of Cirque, Ice apron and Mountain glaciers are also high.

167

The glaciers on SE aspects are few in number and therefore, the contribution in the glacier area is low as well. The total length of the glaciers generally follows the pattern of

area distribution. However the total ice reserves besides the SE and W (23 and 20% respectively), on NW aspect are also higher (17%). The minimum ice reserves (4 %) are on the NE owing to the fact that on this aspect the glacier area is lowest due to small size glaciers.

Table 7.4.10.2: Distribution of glaciers under different aspects in Jhelum River basin

Number Area (km2) Length (m) Ice Reserves (km3) Aspect

Total % Smallest Largest Total % Min. Max. Total Total % N 88 22.9 0.02 3.1 28.02 18.9 105 3385 48091 1.117 16.09NE 41 10.7 0.03 1.09 9.81 6.6 188 2434 26422 0.292 4.21E 48 12.5 0.04 1.81 11.84 8.0 192 1343 26179 0.357 5.14SE 30 7.8 0.02 8.53 21.74 14.7 134 11129 34547 1.581 22.77S 32 8.3 0.03 3.24 14.5 9.8 112 4198 27266 0.622 8.96SW 42 10.9 0.04 2.16 12.04 8.1 204 2170 27789 0.43 6.19W 69 18.0 0.02 6.14 29.03 19.6 144 2208 42773 1.367 19.69NW 34 8.8 0.03 5.61 21.2 14.3 115 3867 25366 1.177 16.95Total 384 148.18 258433 6.943

Table 7.4.10.3: Distribution of glacier types on different aspects in Jhelum River basin

Glacier Types Aspect Mountain Valley Ice cap Ice apron Cirque Niche Total

N 15 1 3 23 39 7 88 NE 2 2 0 11 21 5 41 E 9 0 4 4 28 3 48 SE 2 2 0 5 15 6 30 S 9 1 1 4 12 5 32 SW 5 0 1 9 17 10 42 W 18 0 1 14 29 7 69 NW 3 2 1 9 15 4 34

Total 63 8 11 79 176 47 384

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7.4.11. Summary In summary the total geographic area of the selected ten basins under investigation namely Swat, Chitral, Gilgit, Hunza, Shigar, Shyok, Indus, Shingo, Astor and Jhelum is 128,730.8 sq. km (Table 7.4.11.1). Indus River Basin is the largest basin in the HKH region of Pakistan and covers about 25 % of the area. Another 55% area is shared by Hunza, Chitral, Swat and Gilgit river basins. Shingo and Astor River basins are the smallest basins. Over the vast track of these ten basins, 5,218 glaciers are identified (Figure 7.4.11.1). These glaciers are mainly distributed in the northern part of HKH region covering higher

(a) Mountain glacier (b) Valley glaciers

W29%

NW5%

N24%

NE3%

E14%

SE3%

SW8%

S14%

N13%

NE24%

SE25%

S13%

NW25%

(c) Ice cap glaciers (d) Ice apron glaciers

SW9%

W9%

NW9%

S9%

N27%

E37%

NE14% E

5% SE6%

SW11% S

5%

W18%

N30%

NW11%

(e) Cirque glaciers (f) Niche glaciers

E16%

W16%

NW9%

SW10%

S7%

SE9%

NE12%

N21%

N15% NE

11%

E6% SE

13% S

11%

SW20%

NW9% W

15%

Figure 7.4.10.6: Distribution of different types of glaciers with respect to aspect in

Jhelum River basin.

169

Karakoram and Hindu Kush ranges. These glaciers are also present at the higher elevations of Himalayas. Maximum number of glaciers (1098 and 1050) is in the Indus and Hunza river basins respectively. Among these two basins, the glaciers are larger in size in Hunza River basin compared to Indus River basin. The southern basins like Swat, Shigar, Shyok and Jhelum have relatively less number of glaciers (Figure 7.4.11.2). Astor and Gilgit River basins contribute equal number (11% each) of glaciers. All the ten basins contribute to a total glacier area of about 15,040.8 sq. km which is 11.68% of the total area. The Shingo and Jhelum river basins contribute less than one percent to the glacier area. On contrary only 194 (4%) glaciers in Shigar River basin contribute about 15% to the glacier area and 1098 (22%) glaciers in Indus River basin contribute only about 5% of glacier area.

The total length of glaciers in ten basins is more than 9,718 km (Table 7.4.11.1). The glacier length in Hunza River basin is highest (about 2,915 km) followed by Chitral and Gilgit (1,416 and 1185 respectively). Shyok and Indus basins have about the same total length of glaciers. In Shingo River basin the glaciers are small in size as well as length. Figure 7.4.11.3 shows the distribution of ice reserves in ten basins. To a total of 2,738.5 km3 of ice reserves of 10 basins, the maximum is contributed by Shyok River basin (32%) followed by Hunza (30%) and Shigar river basins (21%). The contribution of southern basins especially Swat, Jhelum and Shingo is extremely low for being 0.74% altogether (Table 7.4.11.1).

Table 7.4.11.1: Summary of glacier inventory in ten basins

Basins Basin Area (km2)

No. of Glaciers

Glacier area (km2)

Total Length (km)

Ice Reserves (km3)

Swat 14656.23 233 223.55 329.84 12.221 Chitral 15322.43 542 1903.67 1416.06 258.817 Gilgit 14082.46 585 968.10 1185.45 83.345 Hunza 16389.48 1050 4677.34 2914.81 808.794 Shigar 7381.70 194 2240.08 829.07 581.268 Shyok 10235.40 372 3547.84 1093.48 891.801 Indus 32571.20 1098 688.00 1042.37 46.381 Shingo 4679.50 172 36.91 99.65 1.009 Astor 4214.00 588 607.03 549.05 47.931 Jhelum 9198.40 384 148.18 258.43 6.943

Total 128730.80 5218 15040.70 9718.21 2738.510

170

Figure 7.4.11.1: Glacier distribution in ten River basins.

171

Indus2%

Astor2% Chitral

10%Gilgit3%

Hunza30%

Shigar21%

Shyok32%

Figure 7.4.11.3: Percentage ice reserves of ten river basins.

Table 7.4.11.2 shows the distribution of various types of glaciers in ten river basins. Among various types of glaciers the maximum number of glaciers is of Mountain type (1918) followed by Cirque and Niche type. The Ice cap type glaciers are minimum in number. Among these ten basins, generally the mountain and sub types of mountain glaciers are higher in number compared to Valley glaciers. In the southern basins like Swat, Jhelum and Shingo the number of Valley glaciers are especially low whereas in the northern basins like Chitral, Hunza and Shigar the number of Valley glaciers is relatively high. Compared to the number of Valley glaciers, the area contribution of these glaciers is higher (Table 7.4.11.3). The Mountain glaciers contribute 18% to the glaciated area while the subtypes of Mountain glaciers collectively contribute only 7%. Ice cap glaciers are smallest and therefore, contribute the minimum area. In Swat, Shingo, Astor and Jhelum River basins the area coverage of Valley glaciers is less than Mountain glaciers while in rest of the basins the Valley glaciers have more area than Mountain glaciers. In Gilgit and Indus river basins the Mountain glaciers also contribute 41 and 31 percent respectively.

Jhelum7%Astor

11%Shingo

3%

Indus22% Shyok

7%Shigar

4%

Hunza21%

Gilgit11%

Chitral10%

Swat4%

Swat2%

Astor4%Indus

5%Chitral13%

Gilgit7%

Shyok24%

Shigar15%

Hunza30%

Number percentage Area percentage

Figure 7.4.11.2: Distribution of glaciers of ten river basins.

172

More than 82% of ice reserves of the basins are contributed by Shyok (32%), Hunza (29%) and Shigar (21%) river basins (Table 7.4.11.5). Another 9% is contributed by Chitral River basin. The contribution of Shingo and Jhelum River basins is very low. To the total ice reserves generally the Valley glaciers are the major contributors followed by Mountain glaciers. Compared to rest of the basins, in Chitral, Hunza, Shigar, Shyok and Indus river basins the contribution of Valley glaciers in total ice reserves is high. In Shingo River basin there is only one Valley glacier which contributes 0.022 km3 ice reserves. Table 7.4.11.5 shows that out of total 5218 glaciers; maximum glaciers are oriented towards N and NE. The E, S and NW aspects have the equal percentage of glacier number. Each basin behaves differently as far as the orientation of the glaciers in various ordinal directions is concerned. The glaciers in Indus, Jhelum and Shyok River basins are generally oriented towards northern and eastern aspects. In Shyok River basin besides the northern aspects the southern aspects have also higher number of glaciers. The Shigar River basin has glaciers in all direction but predominantly on north and north eastern aspects. In this basin north western aspects also have higher numbers.

173

Table 7.4.11.2: Summary of number of various types of glaciers in ten basins.

Basins Type Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum Total

Cirque 45 123 68 149 34 61 471 77 33 176 1237

Ice apron 16 2 55 31 4 13 103 27 64 79 394

Ice cap 5 12 6 27 3 32 33 5 15 11 149

Mountain 99 130 276 407 58 143 254 49 439 63 1918

Niche 45 150 140 235 49 71 205 13 19 47 974

Valley 23 125 40 201 46 52 32 1 18 8 546

Total 233 542 585 1050 194 372 1098 172 588 384 5218

Table 7.4.11.3: Summary of area of various types of glaciers in ten basins.

Basins Type Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum Total

Cirque 14.78 49.48 27.71 82.03 25.69 54.69 105.91 13.98 14.34 36.15 424.76

Ice apron 5.86 0.93 15.99 9.48 0.92 9.14 23.34 2.71 17.21 10.03 95.61

Ice cap 1.07 3.87 1.26 7.29 0.56 26.11 9.63 0.46 2.91 1.48 54.64

Mountain 105.32 224.84 399.42 520.83 102.36 471.06 216.67 16.58 328.75 59.05 2444.88

Niche 25.53 77.02 69.56 153.50 29.01 72.69 41.75 2.56 2.03 9.58 483.23

Valley 70.99 1547.53 454.16 3904.21 2081.54 2914.15 290.70 0.62 241.79 31.89 11537.58

Total 223.55 1903.67 968.10 4677.34 2240.08 3547.84 688.00 36.91 607.03 148.18 15040.7

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Table 7.4.11.4: Summary of ice reserves of various types of glaciers in ten basins.

Basins Type Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum Total

Cirque 0.455 1.728 1.022 3.251 1.146 2.57 2.62 0.331 0.560 1.003 14.686

Ice apron 0.176 0.030 0.480 0.282 0.022 0.35 0.53 0.049 0.430 0.197 2.546

Ice cap 0.024 0.124 0.031 0.199 0.012 1.18 0.28 0.008 0.050 0.029 1.937

Mountain 5.45 15.368 23.673 31.469 6.257 38.16 10.53 0.532 15.970 3.012 150.421

Niche 1.118 2.819 2.944 6.497 1.121 3.56 0.90 0.067 0.001 0.258 19.285

Valley 4.998 238.748 55.195 767.096 572.71 845.98 31.52 0.022 30.920 2.444 2549.633

Total 12.221 258.817 83.345 808.794 581.27 891.80 46.38 1.009 47.931 6.943 2738.51

Table 7.4.11.5: Summary of various types of glaciers under different aspects in selected ten basins.

Type Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum TotalN 32 111 74 159 26 48 231 34 156 88 959

NE 31 84 127 173 38 70 218 36 101 41 919

E 13 28 77 152 27 57 142 26 41 48 611

SE 28 66 52 118 32 48 83 10 37 30 504

S 27 42 62 176 17 57 98 7 34 32 552

SW 35 59 63 117 17 30 89 10 58 42 520

W 29 44 48 56 16 9 118 13 50 69 452

NW 38 108 82 99 21 53 119 36 111 34 701

Total 233 542 585 1050 194 372 1098 172 588 384 5218

175

Chapter 8 Inventory of Glacial Lakes

8.1 BRIEF DESCRIPTION OF GLACIAL LAKE INVENTORY

The inventory of glacial lakes of ten river basins in HKH region of Pakistan namely Swat, Chitral, Gilgit, Hunza Shigar, Shyok, Indus, Shingo, Astor and Jhelum is based on Landsat 7 ETM+ images of 2001 supplemented by the topographic maps of Survey of Pakistan, and NIMA map of U.S.Government.

8.2 GLACIAL LAKES—THEIR NUMBERING, TYPE AND CHARACTERISTICS

A glacial lake is defined as water mass existing in a sufficient amount and extending with a free surface in, under, beside, and/or in front of a glacier and originating from glacier activities and/or retreating processes of a glacier.

The numbering of the lakes started from the mouth of the major stream and proceeded clockwise round the basin.

For the inventory of glacial lakes, it is obvious to note that the lakes associated with perennial snow and ice, originate from glaciers. In some cases the isolated lakes found in the mountains and valleys far away from the glaciers may not have a glacial origin. Due to the faster rate of ice and snow melting, possibly caused by global warming noticed during the last half of the twentieth century, accumulation of water in these lakes has been increasing rapidly. The isolated lakes above 3,500 masl are considered to be the remnants of the glacial lakes left due to the retreat of the glaciers. Some of the glimpses of glacial lakes are shown in Figure 8.2.1.

The lakes are classified into Erosion, Valley trough, Cirque, Blocked, Moraine Dammed (Lateral Moraine and End Moraine Dammed lakes), and Supraglacial lakes.

Erosion lakes

Glacial Erosion lakes are the water bodies formed in a depression after the glacier has retreated. They may be Cirque type and trough Valley type lakes and are stable lakes. These Erosion lakes might be isolated and far away from the present glaciated area.

176

Supraglacial lakes

The Supraglacial lakes develop within the ice mass away from the moraine with dimensions of 50 to 100 meters. These lakes may develop in any position of the glacier but the extension of the lake is less than half the diameter of the Valley glacier. Shifting, merging, and draining of the lakes are the characteristics of the Supraglacial lakes. The merging of lakes results in expansion of the lake area and storage of a huge volume of water with a high level of potential energy. The tendency of a glacial lake towards merging and expanding indicates the danger level of the GLOF.

(a) Kachura Lake, Skardu

(b) Sheosar Lake in Deosai plains (c) Lulusar Lake in Kaghan

(d) Saiful Maluk in winter snow (e) Satpara Lake and its island

Figure 8.2.1: Some glimpses of glacial lakes in Northern Pakistan. Source: (www.geocities.com)

177

Moraine Dammed lakes

In the retreating process of a glacier, glacier ice tends to melt in the lowest part of the glacier surrounded by Lateral Moraine and End Moraines. As a result, many supraglacial ponds are formed on the glacier tongue. These ponds sometimes enlarge to become a large lake by interconnecting with each other and have a tendency to deepen further. A Moraine Dammed lake is thus born. The lake is filled with melt water and rainwater from the drainage area behind the lake and starts flowing from the outlet of the lake even in the winter season when there is minimum flow.

There are two kinds of moraine: an ice-cored moraine and an ice-free moraine. Before the ice body of the glacier completely melts away, glacier ice exists in the moraine and beneath the lake bottom. The ice bodies cored in the moraine and beneath the lake are sometimes called dead ice or fossil ice. As glacier ice continues to melt, the lake becomes deeper and wider. Finally, when ice contained in the moraines and beneath the lake completely melts away, the container of lake water consists of only the bedrock and the moraines.

Blocking lakes

Blocking lakes are formed through glacier and other factors, including the main glacier blocking the branch valley, the glacier branch blocking the main valley, and the lakes through snow avalanche, collapse and debris flow blockade.

Ice-dammed lakes

An Ice-dammed lake is produced on the side(s) of a glacier, when an advancing glacier happens to intercept a tributary/tributaries pouring into a main glacier valley. As such, an Ice core-dammed lake is usually small in size and does not come into contact with glacier ice. This type of lake is less susceptible to GLOF than a Moraine Dammed lake. A glacial lake is formed and maintained only up to a certain stage of glacier fluctuation. If one follows the lifespan of an individual glacier, it is found that the Moraine Dammed glacial lakes build up and disappear with a lapse of time. The Moraine Dammed lakes disappear once they are fully destroyed or when debris fills the lakes completely or the mother glacier advances again to lower altitudes beyond the moraine-dam position. Such glacial lakes are essentially ephemeral and are not sTable from the point of view of the life of glaciers. Generally, Moraine Dammed lakes pose a threat in the basin.

178

8.3 GLACIAL LAKES OF RIVER BASINS OF HKH REGION OF PAKISTAN 8.3.1 Glacial Lakes of Swat River basin

In Swat River basin a total of 255 glacial lakes have been identified which cover an area of more than 15.86 sq. km (Table 8.3.1.1). Generally the glacial lakes are distributed in the northern and north-central parts of the basin (Figure 8.3.1.1). Most of the glacial lakes in the basin are of Erosion (56%), Valley (21%) and End Moraine (14%). There are only three Blocked lakes in the basin covering an area of about 0.26 sq. km. The detailed attribute data of each lake is included in the Annex_gl_8.1.

Due to higher number the Erosion lakes (56%), they contribute highest (38%) in the total lake area followed by End Moraine and Valley lakes. Rest of the 13% lake area is collectively contributed by other types of lakes. Among the Valley lakes the largest lake (Swat_gl 134) has an area of 0.41 sq. km (Figure 8.3.1.2). There are 13 Valley lakes which have area ranging from 0.1 to 0.41 sq. km. Among these 13 lakes two (Swat_gl 230 and Swat_gl 52) are associated with large Cirque and Mountain glaciers (Swat_gr 173 and Swat_gr 33).

One Supra glacial lake Swat_gl 50 is associated with Swat_gr 31. Among 144 Erosion lakes 12 are associated with glaciers. The largest lake (Swat_gl 89) has an area of 0.53 sq. km while the smallest (Swat_gl 14) has 0.002 sq. km. Some of the erosion and valley type lakes are shown in figure 8.3.1.2. A total of 13 End Moraine lakes are associated with glaciers at variable distances. There are only four Lateral Moraine lakes and the largest of these (Swat_gl 125) is associated with Swat _gr 54 at a distance of 730 meters. Four Cirque lakes and two Blocked lakes have area more than 0.1 sq. km.

Table 8. 3.1.1: Summary of glacial lakes in Swat River basin Number Area (m2) Lake Types Total % Area % Largest Smallest

Blocked 3 1.18 259809 1.64 131536 27733Cirque 12 4.71 1396963 8.81 623355 17206

End 37 14.51 4316734 27.22 809688 10340Moraine dammed Lateral 4 1.57 102937 0.65 48266 4538

Erosion 144 56.47 5995846 37.80 528984 1836Supraglacial 1 0.39 9083 0.06 9083 9083Valley 54 21.18 3780086 23.83 413607 4696

Total 255 15861458

179

Figure: 8.3.1.1: Glacial Lakes of Swat River basin.

180

Table 8.3.1.2 presents the details of the largest lake of each category. The largest Blocked, Lateral Moraine and Supraglacial lakes are closed lakes. Among the various kinds of lakes the largest lake is End Morane Dammed lake with an area of about 0.8 sq. km.

Figure 8.3.1.2: Erosion lakes (Swat_gl 120 and 121) associated with Swat _gr 41 on the

left and a Valley lake (Swat_gl 122) on the right.

Table 8.3.1.2: Details of largest lake of each category in Swat River basin

Lake Type Number Area (m)

Associated Glacier Orientation Drainage

Condition

Blocked Swat_gl 196 131536 SW Cs Cirque Swat_gl 53 623355 NW Ds

End Swat_gl 32 809688 Swat_gr 28 N Ds Moraine dammed Lateral Swat_gl 125 48266 Swat_gr 54 N Cs Erosion Swat_gl 89 528984 Swat_gr 34 NE Ds Supraglacial Swat_gl 50 9083 Swat_gr 31 NW Cs Valley Swat_gl 134 413607 N Ds Cs =Closed Lakes and Ds = Drained Lakes

181

8.3.2 Glacial Lakes of Chitral River basin

The Chitral River basin has a total of 187 glacial lakes covering an area of more than 9.36 sq. km (Table 8.3.2.1). Generally the glacial lakes are scattered over the basin along the drainage system (Figure 8.3.2.1). Most of the glacial lakes of the basin have been characterized as Erosion lakes (37%) followed by Valley lakes (28%). Another 11 percent are Supraglacial and 10 percent are End Moraine lakes. Like Swat River basin the Blocked lakes are lowest in number and are only 4 contributing 0.12 sq. km of the area. The attribute data of lakes of this basin is included in Annex_gl_8.2. The Valley lakes contribute maximum lake area of about 6.6 sq. km which is about 70% of the total lake area. The Valley lakes are larger in size since 2 lakes of this type are more than one sq. km in size and another eight lakes range in size from 0.1 to 0.6 sq. km. The largest Valley lake Bash Kargol Chhat (Chitr_gl 160) is more than 1.9 km ling and has an area of about 1.87 sq. km. The smallest of this category (Chitr_gl 120) has a length of only 73 meters and area of 0.003 sq. km.

The Erosion lakes contribute about 15% to the total lake area. Among this category the smallest (Chitr_gl 126) and the largest (Sur Khing Chhat--Chitr_gl 109) lakes have the lake area of 0.003 and 0.2 sq. km respectively. Among the other types of lakes, End Moraine lakes contribute the highest. Even though the Supraglacial lakes are 11% in number they contribute only 2.6 of the lake area.

The details of largest lake of each category are included in Table 8.3.2.2. Among thses lakes, Valley lake (Chitr_gl 160) covers about 1.86 sq. km of the area and is about 2 km long. Locally this lake is named as Bash Kargol Chatt. The next largest lake is of Erosion type having an area of about 2 sq. km and the length of 0.25 km followed by End Moraine lake with an area of 0.16 sq. km and length of about 0.65 km. Typical Valley lakes of this basin in FCC are presented in Figure 8.3.2.1.

Table 8.3.2.1 : Summary of Glacial Lakes in Chitral River basin Number Area (m2) Lake Types Total % Area % Largest Smallest

Blocked 4 2.14 120412 1.29 42701 13174 Cirque 8 4.28 217200 2.32 59256 8867

End 19 10.16 659800 7.04 161827 4032 Moraine dammed Lateral 14 7.49 154416 1.65 22587 3755 Erosion 70 37.43 1370019 14.63 197158 3176 Supraglacial 20 10.70 243589 2.60 29549 3578 Valley 52 27.81 6600433 70.47 1861278 3301

Total 187 9365869

182

Figure: 8.3.2.1: Glacial Lakes of Chitral River basin.

183

Table 8.3.2.2: Details of largest lake of each category in Chitral River basin. Lake

Type Number Area (m)Associated

Glacier Orientation Drainage Condition

Blocked Chitr_gl 93 42701 - NE Ds Cirque Chitr_gl 38 59256 - SE Cs

End Chitr_gl 132 161827 Chitr_gr 311 W Ds Moraine dammed Lateral Chitr_gl 21 22587 - NW Cs Erosion Chitr_gl 109 197158 - NW Ds Supraglacial Chitr_gl 179 29549 Chitr_gr 532 W Cs Valley Chitr_gl 160 1861278 - NE Ds Cs =Closed Lakes and Ds = Drained Lakes

Table 8.3.3.1: Summary of Glacial Lakes in Gilgit River basin Number Area (m2) Lake Types Total % Area % Largest Smallest

Blocked 2 0.33 149819 0.38 134340 15479 Cirque 53 8.63 5055905 12.91 1149976 4098

End 100 16.29 7922893 20.23 728772 3743 Moraine dammed Lateral 49 7.98 1411364 3.60 90215 4835 Erosion 283 46.09 8039296 20.52 215019 2547 Supraglacial 2 0.33 80087 0.20 50153 29934 Valley 125 20.36 16510899 42.15 2723958 2160 Total 614 39170263

184

(a) Scattered Erosion and valley lakes (b) Supraglacial lakes over Valley glacier

(c) A Valley lake (Chitr_gl 130)

Figure 8.3.2.2: Few Glimpses of glacial lakes in Chitral River basin.

185

8.3.3 Glacial Lakes of Gilgit River basin

In Gilgit River basin a total of 614 glacial lakes have been identified which cover more than 39 sq. km of the area (Table 8.3.3.1). Generally the glacial lakes are distributed in the southern parts of the basin (Figure 8.3.3.1). In the northern part of the basin there are few large lakes. Out of the total glacial lakes maximum (283) are Erosion lakes followed by 125 Valley lakes and 100 End Moraine lakes. There are two each Blocked and Supraglacial lakes. The maximum area is contributed by Valley lakes followed by Erosion and End Moraine lakes. Due to small size and less number, the area contribution of Supraglacial and Blocked lakes is very low.

The two Blocked lakes (Gil_gl 603 and Gil_gl 583) have an area of 0.13 and 0.015 sq. km and length of 0.55 and 0.17 km respectively. Out of 53 Cirque lakes only two lakes have an area of about one sq. km. Mostly the Cirque lakes are small in size and are predominantly oriented towards northern aspects (Annex_gl_8.3). Thirteen End Moraine lakes are associated with glaciers either located at a distance or in contact with glacier. There are only five lakes of this category which are drained lakes while all others are classified as closed lakes.

Only six Erosion lakes have associated glacier while 277 lakes are isolated. Except few these, rests are closed lakes. Valley lakes are generally large in size and 12 of them are associated with glaciers. Two of the Valley lakes have area more than two sq. km and another two lakes are greater than 1 sq. km in size. The two of important and well know lakes are Zhoe Sar (Figure 8.3.3.2.) and Atro Sar.

186

Figure: 8.3.3.1: Glacial lakes of Gilgit River basin.

187

The details of the largest lake of each category are included in Table 8.3.3.2. The largest Valley lake (Gil_gl 608) covers an area of more than 2.7 sq. km and is more than 3 km long. The largest Cirque lake of this basin is quite large in size and covers an area of 1.15 sq. km and is about 2 km long. The largest End Moraine lake (Gil_gl 399) is associated with Gil_gr 28 and covers an area of about 0.73 sq. km. The largest lakke of other types of lakes are relatively smaller in size and length especially the Supraglacial lake.

Figure 8.3.3.2`: Zoe Sar (Gil_gl 608)

Table 8.3.3.2: Details of largest lake of each category in Gilgit River basin. Lake

Type Number Area (m) Associated

Glacier Orientation Drainage Condition

Blocked Gil_gl 603 134340 - N Cs Cirque Gil_gl 535 1149976 - N Cs

End Gil_gl 399 728772 Gil_gr 28 NW Cs Moraine dammed Lateral Gil_gl 375 90215 - NW Cs Erosion Gil_gl 122 215019 - NW Cs Supraglacial Gil_gl 610 50153 - NE Ds Valley Gil_gl 608 2723958 Gil_gr 497 NE Ds Cs =Closed Lakes and Ds = Drained Lakes

188

8.3.4 Glacial Lakes of Hunza River basin

The Hunza River basin has a relatively low number of glacial lakes as there are only 110 are identified which cover only 3.22 sq. km (Table 8.3.4.1). These lakes are distributed all over the basin (Figure 8.3.4.1). In this basin Cirque lakes are absent. In this basin there are large size glaciers therefore; Supraglacial lakes are highest in number followed by Valley and Erosion lakes. There are four each of Blocked and End Moraine lakes while Lateral Moraine lakes are only 3 in number. In the total lake area of the basin highest (41.5%) is contributed byValley lakes followed by Supraglacial (34.5%) and Erosion (11.4%) lakes.

The detailed attribute data of all the lakes is presented in Annex_gl_8.4. Among four Blocked lakes the largest and smallest lakes are 0.032 and 0.003 sq. km and all of them are closed lakes. Two are oriented towards S, one SE and one towards NW.

Out of four End Moraine lakes, three are associated with the glaciers and among them two are drained lakes. The smallest lake of this category (Hunza_gl 22) has an area of about 0.008 sq. km. All the three Lateral Moraine lakes are closed lakes and are associated with glaciers. These are oriented towards NW. Out of 20 Erosion lakes eight are associated with glaciers and the largest and smallest lake of this category are 0.086 and 0.004 sq. km in size. Except one lake all these are less than 0.5 km in length. In this basin Supraglacial lakes are relatively large in size and are oriented in all the directions. Since these are associated with glaciers, so all are closed lakes (Figure 8.3.4.2). Except few of the Valley lakes generally these are drained lakes. The largest lake of this category is about 0.3 sq. km and smallest 0.009 sq. km in size. Six lakes of this category are more than 0.5 km long.

Table 8.3.4 .1: Summary of Glacial Lakes in Hunza River basin. Number Area (m2) Lake Types

Total % Area % Largest SmallestBlocked 4 3.6 64271 2.0 32579 3772 Cirque - - - - - -

End 4 3.6 253059 7.9 120054 7677 Moraine dammed Lateral 3 2.7 88210 2.7 54836 14222 Erosion 20 18.2 366183 11.4 86466 4493 Supraglacial 55 50.0 1109241 34.5 78327 2905 Valley 24 21.8 1335153 41.5 292711 9534

Total 110 3216117

189

Figure: 8.3.4.1: Glacial Lakes of Hunza River basin.

190

The largest Blocked lake (Hunza_gl 52) is associated with Hunza_gr 744 and is .3 km long and 0.033 sq. km in size (Table 8.3.4.2). It is oriented towards NW and is a closed lake. The Pasu glacier (Hunza_gr 119) is associated with the largest End Moraine lake (Hunza_gl 6). The glacier is at a distance of 175 meters from this drained lake. The largest Lateral Moraine lake is associated with a large Mountain glacier (Hunza_gr 756) which is about 5.9 sq. km in size. This 0.3 km long lake has an area of 0.055 sq. km. The largest erosion lake is not associated with any glacier and has an area of 0.086 sq. km. It is oriented towards S and classified as a closed lake. Largest Supraglacial lake (Hunza_gl 67) is associated with a well known Hispar valley Glacier. This Supraglacial lake is 0.078 sq. km in size, 0.35 km long and is oriented towards W. The largest valley lake (Hunza_gl 47) is an isolated lake oriented towards NW having an area of 0.29 sq. km and more than half a kilometer long.

8.3.5: Glacial Lakes of Shigar River basin

In this basin there are only 54 glacial lakes covering an area of about 1 sq. km (Table 8.3.5.1). Most of these glacial lakes are distributed in the northern part and along the drainage network (Figure 8.3.5.1). Among the four types of glacial lakes identified in the basin, Supraglacial and Blocked lakes are the major types. As the basin has large glaciated area within high Karakoram Mountains so the glacial lakes are mostly of Supraglacial type. There are numerous small lakes found over large glaciers like Chogo Lungma, Biafo and Baltoro. The significant Supraglacial lakes identified are 30 in number covering an area of about 0.5 sq. km. The largest lake of this category (Shig_gl 18) is associated with glacier Shig_gr 105 and has an area of 0.065 sq. km. The smallest one is associated with the glacier Shig_gr 150 and has area of only 0.005 sq. km.

(a) Small supraglacial lakes over ablation zone of Batura glacier in FCC Pan(R),7(G),6b(B).

(b) Supraglacial lakes over Virjerab glacier in FCC 7(R),4(G),2(B).

Figure 8.3.4.2: Glimpses of supraglacial lakes in Hunza River basin.

191

Table 8.3.5.1: Summary of Glacial Lakes in Shigar River basin Number Area (m2) Lake Types Total % Total % Largest Smallest

Blocked 21 38.89 395214 36.20 108958 2782 Lateral Moraine 1 1.85 2830 0.26 2830 2830 Supraglacial 30 55.56 451185 41.32 64899 5357 Valley 2 3.70 242667 22.22 235908 6759

Total 54 1091896

The Blocked lakes (21) are the second highest in number covering an area of about 0.4 sq. km in the basin. Some of the lakes of this category are shown in Figure 8.3.5.2. The details of these lakes are given in the Annex_gl_8.5. Among the Blocked lakes the largest one is Shig_gl 22 covering an area of about 0.11 sq. km and the length of 481 meters (Table 8.3.5.2). The smallest lake Shig_gl 7 has an area of about 0.003 sq. km and is 65 meters long.

The only one Lateral Moraine lake (Shig_gl 2) covers an area of about 0.003 sq. km and has a length of 222 meters. Though there are only two Valley lakes in this basin but they contribute more than 22% of the lake area. The largest one is Shig_gl 54 having an area of 0.24 sq. km and the smallest one (Shig_gl 1) is only 0.007 sq. km in size.

Table 8.3.4 .2: Details of largest lake of each category in Hunza River basin. Lake

Type Number Area (m)Associated

Glacier Orientation Drainage Condition

Blocked Hunza_gl 52 32579 Hunza_gr 744 NW Cs Cirque - - - - -

End Hunza_gl 6 120054 Hunza_gr 119 NE Ds Moraine dammed Lateral Hunza_gl 54 54836 Hunza_gr 756 NW Cs Erosion Hunza_gl 94 86466 S Cs Supraglacial Hunza_gl 67 78327 Hunza_gr 830 W Cs Valley Hunza_gl 47 292711 NW Ds Cs =Closed Lakes and Ds = Drained Lakes

192

Figure 8.3.5.1: Glacial lakes of Shigar River basin.

193

(a) Blocked Lakes (Shig_gl 10 on left and Shig_gl 9 on right)

(b) A blocked lake Shig_gl 4

(c) Small Supraglacial lakes scattered over Baltoro glacier

Figure 8.3.5.2: Typical Blocked and Supraglacial lakes of Shigar River basin.

194

8.3.6: Glacial Lakes of Shyok River basin

The Shyok basin has only 66 glacial lakes covering the lake area of about 2.7 sq. km (Table 8.3.6.1). In this basin (part of it lying in the territory of Pakistan) most of the glaciers are concentrated in the northeastern part while the glacial lakes are scattered over the southwestern part (Figure 8.3.6.1). Most of the lakes (39.4%) are of Erosion type covering an area of about 0.5 sq. km. Though the End Moraine and Valley lakes are only 12 and 8 in number respectively but they contribute about 40 and 30% of the lake area respectively. The detailed data for each lake is included in the Annex_gl_8.4.

Table 8.3.6.1: Summary of glacial lakes in Shyok River basin. Number Area (m2) Lake Types Total % Total % Largest Smallest

Blocked 4 6.06 82237 3.07 42940 12564 Cirque 2 3.03 55623 2.07 39471 16153

End 12 18.18 1062108 39.61 210368 24882 Moraine dammed Lateral 3 4.55 64810 2.42 29623 14515 Erosion 26 39.39 494656 18.45 75395 3294 Supraglacial 11 16.67 134127 5.00 28327 5959 Valley 8 12.12 787774 29.38 266498 5504

Total 66 2681335

There are only two Cirque lakes contributing 2% of the total lake area. The largest lake (Shyk_gl 12) of this category has an area of about 0.04 sq. km and a length of 240 meters (Table 8.3.6.2). This lake is oriented tow ards northeast and is a closed lake. The smallest lake of this category Shyk_gl 47 which is also a closed lake has an area of about 0.02 sq. km.

The four Blocked lakes are contributing about 3% to the lake area. These all four lakes are closed lakes associated with different glaciers. The largest lake (Shyk_gl 32) has an area of more than 0.04 sq. km and length of 130 meters. The associated glacier with this lake is Shyk_gr 69.

Table 8.3.5.2 : Details of largest lake of each category in Shigar River basin Lake

Types Number Area (m2) Associated

Glacier Orientation Drainage Condition

Blocked Shig_gl 22 108958 - SW Cs Lateral Moraine Shig_gl 2 2830 - SE Cs Supraglacial Shig_gl 18 64899 Shig_gr 105 SE Cs Valley Shig_gl 54 235908 - SW Ds Cs =Closed Lakes and Ds = Drained Lakes

195

Figure 8.3.6.1: Glacial lakes of Shyok River basin.

196

Out of the 26 Erosion lakes the largest one (Shyk_gl 41) is associated with glacier (Shyk_gr 202). It is a closed lake having an area of 0.075 sq. km and length of 521 meters. The Erosion lakes altogether contribute 18.4% of the lake area. The smallest lake of this category (Shyk_gl 13) is a small lake covering an area of 0.003 sq. km and has length of 80 meters.

The End Moraine lakes are 12 in number and contribute about 40% to the lake area. The largest lake of this category (Shyk_gl 65) has an area of 0.21 sq. km and a length of 800 meters (Figure 8.3.6.2). It is oriented towards north and is associated with the glacier Shyk_gr 361. The smallest lake of this category (Shyk_gl 52) is also oriented towards north and is associated with the glacier Shyk_gr 313. It has an area of about 0.025 sq. km and length of 187 meters.

The Supraglacial lakes are 11 in number but generally are of small size contributing only 5% to the total lake area of the basin. All these lakes are associated with some glaciers and are mostly closed lakes. The largest Supraglacial lake (Shyk_gl 58) has an area of about 0.03 sq. km and is associated with the glacier Shyk_gr 339. The smallest one with an area of about 0.006 sq. km is associated with the glacier Shyk_gr 258.

The 8 Valley lakes in the basin contribute more than 29% of the lake area. Most of these lakes are at varying distances from their associated glaciers. Half of these eight lakes are closed type lakes. The largest Valley lake (Shyk_gl 66) is associated with glacier Shyk_gr 363 and is oriented towards north. It has an area of about 0.27 sq. km and a length of 670 meters. The smallest Valley lake (Shyk_gl 4) has an area of about 0.006 sq. km and mean length of 81 meters.

Table 8.3.6.2 : Details of largest lake of each category in Shyok River basin Lake

Type Number Area (m2)Associated

Glacier Orientation Drainage Condition

Blocked Shyk_gl 32 42940 Shyk_gr 69 SE Cs Cirque Shyk_gl 12 39471 - NE Cs

End Shyk_gl 65 210368 Shyk_gr 361 N Ds Moraine dammed Lateral Shyk_gl 59 29623 Shyk_gr 339 NE Cs Erosion Shyk_gl 41 75395 Shyk_gr 202 SW Cs Supraglacial Shyk_gl 58 28327 Shyk_gr 339 N Cs Valley Shyk_gl 66 266498 Shyk_gr 363 N Ds Cs =Closed Lakes and Ds = Drained Lakes

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8.3.7 Glacial Lakes of Indus River basin

The Indus River basin has a total of 574 glacial lakes covering an area of more than 26 sq. km (Table 8.3.7.1). Generally the glacial lakes are distributed in the north western and southeastern parts of the basin (Figure 8.3.7.1). In the eastern part of the basin there are few large lakes as well. Most of the glacial lakes in the basin are of Erosion (40%), End Moraine (17%), Supraglacial (13%) and Lateral Moraine (11%) type. The Valley and Cirque lakes contribute about 10 and 9% in the total number respectively. There are only three Blocked lakes in the basin covering an area of about 0.12 sq. km. The largest lake of this category (Ind_gl 44) has an area of about 0.1 sq. km and is located on the southern aspect in the basin. The detailed attribute data of each lake is included in the Annex_gl_8.7.

(a) A Valley lake (Shyk_gl 10) in FCC 5(R)4(G)2(B)

(b) A Valley (Shyk_gl 64) and a Moraine Dammed (Shyk_gl 65) Lake in panchromatic image

Figure 8.3.6.2 : Few major glacial lakes of Shyok River Basin

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The Cirque lakes cover an area of 20% of the total lake area. The largest Cirque Lake (Ind_gl 40) has an area of more than 0.4 sq. km and a length of 0.9 km. It is oriented towards southeast and is associated with glacier Ind_gr 162 (Table 8.3.7.2). The Erosion lakes are highest in number and are therefore, contribute maximum to the area i.e., about 28%. Most of these lakes are large in size. The largest and the smallest lakes in this category are Ind_gl 254 and Ind_gl 324 respectively.

Table 8.3.7.1: Summary of Glacial Lakes in Indus River basin Number Area (m2) Lake Types Total % Area % Largest Smallest

Blocked 3 0.52 120978 0.46 103228 7021 Cirque 53 9.23 5142216 19.73 411236 8524

End 98 17.07 5365470 20.59 367020 2455 Moraine dammed Lateral 62 10.80 1575085 6.04 109425 3068 Erosion 228 39.72 7264484 27.87 180466 3715 Supraglacial 73 12.72 1265916 4.86 75446 2630 Valley 57 9.93 5329811 20.45 1348826 6185

Total 574 26063960

The Moraine Dammed lakes are altogether 28% out of which the major share is of the End Moraine lakes. Both the End as well as Lateral Moraine lakes have more than 26% of the total lake area in the basin. The largest End Moraine lake is Karosar (Ind_gl 567) have an area of about 0.37 sq. km. The largest Lateral Moraine Lake (Ind_gl 367) has an area of 0.11 sq. km. The smallest lakes of both the categories are of almost of the same size i.e. about 0.003 sq. km.

The 73 Supraglacial lakes contribute about 5% of the total lake area of the basin. Generally these lakes are of small size. The largest (Ind_gl 468) and the smallest (Ind_gl 100) lakes of this category have an area of about 0.075 and 0.003 sq. km respectively. The Ind_gl 468 has a length of 456 meters and is associated with Ind_gr 899.

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Figure: 8.3.7.1: Glacial Lakes of Indus River basin.

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There are only 10% lakes characterized as Valley lakes but they contribute more than 20% of the total lake area of the basin. There are several important glacial lakes of this category like Satpara, Shamais, Haiteharai, Upper Kachura and Lower Kachura. The Satpara (Ind_gl 368) is the largest lake of this category covering an area of more than 1.35 sq. km (Figure 8.3.7.2).

Figure 8.3.7.2: Satpara Lake (Ind_gl 368)

The length of this lake is more than 1.7 km and it is a drained lake. The smallest lake (Ind_gl 214) of this category has an area of only 0.006 sq. km.

Table 8.3.7.2 : Details of largest lake of each category in Indus River basin Lake

Type Number Area (m2)Associated

Glacier Orientation Drainage Condition

Blocked Ind_gl 44 103228 - S Cs Cirque Ind_gl 40 411236 Ind_gr 162 SE Ds

End Ind_gl 567 367020 - SW Ds Moraine dammed Lateral Ind_gl 367 109425 - W Cs Erosion Ind_gl 254 180466 - NW Cs Supraglacial Ind_gl 468 75446 Ind_gr 899 NE Cs Valley Ind_gl 368 1348826 - N Ds

Cs =Closed Lakes and Ds = Drained Lakes

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8.3.8 Glacial Lakes of Shingo River basin

In Shingo River basin there are total of 238 glacial lakes covering an area of about 11.6 sq. km (Table 8.3.8.1). These lakes are mainly scattered in the northeastern part of the basin (Figure 8.3.8.1). In this basin only 3 each Lateral Moraine and Supraglacial lakes are present. Mostly (59.2%) the lakes are categorized as Erosion lakes followed by Valley lakes (17.2%). The Cirque and End Moraine lakes are about 10% each while there is only one Blocked lake. The details of these glacial lakes are included in Annex_gl_8.8.

Table 8.3.8.1 : Summary of Glacial Lakes in Shingo River basin Number Area (m2) Lake Types Total % Total % Largest Smallest

Blocked 1 0.42 27606 0.24 27606 27606 Cirque 25 10.50 1568342 13.53 259860 3886

End 24 10.08 874913 7.55 126852 4533 Moraine dammed Lateral 3 1.26 106241 0.92 84125 9877 Erosion 141 59.24 5653622 48.78 272231 3380 Supraglacial 3 1.26 39041 0.34 15603 10395 Valley 41 17.22 3319960 28.65 1359533 5185

Total 238 11589725

Erosion lakes are highest in number and contribute about 49% to the lake area of the basin. The higher number of these glacial lakes may indicate a past retreat of the glaciers in the basin. The largest Erosion lake (Shin_gl 142) has a size of more than 0.27 sq. km and a length of more than 0.9 km. The smallest lake of this category (Shin_gl 24) has an area of only about 0.003 sq. km and length of 82 meters.

The 41 Valley lakes contribute the second highest percentage (29%) to the lake area. The largest lake Sheosar (Shin_gl 96) has an area of about 1.36 sq. km and length more than 1.3 km (Figure 8.3.8.2). The smallest Valley Lake (Shin_gl 9) has an area of only about 0.005 sq. km and length of 85 meters. It is oriented towards northeast and has drainage.

The area covered by 25 Cirque lakes is about 1.57 sq. km which is about 13.5% of the total lake area. The largest lake of this category is Shin_gl 75 which has an area of 0.26 sq. km and length of about 1 km (Table 8.3.8.2). The smallest Cirque lake (Shin_gl 166) is about 0.004 sq. km in size with a length of only 73 meters.

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Figure 8.3.8.1: Glacial lakes of Shingo River basin.

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The End Moraine Lakes contribute 8% of the area and the largest of this category is Shin_gl 115 having an area of about 0.13 sq. km is more than 0.4 km long. The smallest one is Shin_gl 41 with an area of 0.005 sq. km and a length of 108 meters.

There are only three Supraglacial lakes in the basin, which contribute about 0.4% to the lake area. The largest (Shin_gl 107) this category has an area of about 0.015 sq. km.

(a) Scattered glacial lakes (b) Sheosar Lake (Shin_gl 96)

Figure 8.3.8.2: Glacial lakes of Shingo River basin in FCC Pan(R)7(G)6b(B)

Table 8.3.8.2 : Details of largest lake of each category in Shingo River basin Lake

Types Number Length (m)Associated

Glacier Orientation Drainage Condition

Cirque Shin_gl 75 963 - N Ds End Shin_gl 115 437 - SW Ds Moraine

Dammed Lateral Shin_gl 232 108 - NE Cs Valley Shin_gl 96 1304 - S Ds Blocked Shin_gl 237 266 - SE Cs Supraglacial Shin_gl 107 204 - NE Cs Erosion Shin_gl 142 936 - SW Cs Cs =Closed Lake and Ds = Drained Lake

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8.3.9 Glacial Lakes of Astor River Basin The Astor river basin has a total of 126 glacial lakes having surface area of 5.53 km2 (Table 8.3.9.1). These lakes are mainly distributed in the southern as well as southeastern part of the basin (Figure 8.3.9.1). Most of these glacial lakes are Erosion type (33%) followed by Valley(31%) and Cirque (23%). The 42 Erosion lakes identified in the basin cover 13.7% lake area in the Basin. They have the cumulative surface area of 0.75 sq. km. The largest and the smallest lake in this category have an area of 0.06 and 0.002 sq. km respectively. The Erosionlakes are generally stable and are therefore less susceptible to GLOF. The database of each glacial lake of this basin is presented in Annex_gl 8.9.

There are altogether 39 Valley Lakes, which contributes around 34% lake area in the Astor Basin. The largest and smallest Valley Lakes have the area of 0.34 and 0.003 sq. km respectively. The lake area contributed by this type of lakes is the second highest in the basin

The Cirque lakes are 29 in number, which is third highest in number in the Astor Basin. The total lake surface area covered by this type of lakes is around 2 sq. km, which is the highest (37.6%) surface cover in the Astor Basin. The largest lake in the basin is Cirque Lake (Astor_gl 92), which has 0.54 sq. km surface area.

Though the Blocked lakes are only 8 in number but they contribute around 6 percent in number as well as total lake area in the basin. These lakes are formed due to blockage by landslide debris and/or moraine debris in the valley. Generally these types of lakes are susceptible to breaching of dam as the lake water increases. The largest and smallest lake of this class has an area of 0.16 and 0.003 sq. km respectively. Some of the glimpses of various types of glacial lake in the basin are shown in figure 8.3.9.2.

Table 8.3.9.1: Summary of Glacial Lakes in Astor basin Number Area (m2) Lake Types

No. (%) Area (%) Largest Smallest Blocked 8 6.3 324421 5.9 155047 3182.43 Cirque 29 23.0 2079795 37.6 541924 3574.57

End 4 3.2 382284 6.9 160565 45631.63 Moraine dammed Lateral 3 2.4 77710 1.4 53465 10621.57 Erosion 42 33.3 755163 13.7 59900 2277.09 Supraglacial 1 0.8 21088 0.4 21088 21087.21 Valley 39 30.9 1887542 34.1 342952 2890.21

Total 126 5528003

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Figure 8.3.9.1: Glacial lakes of Astor River basin.

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A total of 7 lakes are classified as Moraine Dammed lakes out of which 4 are End Moraine and three are Lateral Moraine. The End Moraine lakes are relatively large in size. The largest End Moraine dammed lake Astor_gl 108 covers area of 0.16 sq. km and is associated with the glacier Astor_gr 445 (Table 8.3.9.2). There is only one Supraglacial lake (Astor_gl_125), which is formed within the glacier moraine of glacier number Ast_gr 579. The lake has an area of 0.02 sq. km. The details of the largest glacial lake of each category in the basin are included in the Table 8.3.9.2.

(a) Valley and Erosion lakes (b) A typical Cirque lake

(c) Scattered Erosion lakes (d) A closed End Moraine

Figure 8.3.9.2: Typical glacial lakes in Astor River Basin

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8.3.10 Glacial Lakes of Jhelum River basin

The Jhelum River basin has a total of 196 glacial lakes covering an area of about 11.8 sq. km.Most of these lakes are concentrated in the northern and eastern parts of the basin (Figure 8.3.10.1). More than 55% of the lakes are Erosion type (Table 8.3.10.1). The Cirque lakes are43 in number followed by 24 End Moraine and 10 Valley lakes. The detailed database of each lake is presented in the Annex_gl_8.10.

Table 8.3.10.1 : Summary of Glacial Lakes in Jhelum River basin Number Area (m2) Lake Types Total % Total % Largest Smallest

Blocked 1 0.51 37565 0.32 37565 37565 Cirque 43 21.94 4055975 34.41 1036592 7866

End 24 12.24 1615167 13.70 713186 4731 Moraine dammed Lateral 7 3.57 96115 0.82 27055 7933 Erosion 110 56.12 3508061 29.77 791251 2576 Supraglacial 1 0.51 10598 0.09 10598 10598 Valley 10 5.10 2462348 20.89 874930 6412

Total 196 11785829

There are total 110 Erosion lakes covering an area of 3.5 sq. km in the basin. The largest Erosion lake (Jhe_gl 170) has an area of about 0.8 sq. km and has a length of more than 1 km. It is oriented towards northeast and is a drained lake (Table 8.3.10.2). The smallest lake of this category (Jhe_gl 182) has an area of about 0.003 sq. km and is oriented towards northeast.

Table 8.3.9.2: Details of largest lake of each category in Astor River Basin Lake

Types Number Area (m2) Associated

Glacier Orientation Drainage Condition

Blocked Astor_gl 122 155047 Astor_gr 579 NE Cs Cirque Astor_gl 92 541924 NE Ds

End Astor_gl 108 160565 Astor_gr 445 NW Cs Moraine dammed Lateral Astor_gl 105 53465 Astor_gr 420 E Cs Erosion Astor_gl 91 59900 E Ds Supraglacial Astor_gl 125 21088 Astor_gr 579 NE Cs Valley Astor_gl 90 342952 W Ds Cs =Closed Lakes and Ds = Drained Lakes

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There are only 10 Valley lakes but are of large size since they contribute about 21% of the total lake area of the basin. The largest Valley lake, the Lolusar lake (Jhe_gl 14) is a drained lake with an area of about 0.9 sq. km (Figure 8.3.10.2). This lake is oriented towards northeast. The Saiful Maluk lake (Jhe_gl 73) is another important Valley lake of this basin, which has an area of 0.44 sq. km and length of 0.8 km. This lake drains into River Kunhar - amajor tributary of Jhelum River. The smallest Valley lake Jhe_gl 10 is a drained lake with an area of more than 0.006 sq. km and is oriented towards east.

There are 43 Cirque lakes covering an area of more than 4 sq. km. The largest Cirque lake (Jhe_gl 89) covers an area of more than 1 sq. km. The smallest Cirque lake has an area of about 0.011 sq. km. There is only 1 Blocked lake (Jhe_gl 80) covering an area of 0.38 sq. kmand is oriented towards southeast. Similarly there is only one Supraglacial lake (Jhe_gl 179) having an area of 0.011 sq. km and is oriented towards north.

The largest End Moraine lake (Jhe_gl 131) occupies an area of more than 0.71 sq. km and is oriented towards northwest. The smallest lake (Jhe_gl 60) of this category has an area of about 0.005. Lateral Moraine lakes are smaller in size and the largest lake of this category (Jhe_gl 91) has an area of only 0.027 sq. km.

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Figure 8.3.10.1: Glacial lakes of Jhelum River Basin.

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(a) Lake Saiful Maluk (Jhe_gl 73) (b) Lake Lulusar (Jhe_gl 14) in FCC 542

(c) A Valley lake (Jhe_gl 101) in FCC 542 (d) An Erosion lake (Jhe_gl 170) in FCC 543

Figure 8.3.10.2: Few important glacial lakes of Jhelum River basin.

Table 8.3.10.2 : Details of largest lake of each category in Jhelum River basin Lake

Types Number Area (m2)Associated

Glacier Orientation Drainage Condition

Blocked Jhe_gl 80 37565 - SE Cs Cirque Jhe_gl 89 1036592 - W Ds

End Jhe_gl 131 713186 - NW Cs Moraine dammed Lateral Jhe_gl 91 27055 - NE Cs Erosion Jhe_gl 170 791251 - N Ds Supraglacial Jhe_gl 179 10598 - N Cs Valley Jhe_gl 14 874930 - NE Ds Cs =Closed Lakes and Ds = Drained Lakes

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8.3.11 Summary

In summary, a total of 2,420 glacial lakes have been identified in ten river basins of HKH region of Pakistan (Table 8.3.11.1). The maximum glacial lakes are identified in Gilgit River basin (614), followed by Indus (574), Swat (255) and Shingo (238) River basins. The lowest number of glacial lakes is in Shigar (54) and Shyok (66) River basins. Among various types of lakes the highest number is of Erosion type (1,064) due to the fact that in all the basins except Hunza and Shigar river basins. In Hunza River basin they are low in number and in Shigar they do not exist. These are followed by Valley lakes (412) and End Moraine Dammed (322) lakes. Blocked lakes are lowest in number (51) out of which 21 are present in Shigar River basin while in Shingo and Jhelum river basins these are one each. The Cirque lakes are more common in Gilgit, Indus, Jhelum, Astor and Shingo River basins. Similarly the End Moraine lakes are also common in these basins alongwith Swat River basin while Lateral Moraine lakes are highest in number in Indus and Gilgit River basins. The Supraglacial lakes are common in the basins where there are large size glaciers like Indus, Hunza, and Shigar. Very few Valley lakes are present in the northern basins like Shigar (2) and Shyok (8) River basins.

Figure 8.3.11.1 shows the distribution of glacial lakes in ten river basins. Generally the lakes are distributed all over the ten basins but mostly concentrated in different pockets. The maximum concentration is observed in the northern part of Indus River basin and adjoining southern part of Gilgit River basin. One cluster can also be observed in the northeastern part of Swat River basin. In the northern part of Jhelum River basin and eastern part of Shingo River basin bordering the Indus River basin clusters of lakes are found. In the center of Astor River basin the glacial lakes are quite prominent.

A total of 2,420 glacial lakes in HKH region of Pakistan contribute 126.35 sq. km of lake area. The maximum lake area is recorded for Gilgit River basin (about 39.2 sq. km) followed by Indus River basin (26 sq. km). Just like the lowest number, the lowest lake area was observed in Shigar and Shyok River basins (Table 8.3.11.2). The southern basins especially Shingo and Jhelum contribute the equal lake area (about 12 sq. km each). Among the various types of lakes, Valley lakes are the largest and altogether contribute about 33% of the total lake area followed by Erosion (26.5%) and End Moraine Dammed (18%) lakes. Generally Blocked, Supraglacial and Later Moraine lakes are small in size and contribute very low lake area.

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Table 8.3.11.1: Summary of number of glacial lake types in selected ten Basins.

Types Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum Total

Blocked 3 4 2 4 21 4 3 1 8 1 51

Cirque 12 8 53 - - 2 53 25 29 43 225

End 37 19 100 4 - 12 98 24 4 24 322 Moraine dammed Lateral 4 14 49 3 1 3 62 3 3 7 149

Erosion 144 70 283 20 - 26 228 141 42 110 1064

Supraglacial 1 20 2 55 30 11 73 3 1 1 197

Valley 54 52 125 24 2 8 57 41 39 10 412 Total 255 187 614 110 54 66 574 238 126 196 2420

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Figure 8.3.11.1: Distribution of glacial lakes in the River basins of Pakistan

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Table 8.3.11.2: Summary of area (km2) of different glacial lake types in ten Basins.

Lake types River Basin Blocked Cirque End

Moraine Lateral

Moraine Erosion Supraglacial Valley Total

Swat 0.260 1.397 4.317 0.103 5.996 0.009 3.780 15.862Chitral 0.120 0.217 0.660 0.154 1.370 0.244 6.600 9.365Gilgit 0.150 5.056 7.923 1.411 8.039 0.080 16.511 39.17Hunza 0.064 - 0.253 0.088 0.366 1.109 1.335 3.215Shigar 0.395 - - 0.003 - 0.451 0.243 1.092Shyok 0.082 0.056 1.062 0.065 0.495 0.134 0.788 2.682Indus 0.121 5.142 5.365 1.575 7.264 1.266 5.330 26.063Shingo 0.028 1.568 0.875 0.106 5.654 0.039 3.320 11.59Astor 0.324 2.080 0.382 0.078 0.755 0.0210 1.888 5.528Jhelum 0.038 4.056 1.615 0.096 3.508 0.011 2.462 11.786

Total 1.582 19.572 22.452 3.679 33.447 3.364 42.257 126.353

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Chapter 9

Glacial Lake Outburst Floods and Damages in the Country

9.1 INTRODUCTION

Periodic or occasional release of large amounts of stored water in a catastrophic outburst flood is widely referred to as a jokulhlaup (Iceland), a debacle (French), an aluvión (South America), or a Glacial Lake Outburst Flood (Himalaya). A jokulhlaup is an outburst which may be associated with volcanic activity, a debacle is an outburst but from a pro-glacial lake, an aluvión is a catastrophic flood of liquid mud, irrespective of its cause, generally transporting large boulders, and a GLOF is a catastrophic discharge of water under pressure from a glacier. GLOF events are severe geo-morphological hazards and their floodwaters can wreak havoc on all human structures located on their path. Much of the damage created during GLOF events is associated with the large amounts of debris that accompany the floodwaters. Damage to settlements and farmland can take place at very great distances from the outburst source, for example, in Pakistan the damage occurred 1,300 km from the outburst source (WECS 1987 b).

9.2 CAUSES OF LAKE CREATION Global Warming

There is growing concern that human activities may change the climate of the globe. Past and continuing emissions of carbon dioxide (CO2) and other gases will cause the temperature of the earth’s surface to increase -- this is popularly termed ‘global warming’ or the ‘greenhouse effect’. The ‘greenhouse effect’ gives an extra temperature rise.

Glacier Retreat

An important factor in the formation of glacial lakes is the rising global temperature (‘greenhouse effect’), which causes glacial retreat in many mountain regions. During the so-called ‘Little Ice Age’ (AD 1550–1850), many glaciers were longer than today. Moraines formed in front of the glaciers at that time block the lakes nowadays. Glaciation and inter-glaciation are natural processes that have occurred several times during the last 10,000 years. As a general rule, it can be said that glaciers in the Himalayas have retreated about one Km since the Little Ice Age, a situation that provides a large space for retaining melt water, leading to the formation of moraine-dammed lakes (LIGG/WECS/NEA. 1988 and Mool et al., 2001).

Röthlisberger and Geyh (1985) conclude in their study on ‘glacier variations in the Himalaya and Karakorum’ that a rapid retreat of nearly all glaciers with small oscillation was found in the period from 1860/1900–1980.

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Causes of Glacial Lake Water Level Rise

The rise in water level in glacial lakes dammed by moraines creates a situation that endangers the lake to reach a breaching point. The causes of water level rise in glacial lakes are given below.

Rapid change in climatic conditions that increase solar radiation causing rapid melting of glacier ice and snow with or without the retreat of the glacier

Intensive precipitation events

Decrease in sufficient seepage across the moraine to balance the inflow because of

sedimentation of silt from the glacier runoff, enhanced by the dust flow into the lake

Blocking of ice conduits by sedimentation or by enhanced plastic ice flow in the

case of a glacial advance Thick layer of glacial ice (dead ice) weighed down by sediment below the lake

bottom, which stops subsurface infiltration or seepage from the lake bottom. Shrinking of the glacier tongue higher up, causing melt water that previously left

the glacier somewhere outside the moraine, where it may have continued underground through talus, not to follow the path of the glacier

Blocking of an outlet by an advancing tributary glacier

Landslide at the inner part of the moraine wall, or from slopes above the lake level

Melting of ice from an ice-core moraine wall

Melting of ice due to subterranean thermal activities (volcanogenic, tectonic)

Inter-basin sub-surface flow of water from one lake to another due to height

difference and availability of flow path

9.3 BURSTING MECHANISMS

Different triggering mechanisms of GLOF events depend on the nature of the damming materials, the position of the lake, the volume of the water, the nature and position of the associated mother glacier, physical and topographical conditions, and other physical conditions of the surroundings.

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Mechanism of Ice Core-dammed Lake Failure

Ice-core dammed (glacier-dammed) lakes drain mainly in two ways.

• through or underneath the ice • over the ice

Initiation of opening within or under the ice dam (glacier) occurs in six ways.

• Flotation of the ice dam (a lake can only be drained sub-glacially if it can lift the damming ice barrier sufficiently for the water to find its way underneath)

• Pressure deformation (plastic yielding of the ice dam due to a hydrostatic pressure difference between the lake water and the adjacent less dense ice of the dam; outward progression of cracks or crevasses under shear stress due to a combination of glacier flow and high hydrostatic pressure)

• Melting of a tunnel through or under the ice • Drainage associated with tectonic activity • Water overflowing the ice dam generally along the lower margin • Sub-glacial melting by volcanic heat

The bursting mechanism for ice core-dammed lakes can be highly complex and involve most or some of the above-stated hypothesis. Marcus (1960) considered ice core-dammed bursting as a set of interdependent processes rather than one hypothesis.

A landslide adjacent to the lake and subsequent partial abrasion on the ice can cause the draining of ice core-moraine-dammed lakes by overtopping as the water flows over, the glacier retreats, and the lake fills rapidly.

Mechanism of moraine-dammed lake failure

Moraine-dammed lakes are generally drained by rapid incision of the sediment barrier by outpouring waters. Once the incision begins, the hustling water flowing through the outlet can accelerate erosion and enlargement of the outlet, setting off a catastrophic positive feedback process resulting in the rapid release of huge amounts of sediment-laden water. Peak discharge from breached moraine-dammed lakes just downstream from the moraine can be estimated from an empirical relationship developed by Costa (1985) as shown in Figure 9.1. The onset of rapid incision of the barrier can be triggered by waves generated by glacier calving or ice avalanching, or by an increase in water level associated with glacial advance.

Dam failure can occur for the following reasons:

• melting ice core within the moraine dam, • rock and/or ice avalanche into a dammed lake, • settlement and/or piping within the moraine dam, • sub-glacial drainage, and • engineering works.

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Figure 9.1: Peak discharge from breached moraine-dammed lakes can be estimated from an empirical relationship developed by Costa (1985).

Melting Ice-core

The impervious ice core within a moraine dam melts, lowering the effective height of the dam, thus allowing the lake water to drain over the residual ice core. The discharge increases as the ice core melts, and as greater amounts of water filter through the moraine, carrying fine materials. The resulting regressive erosion of the moraine dam ultimately leads to its failure.

Overtopping by Displacement Waves

Lake water is displaced by the sudden influx of rock and/or ice avalanche debris. The resultant waves overtop the freeboard of the dam causing regressive and eventual failure.

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Settlement and/or Piping

Earthquake shocks can cause settlement of the moraine. This reduces the dam freeboard to a point that the lake water drains over the moraine and causes regressive erosion and eventual failure.

Sub-glacial Drainage

A receding glacier with a terminus grounded within a pro-glacial lake can have its volume reduced without its ice front receding up-valley. When the volume of melt water within the lake increases to a point that the formerly grounded glacier floats, an instantaneous sub-glacial drainage occurs. Such drainage can destroy any moraine dam, allowing the lake to discharge until the glacier loses its buoyancy and grounds again.

Engineering Works

Artificial measures taken to lower the water levels or to change dam structures may trigger catastrophic discharge events. For example, in Peru in 1953, during the artificial lowering of the water level, an earth slide caused 12m high displacement waves, which poured into a trench, excavated as part of the engineering works and almost led to the total failure of the moraine dam.

9.4 SURGE PROPAGATION

As GLOFs pose severe threats to human beings, man-made structures, agricultural fields, and natural vegetation it is important to make accurate estimates of the likely magnitude of future floods. Several methods have been devised to predict peak discharges, which are the most erosive and destructive phases of floods. The surge propagation hydrograph depends upon the type of GLOF event, i.e., from moraine-dammed lake or from ice-dammed lake (Figure 9.2). The duration of a surge wave from an ice-dammed lake may last for days to even weeks, while from a moraine-dammed lake the duration is shorter, minutes to hours. The peak discharge from the moraine-dammed lake is usually higher than from ice-dammed lakes.

The following methods have been proposed for estimation of peak discharges.

1) Clague and Mathews formula

Clague and Mathews (1973) were the first to show the relationship between the volume of water released from ice-dammed lakes and peak flood discharges.

Qmax = 75(V0*10–6)0.67

where Qmax = peak flood discharge (m3 s-1)

V0 = total volume of water drained out from lake (m3)

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Figure 9.2: Difference in release hydrograph between moraine and ice-dammed lakes (WECS 1987a).

The above relationship was later modified by Costa (1988) as the peak discharge yielded from the equation was higher than that measured for Flood Lake in British Columbia that occurred in August 1979:

Qmax = 113(V0*10–6)0.64

Later Desloges et al. (1989) proposed:

Qmax=17V0*19(V0–6)0.64

This method of discharge prediction is not based on any physical mechanism, but seems to give reasonable results.

2) Mean versus maximum discharge method

If the volume of water released by a flood and the flood duration are known, the mean and peak discharges can be calculated. Generally the flood duration will not be known in

221

advance. Hence, this method cannot be used to determine the magnitude of future floods. Observations of several outburst floods in North America, Iceland, and Scandinavia have shown that peak discharges are between two to six times higher than the mean discharge for the whole event.

3) Slope area method

This method is based on measured physical parameters such as dimensions and slope of channel during peak flood conditions from direct observations or geo-morphological evidence.

Qmax = vA

The peak velocity is calculated by the Gauckler–Manning formula (Williams 1988)

v = r 0.67 S 0.50/n

where

v = peak velocity

S = bed slope for a 100m channel reach

n = Manning’s roughness coefficient

r = hydraulic radius of the channel

r = A/p

where

A = cross-sectional area of the channel

p = perimeter of the channel under water

For sediment floored channels, bed roughness is mainly a function of bed material, particle size, and bed form or shape and can be estimated from:

n = 0.038D 0.167

where

D = average intermediate axis of the largest particles on the channel floor.

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Desloges et al. (1989) compared the results from all the three methods for a jokulhlaup from the ice-dammed Ape Lake, British Columbia. All the methods gave comparable results.

• The Clague and Mathews’ method gave a calculated peak discharge of 1,680 ± 380 m3s-1

• The mean versus maximum discharge method gave 1,080–3,240 m3 s–1. • The slope area method gave 1,534 and 1,155 m3 s–1 at a distance of 1 and 12 km

from the outlet respectively.

These general relationships are useful for determining the order of magnitude of initial release that may propagate down the system. However, to predict the magnitude of future floods, the first method should be applied, because the volume of lake water can be estimated in advance. Attenuation of a peak discharge of 15,000–20,000m s–1 has been reported for the Poiqu River in Tibet (Sun Koshi in Nepal) within a distance of 50 km (XuDaoming 1985). Surges can be serious hazards in populated areas, engulfing occupied land, generating sudden floods, or disrupting local communications below and across glaciers. They tend to recur in cycles peculiar to each glacier involved and out of phase with general patterns of glacier advance and retreat. In regions with many surging glaciers, of which the Karakoram Himalaya is one, surges complicate the normally rather sensitive relations between glaciers and climate. There is a consensus that, whatever the controlling factors and exact mechanisms, the key to surging lies in conditions that promote large, episodic instability at the glacier bed. Proposed trigger mechanisms include fluctuations in thermal or hydrological conditions or in deformable subglacial sediment, acting alone or in combination (Clarke et al. 1984, Kamb 1987 and Raymond, 1987). Nevertheless, the geography of surges is highly uneven. There are large numbers in just a few regions, while none have been recognized in most glaciated areas. This suggests there are special but varying combinations of environmental conditions that promote or suppress surging. It is in relation to these questions that the Karakoram glaciers and the kinds of evidence available for them are of broadest scientific interest. Many Karakoram glaciers, and all of those known to surge, are predominantly or wholly avalanche fed (von Klebelsberg 1925B6). The highest precipitation occurs in the perennial ice climate zone between 5,000 and 7,000 m (Hewitt 1993). Avalanches carry this more abundant snow directly to the glaciers. Much of it accumulates at or below the regional snow and firn limits. Avalanche-derived ice tends to be heavily freighted with debris. This relatively dirty ice contributes to higher melting rates in the upper and middle ablation zones, while thick supraglacial debris suppresses melting in the lower ablation zones. Enormous ramps of debris develop and build outward beside and beneath the ablation zones of these avalanche-fed glaciers (Goudie et al 1984 and Hewitt, 1993). Surging may be influenced by an unusual buildup of deformable sediment beneath these zones and/or by unstable transitions from frozen to unfrozen bed conditions.

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Karakoram surges occur in a highly active tectonic zone with globally extreme rates of uplift and denudation (Searle, 1991). The glaciers drape the highest parts of the range, where a series of steeply inclined lithospheric thrust faults occur. However, structures and rock types are complex and poorly known where blanketed by snow and ice. Most surging glaciers cross two or more major formations. No specific or distinctive relationship of surging to lithology, indicated in some other regions, has yet been found. Hot springs are widespread across the region and it has been suggested that they, or the geothermal heat flow implied, could be a factor in surges. Studies in the Yukon Territory of Canada and Svalbard found that surge-type glaciers tend to be longer, wider, and of lower gradient than normal glaciers. We lack the data for a comparable analysis for the Karakoram. Meanwhile, no surges are recorded for more than 30 glaciers that are longer. Among the longest, widest, and lowest gradient glaciers, Siachen (75 km long), Biafo (68 km), Batura (60 km), Chogo Lungma (47 km), and Chiantar (35 km) have exhibited normal advance and retreat over the past one or two centuries (Mercer, 1975). As with Panmah-Chiring, main glaciers not known to surge are much longer, of gentler slope, and wider than their surging tributaries. The orientation of the watershed and ice stream seems to be unimportant or incidental to surging in Alaska-Yukon (Clarke, 1991). However, two thirds of Karakoram surging ice streams originate mainly or wholly on slopes with a northerly aspect and most flow in a northerly direction. The one fifth with southerly orientation includes the more extreme, high-elevation watersheds with steep-walled, avalanche-fed glaciers. A detailed review has been made by Hewitt (1969) about the surges of major glaciers in Karakoram Range in Pakistan (Annex_9.1) 9.5 SEDIMENT PROCESSES DURING A GLACIAL LAKE OUTBURST FLOOD During a GLOF, the flow velocity and discharge are exceptionally high and it becomes practically impossible to carry out any measurement. Field observations after a GLOF event have shown a much higher sediment concentration of rivers than before the GLOF event (Electrowatt Engineering Service Ltd 1982 and WECS 1995a). WECS (1995) calculated the volume of scoured sediment as 22.5*104 m3 after the Chhubung GLOF in 1991. A high concentration of 350,000 mg–1 during a GLOF in the Indus River at Darband in 1962 is reported by Hewitt (1985). Figure 9.3 gives a hypothetical GLOF illustration showing discharge and variation in sediment concentration (WECS 1987a). The total sediment load is generally accepted as the wash load, which moves through a river system and finally deposits in the deltas. During a GLOF event, stones the size of small houses can be easily moved (WECS 1987b). The relationship between flow velocity and particle diameter can also be used to calculate the size of boulders that can be moved during such events.

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Figure 9.3: Hypothetical illustration of GLOF showing discharge and variation in sediment concentration (WECS 1987a)

9.6 SOCIOECONOMIC EFFECTS OF GLACIAL LAKE OUTBURST FLOODS

GLOFs create conditions for two very different types of flooding: upstream flooding as a result of impoundment and downstream flooding as a result of dam failure. The threat to life from upstream flooding is minimal because the water level behind the dam rises relatively slowly, although property damage can be substantial as the basin of the natural impoundment fills. It is usually possible to estimate accurately the extent and rate of upstream flooding from landslide dams. Such estimates require knowledge of the height of the dam crest, rates of stream flow into the dam lake, rates of seepage through or beneath the dam, and information on the topography upstream from the dam.

Downstream flash floods, resulting from the failure of landslide dams, are usually much larger than those originating directly from snowmelt or rainfall and are a significant threat to life and property. The losses are extensive in terms of damage to roads, bridges, trekking trails, villages, agricultural land, natural vegetation, as well as the loss of human lives and infrastructure. The sociological impacts can be direct when human lives are lost or indirect when the agricultural lands are converted to debris filled lands and the village has to be shifted. The records of past GLOF events in the Himalayas show that once every three to ten years, a GLOF has occurred with varying degrees of socioeconomic impact. Therefore, the

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most appropriate mitigation methods must be applied after conducting a proper hazard assessment study based on an evaluation of possible economic loss.

During recent decades there has been a rapid retreat of glaciers all over the world, new lakes are being formed, and the size of the existing lakes attached to the glaciers is increasing. Another emerging hypothesis of more GLOF events is the change in the pattern of rainfall (Awan, 2002).

9.7 BRIEF REVIEW OF GLACIAL LAKE OUTBURST FLOOD EVENTS AND DAMAGES CAUSED IN PAKISTAN

The history of GLOF and its hazards are as old as the glacial history of northern Pakistan. During the late Pleistocene and Little Ice Age, the damages caused by GLOF were large-scale and extensive compared to the recent ones. In the past 50 years, the general 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 in glacial advance which may be a precursor of an era of renewed dam burst floods. The flood risks associated with monsoonal storm conditions are common in summer, in the lowland areas of Pakistan. However, the larger part of summer high flows in the lndus system are due to snow and ice melting. At certain periods in the past, for example, the 1920s and 30s glacier dams and dam burst floods, in the Indus system, were a major and recurrent risk. The same risks still exist and, further, they are anticipated in the future. An understanding of the mountainous headwater of the Indus and especially of the snow and ice conditions is lacking and/or inadequate in Pakistan. This is the main gap in the knowledge essential for hydrological forecasting of the Indus system. In a broader context, this is the most conspicuous gap in our knowledge of the range of the global snow and ice environments.

An environment such as the Upper Indus basin presents a range of potentially dangerous conditions for man and his installations. Thirty-five destructive outburst floods are recorded in the Karakoram region in the past two hundred years (Figure 9.4). Thirty glaciers are known to have advanced across major headwater streams of the Indus and Yarkhun. Some ice dams may have been the result of glacier surges. A surge is commonly accompanied by increased water and sediment 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 (Khan 1994). Some of the surge and flood events reported by different sources are given in Table 9.1.

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Figure 9.4: Location of destructive outburst floods recorded in the Karakoram region in the past 200 years (Khan 1994).

9.8 SOME EXAMPLES OF GLOF EVENTS

There are many flood events recorded in Pakistan. Most of the available information is on the floods caused by climatic disturbances like cloud burst in the catchments particularly in monsoon season. Generally the detailed information on the specific GLOF events is limited. The monetary losses and death toll of the floods in Pakistan has been reported by various sources and some times there is no agreement among these figures (Table 9.1 and 9.2 and 9.3). The death toll of 1950 GLOF event recorded was 2,900 (www.southasianfloods.org/regional/pakistan), 2,190 (www.southasianfloods.org/document) and 2910 (www.icimod.org.np/publications/newsletter/New38).

Some of the main events recorded are as follows:

• In 1884 an ice dam burst in the Shimshal valley, a northern tributary of the Hunza, and led to a three-metre 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 1905. 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 by over 15 m above its normal summer flood level at Chalt. Other events occurred in 1927 and 1928. In 1959, a sudden burst took place in a lake dammed by one of the big glaciers in the Shimshal valley. The flood caused by the

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Table 9.1: Inventory of Glacier Surges in the Karakoram Himalaya Date Glacier (valley) Surge Sources 1860s (?) Karambar Probable surge. Hayward (1871) (Gilgit-Ishkoman) Damaging floods Kreutzmann (1994) on Gilgit R. 1860-61 "Maedan" Probable surge pushing Schlagentweit (1866) Panmah tributary aside Chiring and Godwin-Austen (1864) (Braldu) Nobande Sobande, overriding flanks and draining lakes. 1861 attrib. Karambar ice dam burst. 1868-69 Aktash Terminus advanced Shaw (1871) 1,600 m in three months 1886-87 Chiring, Panmah "Immense ice-slip Younghusband (1892) tributary (Braldu) on glacier and Shipton (1938) gigantic blocks of ice..." prevented crossing to Skinmang and access to 'New' Mustagh Pass late 19th Garumbar, Approx. 2.5 km Mason (1931 century Hispar tributary advance. late 1800s (?) Sumaiyar Advanced to join Conway (1894) Bur-Burpu Bualtar. (Hispar-Nagyr) 1890-92 Pumarikish tributary Overriding lateral Conway (1894 (Hispar) maraines and pushing main glacier aside. 1892-93 Minapin (Hunza) 370 m sudden Mason (1930; 1935 advance. 1,200 m advance in all. 1893-95 Hassanabad (Hunza) 9.7 km in 2.5 Hayden (1907) months. "...2 miles Workman (1911) in present summer Neve (1907) ( 1895)...then stopped..." 1895-1905 Karabar (Ishkoman) Surge dammed river Todd (1930) 1905 glacier lake Kreutzmann (1994) outburst and largest flood disaster on Gilgit River 1901-02 Yengutz Har "2,600 m in spring" Mason (1931)

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(Hispar) "...2 miles...in 8 days" 1902-03 Aktash (Upper Sudden, rapid Longstaff (1910) Shyok) advance. 1902-03 Chogo Lungma "...several miles..." Workman and Workman tributary (Shigar- (1908) Basha) 1929-30 Bualtar (=Hopar) 550 m and further Mason (1931) (Hispar-Nagyr) 150 m during summer. 1930 Karambar "...100 paces (in.) Mason (1931) (Gilgit-Ishkoman) three weeks of March..." 1930 Sultan Chhussky "...enormous push Visser and Visser-Hooft (Upper Shyok) forward...200-300 (1935-1938) million meters cubed of ice..." 1931 Drenmang/Panmah Reconstructed from Shipton (1938 tributary (Braldu) location of surge lobe unpublished) in Nobande Sobande in 1937. 1935-36 Aktash (Upper 2.5 km in 7 months Lyall-Grant and Mason Shyok) (1940) 1953 Kutiah (Stak Valley) 12 km in 2 months Desio (1954 March to early May (Desio et al, 1961) 1955 Karambar Surge blocked Hewitt (unpubl. notes) (Gilgit-Ishkoman) valley but Karambar R. maintained tunnel under the ice. 1958 (?) Aktash Rapid advance Mercer (1975) (Upper Shyok) 1974-77 Balt Bare (Hunza) 2 km rapid advance Wang et al (1984) in 1976-77, preceded by huge debris flow in 1974 1977-78 Drenmang/Panmah Rapid advance Hewitt (unpubl. from tributary (Braldu) of lobe into satellite imagery) Nobande Sobande. 1986-90 Bualtar (=Hopar) Two surges, one Gardner and Hewitt (Hispar-Nagyr) following rock (1990) avalanche (1986-87, Hewitt (unpubl. field and second in 1989- notes) 90, 2 km advance. 1988-89 Pumarikish/Hispar 1.5 km surge Wake and

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tributary pushing main Searle(1993) (Hispar) glacier aside. 1989-93 Lokpar/Alling Surge of Lokpar Hewitt (unpubl. field tributary tributary followed notes) (Shyok-Hushe) by steepening and 1.5 km+ advance of main terminus. Dam burst flood from ice margin lakes (1990). 1992 (?) Sumaiyar Bar/ Report of sudden, Hewitt (unpubl. Barpu tributary. massive thickening notes) (Hunza-Hispar) and other surge-like behavior. 1993 Karambar Surge began in April Hewitt (unpubl. field (Gilgit-Ishkoman) and glacier notes advancing 7-10 m per day in June. 1993 (?) Masherbrum Gl. Thickening and Hewitt (unpubl (Hushe) surge-like behavior notes) of upper glacier. 1994-96 Chiring/Panmah Surge advanced Hewitt (unpubl. field tributary 2.5 km, pushing notes) (Braldu) aside ice of main glacier. 1990s Liligo tributary 2 km rapid advance Hewitt (unpubl. from of Baltoro to reach main glacier satellite imagery) (Braldu) 1990s Moni tributary & 2 km rapid advance Hewitt (unpubl. from Sarpo Laggo across and down satellite imagery) (Shaksgaur) main glacier. Sorce: Hewitt, K. 1998. Recent Glacier Surges in the Karakoram Himalaya, South Central Asia. www.agu.org/eos_elec/97016e.html.

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• burst had a depth of around 30 m at the junction of Shimshal and Hunza, (about 40 km from the assumed position of the lake) and destroyed the village of Passu near the Hunza river (Goudie et al. 1984).

• GLOF events of 1929 and 1932 from Chung Khumdan in the Shyok basin in Upper Indus, it was estimated that volume released was about 13.5 million cubic meters and peak discharge of 22,650 cubic meters per second, in August 1929, which is considered as the largest discharges measured for the entire Upper Indus and at Attock 1,300 Km downstream with discharge greater than 15,000 cubic meters per second.

• Between 1973 and 1974 the Batura glacier melt water stream suddenly shifted its course a few hundred metres, the consequence of which was the removal of a section of the Karakoram Highway embankment and the destruction of a major bridge.

• In 1977 the Balt Bare glacier above the village of Shiskat released a surge of melt water which on its decent collected boulders, stones, grit, and soil. The resulting mud flash took away several houses from the village before spreading across the valley floor to block off the river. The 20m high dam created a lake that stretched back almost to Pasu and in the process drowned several kilometers of newly constructed road. When the dam finally yielded to the water pressure (bombing by the Pakistan Air Force being ineffective), one important bridge and a long stretch of roadway was buried on accumulated lakebed silt but by this time a completely new road section and bridge was under construction (Francis et al. 1984).

• In Darkot and Barandos (September 1978), the flooding of a lake outburst caused by low frequency events, were responsible for the removal of fields and for the deposition of up to 4 m of stone debris. At Darkot, 80 houses and a school were washed away (Hughes 1984).

Table 9.2: Historical flood damages in Pakistan Value of Property Damaged

(Rs. in Million) Year Unadjusted Adjusted

Lives Lost

Villages Affected

1950 199.80 11,282.00 2,190 10,000 1957 155.50 7,356.00 160 11,609 1959 152.50 6,958.00 83 4,498 1973 5,137.00 118,684.00 474 9,719 1976 5,880.00 80,504.00 425 18,390 1978 4,478.00 51,489.00 393 9,199 1988 6,879.00 25,630.00 508 1,000 1992 34,751.00 69,580.00 1,008 13,208 1995 6,125.00 8,698.00 591 6,852 Total 63,757.8 380,181.00 5,832 84,475

Source: (www.southasianfloods.org/document)

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Table 9.3: Estimated damages during major flood events in Pakistan

Year

Direct Monitory Losses (US $ in

million) adjusted to 1995 price level

Lives Lost Villages Affected

Area Flooded (square miles)

1950 227 2,910 10.000 700 1955 176 679 6.945 8,000 1956 148 160 11.609 29,065 1957 140 83 4.498 6,251 1958 49 96 2.459 5,863 1959 100 88 3.902 4,072 1973 2,388 474 9.719 16,200 1976 1,621 425 18.390 32,000 1978 1,036 393 9.199 11,952 1980 63 75 862 744 1981 139 82 2.071 1,637 1982 8 41 289 101 1983 63 39 643 735 1984 35 42 251 427 1985 7 30 171 89 1988 399 508 100 2,400 1992 1,400 1,008 13.208 15,140 1994 392 N.A. N.A. N.A. 1995 175 N.A N.A N.A 1996 8,924 N.A N.A N.A

Source: Mountain Flash Floods: A General Overview (www.icimod.org.np/publications/newsletter/New38)

• On August 6th, 1999 a debris-flow occurred from a right bank between Khalti Lake and Gupis. There is reported to be a small glacier (Charti Glacier) at the head of this valley and also 2 glacial lakes below the glacier terminus. The debris-flow crossed the Gupis to Shandur Road and blocked the Ghizer River, creating a lake about 1.5 km in length, now known as Khankhui Lake. The duration of blockage is not known, but the flow over the debris lobe is still constricted to a 5- meter channel, with rapids downstream over a distance of 150 m. This event also occurred without accompanying rainfall.

• A GLOF and debri-flow occurred on July 27th 2000 at Kande from a tributary of the Hushe River (tributary of the Shyok). Villagers referred to a supraglacial lake on the glacier before the flood occurred. A previous flood had occurred from the same source on 25 July 1997, but was much less severe than the one in 2000. Kande village was virtually destroyed in the flood, including 124 houses and a primary school. The event happened in the middle of the day, during a period of exceptionally hot weather and without rain. Villagers heard a roar in the hills about 10 minutes before the arrival of the flood and fled to higher ground and so

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there were no fatalities. The initial flood/debris wave did most of the damage, but sporadic bursts of water occurred for a further 8 days.

• On June 10th 2000 a lake formed again in the Shimshal valley, as described above. Water began to flow over the top of the icedam on 28 May and breached on 10 June. The level in the Hunza was reported as increasing by 10 feet at Passu, but only 2 feet at Hunza. No serious damage resulted, as the breach occurred early in the year when the lake size was small (Awan, 2002).

Chung Khumdan Dam Burst

Glacier survey 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. The advance of the Chung Khumdan glacier - a tributary of the Shyok, had formed this ice dam. The 1929 outburst flood of Chung Khumdan glacier was monitored from near the glacier for over 1,500 km downstream. The filling of the reservoir and the timing and magnitude of the resulting outburst floods in 1929 is shown in Table 9.4.

Table 9.4: Details of Chung Khumdan Dam and Glacier (1929)

Dam Glacier Length of lake: 16 km Orientation: E Average width: 1.6 km Max. length: 20 km Slope of valley floor: 1 in 130 Width at lower ablation zone: 2.5 kmDepth of dam: 120 m Terminus altitude: 4715masl Volume: 1.5 X 109 m3 Highest point on basin: 5250m Width of ice barrier: 2.4km Rate of rise of lake in August: 0.3-0.45m/day

Gunn (1930) estimated the reservoir to have contained almost 13.5 x 108m3. Some 3x105m3 of ice were also carried by the flood and stranded on large blocks in the valley below the dam. At the peak of the steeply rising and falling flood, water discharges in excess of 22,650 m3 S-1 (800,000 cfs) were indicated, which is the largest discharge ever measured for the entire upper lndus at Attock. The only information available for 1926, 1929 and 1932 Khumdan outbursts is that breaching began through subglacial tunnels, but then carried away the entire thickness of ice above (Khan 1994).

A significant number of floods, resulting from landslide or debris flow dambreaks, have also been occurred over the last three decades, but examples from earlier dates are restricted to events of extreme magnitude. Table 9.5 provides a summary list of such events, drawn from a variety of sources. In 1972/3 a mudflow blocked the Hunza River at Batura, following 10.3 mm rainfall in 2 days – date given as 1972 (Miller 1984). Shifeng, Y. and Wang, W. (1980) in the introduction to the glaciological study of the Batura glacier refer to 1973 flood, which

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damaged the highway and bridge over the Batura channel. The team of Chinese glaciologists was sent to Batura Glacier, in response to this event and to consider reconstruction, and work was done during 1974 and 1975. The report gives no further english description of the event.

Table 9.5: Floods generated by landslide and debris flow dam breaks

Year Date Location River/Basin Source

1841 June Lichar Ghar Indus Drew, Hewitt

1858 August Phungurh Hunza Belcher, Goudie et al

1937 July Hunza Said

1974 11 April Baltbar near Batura Hunza Cai Xiangxing et al

1974 14 August Baltbar Hunza Cai Xiangxing et al

1977/78 Darkot Yasin/Gilgit Raschid (1995) Whiteman (1985)

1970s Yashpur, Henzel Gilgit Awan

1999 July? Juj Bargo Ghizer/Gilgit Awan On April 11th 1974 a mudflow, with a front 20 to 30 m high, occurred from Baltbar Nallah, a left bank tributary 18 km south of Batura. A fan was formed 300 to 400 m wide, over 150 m long and 80 to 100 m high, blocking the Hunza River and submerging the Friendship Bridge constructed in 1970 and creating a lake 12 km long (Zhang, X. and Shifeng, W., 1980). Mr Ali Madad, owner and manager of the Kisar Inn, Altit, was an eye-witness to the debri flood. He recalls that he and his uncle had reached the Nallah near Gulmit when they stopped their jeep and his uncle went forward to inspect the bridge, there having been some previous rains. Suddenly, he heard a roaring sound and saw a smoke-like mist upstream. A wave-front of stones and mud rushed down the valley, overwhelmed the bridge and killed his uncle instantly, along with some villagers working in nearby fields. He fled and narrowly escaped. In 1988, a concerted effort was made by Snow and Ice Hydrology Project (SIHP) to study lakes created by natural dams in the upper Hunza basin, concentrating on the main Hunza Valley between Gulmit, Batura and Shimshal Valley (Figures 9.5 and 9.6). In the Gulmit to Batura section of the Hunza Valley there is geomorphological evidence for a complex history of lakes in the form of extensive lacustrine deposits. Johnson (1988) discussed in depth the geomorphological and sedimentological analysis of the Hunza Valley lake sediments and also the hazards created by the development of smaller ice-marginal lakes. Similarly, Kelly (1988) outlines the historical development and disappearance of Virjerab Lake (Figure 9.5). Under certain conditions an advance of Khurdopin and Yurkshin Garden Glaciers can temporarily block the main Shimshal Valley, impounding runoff from Virjerab Glacier and resulting in the formation of a large lake. The total lake volume was estimated to have been 2.0x108 m3. The instantaneous maximum discharge was

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calculated to be 2600 m3 s-1, or approximately twelve times greater than the average July discharge of the Indus River at Beham Qila.

Figure 9.5: Virjerab ice-dammed lake site in Shimshal valley of Hunza River Basin. Figure 9.6: Ice and mass movement dammed lake sites in Hunza River basin; A, B, C, D sites of dammed

lakes studied by Johnson (1988), E) 1974 Mudflow dam and F) 1858 Rockfall dam. In 1974 a debris flow from a left-bank gully followed heavy rainfall and blocked the Hunza River, which then had a flow of 250 m3/sec. The mudflow had a front 5 m high;

Shimshal River

Pasu glacier

Batura glacier

Hunza River

Batura Gorge A

B

C

D

E

F

Ghulkin glacier

Gulmit

Virjerab glacier

Khurdopin glacier

Yazghil glacier

Shimshal River

Virjerab Lake Basin

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the stage rose rapidly and submerged the bridge over the Hunza. One hour later, the river cut through the fan deposits. Raschid (1995) quotes a resident of Darkot on the Upper Yasin River as saying “In 1977 a flood of rocks and mud all but obliterated the village and destroyed every inch of farmland”. Whiteman (1985) refers to this event as occurring in 1978. A gigantic mud flow on 12th July, 2000, comprising heavy boulders and wooden logs, etc. washed away an arch bridge at Shatial. The intensity of the flow was so high that it broke the 100 ft high bridge like match sticks(Figure 9.7a). After overcoming the worst site restrictions a new bridge of 170 ft was constructed by army engineers in Shatial (Farrukh, 2002).

(a) Mud flow washed away the bridge

(b) Launching of a new bridge

Figure 9.7: Effect of a gigantic mud flow in Shatial.

A debris-flow from a small steep left-bank nallah at Juj Bargo produced a debris lobe across the river against the rock-face on the right bank on 31 Jul/August. A lake was formed upstream and destroyed the small village of Juj Bargo and still (in 2001) extends about 1 km in length upstream from the remaining barrier. The site is a short distance upstream from Gakuch and the Ishkoman confluence (Awan 2002).

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9.9 LAKE OUTBURST FLOOD HAZARDS

The significance of these floods lies especially in the exceptional risk to human communities or installations, and also in their role in erosion and sedimentation. Over much of their course in the mountains, the recorded floods reach heights well above peak discharges from summer melting. The dynamic character greatly magnifies their erosion competence and capacity. These two matters are of singular importance in the context of erosion of the Karakoram valleys, and sediment transport into downstream reservoirs. Huge numbers of landslides have been reported on terraces and valley sides after the passage of dam burst floods. If one extrapolates the existing sediment rating curve for Darband or Attock before the Tarbela Dam was built, the 1929 flood curve would have carried the equivalent of one average year’s sediment yield. These erosion events could increase the rate of sedimentation in artificial dams on these rivers, and reduce their economic lifetime.

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Chapter 10 Potentially Dangerous Glacial Lakes On the basis of actively retreating glaciers and other criteria, the potentially dangerous glacial lakes can be identified using the spatial and attribute database complemented by multi-temporal, remote–sensing data sets. Medium to large scale aerial photographs are also useful for detailed geomorphic studies and for evaluation of the active glaciers and potentially dangerous lakes.

In general, based on geo-morphological characteristics, glacial lakes can be grouped into three types: glacial Erosion lakes, glacial Cirque lakes, and Moraine Dammed lakes. The former two types of glacial lakes occupy the lowlands or emptying cirques eroded by ancient glaciers. These glacial lakes are more or less located away from present-day glaciers and the downstream banks are usually made of bedrock or covered with a thinner layer of loose sediment. Both of these glacial lakes do not generally pose an outburst danger. On the other hand, the Moraine Dammed glacial lakes have the potential for bursting. A standard index to define a lake that is a source of potential danger because of possible bursting does not exist.

Moraine Dammed glacial lakes, which are still in contact or very near to the glaciers, are usually dangerous. The present study defines all the lakes formed by the activity of glaciers including in the past as ‘glacial lakes’. Moraine Dammed glacial lakes are usually dangerous. These glacial lakes were partly formed between present-day glaciers and Little Ice Age moraine. The depositions of Little Ice Age moraines are usually about 300 years old, form high and narrow arch-shaped ridges usually with a height of 20–150 m, and often contain dead glacier ice layers beneath them. These End Moraines are loose and unstable in nature. The advance and retreat of the glacier affect the hydrology between the present-day 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. Such phenomena have been well known in the past in several cases of Moraine Dammed lakes, although the mechanisms at play are not fully understood.

10.1 CRITERIA FOR IDENTIFICATION

The criteria for identifying the potentially dangerous glacial lakes are based on field observations, processes and records of past events, geo-morphological and geo-technical characteristics of the lake and surroundings, and other physical conditions.

Rise in Lake Water Level

In general, the lakes, which have a volume of more than 0.01 km3 are found to have past events. A lake, which has a larger volume than this, is deeper, with the deeper part near the dam (lower part of lake) rather than near the glacier tongue, and has rapid increase in lake water volume is an indication that a lake is potentially dangerous.

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Activity of Supraglacial lakes

As time passes, groups of closely spaced Supraglacial lakes of smaller size at glacier tongues merge and form bigger lakes. Using temporal satellite images, one can identify the successive merging of Supraglacial lakes and the formation of a bigger lake. These activities of Supraglacial lakes are indications that the lakes are becoming potentially dangerous.

Position of Lakes

The potentially dangerous lakes are generally at the lower part of the ablation area of the glacier near to the End Moraine, and the mother glacier should be sufficiently large to create a potentially dangerous lake environment. Regular monitoring needs to be carried out for such lakes with the help of multi-temporal satellite images, aerial photographs, and field observations.

In general, 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 km2 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 km2 associated (in contact or distance less than 0.5 km) with steep hanging glaciers are considered to be potentially dangerous. Even the smaller size steep hanging glacier may pose a danger to the lake.

Dam Conditions

The natural conditions of the moraine damming the lake determine the lake stability. The lake stability will be less if the moraine dam has a combination of the following characteristics:

• narrower in the crest area • no drainage outflow or outlet not well defined • steeper slope of the moraine walls • ice cored • very tall (from toe to crest) • mass movement or potential mass movement in the inner slope and/or outer slope • breached and closed in the past and refilled again with water • seepage flow at moraine walls

A Moraine Dammed lake, which has breached and closed subsequently in the past and has refilled again with water, can breach again. Nagma Pokhari Lake in the Tamor basin of Nepal burst out in 1980. The study of recent aerial photographs and satellite images shows a very quick regaining of lake water volume. Zhangzangbo Lake in the Poiqu basin in Tibet (China) burst out in 1964 and again in 1981. Recent satellite images show that the lake has refilled with water and, therefore, could pose danger. Ayaco Lake in the Pumqu basin in Tibet (China) burst out in 1968, 1969 and 1970 and at present it is refilled again with water and poses danger. Similarly in Pakistan in 1884 an ice dam burst in the Shimshal valley, a northern tributary of the Hunza River and led to a three-metre rise in

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the river level causing considerable devastation at Ganesh and Baltit. This was followed by a similar event in 1893 and then again in 1905. 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. Regular monitoring of such lakes is necessary using multi-temporal satellite images.

Conditions of Associated Mother Glacier

Generally, the bigger Valley glaciers with tongues reaching an elevation of below 5,000 masl have well-developed glacial lakes. Even the actively retreating and steep hanging glaciers on the banks of lakes may be a potential cause of danger. The following general characteristics of associated mother glaciers can create danger to Moraine Dammed lakes:

• hanging glacier in contact with the lake, • bigger glacier area, • fast retreating, • debris cover at glacier tongue area, • steep gradient at glacier tongue area, • presence of crevasses and ponds at glacier tongue area, • toppling/collapses of glacier masses at the glacier tongue, and • ice blocks draining to lake. Physical Conditions of the Surrounding Area

Besides moraines, mother glaciers, and lake conditions, and other physical conditions of the surrounding area as given below may also cause the lake to be potentially dangerous:

• potential rockfall/slide (mass movements) site around the lake which can fall into the lake suddenly,

• 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, • climatic conditions of successive years being a relatively wet and cold year

followed by a hot and wet or hot and dry year, • very recent moraines damming the lake at the tributary glaciers that used to be just

a part of a former complex of Valley Glacier, middle moraines as a result of the fast retreat of a complex mother Valley Glacier, and

• sudden advance of a glacier towards the lower tributary or the mother glacier having a well-developed lake at its tongue

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10.2 MAJOR GLACIAL LAKES ASSOCIATED WITH THE GLACIERS AND POTENTIALLY DANGEROUS GLACIAL LAKES OF TEN RIVER BASINS IN HKH REGION OF PAKISTAN

For identification of potentially dangerous glacial lakes, the glacial lakes associated with glaciers such as Supraglacial, Valley, Cirque and /or dammed by Lateral Moraine or End Moraine with an area larger than 0.02 km2 have been considered and they have been defined as major glacial lakes. The details of the major lakes of all the five basins are included in the subsequent sections.

10.2.1 Swat River basin

In Swat River basin out of 255 glacial lakes, 163 lakes have been characterized as major lakes. These major lakes contribute about 94% of the lake area of the basin. The detail of each major lake is given in the Table 10.2.1.1. Out of these, maximum are Erosion lake (80) followed by Valley (37) and End Moraine dammed (31) lakes (Table10.2.1.2). There are only three Blocked and two Lateral Moraine Dammed lakes. Out of the total area of major lakes, the highest contribution is of Erosion type lakes. End Moraine and Valley lakes contribute about the same area. Since the Blocked and Lateral Moraine lakes are few in number, their contribution in the lake area is also low. The number of various types of lakes follows the pattern of their area.

The Valley lakes are quite high in number and the largest lake of this category (Swat_gl 134) has an area of 0.41 sq. km. There are 15 lakes of this type having an area of more than 0.1 sq. km. The largest Erosion lake (Swat_gl 89) has an area of 0.53 sq. km is associated with a Valley glacier (Swat_gr 34) at a distance of 57 m. The 12 lakes of this type are larger than 0.1 sq. km. The largest End Moraine lake (Swat_gl 32) has an area of 0.81 sq. km and is located at a distance of 595 meters from a glacier Swat_gr 28. Only four Cirque lakes and two Block lakes have an area of more than 0.1 sq. km. Table 10.2.1.1: Major Lakes of Swat River basin.

S. No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier (m)

1 Swat_gl 202 Blocked 27733 Swat_gr 114 572 Swat_gl 27 Blocked 100540 3 Swat_gl 196 Blocked 131536 4 Swat_gl 69 Cirque 29458 5 Swat_gl 174 Cirque 38384 6 Swat_gl 60 Cirque 50058 7 Swat_gl 70 Cirque 63628 8 Swat_gl 71 Cirque 69278 9 Swat_gl 4 Cirque 87910

10 Swat_gl 81 Cirque 102935 11 Swat_gl 72 Cirque 126031 12 Swat_gl 76 Cirque 168793 13 Swat_gl 53 Cirque 623355 14 Swat_gl 47 End Moraine 20213 15 Swat_gl 24 End Moraine 20575 16 Swat_gl 232 End Moraine 21711

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17 Swat_gl 229 End Moraine 23614 18 Swat_gl 130 End Moraine 24306 Swat_gr 55 67119 Swat_gl 25 End Moraine 39370 20 Swat_gl 98 End Moraine 39595 21 Swat_gl 102 End Moraine 46102 22 Swat_gl 208 End Moraine 50060 Swat_gr 145 23 Swat_gl 155 End Moraine 50805 24 Swat_gl 86 End Moraine 54429 25 Swat_gl 18 End Moraine 54730 26 Swat_gl 49 End Moraine 61093 Swat_gr 31 27 Swat_gl 203 End Moraine 68917 Swat_gr 119 47028 Swat_gl 96 End Moraine 69282 29 Swat_gl 221 End Moraine 73956 30 Swat_gl 23 End Moraine 92125 Swat_gr 6 44231 Swat_gl 255 End Moraine 92482 32 Swat_gl 172 End Moraine 106274 33 Swat_gl 213 End Moraine 137532 34 Swat_gl 107 End Moraine 141750 35 Swat_gl 90 End Moraine 146887 Swat_gr 35 40336 Swat_gl 187 End Moraine 158596 37 Swat_gl 183 End Moraine 160213 38 Swat_gl 211 End Moraine 209326 Swat_gr 151 55039 Swat_gl 142 End Moraine 221979 40 Swat_gl 28 End Moraine 223806 Swat_gr 21 41 Swat_gl 234 End Moraine 260274 Swat_gr 178 35442 Swat_gl 189 End Moraine 274358 43 Swat_gl 129 End Moraine 480899 Swat_gr 54 175544 Swat_gl 32 End Moraine 809688 Swat_gr 28 59545 Swat_gl 194 Erosion 20064 46 Swat_gl 238 Erosion 20414 47 Swat_gl 215 Erosion 21106 48 Swat_gl 57 Erosion 21347 49 Swat_gl 214 Erosion 21452 50 Swat_gl 67 Erosion 22106 51 Swat_gl 10 Erosion 22677 52 Swat_gl 103 Erosion 23739 53 Swat_gl 95 Erosion 24026 54 Swat_gl 66 Erosion 24049 55 Swat_gl 210 Erosion 24220 56 Swat_gl 150 Erosion 24603 57 Swat_gl 239 Erosion 24825 58 Swat_gl 170 Erosion 25257 59 Swat_gl 151 Erosion 26320 60 Swat_gl 252 Erosion 26542 61 Swat_gl 145 Erosion 26685 62 Swat_gl 175 Erosion 26712 63 Swat_gl 1 Erosion 26807 64 Swat_gl 247 Erosion 26897 Swat_gr 209 142965 Swat_gl 241 Erosion 27939 66 Swat_gl 94 Erosion 28357 67 Swat_gl 9 Erosion 28715

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68 Swat_gl 63 Erosion 28754 69 Swat_gl 113 Erosion 29030 70 Swat_gl 82 Erosion 29257 71 Swat_gl 222 Erosion 29409 72 Swat_gl 58 Erosion 30090 73 Swat_gl 171 Erosion 30594 74 Swat_gl 127 Erosion 30620 Swat_gr 54 76175 Swat_gl 104 Erosion 31376 76 Swat_gl 112 Erosion 32019 77 Swat_gl 75 Erosion 32132 78 Swat_gl 123 Erosion 33937 79 Swat_gl 243 Erosion 34011 80 Swat_gl 184 Erosion 34197 81 Swat_gl 55 Erosion 34839 82 Swat_gl 191 Erosion 34982 83 Swat_gl 29 Erosion 36726 84 Swat_gl 160 Erosion 38419 85 Swat_gl 153 Erosion 39476 86 Swat_gl 16 Erosion 39753 87 Swat_gl 246 Erosion 39779 88 Swat_gl 207 Erosion 40568 89 Swat_gl 159 Erosion 41469 90 Swat_gl 149 Erosion 42520 91 Swat_gl 7 Erosion 43321 92 Swat_gl 109 Erosion 44868 93 Swat_gl 192 Erosion 45450 Swat_gr 84 57894 Swat_gl 132 Erosion 45671 95 Swat_gl 146 Erosion 46973 96 Swat_gl 68 Erosion 49657 97 Swat_gl 77 Erosion 49827 98 Swat_gl 158 Erosion 50149 99 Swat_gl 152 Erosion 52474

100 Swat_gl 20 Erosion 53047 101 Swat_gl 135 Erosion 53103 102 Swat_gl 143 Erosion 55458 103 Swat_gl 84 Erosion 56386 104 Swat_gl 209 Erosion 57385 105 Swat_gl 205 Erosion 57929 106 Swat_gl 156 Erosion 60549 107 Swat_gl 111 Erosion 72108 108 Swat_gl 141 Erosion 73370 109 Swat_gl 126 Erosion 75081 Swat_gr 54 222110 Swat_gl 17 Erosion 81803 111 Swat_gl 12 Erosion 89970 112 Swat_gl 93 Erosion 92806 113 Swat_gl 147 Erosion 101575 114 Swat_gl 38 Erosion 116173 115 Swat_gl 2 Erosion 127224 116 Swat_gl 106 Erosion 140910 117 Swat_gl 157 Erosion 141402 118 Swat_gl 44 Erosion 146252

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119 Swat_gl 21 Erosion 147399 120 Swat_gl 120 Erosion 202881 Swat_gr 41 121 Swat_gl 37 Erosion 285237 122 Swat_gl 240 Erosion 312778 123 Swat_gl 121 Erosion 444671 Swat_gr 41 380124 Swat_gl 89 Erosion 528984 Swat_gr 34 57125 Swat_gl 237 Lateral Moraine 44092 126 Swat_gl 125 Lateral Moraine 48266 Swat_gr 54 730127 Swat_gl 30 Valley 20685 128 Swat_gl 61 Valley 22219 129 Swat_gl 128 Valley 23441 Swat_gr 54 1443130 Swat_gl 139 Valley 26397 131 Swat_gl 231 Valley 26987 Swat_gr 177 514132 Swat_gl 116 Valley 27727 133 Swat_gl 140 Valley 28099 134 Swat_gl 163 Valley 32817 135 Swat_gl 83 Valley 33143 136 Swat_gl 242 Valley 34080 137 Swat_gl 138 Valley 35287 138 Swat_gl 110 Valley 39641 139 Swat_gl 220 Valley 42109 140 Swat_gl 224 Valley 43306 141 Swat_gl 117 Valley 47665 142 Swat_gl 225 Valley 53055 Swat_gr 170 3048143 Swat_gl 79 Valley 55458 144 Swat_gl 236 Valley 59404 145 Swat_gl 169 Valley 59578 146 Swat_gl 188 Valley 79325 147 Swat_gl 217 Valley 79555 148 Swat_gl 193 Valley 82273 149 Swat_gl 165 Valley 95435 150 Swat_gl 233 Valley 99992 151 Swat_gl 52 Valley 101777 Swat_gr 33 833152 Swat_gl 230 Valley 103539 Swat_gr 173 1728153 Swat_gl 133 Valley 106857 154 Swat_gl 33 Valley 110685 155 Swat_gl 48 Valley 128893 156 Swat_gl 118 Valley 141824 157 Swat_gl 218 Valley 157742 158 Swat_gl 31 Valley 163688 159 Swat_gl 122 Valley 186830 160 Swat_gl 173 Valley 208206 161 Swat_gl 195 Valley 232256 162 Swat_gl 204 Valley 365369 163 Swat_gl 134 Valley 413607

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In Swat River basin only two End Moraine lakes have been classified as potentially dangerous lakes (Figure 10.2.1.1). These two lakes are located in the extreme north western part adjacent to the Chitral River basin. The Swat_gl 28 has an area of 0.224 sq. km and is associated with Swat_gr 21 (Table 10.2.1.3). It is dangerous because the associated glacier is a large Valley glacier having an area of about 4.694 sq. km. The second dangerous lake (Swat_gl 189) is located near massive glaciated area which is quite clear in Figure 10.2.1.2.

Table 10.2.1.2: Summary of Major Lakes of Swat River basin. Area (m2) S. No. Type Number Area (km2) Largest Smallest

1 Blocked 3 0.260 131536 27733 2 Cirque 10 1.360 623355 29458 3 End Moraine 31 4.235 809688 20213 4 Lateral Moraine 2 0.092 48266 44092 5 Erosion 80 5.362 528984 20064 6 Valley 37 3.569 413607 20685 Total 163 14.878

Table 10.2.1.3: Potentially dangerous glacial lakes in Swat River basin.

S. No. Lake type Lake Number

Total Area (m2)

Associated Glacier

Distance to glacier Remarks

1 End Moraine Swat_gl 28 223806 Swat_gr 21 - In contact with large glacier source

2 End Moraine Swat_gl 189 274358 - Near massive glaciers source

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Figure 10.2.1.1: Distribution of potentially dangerous glacial lakes in Jhelum River basin.

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(a) Swat_gl 189 (b) Swat_gl 28

Figure 10.2.1.2: Potentially dangerous glacial lakes in Swat River basin. 10.2.2 Chitral River basin

In Chitral River basin out of 187 glacial lakes, 70 lakes have been characterized as major lakes. These major lakes contribute about 68% of the accumulative lake area of the basin. The detail of each major lake is given in the Table 10.2.2.1. Out of these, maximum are Valley lakes (30) followed by Erosion (17) and End Moraine dammed (12) lakes (Table10.2.2.2). There is only one Supraglacial, two Lateral Moraine and three Blocked lakes in the basin. Out of total area of major lakes, the highest contribution (78%) is of Valley lakes followed by (10%) Erosion lakes. Supraglacial, Lateral Moraine, blocked and Cirque lakes are few in the basin and therefore contribute minimum to the accumulative area of major lakes of the basin.

The largest and smallest Valley lakes (Chitr_gl 160 and Chitr_gl 184) have area of more than 1.86 and 0.02 sq. km respectively. There are two such lakes which have area more than 1 sq. km while the area of another eight ranges from 0.6 to 0.11 sq. km. Five lakes of this type are associated with glaciers. One Supraglacial lake is small in size for being only 0.03 sq. km. Both the Lateral Moraine dammed lakes are small in size. Except the largest Erosion lake (Chitr_gl 109) all lakes of this type are less than 0.1 sq. km. Among the End Moraine dammed lakes, except one (Chitr_gl 133) all are in contact with glaciers. Generally the Blocked and Cirque lakes are relatively small in size.

Table 10.2.2.1: Major Lakes of Chitral River basin.

S. No. Lake number Type Area (m2) Associated glacier

No. Distance to glacier (m)

1 Chitr_gl 147 Blocked 22315 Chitr_gr 398 3742 Chitr_gl 144 Blocked 42222 Chitr_gr 358 3 Chitr_gl 93 Blocked 42701 4 Chitr_gl 187 Cirque 20779 5 Chitr_gl 183 Cirque 22829 6 Chitr_gl 181 Cirque 28131 7 Chitr_gl 186 Cirque 50273 8 Chitr_gl 38 Cirque 59256 9 Chitr_gl 11 End Moraine 23757 Chitr_gr 7

10 Chitr_gl 141 End Moraine 26632 Chitr_gr 331

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11 Chitr_gl 42 End Moraine 28819 Chitr_gr 50 12 Chitr_gl 133 End Moraine 30528 13 Chitr_gl 24 End Moraine 30556 Chitr_gr 22 14 Chitr_gl 91 End Moraine 32149 Chitr_gr 216 15 Chitr_gl 30 End Moraine 37185 Chitr_gr 35 16 Chitr_gl 145 End Moraine 45915 Chitr_gr 365 17 Chitr_gl 155 End Moraine 50821 Chitr_gr 415 83118 Chitr_gl 61 End Moraine 51640 Chitr_gr 108 19 Chitr_gl 170 End Moraine 62826 Chitr_gr 514 20 Chitr_gl 132 End Moraine 161827 Chitr_gr 311 21 Chitr_gl 13 Erosion 22060 22 Chitr_gl 10 Erosion 22523 Chitr_gr 5 23 Chitr_gl 102 Erosion 26359 24 Chitr_gl 185 Erosion 29730 25 Chitr_gl 3 Erosion 31715 26 Chitr_gl 103 Erosion 33111 27 Chitr_gl 107 Erosion 33894 28 Chitr_gl 63 Erosion 35538 29 Chitr_gl 97 Erosion 36350 30 Chitr_gl 31 Erosion 38835 31 Chitr_gl 65 Erosion 43493 32 Chitr_gl 62 Erosion 48471 33 Chitr_gl 105 Erosion 52362 34 Chitr_gl 112 Erosion 58018 35 Chitr_gl 101 Erosion 61406 36 Chitr_gl 104 Erosion 85374 37 Chitr_gl 109 Erosion 197158 38 Chitr_gl 67 Lateral Moraine 20424 39 Chitr_gl 21 Lateral Moraine 22587 40 Chitr_gl 179 Supraglacial 29549 Chitr_gr 532 41 Chitr_gl 184 Valley 20797 42 Chitr_gl 169 Valley 22921 43 Chitr_gl 119 Valley 22960 44 Chitr_gl 123 Valley 23692 45 Chitr_gl 114 Valley 24032 46 Chitr_gl 95 Valley 25502 47 Chitr_gl 134 Valley 26923 48 Chitr_gl 43 Valley 32552 Chitr_gr 52 55349 Chitr_gl 135 Valley 33915 Chitr_gr 325 63850 Chitr_gl 161 Valley 34138 Chitr_gr 457 26451 Chitr_gl 121 Valley 34374 52 Chitr_gl 136 Valley 40252 53 Chitr_gl 100 Valley 42407 54 Chitr_gl 168 Valley 47224 Chitr_gr 510 175755 Chitr_gl 99 Valley 47585 56 Chitr_gl 7 Valley 54309 57 Chitr_gl 131 Valley 60017 58 Chitr_gl 124 Valley 64146 59 Chitr_gl 118 Valley 94151 60 Chitr_gl 174 Valley 98964 61 Chitr_gl 173 Valley 113404

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62 Chitr_gl 89 Valley 127712 Chitr_gr 216 63 Chitr_gl 96 Valley 207466 64 Chitr_gl 146 Valley 228294 65 Chitr_gl 148 Valley 290994 66 Chitr_gl 94 Valley 303726 67 Chitr_gl 150 Valley 591274 68 Chitr_gl 162 Valley 599406 69 Chitr_gl 130 Valley 1184751 70 Chitr_gl 160 Valley 1861278

In this basin only one potentially dangerous lake has been identified which is located in the southwestern part of the basin which is bordering with Afghanistan Figure10.2.2.1. This lake is End Moraine type (Chitr_gl 61) having an area of 0.052 sq. km and is in contact with a Mountain type large size glacier (Chitr_gr 108) having an area of 1.75 sq. km (Figure 10.2.2.2).

Table 10.2.2.2: Summary of Major Lakes of Chitral River basin. Area (m2) S. No. Type Number Area

(km2) Largest Smallest 1 Blocked 3 0.107 42701 22315 2 Cirque 5 0.181 59256 20779 3 End Moraine 12 0.583 161827 23757 4 Lateral Moraine 2 0.043 22587 20424 5 Erosion 17 0.856 197158 22060 6 Supraglacial 1 0.043 - - 7 Valley 30 0.030 1861278 20797

Total 70 6.359 2344807 130132

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Figure 10.2.2.1: Distribution of potentially dangerous glacial lakes in Chitral River basin.

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10.2.3 Gilgit River basin

In Gilgit River basin out of 614 glacial lakes, 380 lakes have been characterized as major lakes which are about 62% of the total lakes. These major lakes contribute about 93% of the lake area of the basin. The detail of each major lake is given in the Table 10.2.3.1. Out of these, maximum are Erosion lakes (140) followed by Valley (93) and End Moraine dammed (74) lakes (Table10.2.3.2). There is only one Blocked and two Supraglacial lakes. Out of the total area of major lakes, the highest contribution is of Valley type lakes followed by End Moraine and Erosion lakes (21 and 18% respectively). The Supraglacial and Blocked lakes are very small and contribute altogether less than 0.22 sq. km.

The Erosion lakes are quite high in number and the largest lake of this category (Gil_gl 122) has an area of 0.21 sq. km. There are 11 lakes of this type having an area ranging from 0.1 to 0.22 sq. km. The smallest lake of this category (Gil_189) has an area of only 0.02 sq. km. The major Valley lakes range in size from 0.02 (Gil_gl 369) to 2.72 sq. km (Gil_gl 608). There are four valley lakes in this basin which have area more than one sq. km. Out of total of 93 major Valley lakes 12 are associated with glaciers at variable distance. Except two End Moraine dammed lakes all have area less than 0.33 sq. km. The smallest lake of this type (Gil_gl 408) has an area of 0.02 sq. km.

Figure 10.2.2.2: Potentially dangerous glacial lake (Chitr_gl 61) of Chitral River basin.

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Table 10.2.3.1: Major Lakes of Gilgit River basin

S. No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier

(m) 1 Gil_gl 603 Blocked 134340 2 Gil_gl 44 Cirque 21069 3 Gil_gl 53 Cirque 23061 4 Gil_gl 141 Cirque 23295 5 Gil_gl 150 Cirque 24263 6 Gil_gl 126 Cirque 24286 7 Gil_gl 114 Cirque 25240 8 Gil_gl 215 Cirque 25302 9 Gil_gl 119 Cirque 26290 10 Gil_gl 571 Cirque 26371 11 Gil_gl 71 Cirque 26533 12 Gil_gl 5 Cirque 27645 13 Gil_gl 596 Cirque 35201 14 Gil_gl 94 Cirque 35897 15 Gil_gl 120 Cirque 37558 16 Gil_gl 68 Cirque 39236 17 Gil_gl 39 Cirque 40137 18 Gil_gl 297 Cirque 42511 19 Gil_gl 162 Cirque 43573 20 Gil_gl 100 Cirque 43819 21 Gil_gl 8 Cirque 49628 22 Gil_gl 147 Cirque 52466 23 Gil_gl 311 Cirque 52709 24 Gil_gl 4 Cirque 53374 25 Gil_gl 159 Cirque 55583 26 Gil_gl 277 Cirque 55866 27 Gil_gl 58 Cirque 58442 28 Gil_gl 63 Cirque 69121 29 Gil_gl 34 Cirque 70846 30 Gil_gl 3 Cirque 79145 31 Gil_gl 74 Cirque 91326 32 Gil_gl 270 Cirque 102655 33 Gil_gl 16 Cirque 115515 34 Gil_gl 190 Cirque 116489 35 Gil_gl 18 Cirque 117409 36 Gil_gl 95 Cirque 118752 37 Gil_gl 306 Cirque 120579 38 Gil_gl 86 Cirque 124139 39 Gil_gl 15 Cirque 133902 40 Gil_gl 110 Cirque 166166 41 Gil_gl 40 Cirque 178679 42 Gil_gl 203 Cirque 300438 43 Gil_gl 298 Cirque 902330

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44 Gil_gl 535 Cirque 1149976 45 Gil_gl 408 End Moraine 20209 46 Gil_gl 37 End Moraine 21032 47 Gil_gl 420 End Moraine 22562 48 Gil_gl 221 End Moraine 22619 49 Gil_gl 474 End Moraine 23377 50 Gil_gl 106 End Moraine 25129 51 Gil_gl 252 End Moraine 26138 52 Gil_gl 396 End Moraine 26741 53 Gil_gl 466 End Moraine 26941 54 Gil_gl 422 End Moraine 28128 55 Gil_gl 407 End Moraine 28244 56 Gil_gl 164 End Moraine 28637 57 Gil_gl 257 End Moraine 30346 Gil_gr 17 16758 Gil_gl 426 End Moraine 30584 59 Gil_gl 312 End Moraine 30726 60 Gil_gl 472 End Moraine 30838 61 Gil_gl 401 End Moraine 32061 62 Gil_gl 33 End Moraine 32518 63 Gil_gl 504 End Moraine 33401 64 Gil_gl 217 End Moraine 34161 65 Gil_gl 419 End Moraine 34247 66 Gil_gl 35 End Moraine 35646 67 Gil_gl 175 End Moraine 37431 68 Gil_gl 309 End Moraine 37788 69 Gil_gl 356 End Moraine 40425 70 Gil_gl 232 End Moraine 45696 71 Gil_gl 378 End Moraine 46017 72 Gil_gl 579 End Moraine 46216 Gil_gr 239 23673 Gil_gl 421 End Moraine 47480 74 Gil_gl 342 End Moraine 48376 75 Gil_gl 47 End Moraine 49756 76 Gil_gl 117 End Moraine 50347 77 Gil_gl 430 End Moraine 50540 78 Gil_gl 411 End Moraine 52890 79 Gil_gl 412 End Moraine 53041 80 Gil_gl 340 End Moraine 53567 81 Gil_gl 433 End Moraine 58678 82 Gil_gl 255 End Moraine 60334 83 Gil_gl 165 End Moraine 61361 84 Gil_gl 168 End Moraine 63623 85 Gil_gl 291 End Moraine 66153 86 Gil_gl 102 End Moraine 69365 87 Gil_gl 410 End Moraine 71140 88 Gil_gl 423 End Moraine 73533 89 Gil_gl 452 End Moraine 79521 90 Gil_gl 529 End Moraine 79931

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91 Gil_gl 367 End Moraine 80877 92 Gil_gl 510 End Moraine 81917 Gil_gr 84 16293 Gil_gl 372 End Moraine 84521 94 Gil_gl 234 End Moraine 84932 95 Gil_gl 327 End Moraine 85892 96 Gil_gl 293 End Moraine 89727 97 Gil_gl 550 End Moraine 96354 Gil_gr 191 46498 Gil_gl 563 End Moraine 102381 99 Gil_gl 248 End Moraine 121991 Gil_gr 15 367100 Gil_gl 303 End Moraine 122085 Gil_gr 20 526101 Gil_gl 409 End Moraine 123048 102 Gil_gl 414 End Moraine 133026 103 Gil_gl 241 End Moraine 134823 104 Gil_gl 201 End Moraine 148120 Gil_gr 8 334105 Gil_gl 320 End Moraine 188203 106 Gil_gl 590 End Moraine 192428 Gil_gr 366 107 Gil_gl 505 End Moraine 212185 Gil_gr 79 820108 Gil_gl 336 End Moraine 213504 Gil_gr 22 225109 Gil_gl 395 End Moraine 221194 110 Gil_gl 244 End Moraine 224107 111 Gil_gl 251 End Moraine 229912 112 Gil_gl 561 End Moraine 234904 113 Gil_gl 260 End Moraine 247115 114 Gil_gl 469 End Moraine 265212 375115 Gil_gl 266 End Moraine 279028 Gil_gr 18 442116 Gil_gl 324 End Moraine 327673 Gil_gr 21 173117 Gil_gl 449 End Moraine 584500 118 Gil_gl 399 End Moraine 728772 Gil_gr 28 119 Gil_gl 189 Erosion 20046 120 Gil_gl 96 Erosion 20124 121 Gil_gl 573 Erosion 20130 122 Gil_gl 328 Erosion 20150 123 Gil_gl 600 Erosion 20299 124 Gil_gl 133 Erosion 20319 125 Gil_gl 240 Erosion 20354 126 Gil_gl 88 Erosion 20503 127 Gil_gl 480 Erosion 20542 128 Gil_gl 195 Erosion 20590 129 Gil_gl 506 Erosion 20867 130 Gil_gl 554 Erosion 21007 131 Gil_gl 576 Erosion 21241 132 Gil_gl 27 Erosion 21303 133 Gil_gl 69 Erosion 21391 134 Gil_gl 226 Erosion 21796 135 Gil_gl 25 Erosion 22154 136 Gil_gl 415 Erosion 22310 137 Gil_gl 129 Erosion 22843

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138 Gil_gl 85 Erosion 23053 139 Gil_gl 574 Erosion 23070 140 Gil_gl 494 Erosion 23715 141 Gil_gl 465 Erosion 23851 142 Gil_gl 228 Erosion 24122 143 Gil_gl 132 Erosion 24395 144 Gil_gl 568 Erosion 24674 145 Gil_gl 172 Erosion 24708 146 Gil_gl 26 Erosion 24784 147 Gil_gl 496 Erosion 24808 148 Gil_gl 89 Erosion 24975 149 Gil_gl 318 Erosion 25228 150 Gil_gl 489 Erosion 25384 151 Gil_gl 178 Erosion 25442 152 Gil_gl 7 Erosion 25495 153 Gil_gl 200 Erosion 26197 154 Gil_gl 464 Erosion 26342 155 Gil_gl 355 Erosion 26835 156 Gil_gl 598 Erosion 26922 Gil_gr 346 371157 Gil_gl 38 Erosion 27224 158 Gil_gl 24 Erosion 27708 159 Gil_gl 353 Erosion 27758 160 Gil_gl 206 Erosion 28066 161 Gil_gl 84 Erosion 28791 162 Gil_gl 460 Erosion 28819 163 Gil_gl 144 Erosion 29007 164 Gil_gl 455 Erosion 29224 165 Gil_gl 490 Erosion 29324 166 Gil_gl 377 Erosion 29406 167 Gil_gl 572 Erosion 29724 168 Gil_gl 20 Erosion 29730 169 Gil_gl 445 Erosion 29853 170 Gil_gl 553 Erosion 29905 171 Gil_gl 148 Erosion 30087 172 Gil_gl 30 Erosion 30986 173 Gil_gl 52 Erosion 31062 174 Gil_gl 236 Erosion 31927 175 Gil_gl 160 Erosion 31938 176 Gil_gl 493 Erosion 32147 177 Gil_gl 265 Erosion 32452 178 Gil_gl 607 Erosion 32947 179 Gil_gl 337 Erosion 33186 180 Gil_gl 599 Erosion 33332 181 Gil_gl 462 Erosion 33612 182 Gil_gl 1 Erosion 34518 183 Gil_gl 440 Erosion 35393 184 Gil_gl 111 Erosion 35413

255

185 Gil_gl 437 Erosion 35562 186 Gil_gl 307 Erosion 35690 187 Gil_gl 181 Erosion 36121 188 Gil_gl 434 Erosion 36362 189 Gil_gl 213 Erosion 36366 190 Gil_gl 134 Erosion 36783 191 Gil_gl 167 Erosion 36848 192 Gil_gl 55 Erosion 37031 193 Gil_gl 235 Erosion 37075 194 Gil_gl 161 Erosion 37820 195 Gil_gl 366 Erosion 38147 196 Gil_gl 325 Erosion 38500 197 Gil_gl 385 Erosion 38883 198 Gil_gl 393 Erosion 39139 199 Gil_gl 275 Erosion 39235 200 Gil_gl 2 Erosion 40286 201 Gil_gl 373 Erosion 40896 202 Gil_gl 588 Erosion 41166 203 Gil_gl 75 Erosion 41239 204 Gil_gl 143 Erosion 41282 205 Gil_gl 439 Erosion 41692 206 Gil_gl 65 Erosion 41929 207 Gil_gl 559 Erosion 42396 208 Gil_gl 492 Erosion 42919 209 Gil_gl 405 Erosion 42959 210 Gil_gl 566 Erosion 45150 211 Gil_gl 188 Erosion 45533 212 Gil_gl 555 Erosion 45806 213 Gil_gl 182 Erosion 45824 214 Gil_gl 131 Erosion 46371 215 Gil_gl 64 Erosion 46386 216 Gil_gl 259 Erosion 46799 217 Gil_gl 338 Erosion 46993 218 Gil_gl 478 Erosion 47104 219 Gil_gl 78 Erosion 47815 220 Gil_gl 475 Erosion 48285 Gil_gr 51 250221 Gil_gl 323 Erosion 48421 222 Gil_gl 29 Erosion 49713 223 Gil_gl 354 Erosion 50669 224 Gil_gl 332 Erosion 52338 225 Gil_gl 376 Erosion 52412 226 Gil_gl 458 Erosion 52611 227 Gil_gl 321 Erosion 55105 228 Gil_gl 402 Erosion 56184 229 Gil_gl 594 Erosion 56280 230 Gil_gl 183 Erosion 56617 231 Gil_gl 157 Erosion 56852

256

232 Gil_gl 92 Erosion 57120 233 Gil_gl 498 Erosion 57632 234 Gil_gl 70 Erosion 60021 235 Gil_gl 502 Erosion 62771 236 Gil_gl 22 Erosion 66292 237 Gil_gl 227 Erosion 67687 238 Gil_gl 595 Erosion 70571 239 Gil_gl 484 Erosion 72014 240 Gil_gl 36 Erosion 73159 241 Gil_gl 115 Erosion 75404 242 Gil_gl 497 Erosion 78344 243 Gil_gl 503 Erosion 80882 Gil_gr 75 410244 Gil_gl 32 Erosion 81614 245 Gil_gl 564 Erosion 86515 246 Gil_gl 187 Erosion 88655 247 Gil_gl 77 Erosion 89409 248 Gil_gl 442 Erosion 106282 249 Gil_gl 575 Erosion 107284 250 Gil_gl 416 Erosion 108999 251 Gil_gl 121 Erosion 111954 252 Gil_gl 171 Erosion 120346 253 Gil_gl 6 Erosion 126518 254 Gil_gl 380 Erosion 148058 255 Gil_gl 495 Erosion 150769 256 Gil_gl 72 Erosion 157537 257 Gil_gl 124 Erosion 166394 258 Gil_gl 122 Erosion 215019 259 Gil_gl 390 Lateral Moraine 20701 260 Gil_gl 285 Lateral Moraine 21631 261 Gil_gl 193 Lateral Moraine 21909 262 Gil_gl 261 Lateral Moraine 23125 263 Gil_gl 145 Lateral Moraine 24877 264 Gil_gl 482 Lateral Moraine 25586 265 Gil_gl 242 Lateral Moraine 27385 266 Gil_gl 486 Lateral Moraine 27765 267 Gil_gl 431 Lateral Moraine 29184 268 Gil_gl 205 Lateral Moraine 29193 269 Gil_gl 283 Lateral Moraine 34012 270 Gil_gl 180 Lateral Moraine 34207 271 Gil_gl 398 Lateral Moraine 34408 272 Gil_gl 438 Lateral Moraine 35941 273 Gil_gl 507 Lateral Moraine 37332 274 Gil_gl 382 Lateral Moraine 39949 275 Gil_gl 194 Lateral Moraine 42616 276 Gil_gl 501 Lateral Moraine 45214 277 Gil_gl 179 Lateral Moraine 48178 278 Gil_gl 512 Lateral Moraine 52322

257

279 Gil_gl 558 Lateral Moraine 53642 280 Gil_gl 379 Lateral Moraine 53993 281 Gil_gl 569 Lateral Moraine 58162 282 Gil_gl 447 Lateral Moraine 66383 283 Gil_gl 214 Lateral Moraine 73690 284 Gil_gl 450 Lateral Moraine 78572 285 Gil_gl 375 Lateral Moraine 90215 286 Gil_gl 609 Supraglacial 29934 Gil_gr 496 287 Gil_gl 610 Supraglacial 50153 288 Gil_gl 369 Valley 20106 289 Gil_gl 249 Valley 21025 290 Gil_gl 515 Valley 21119 291 Gil_gl 500 Valley 21239 292 Gil_gl 351 Valley 22594 293 Gil_gl 103 Valley 23143 294 Gil_gl 522 Valley 25643 295 Gil_gl 524 Valley 25998 296 Gil_gl 352 Valley 26178 297 Gil_gl 580 Valley 26664 Gil_gr 247 203298 Gil_gl 137 Valley 27481 299 Gil_gl 388 Valley 27648 300 Gil_gl 28 Valley 29008 301 Gil_gl 350 Valley 29950 302 Gil_gl 334 Valley 30374 303 Gil_gl 250 Valley 31080 304 Gil_gl 169 Valley 32459 305 Gil_gl 296 Valley 32761 306 Gil_gl 381 Valley 33019 307 Gil_gl 220 Valley 33291 308 Gil_gl 54 Valley 33399 309 Gil_gl 528 Valley 33531 310 Gil_gl 525 Valley 33923 Gil_gr 137 210311 Gil_gl 238 Valley 35384 312 Gil_gl 331 Valley 35754 313 Gil_gl 537 Valley 35922 314 Gil_gl 101 Valley 36135 315 Gil_gl 136 Valley 36887 316 Gil_gl 247 Valley 38175 317 Gil_gl 612 Valley 38296 Gil_gr 561 308318 Gil_gl 152 Valley 40502 319 Gil_gl 613 Valley 42647 320 Gil_gl 295 Valley 42773 321 Gil_gl 302 Valley 43090 322 Gil_gl 523 Valley 44012 323 Gil_gl 246 Valley 44423 324 Gil_gl 532 Valley 48481 325 Gil_gl 76 Valley 49412

258

326 Gil_gl 170 Valley 55662 327 Gil_gl 223 Valley 56597 328 Gil_gl 531 Valley 56950 329 Gil_gl 210 Valley 57560 330 Gil_gl 81 Valley 57766 331 Gil_gl 290 Valley 62299 332 Gil_gl 314 Valley 64939 333 Gil_gl 279 Valley 66799 334 Gil_gl 487 Valley 71660 335 Gil_gl 584 Valley 75929 336 Gil_gl 548 Valley 77573 337 Gil_gl 208 Valley 79665 338 Gil_gl 552 Valley 81269 Gil_gr 212 288339 Gil_gl 485 Valley 83363 340 Gil_gl 239 Valley 86686 341 Gil_gl 536 Valley 88044 342 Gil_gl 256 Valley 90801 343 Gil_gl 166 Valley 92445 344 Gil_gl 519 Valley 92987 345 Gil_gl 112 Valley 96574 346 Gil_gl 41 Valley 96820 347 Gil_gl 520 Valley 97059 348 Gil_gl 518 Valley 99843 349 Gil_gl 534 Valley 101265 350 Gil_gl 479 Valley 101805 351 Gil_gl 48 Valley 102138 352 Gil_gl 587 Valley 102779 Gil_gr 306 480353 Gil_gl 517 Valley 105330 354 Gil_gl 305 Valley 108339 355 Gil_gl 62 Valley 110284 356 Gil_gl 174 Valley 114853 357 Gil_gl 315 Valley 116924 358 Gil_gl 453 Valley 125466 359 Gil_gl 105 Valley 136296 360 Gil_gl 499 Valley 143188 Gil_gr 72 1720361 Gil_gl 514 Valley 148367 362 Gil_gl 113 Valley 192517 363 Gil_gl 585 Valley 198932 Gil_gr 299 585364 Gil_gl 516 Valley 199170 365 Gil_gl 586 Valley 200279 366 Gil_gl 589 Valley 204484 412367 Gil_gl 83 Valley 210564 368 Gil_gl 216 Valley 214289 Gil_gr 11 460369 Gil_gl 51 Valley 215892 370 Gil_gl 197 Valley 221969 Gil_gr 7 262371 Gil_gl 289 Valley 240851 372 Gil_gl 233 Valley 247896 Gil_gr 13 779

259

373 Gil_gl 611 Valley 285810 159374 Gil_gl 483 Valley 333350 Gil_gr 58 534375 Gil_gl 138 Valley 442418 376 Gil_gl 258 Valley 921194 377 Gil_gl 530 Valley 1003993 378 Gil_gl 606 Valley 1317341 822379 Gil_gl 527 Valley 2218957 380 Gil_gl 608 Valley 2723958 Gil_gr 497 420

There are eight potentially dangerous glacial lakes have been identified in this basin (Figure 10.2.3.1). Four of these dangerous lakes are located in the southern part of the basin which boarders with the Indus River basin. One each of these lakes is located in the central eastern and western part of the basin close to the basin boundary to Hunza and Chitral River basins respectively. The remaining two dangerous lakes are located in the central part of the basin.

Table 10.2.3.2: Summary of Major Lakes of Gilgit River basin. Area (m2) S. No. Type Number (%) Largest Smallest

1 Blocked 1 0.26 134340 - 2 Cirque 43 11.32 1149976 21069 3 End Moraine 74 19.47 728772 20209 4 Lateral Moraine 27 7.11 90215 20701 5 Erosion 140 36.84 215019 20046 6 Supraglacial 2 0.53 50153 29934 7 Valley 93 24.47 2723958 20106 Total 380 100.00

260

Among these eight dangerous lakes six are End Moraine and two are Valley type lakes (Table 10.2.3.3). All the End Moraine lakes are either close to large glaciers or are in contact with the hanging glaciers. The dangerous glacial lake (Gil_gl 399 and Gil_gl 505) of this category are associated with large size Mountain (Gil_gr 28) and Cirque (Gil_gr 79) glaciers respectively (Figure 10.2.3.2).

Figure 10.2.3.1: Distribution of potentially dangerous lakes of Gilgit River basin.

261

Both the Valley dangerous lakes (Gil_gl 611 and Gil_gl 589) are close to several hanging glaciers at a distance of 159 and 412 meters respectively.

Table 10.2.3.3: Potentially dangerous glacial lakes in Gilgit River basin.

S. No. Lake type Lake

Number Area (m2)

Associated Glacier

Distance to glacier Remarks

1 End Moraine Gil_gl 550 96354 Gil_gr 191 464 Followed by large glacier source

2 End Moraine Gil_gl 590 192428 Gil_gr 366 - In contact with large hanging glacier

3 End Moraine Gil_gl 505 212185 Gil_gr 79 820 Massive hanging glacier source

4 End Moraine Gil_gl 336 213504 Gil_gr 22 225 Near to hanging glacier source

5 End Moraine Gil_gl 469 265212 - 375 Near massive mountain glaciers

6 End Moraine Gil_gl 399 728772 Gil_gr 28 - In contact with hanging glacier source

7 Valley Gil_gl 589 204484 - 412 Near several hanging glaciers

8 Valley Gil_gl 611 285810 - 159 Near several hanging glaciers

(a) Gil_gl 505 (b) Gil_gl 399

Figure 10.2.3.2: Potentially dangerous glacial lakes in Gilgit River basin.

262

10.2.4 Hunza River basin

In Hunza River basin out of 110 glacial lakes, 47 lakes have been characterized as major lakes. The detail of each major lake is given in the Table 10.2.4.1. Out of these, maximum are Supraglacial lakes (20) because in the basin there are large size glaciers. This type is followed by Valley lakes (17). Cirque type lakes are not present in this basin (Table 10.2.4.2). The other types of lakes are few in number and therefore contribute very little to the accumulative area of the major lakes of the basin.

In this basin maximum lake area (49%) is contributed by Valley lakes followed by Supraglacial lakes (28%). Rest of the 23% lake area is collectively contributed by Moraine dammed, Erosion and Blocked lakes. Contribution of relatively low number of Valley lakes to the higher lake area is an indicator of relatively large size Valley lakes with area ranging from 0.022 (Hunza_gl 8) to 0.292 (Hunza_gl 47).The largest End Moraine dammed (Hunza_gl 6) has an area 0.12 sq. km and is at a distance of 175 meters from a large size Valley glacier (Passu Glacier, Hunza_gr 119). Due to high altitude and low temperatures in the basin, the number is not very high as well as the lake area is low.

Table 10.2.4.1: Major Lakes of Hunza River basin.

S. No. Lake number Type Area (m2)Associated glacier No.

Distance to glacier (m)

1 Hunza_gl 52 Blocked 32579 Hunza_gr 744 2 Hunza_gl 75 End Moraine 39880 Hunza_gr 830 3 Hunza_gl 65 End Moraine 85448 Hunza_gr 830 888 4 Hunza_gl 6 End Moraine 120054 Hunza_gr 119 1755 Hunza_gl 110 Erosion 20277 Hunza_gr 1010 6 Hunza_gl 104 Erosion 25126 Hunza_gr 987 7 Hunza_gl 96 Erosion 25675 8 Hunza_gl 77 Erosion 72408 9 Hunza_gl 94 Erosion 86466

10 Hunza_gl 54 Lateral Moraine 54836 Hunza_gr 756 11 Hunza_gl 69 Supraglacial 20121 Hunza_gr 830 12 Hunza_gl 17 Supraglacial 20776 Hunza_gr 120 13 Hunza_gl 64 Supraglacial 21620 Hunza_gr 830 112914 Hunza_gl 56 Supraglacial 23609 Hunza_gr 830 15 Hunza_gl 29 Supraglacial 23750 Hunza_gr 179 16 Hunza_gl 60 Supraglacial 24841 Hunza_gr 830 17 Hunza_gl 48 Supraglacial 26179 Hunza_gr 744 18 Hunza_gl 66 Supraglacial 26250 Hunza_gr 830 19 Hunza_gl 72 Supraglacial 30625 Hunza_gr 830 20 Hunza_gl 57 Supraglacial 32426 Hunza_gr 830 21 Hunza_gl 85 Supraglacial 32721 Hunza_gr 937 22 Hunza_gl 62 Supraglacial 32777 Hunza_gr 830 23 Hunza_gl 51 Supraglacial 37901 Hunza_gr 744 24 Hunza_gl 55 Supraglacial 38874 Hunza_gr 830 25 Hunza_gl 58 Supraglacial 41813 Hunza_gr 830 26 Hunza_gl 73 Supraglacial 45226 Hunza_gr 830 27 Hunza_gl 63 Supraglacial 46385 Hunza_gr 830 28 Hunza_gl 61 Supraglacial 48260 Hunza_gr 830 29 Hunza_gl 76 Supraglacial 57528 Hunza_gr 830

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30 Hunza_gl 67 Supraglacial 78327 Hunza_gr 830 31 Hunza_gl 8 Valley 22511 32 Hunza_gl 45 Valley 23484 33 Hunza_gl 21 Valley 24316 34 Hunza_gl 39 Valley 26111 35 Hunza_gl 1 Valley 27638 36 Hunza_gl 35 Valley 28302 37 Hunza_gl 20 Valley 33793 38 Hunza_gl 92 Valley 48752 39 Hunza_gl 44 Valley 49482 40 Hunza_gl 41 Valley 54693 41 Hunza_gl 36 Valley 58737 42 Hunza_gl 33 Valley 65966 43 Hunza_gl 46 Valley 80514 44 Hunza_gl 37 Valley 93021 45 Hunza_gl 38 Valley 142537 46 Hunza_gl 5 Valley 164349 54647 Hunza_gl 47 Valley 292711

In addition, the high relief and unstable deposits along the valley sides have made the slopes prone to mass movements. The upper Hunza basin provides an ideal and easily accessible location for the study of ice-dammed and mass movement-dammed lakes. The termini of a number of glaciers lie close to the floor of the Hunza Valley and have in the late Pleistocene, and probably also in the Neo-glacial, advanced across it. Consequently, there have been a number of interruptions of the drainage of the Hunza River by ice or debris dams.

There is only one dangerous lake has been identified in Hunza River basin (Figure 10.2.4.1). This lake is the largest major End Moraine dammed lake (Hunza_gl 6) with an area of 0.12 sq. km. This lake is located at a distance of 175 meters from a large size Valley glacier named Passu having an area of 62.9 sq. km, length of 26 km and ice reserves of 10.89 km3.

Table 10.2.4.2: Summary of Major Lakes of Hunza River basin. Area (m2) S. No. Type Number Area (km2) Largest Smallest

1 Blocked 1 0.033 32579 - 2 Cirque - - - - 3 End Moraine 3 0.245 120054 39880 4 Lateral Moraine 1 0.055 54836 - 5 Erosion 5 0.230 86466 20277 6 Supraglacial 20 0.710 78327 20121 7 Valley 17 1.237 292711 22511 Total 47 2.477

264

Figure 10.2.4.1: Potentially dangerous glacial lake in Hunza River basin.

265

Figure 10.2.4.2: Potentially dangerous glacial lake (Hunza_gl 6).

10.2.5 Shigar River basin

In the Shigar River basin, out of 54 glacial lakes, only 11 lakes are characterized as major glacial lakes (Table 10.2.5.1). Since most of the northern part of the basin is covered by large glaciers and ice masses in the high Karakoram Range so the lakes developed are less in number and smaller in size. Most of these lakes are of Supraglacial and Blocked type. There are five each major Blocked and Supraglacial lakes among the 11 major lakes. The largest Blocked lake (Shig_gl 22) has an area of 0.11 sq. km and the smallest Shig_gl 15 has 0.028 sq. km (Table 10.13). The Supraglacial lakes are relatively small in size as the largest lake of this category (Shig_gl 18) has only area of about 0.065 sq. km. The one Valley lake (Shig_gl 54) has an area of about 0.24 sq. km

Table 10.2.5.1: Major Lakes of Shigar River basin.

S.No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier (m)

1 Shig_gl 4 Blocked 35970 2 Shig_gl 13 Blocked 41964 Shig_gr 113 3 Shig_gl 14 Blocked 36460 Shig_gr 113 4 Shig_gl 15 Blocked 27935 5 Shig_gl 18 Supraglacial 64899 Shig_gr 105 6 Shig_gl 22 Blocked 108958 7 Shig_gl 24 Supraglacial 26090 Shig_gr 129 8 Shig_gl 34 Supraglacial 34183 Shig_gr 139 9 Shig_gl 35 Supraglacial 21045 Shig_gr 140 10 Shig_gl 41 Supraglacial 39727 Shig_gr 146 11 Shig_gl 54 Valley 235908

266

Table 10.2.5.2: Summary of Major Lakes in Shigar River basin Area (m2) S. No. Type Number Area

(km2) Largest Smallest 1 Blocked 5 0.251 108958 27935 2 Supraglacial 5 0.186 64899 21045 3 Valley 1 0.236 235908 - Total 11 0.673

No potentially dangerous lake has been identified in this basin.

10.2.6 Shyok River Basin

In Shyok River basin out of 66 glacial lakes 31 are characterized as major glacial lakes (Table 10.2.6.1). The maximum major lakes (12) are of End Moraine type (Table 10.2.6.2). The largest lake of this category Shyk_gl 65 has an area of 0.21 sq. km. The other lake types include Valley, Erosion (7 each), Lateral Moraine (2) and Cirque, Blocked and Supraglacial lakes one each. The largest Valley lake Shyk_gl 66 has an area of about 0.27 sq. km. All the End and Lateral Moraine lakes have associated glaciers.

Table 10.2.6.1: Major Lakes of Shyok River basin

S.No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier

(m) 1 Shyk_gl 32 Blocked 42940 Shyk_gr 69 2 Shyk_gl 12 Cirque 39471 3 Shyk_gl 52 End Moraine 24882 Shyk_gr 313 4 Shyk_gl 48 End Moraine 31026 Shyk_gr 297 5 Shyk_gl 61 End Moraine 33878 Shyk_gr 347 6 Shyk_gl 63 End Moraine 51718 Shyk_gr 360 7 Shyk_gl 50 End Moraine 65219 Shyk_gr 303 8 Shyk_gl 46 End Moraine 75689 Shyk_gr 294 9 Shyk_gl 60 End Moraine 79945 Shyk_gr 345 10 Shyk_gl 37 End Moraine 89130 Shyk_gr 118 11 Shyk_gl 62 End Moraine 94266 Shyk_gr 355 12 Shyk_gl 45 End Moraine 127165 Shyk_gr 293 13 Shyk_gl 38 End Moraine 178822 Shyk_gr 173 14 Shyk_gl 65 End Moraine 210368 Shyk_gr 361 15 Shyk_gl 56 Erosion 24694 Shyk_gr 326 16 Shyk_gl 57 Erosion 26525 Shyk_gr 326 17 Shyk_gl 11 Erosion 33774 Shyk_gr 11 18 Shyk_gl 2 Erosion 34380 19 Shyk_gl 55 Erosion 40421 Shyk_gr 326 20 Shyk_gl 17 Erosion 47581 21 Shyk_gl 41 Erosion 75395 Shyk_gr 202 22 Shyk_gl 39 Lateral Moraine 20672 Shyk_gr 202 23 Shyk_gl 59 Lateral Moraine 29623 Shyk_gr 339 24 Shyk_gl 58 Supraglacial 28327 Shyk_gr 339

267

25 Shyk_gl 8 Valley 33694 Shyk_gr 2 26 Shyk_gl 49 Valley 34317 Shyk_gr 303 27 Shyk_gl 19 Valley 74035 28 Shyk_gl 10 Valley 95731 Shyk_gr 11 798 29 Shyk_gl 64 Valley 107112 Shyk_gr 360 432 30 Shyk_gl 51 Valley 170883 Shyk_gr 305 435 31 Shyk_gl 66 Valley 266498 Shyk_gr 363

Out of these 31 major lakes six are characterized as potentially dangerous lakes (Table 10.2.6.3). These lakes are mainly located in the southern half of the basin (Figure 10.2.6.1). Most of these lakes are associated with large glaciers. Majority of dangerous lakes (4) belongs to End Moraine type. Most of these are in contact with their source glaciers (Figure 10.2.6.2). The two dangerous lakes one Valley (Shyk_gl 64) and the other End Moraine dammed (Shyk_gl 65) lake are located close to each other. A mountain separates them and they drain into the main Shyok River near a small town Bara (Figure 10.2.6.3). The two Valley lakes identified as potentially dangerous are Shyk_gl 51 and Shyk_gl 64. They are both at distances less than 500 meters from their source glaciers. The lake Shyk_gl 64 is followed by another lake of End Moraine type developed in contact with a large glacier Shyk_gr 360 at a distance of 432 meters.

Table 10.2.6.3: Potentially dangerous glacial lakes in Shyok River basin.

S.No. Lake type Lake Number Area (m2) Associated

Glacier Distance to glacier Remarks

1 End Moraine Shyk_gl 60 79945 Shyk_gr 345 In contact with hanging glacier

2 End Moraine Shyk_gl 62 94266 Shyk_gr 355 In contact with large glacier

3 End Moraine Shyk_gl 45 127165 Shyk_gr 293 In contact with large glacier

4 End Moraine Shyk_gl 65 210368 Shyk_gr 361 Large glacier source

5 Valley Shyk_gl 64 107112 Shyk_gr 360 432Preceded by a lake and large glacier

6 Valley Shyk_gl 51 170883 Shyk_gr 305 435 Large glacier source

Table 10.2.6.2: Summary of Major Lakes of Shyok River basin. Area (m2) S. No. Type Number Area (km2) Largest Smallest

1 Blocked 1 0.043 42940 - 2 Cirque 1 0.039 39471 - 3 End Moraine 12 1.062 210368 24882 4 Lateral Moraine 2 0.050 29623 20672 5 Erosion 7 0.283 75395 24694 6 Supraglacial 1 0.028 28327 - 7 Valley 7 0.782 266498 33694

Total 31

268

Figure 10.2.6.1: Distribution of potentially dangerous lakes in Shyok River basin.

269

Figure 10.2.6.2: Potentially dangerous glacial lakes of Shyok River basin.

Shyk_gl 64 Shyk_gl 65

270

(a) Shyk_gl 65 (left on 3D)

(b) Shyk_gl 64 (right on 3D)

Photo taken in July, 2004

Figure 10.2.6.3: A 3D View of toposheet indicating two potentially dangerous lakes. 10.2.7 Indus River basin

In the Indus River basin out of 574 glacial lakes a total of 328 lakes of different categories have been classified as major lakes. Generally the largest lake of all these categories has an area of more than 0.1 sq. km except Supraglacial lakes. The Valley lakes are large in size since the largest lake of this category (Ind_gl 368) has an area of about 1.35 sq. km (Table 10.2.7.1).

Table 10.2.7.1: Major Lakes of Indus River basin

S.No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier

(m) 1 Ind_gl 44 Blocked 103228 2 Ind_gl 240 Cirque 22069 3 Ind_gl 418 Cirque 22735 4 Ind_gl 190 Cirque 22814 5 Ind_gl 538 Cirque 23987

271

6 Ind_gl 536 Cirque 26029 7 Ind_gl 534 Cirque 31961 8 Ind_gl 250 Cirque 35263 9 Ind_gl 404 Cirque 35855

10 Ind_gl 246 Cirque 36008 11 Ind_gl 442 Cirque 36240 12 Ind_gl 96 Cirque 38841 13 Ind_gl 470 Cirque 40517 14 Ind_gl 449 Cirque 40790 15 Ind_gl 433 Cirque 40914 16 Ind_gl 469 Cirque 46815 Ind_gr 902 17 Ind_gl 26 Cirque 48338 18 Ind_gl 495 Cirque 48489 19 Ind_gl 425 Cirque 49062 20 Ind_gl 27 Cirque 56022 21 Ind_gl 315 Cirque 56541 22 Ind_gl 482 Cirque 64288 23 Ind_gl 526 Cirque 65955 24 Ind_gl 24 Cirque 67823 Ind_gr 134 243 25 Ind_gl 187 Cirque 71339 26 Ind_gl 182 Cirque 72853 27 Ind_gl 213 Cirque 74497 28 Ind_gl 51 Cirque 77880 29 Ind_gl 201 Cirque 86325 30 Ind_gl 91 Cirque 89290 Ind_gr 180 530 31 Ind_gl 216 Cirque 93742 32 Ind_gl 191 Cirque 94110 33 Ind_gl 465 Cirque 98708 34 Ind_gl 251 Cirque 99576 35 Ind_gl 511 Cirque 99671 Ind_gr 924 36 Ind_gl 107 Cirque 100153 37 Ind_gl 497 Cirque 116800 38 Ind_gl 459 Cirque 117037 39 Ind_gl 548 Cirque 117717 40 Ind_gl 484 Cirque 123371 41 Ind_gl 258 Cirque 133754 42 Ind_gl 125 Cirque 144937 Ind_gr 213 43 Ind_gl 502 Cirque 149108 44 Ind_gl 500 Cirque 161686 45 Ind_gl 440 Cirque 161813 46 Ind_gl 519 Cirque 168166 Ind_gr 928 47 Ind_gl 64 Cirque 172759 48 Ind_gl 210 Cirque 235664 49 Ind_gl 162 Cirque 269774 Ind_gr 313 50 Ind_gl 228 Cirque 299200 51 Ind_gl 148 Cirque 318811 52 Ind_gl 40 Cirque 411236 Ind_gr 162 637

272

53 Ind_gl 104 End Moraine 20486 Ind_gr 192 162 54 Ind_gl 462 End Moraine 21906 55 Ind_gl 137 End Moraine 21927 56 Ind_gl 307 End Moraine 21969 Ind_gr 589 57 Ind_gl 278 End Moraine 22569 Ind_gr 433 58 Ind_gl 34 End Moraine 23247 Ind_gr 151 59 Ind_gl 335 End Moraine 23465 60 Ind_gl 93 End Moraine 24066 Ind_gr 181 836 61 Ind_gl 562 End Moraine 24565 Ind_gr 983 631 62 Ind_gl 294 End Moraine 26355 Ind_gr 488 63 Ind_gl 360 End Moraine 26487 64 Ind_gl 513 End Moraine 26975 65 Ind_gl 127 End Moraine 27518 Ind_gr 229 66 Ind_gl 120 End Moraine 30349 Ind_gr 209 67 Ind_gl 157 End Moraine 30370 Ind_gr 310 285 68 Ind_gl 161 End Moraine 30515 Ind_gr 312 536 69 Ind_gl 537 End Moraine 31167 70 Ind_gl 397 End Moraine 31279 Ind_gr 667 621 71 Ind_gl 103 End Moraine 32885 Ind_gr 191 1071 72 Ind_gl 261 End Moraine 33050 73 Ind_gl 239 End Moraine 33242 74 Ind_gl 392 End Moraine 33270 Ind_gr 655 1048 75 Ind_gl 353 End Moraine 33471 76 Ind_gl 394 End Moraine 33806 Ind_gr 656 77 Ind_gl 219 End Moraine 36372 78 Ind_gl 285 End Moraine 37468 Ind_gr 464 79 Ind_gl 543 End Moraine 40370 80 Ind_gl 223 End Moraine 40503 81 Ind_gl 128 End Moraine 41175 Ind_gr 237 82 Ind_gl 379 End Moraine 43385 536 83 Ind_gl 38 End Moraine 43572 Ind_gr 160 700 84 Ind_gl 444 End Moraine 43848 85 Ind_gl 386 End Moraine 44073 Ind_gr 641 298 86 Ind_gl 78 End Moraine 45323 Ind_gr 176 87 Ind_gl 390 End Moraine 49703 Ind_gr 644 462 88 Ind_gl 525 End Moraine 55679 89 Ind_gl 419 End Moraine 55766 90 Ind_gl 457 End Moraine 56880 Ind_gr 886 177 91 Ind_gl 218 End Moraine 59403 92 Ind_gl 554 End Moraine 59785 93 Ind_gl 312 End Moraine 59850 94 Ind_gl 439 End Moraine 67874 95 Ind_gl 327 End Moraine 68866 96 Ind_gl 412 End Moraine 69455 97 Ind_gl 464 End Moraine 82417 Ind_gr 893 1862 98 Ind_gl 304 End Moraine 83058 99 Ind_gl 121 End Moraine 84571 Ind_gr 208

273

100 Ind_gl 330 End Moraine 88874 Ind_gr 556 306 101 Ind_gl 515 End Moraine 95923 Ind_gr 925 455 102 Ind_gl 281 End Moraine 98439 Ind_gr 440 103 Ind_gl 47 End Moraine 109142 Ind_gr 166 104 Ind_gl 407 End Moraine 117674 105 Ind_gl 160 End Moraine 124427 Ind_gr 311 106 Ind_gl 290 End Moraine 132533 Ind_gr 470 107 Ind_gl 522 End Moraine 136622 108 Ind_gl 208 End Moraine 136992 Ind_gr 319 798 109 Ind_gl 383 End Moraine 139032 110 Ind_gl 545 End Moraine 140122 Ind_gr 934 712 111 Ind_gl 351 End Moraine 143007 112 Ind_gl 41 End Moraine 169783 Ind_gr 165 505 113 Ind_gl 408 End Moraine 215831 Ind_gr 682 1302 114 Ind_gl 135 End Moraine 237005 Ind_gr 263 450 115 Ind_gl 146 End Moraine 274437 Ind_gr 289 817 116 Ind_gl 147 End Moraine 282395 Ind_gr 295 388 117 Ind_gl 567 End Moraine 367020 118 Ind_gl 212 Erosion 20111 119 Ind_gl 59 Erosion 20762 120 Ind_gl 504 Erosion 20823 Ind_gr 917 121 Ind_gl 346 Erosion 20927 122 Ind_gl 86 Erosion 20987 123 Ind_gl 454 Erosion 21005 124 Ind_gl 309 Erosion 21940 Ind_gr 513 125 Ind_gl 76 Erosion 22706 Ind_gr 172 126 Ind_gl 199 Erosion 23376 127 Ind_gl 265 Erosion 23580 128 Ind_gl 561 Erosion 23684 Ind_gr 983 1601 129 Ind_gl 437 Erosion 23982 130 Ind_gl 506 Erosion 24554 131 Ind_gl 188 Erosion 24933 132 Ind_gl 423 Erosion 25110 133 Ind_gl 453 Erosion 25337 134 Ind_gl 496 Erosion 25792 135 Ind_gl 345 Erosion 25861 136 Ind_gl 230 Erosion 26144 137 Ind_gl 173 Erosion 26177 138 Ind_gl 347 Erosion 26248 139 Ind_gl 179 Erosion 26339 140 Ind_gl 523 Erosion 26810 141 Ind_gl 211 Erosion 27117 142 Ind_gl 52 Erosion 27232 143 Ind_gl 481 Erosion 27576 144 Ind_gl 447 Erosion 27703 145 Ind_gl 263 Erosion 27921 146 Ind_gl 2 Erosion 28116

274

147 Ind_gl 193 Erosion 28501 Ind_gr 317 148 Ind_gl 387 Erosion 29527 Ind_gr 642 1128 149 Ind_gl 331 Erosion 29716 Ind_gr 562 150 Ind_gl 63 Erosion 30037 151 Ind_gl 478 Erosion 30178 152 Ind_gl 115 Erosion 30960 153 Ind_gl 53 Erosion 32553 154 Ind_gl 221 Erosion 32804 155 Ind_gl 430 Erosion 32934 156 Ind_gl 480 Erosion 33127 157 Ind_gl 36 Erosion 33410 Ind_gr 159 158 Ind_gl 521 Erosion 33710 159 Ind_gl 155 Erosion 33886 160 Ind_gl 65 Erosion 34318 161 Ind_gl 260 Erosion 34582 162 Ind_gl 336 Erosion 34631 Ind_gr 595 163 Ind_gl 438 Erosion 35002 164 Ind_gl 317 Erosion 35520 Ind_gr 529 165 Ind_gl 50 Erosion 36720 166 Ind_gl 116 Erosion 36900 167 Ind_gl 358 Erosion 37210 168 Ind_gl 196 Erosion 37238 169 Ind_gl 363 Erosion 37340 170 Ind_gl 81 Erosion 37737 Ind_gr 178 171 Ind_gl 178 Erosion 39562 172 Ind_gl 195 Erosion 39984 173 Ind_gl 349 Erosion 40339 174 Ind_gl 192 Erosion 40589 175 Ind_gl 310 Erosion 40910 Ind_gr 513 176 Ind_gl 186 Erosion 41108 177 Ind_gl 319 Erosion 41218 Ind_gr 529 178 Ind_gl 308 Erosion 41362 Ind_gr 513 179 Ind_gl 264 Erosion 41499 180 Ind_gl 544 Erosion 43154 181 Ind_gl 236 Erosion 43435 182 Ind_gl 113 Erosion 44599 Ind_gr 205 506 183 Ind_gl 198 Erosion 44958 184 Ind_gl 257 Erosion 45244 185 Ind_gl 61 Erosion 45608 186 Ind_gl 276 Erosion 45977 187 Ind_gl 170 Erosion 46107 188 Ind_gl 169 Erosion 47966 189 Ind_gl 66 Erosion 49628 190 Ind_gl 174 Erosion 49794 191 Ind_gl 274 Erosion 49984 192 Ind_gl 441 Erosion 50783 193 Ind_gl 256 Erosion 53693

275

194 Ind_gl 131 Erosion 54290 195 Ind_gl 568 Erosion 55303 196 Ind_gl 354 Erosion 55398 197 Ind_gl 242 Erosion 56930 198 Ind_gl 11 Erosion 57687 199 Ind_gl 97 Erosion 57845 200 Ind_gl 46 Erosion 57991 201 Ind_gl 476 Erosion 58100 202 Ind_gl 359 Erosion 59347 203 Ind_gl 477 Erosion 59538 204 Ind_gl 289 Erosion 61610 205 Ind_gl 463 Erosion 62304 Ind_gr 893 206 Ind_gl 172 Erosion 62532 207 Ind_gl 451 Erosion 64088 208 Ind_gl 13 Erosion 65436 Ind_gr 100 1220 209 Ind_gl 286 Erosion 66744 210 Ind_gl 267 Erosion 67675 211 Ind_gl 95 Erosion 68722 Ind_gr 183 212 Ind_gl 83 Erosion 69762 213 Ind_gl 168 Erosion 73930 214 Ind_gl 217 Erosion 75275 215 Ind_gl 514 Erosion 75282 216 Ind_gl 142 Erosion 81243 217 Ind_gl 342 Erosion 82094 Ind_gr 597 218 Ind_gl 492 Erosion 84001 219 Ind_gl 90 Erosion 84349 Ind_gr 180 930 220 Ind_gl 243 Erosion 93031 Ind_gr 328 221 Ind_gl 32 Erosion 97969 222 Ind_gl 112 Erosion 98118 Ind_gr 204 371 223 Ind_gl 429 Erosion 99603 224 Ind_gl 35 Erosion 109746 Ind_gr 158 225 Ind_gl 180 Erosion 118027 226 Ind_gl 184 Erosion 120449 227 Ind_gl 524 Erosion 124809 228 Ind_gl 181 Erosion 125963 229 Ind_gl 277 Erosion 149241 Ind_gr 431 230 Ind_gl 80 Erosion 155879 Ind_gr 177 231 Ind_gl 33 Erosion 164973 Ind_gr 150 232 Ind_gl 254 Erosion 180466 233 Ind_gl 352 Lateral Moraine 20411 234 Ind_gl 402 Lateral Moraine 20697 Ind_gr 670 1272 235 Ind_gl 118 Lateral Moraine 20782 236 Ind_gl 291 Lateral Moraine 21251 237 Ind_gl 313 Lateral Moraine 21418 238 Ind_gl 385 Lateral Moraine 22538 Ind_gr 636 486 239 Ind_gl 472 Lateral Moraine 22807 240 Ind_gl 563 Lateral Moraine 23666 Ind_gr 984 600

276

241 Ind_gl 389 Lateral Moraine 23732 Ind_gr 643 235 242 Ind_gl 518 Lateral Moraine 23899 Ind_gr 927 243 Ind_gl 452 Lateral Moraine 24936 244 Ind_gl 5 Lateral Moraine 25439 245 Ind_gl 460 Lateral Moraine 29196 246 Ind_gl 215 Lateral Moraine 29453 247 Ind_gl 551 Lateral Moraine 29722 248 Ind_gl 406 Lateral Moraine 34931 Ind_gr 679 1279 249 Ind_gl 400 Lateral Moraine 35791 Ind_gr 668 657 250 Ind_gl 356 Lateral Moraine 35910 251 Ind_gl 373 Lateral Moraine 36745 Ind_gr 604 252 Ind_gl 391 Lateral Moraine 37357 Ind_gr 645 501 253 Ind_gl 270 Lateral Moraine 37923 254 Ind_gl 314 Lateral Moraine 38431 Ind_gr 523 255 Ind_gl 271 Lateral Moraine 39711 256 Ind_gl 409 Lateral Moraine 42599 Ind_gr 683 502 257 Ind_gl 410 Lateral Moraine 49469 Ind_gr 683 167 258 Ind_gl 550 Lateral Moraine 52634 259 Ind_gl 202 Lateral Moraine 53607 260 Ind_gl 466 Lateral Moraine 61467 Ind_gr 896 261 Ind_gl 485 Lateral Moraine 72989 262 Ind_gl 508 Lateral Moraine 80797 Ind_gr 923 263 Ind_gl 372 Lateral Moraine 85705 Ind_gr 603 788 264 Ind_gl 367 Lateral Moraine 109425 265 Ind_gl 72 Supraglacial 20478 266 Ind_gl 143 Supraglacial 20489 267 Ind_gl 154 Supraglacial 20543 268 Ind_gl 321 Supraglacial 21358 269 Ind_gl 417 Supraglacial 21578 Ind_gr 867 331 270 Ind_gl 486 Supraglacial 22950 271 Ind_gl 475 Supraglacial 23899 272 Ind_gl 446 Supraglacial 23953 273 Ind_gl 171 Supraglacial 26238 274 Ind_gl 509 Supraglacial 26757 Ind_gr 923 275 Ind_gl 473 Supraglacial 27339 276 Ind_gl 134 Supraglacial 27648 277 Ind_gl 20 Supraglacial 29677 Ind_gr 119 278 Ind_gl 474 Supraglacial 29705 279 Ind_gl 232 Supraglacial 29712 280 Ind_gl 200 Supraglacial 30210 Ind_gr 318 281 Ind_gl 381 Supraglacial 31158 282 Ind_gl 163 Supraglacial 34982 283 Ind_gl 67 Supraglacial 35356 284 Ind_gl 316 Supraglacial 44300 Ind_gr 531 285 Ind_gl 54 Supraglacial 47636 Ind_gr 168 286 Ind_gl 175 Supraglacial 48893 Ind_gr 316 287 Ind_gl 467 Supraglacial 49563 Ind_gr 899

277

288 Ind_gl 21 Supraglacial 54659 Ind_gr 119 289 Ind_gl 468 Supraglacial 75446 Ind_gr 899 290 Ind_gl 183 Valley 23744 291 Ind_gl 382 Valley 24018 292 Ind_gl 380 Valley 24131 293 Ind_gl 45 Valley 25706 Ind_gr 166 294 Ind_gl 106 Valley 27500 Ind_gr 193 1230 295 Ind_gl 62 Valley 29193 296 Ind_gl 109 Valley 33181 297 Ind_gl 108 Valley 37937 298 Ind_gl 326 Valley 38116 299 Ind_gl 119 Valley 39436 300 Ind_gl 57 Valley 41379 301 Ind_gl 124 Valley 45968 Ind_gr 212 302 Ind_gl 30 Valley 47920 303 Ind_gl 253 Valley 52565 304 Ind_gl 273 Valley 53446 305 Ind_gl 1 Valley 54966 306 Ind_gl 494 Valley 63215 307 Ind_gl 553 Valley 65578 308 Ind_gl 31 Valley 66687 309 Ind_gl 88 Valley 66843 Ind_gr 180 1917 310 Ind_gl 413 Valley 68048 Ind_gr 690 311 Ind_gl 247 Valley 68441 312 Ind_gl 7 Valley 70774 313 Ind_gl 493 Valley 74627 314 Ind_gl 149 Valley 77589 Ind_gr 299 1141 315 Ind_gl 14 Valley 78454 Ind_gr 103 2058 316 Ind_gl 292 Valley 82636 Ind_gr 484 317 Ind_gl 132 Valley 103612 318 Ind_gl 130 Valley 106096 Ind_gr 245 472 319 Ind_gl 288 Valley 119316 320 Ind_gl 156 Valley 127326 321 Ind_gl 122 Valley 166922 322 Ind_gl 141 Valley 224441 Ind_gr 279 507 323 Ind_gl 145 Valley 225652 Ind_gr 288 972 324 Ind_gl 272 Valley 226388 325 Ind_gl 416 Valley 307605 326 Ind_gl 138 Valley 343722 Ind_gr 268 967 327 Ind_gl 547 Valley 427697 328 Ind_gl 368 Valley 1348826

278

Out of the 328 major lakes, about 35% are Erosion type (Table 10.2.7.2). The largest lake of this category is Ind_gl 254 having an area of 0.18 sq. km and the smallest one is Ind_gl 212 having an area of 0.02 sq. km. The Moraine Dammed lakes are 97 in number out of which 65 are End Moraine dammed lakes. There are 39 major Valley lakes, out of which the largest lake (Ind_gl 368) has an area of about 1.35 sq. km. while the smallest (Ind_gl 183) has an area of 0.024 sq. km.

Among these major lakes, the lakes identified as potentially dangerous are 15 in number (Figure 10.2.7.1). The details of each potentially dangerous lake are included in Table 102.7.3. These potentially dangerous lakes are located in the central western part and the southeastern parts of the basin. The maximum of 9 End Moraine lakes have been identified as potentially dangerous lakes. Most of these lakes are either very close or in contact with the hanging glacier. Few of them like Ind_gl 394 are close to large glaciers (Ind_gr 656). One of these lakes Ind_gl 351 has a snow avalanche source.

The four Cirque lakes have been characterized as potentially dangerous lakes. These lakes are mostly associated with hanging glaciers (Figure10.2.7.2).

One of the two potentially dangerous Valley lakes is at a distance of 472 m from the associated hanging glacier Ind_gr 245. The other (Ind_gl 95) is in contact with the hanging glacier Ind_gr 183.

Table 10.2.7.2: Summary of Major Lakes of Indus River basin. Area(m2) S. No. Type Number Area (km2) Largest Smallest

1 Blocked 1 0.103 103228 - 2 Cirque 51 5.117 411236 22069 3 End Moraine 65 4.944 367020 20486 4 Lateral Moraine 32 1.265 109425 20411 5 Erosion 115 5.905 180466 20111 6 Supraglacial 25 0.825 75446 20478 7 Valley 39 5.110 1348826 23744 Total 328 23.269

279

Table 10.2.7.3: Potentially dangerous glacial lakes in Indus River basin.

S.No. Lake type Lake Number Area (m2) Associated

Glacier Distance to glacier (m) Remarks

1 Cirque Ind_gl 125 144937 Ind_gr 213 In contact with hanging glacier

2 Cirque Ind_gl 502 149108 Near hanging ice mass

3 Cirque Ind_gl 519 168166 Ind_gr 928 Large lake near hanging glacier

4 Cirque Ind_gl 162 269774 Ind_gr 313 In contact with hanging glacier

5 End Moraine Ind_gl 394 33806 Ind_gr 656 In contact with large glacier

6 End Moraine Ind_gl 444 43848 Ind_gr 878 In contact with hanging glacier

7 End Moraine Ind_gl 457 56880 Ind_gr 886 177 Near hanging glacier 8 End Moraine Ind_gl 47 109142 Ind_gr 166 Near hanging glacier 9 End Moraine Ind_gl 160 124427 Ind_gr 311 Near hanging glacier

10 End Moraine Ind_gl 290 132533 Ind_gr 470 In contact with hanging glacier

11 End Moraine Ind_gl 351 143007 Snow avalanche source

12 End Moraine Ind_gl 41 169783 Ind_gr 165 505 Large lake near hanging glacier

13 End Moraine Ind_gl 135 237005 Ind_gr 263 450 Near hanging glacier 14 End Moraine Ind_gl 147 282395 Ind_gr 295 388 Near hanging glacier 15 Valley Ind_gl 130 106096 Ind_gr 245 472 Near hanging glacier

280

Figure 10.2.7.1: Distribution of potentially dangerous glacial lakes in Indus River basin.

281

(a) Ind_gl 519. (b) Ind_gl 444

Figure 10.2.7.2: Potentially dangerous glacial lakes in Indus River basin in FCC Pan,7,4. 10.2.8 Shingo River basin

Out of 238 glacial lakes of this basin 139 lakes are characterized as major lakes (Table 10.2.8.1). The Erosion type lakes are maximum (78) followed by Valley lakes (26). The Cirque lakes are 19 in number while End Moraine lakes are only 14 in number. The largest Erosion lake Shin_gl 142 has an area of 0.27 sq. km while the largest Valley lake Shin_gl 96 has an area of about 1.36 sq. km (Table 10.2.8.2).

Table 10.2.8.1: Major Lakes of Shingo River basin

S.No. Lake number Type Area (m2) Associated

glacier

Distance to glacier

(m)

1 Shin_gl 237 Blocked 27606 Shin_gl 170 2 Shin_gl 100 Cirque 20357 3 Shin_gl 93 Cirque 20884 4 Shin_gl 50 Cirque 22097 5 Shin_gl 97 Cirque 27759 6 Shin_gl 211 Cirque 27892 7 Shin_gl 124 Cirque 29945 8 Shin_gl 74 Cirque 30613 9 Shin_gl 202 Cirque 36496

10 Shin_gl 82 Cirque 49071 11 Shin_gl 1 Cirque 49418 12 Shin_gl 141 Cirque 55961 13 Shin_gl 128 Cirque 59270 14 Shin_gl 120 Cirque 89242 Shin_gr 98 41315 Shin_gl 189 Cirque 101203 16 Shin_gl 68 Cirque 104845 17 Shin_gl 135 Cirque 134008

282

18 Shin_gl 112 Cirque 174399 19 Shin_gl 53 Cirque 193496 Shin_gr 75 20 Shin_gl 75 Cirque 259860 Shin_gr 85 21 Shin_gl 110 End Moraine 20152 22 Shin_gl 235 End Moraine 25601 Shin_gl 170 23 Shin_gl 36 End Moraine 27758 24 Shin_gl 225 End Moraine 31686 25 Shin_gl 51 End Moraine 36933 26 Shin_gl 103 End Moraine 36940 27 Shin_gl 220 End Moraine 45193 Shin_gr 151 28 Shin_gl 215 End Moraine 46853 29 Shin_gl 238 End Moraine 56813 Shin_gl 172 30 Shin_gl 86 End Moraine 58906 31 Shin_gl 4 End Moraine 67136 32 Shin_gl 167 End Moraine 72199 Shin_gr 118 33 Shin_gl 118 End Moraine 89450 34 Shin_gl 115 End Moraine 126852 Shin_gr 89 18035 Shin_gl 178 Erosion 20053 36 Shin_gl 78 Erosion 20760 37 Shin_gl 27 Erosion 21269 38 Shin_gl 46 Erosion 21575 39 Shin_gl 60 Erosion 21705 40 Shin_gl 180 Erosion 21734 41 Shin_gl 38 Erosion 21741 42 Shin_gl 156 Erosion 22096 43 Shin_gl 11 Erosion 22293 44 Shin_gl 55 Erosion 22703 45 Shin_gl 43 Erosion 23011 46 Shin_gl 28 Erosion 23534 47 Shin_gl 147 Erosion 23923 48 Shin_gl 236 Erosion 23933 Shin_gl 170 49 Shin_gl 108 Erosion 23959 50 Shin_gl 197 Erosion 24118 51 Shin_gl 198 Erosion 24585 52 Shin_gl 117 Erosion 25620 53 Shin_gl 134 Erosion 26289 54 Shin_gl 129 Erosion 27499 55 Shin_gl 176 Erosion 28457 56 Shin_gl 177 Erosion 29964 57 Shin_gl 187 Erosion 30060 58 Shin_gl 30 Erosion 32160 59 Shin_gl 162 Erosion 34132 60 Shin_gl 7 Erosion 35008 61 Shin_gl 191 Erosion 35174 62 Shin_gl 57 Erosion 35282 63 Shin_gl 29 Erosion 35297 64 Shin_gl 152 Erosion 35477 65 Shin_gl 230 Erosion 36526 66 Shin_gl 130 Erosion 36658

283

67 Shin_gl 132 Erosion 38312 68 Shin_gl 203 Erosion 38337 69 Shin_gl 171 Erosion 38386 70 Shin_gl 126 Erosion 38704 71 Shin_gl 14 Erosion 39711 72 Shin_gl 174 Erosion 39895 73 Shin_gl 131 Erosion 39987 74 Shin_gl 144 Erosion 40208 75 Shin_gl 56 Erosion 41148 76 Shin_gl 223 Erosion 41514 77 Shin_gl 31 Erosion 41667 78 Shin_gl 79 Erosion 43307 79 Shin_gl 133 Erosion 46370 80 Shin_gl 136 Erosion 47057 81 Shin_gl 182 Erosion 47140 82 Shin_gl 196 Erosion 47806 83 Shin_gl 99 Erosion 52278 84 Shin_gl 138 Erosion 55183 Shin_gr 84 85 Shin_gl 186 Erosion 56459 86 Shin_gl 70 Erosion 59651 87 Shin_gl 67 Erosion 60908 88 Shin_gl 111 Erosion 61006 89 Shin_gl 61 Erosion 64801 90 Shin_gl 183 Erosion 65358 91 Shin_gl 140 Erosion 67236 92 Shin_gl 175 Erosion 72178 93 Shin_gl 192 Erosion 73645 94 Shin_gl 80 Erosion 77801 95 Shin_gl 15 Erosion 82424 Shin_gr 56 70096 Shin_gl 65 Erosion 84445 97 Shin_gl 163 Erosion 86846 98 Shin_gl 12 Erosion 89168 99 Shin_gl 213 Erosion 97480

100 Shin_gl 201 Erosion 100240 101 Shin_gl 181 Erosion 105425 102 Shin_gl 143 Erosion 111339 103 Shin_gl 146 Erosion 122350 104 Shin_gl 219 Erosion 134497 Shin_gr 150 105 Shin_gl 190 Erosion 151512 Shin_gr 121 106 Shin_gl 94 Erosion 161000 107 Shin_gl 168 Erosion 164901 108 Shin_gl 184 Erosion 190002 109 Shin_gl 188 Erosion 198654 110 Shin_gl 121 Erosion 211179 Shin_gr 99 111 Shin_gl 151 Erosion 265731 112 Shin_gl 142 Erosion 272231 Shin_gr 85 113 Shin_gl 232 Lateral Moraine 84125 114 Shin_gl 148 Valley 23145 115 Shin_gl 226 Valley 23997

284

116 Shin_gl 205 Valley 24522 117 Shin_gl 8 Valley 24533 118 Shin_gl 204 Valley 24937 119 Shin_gl 105 Valley 25729 120 Shin_gl 90 Valley 28041 121 Shin_gl 195 Valley 29327 122 Shin_gl 81 Valley 31604 123 Shin_gl 170 Valley 41208 124 Shin_gl 13 Valley 41319 125 Shin_gl 193 Valley 48906 126 Shin_gl 73 Valley 52736 127 Shin_gl 158 Valley 57222 128 Shin_gl 217 Valley 59133 129 Shin_gl 19 Valley 60862 130 Shin_gl 157 Valley 69091 131 Shin_gl 159 Valley 77525 132 Shin_gl 227 Valley 83520 Shin_gl 157 200133 Shin_gl 172 Valley 133999 134 Shin_gl 155 Valley 144520 135 Shin_gl 92 Valley 146978 136 Shin_gl 95 Valley 152912 137 Shin_gl 214 Valley 185339 138 Shin_gl 153 Valley 196807 139 Shin_gl 96 Valley 1359533

Table 10.2.8.2: Summary of Major Lakes of Shingo River basin. Area(m2) S. No. Type Number Area (km2) Largest Smallest

1 Blocked 1 0.028 27606 2 Cirque 19 0.799 259860 20357 3 End Moraine 14 0.742 126852 20152 4 Lateral Moraine 1 0.084 84125 5 Erosion 78 4.932 272231 20053 6 Supraglacial - - - - 7 Valley 26 3.147 1359533 23145 Total 139 9.732

285

The details of potentially dangerous lakes are presented in Table 10.2.8.3. Out of 5 dangerous lakes of this basin three are End Moraine, and one each Cirque and Valley. Four of these lakes are located in the northern part while the fifth one is in the central part of the basin (Figure 10.2.8.1).

The Cirque lake (Shin_gl 75) is in contact with a hanging glacier (Shin_gr 85) which is the main source of snow avalanches (Figure 10.2.8.2). Out of three End Moraine lakes the Shin_gl 115 is located at a distance of 180 meters from the glacier Shin_gr 89. The other two End Moraine lakes (Shin_gl 167 and Shin_gl 220) are in contact with the glaciers (Shin_gl 118 and Shin_gl 151 respectively).

The potentially dangerous Valley lake (Shin_gl 227) have a source glacier (Shin_gr 157) at a distance of 200 meters.

Table 10.2.8.3: Potentially dangerous glacial lakes in Shingo River basin.

S.No. Lake Type Lake Number Area (m2 ) Associated

Glacier

Distance to glacier

(m) Remarks

1 Cirque Shin_gl 75 254810 Shin_gr 85 In contact with hanging glacier

2 End Moraine Shin_gl 115 126852 Shin_gr 89 180 Near hanging glacier

3 End Moraine Shin_gl 167 72199 Shin_gr 118 In contact with hanging glacier

4 End Moraine Shin_gl 220 45193 Shin_gr 151 Lake in contact with hanging glacier

5 Valley Shin_gl 227 83520 Shin_gr 157 200 Near hanging glacier source

286

Figure 10.2.8.1: Distribution of potentially dangerous glacial lakes of Shingo River basin.

287

10.2.9 Astor River basin

There are 126 glacial lakes in Astor River basin out of which 64 are major lakes (Table 10.2.9.1). Most of the major glacial lakes are in contact with or at a distance of less than 500 meters from the glaciers. Table 10.2.9.2 gives the summary of major lakes. Out of 64 major lakes maximum are of Cirque type (21) followed by Valley (19) and Erosion (15). One each is the lateral Moraine and Supra glacial lake. The accumulative area contributed by the major lakes is 4.953 sq. km out of which maximum is contributed by Cirque and Valley lakes. The Valley lakes ranges in size from 0.02 (Astor_gl 86) to 0.167 (Astor_gl 4) sq. km. Generally Cirque lakes are larger in size since they range from 0.063 (Astor_gl 22) to 0.541 (Astor_gl 92) sq. km. The remaining lake area is contributed by other types of lakes.

(a) Cirque lake (Shin_gl_75)

(b) End Moraine lake (Shin_gl_167)

Figure 10.2.8.2: Dangerous glacial lakes of Shingo River basin

288

Table 10.2.9.1: Major glacial lakes associated with the glaciers in Astor River Basin.

S.No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier

(m) 1 Astor_gl 109 Blocked 65847 Astor_gr 445 2 Astor_gl 123 Blocked 72747 Astor_gr 579 3103 Astor_gl 122 Blocked 155047 Astor_gr 579 3354 Astor_gl 22 Cirque 63245 Astor_gr 157 5 Astor_gl 48 Cirque 74658 Astor_gr 250 6 Astor_gl 25 Cirque 139441 Astor_gr 163 7 Astor_gl 75 Cirque 20530 Astor_gr 366 8 Astor_gl 69 Cirque 20939 Astor_gr 346 9 Astor_gl 79 Cirque 21861 Astor_gr 369 10 Astor_gl 39 Cirque 22975 Astor_gr 217 11 Astor_gl 73 Cirque 25438 Astor_gr 360 20012 Astor_gl 81 Cirque 29493 Astor_gr 370 13 Astor_gl 1 Cirque 34823 14 Astor_gl 116 Cirque 36434 Astor_gr 466 15 Astor_gl 77 Cirque 41333 Astor_gr 368 16 Astor_gl 94 Cirque 51352 17 Astor_gl 36 Cirque 53376 Astor_gr 199 18 Astor_gl 93 Cirque 61420 19 Astor_gl 41 Cirque 91559 Astor_gr 220 20 Astor_gl 51 Cirque 106373 Astor_gr 252 21 Astor_gl 95 Cirque 147588 22 Astor_gl 40 Cirque 159634 Astor_gr 218 23 Astor_gl 96 Cirque 246619 24 Astor_gl 92 Cirque 541924 25 Astor_gl 110 Erosion 22093 26 Astor_gl 21 Erosion 23029 Astor_gr 157 31027 Astor_gl 87 Erosion 24083 Astor_gr 378 28 Astor_gl 23 Erosion 27059 Astor_gr 160 32029 Astor_gl 42 Erosion 27787 Astor_gr 221 30 Astor_gl 98 Erosion 28439 31 Astor_gl 62 Erosion 29172 Astor_gr 308 48032 Astor_gl 49 Erosion 29713 33 Astor_gl 17 Erosion 31314 34 Astor_gl 102 Erosion 33056 Astor_gr 415 35535 Astor_gl 2 Erosion 37940 Astor_gr 56 65036 Astor_gl 126 Erosion 39231 Astor_gr 588 15537 Astor_gl 20 Erosion 50999 38 Astor_gl 15 Erosion 55002 39 Astor_gl 91 Erosion 59900 40 Astor_gl 105 Lateral Moraine 53465 Astor_gr 420 41 Astor_gl 107 End Moraine 45632 Astor_gr 444 42 Astor_gl 53 End Moraine 82314 Astor_gr 254 7543 Astor_gl 121 End Moraine 93774 Astor_gr 564 44 Astor_gl 108 End Moraine 160565 Astor_gr 445

289

45 Astor_gl 125 Supraglacial 21088 Astor_gr 579 46 Astor_gl 86 Valley 20320 Astor_gr 378 47 Astor_gl 74 Valley 25353 Astor_gr 361 48 Astor_gl 55 Valley 32282 Astor_gr 255 25549 Astor_gl 54 Valley 34620 Astor_gr 255 50 Astor_gl 64 Valley 41442 Astor_gr 310 124051 Astor_gl 16 Valley 57846 Astor_gr 150 52 Astor_gl 71 Valley 74600 Astor_gr 357 53 Astor_gl 63 Valley 78751 Astor_gr 309 87554 Astor_gl 50 Valley 309309 Astor_gr 252 12555 Astor_gl 90 Valley 342952 56 Astor_gl 112 Valley 23108 Astor_gr 449 47057 Astor_gl 85 Valley 26378 Astor_gr 377 58 Astor_gl 82 Valley 32877 Astor_gr 373 104059 Astor_gl 101 Valley 36035 60 Astor_gl 5 Valley 56438 Astor_gr 111 73061 Astor_gl 118 Valley 85756 62 Astor_gl 3 Valley 121362 Astor_gr 98 37663 Astor_gl 59 Valley 124842 Astor_gr 292 34064 Astor_gl 4 Valley 167989 Astor_gr 99 680

The Moraine Dammed lakes are four in number and all of them are associated with glaciers. The largest and the smallest lake in this group have an area of 0.16 and 0.04 km2 respectively. In the present study 9 glacial lakes are identified as potentially dangerous lakes (Table 10.2.9.3 and Figure 10.2.9.1). The lakes identified as potentially dangerous consist of 5 Cirque, 3 End Moraine and one Valley lakes. The potentially dangerous glacial lakes are Astor_gl 25, Astor_gl 36, Astor_gl 40, Astor_gl 48, Astor_gl 50, Astor_gl 51, Astor_gl 53, Astor_gl 108 and Astor_gl 121(Figure 10.2.9.2). All the Cirque lakes, which were identified as potentially dangerous glacial lakes are situated at the toe of the hanging glacier. Normally if the hanging glacier is associated with the glacial lake, the lakes will be in dangerous condition as the ice mass can slipped and plunge to the lake resulting the surge and breaching the dam causing glacial lake outburst flood.

Table 10.2.9.2: Summary of Major Lakes of Astor River basin. Area (m2) S. No. Type Number Area (km2) Largest Smallest

1 Blocked 3 0.294 155047 65847 2 Cirque 21 1.991 541924 63245 3 End Moraine 4 0.382 160565 45632 5 Lateral Moraine 1 0.053 53465 - 4 Erosion 15 0.519 59900 22093 Supraglacial 1 0.021 21088 -

6 Valley 19 1.692 167989 20320 Total 64 4.953

290

Table 10.2.9.3: Potentially dangerous glacial lakes in Astor River basin.

S.No Lake type Lake Number Area (m2) Associated

Glacier

Distance to glacier

(m) Remarks

1 Cirque Astor_gl 36 53376 Astor_gr 199 Hanging glacier source

2 Cirque Astor_gl 48 74658 Astor_gr 250 Snow avalanche source

3 Cirque Astor_gl 51 106373 Astor_gr 254 Hanging glacier source

4 Cirque Astor_gl 25 139441 Astor_gr 163 In contact with hanging glacier

5 Cirque Astor_gl 40 159634 Astor_gr 218 Hanging glacier source

6 End Moraine Astor_gl 53 82314 Astor_gr 254 75 Close to large glacier

7 End Moraine Astor_gl 121 93774 Astor_gr 564 At active glacier tongue

8 End Moraine Astor_gl 108 160565 Astor_gr 445 In contact with large glacier

9 Valley Astor_gl 50 309309 Astor_gr 252 125

Situated in hanging valley ,dangerous glacial lake 300m upstream

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The Valley Lake Astor_gl 50 has the area of 0.30 sq. km and is formed by merging of closely developed lakes along the river valley. The lake is just 300 meters downstream from the potentially dangerous glacial lake. As the upstream lake is in danger, ultimately the lakes downstream are in danger.

Figure 10.2.9.1: Distribution of potentially dangerous glacial lakes in Astor River basin

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Figure 10.2.9.2: Potentially dangerous glacial lake (Astor_gl 108).

Out of three End Moraine lakes, the largest one (Astor_gl 108) is in contact with a large glacier Astor_gr 445. The other two End Moraine lakes (Ast_gl 121 and Ast_gl 53) are dangerous because one of them is near a large glacier (Astor_gr 564) and the other one is at a distance of 75 meters from a glacier (Astor_gr 254).

10.2.10 Jhelum River basin In Jhelum River basin out of 196 glacial lakes, 95 lakes have been characterized as major lakes. The detail of each major lake is given in the Table 10.2.10.1. Out of these, maximum are Erosion lake (41) followed by Cirque lakes (33). There is only one Blocked and one Lateral Moraine dammed lakes. The Valley lakes are eight in number (Table 10.2.10.2). The largest Cirque lake (Jhe_gl 89) and Valley lake (Jhe_gl 14) have an area of 1.04 and 0.87 sq. km respectively. The accumulative lake area of all the major lakes is 10.66 sq. km out of which Cirque type has about 37% followed by Erosion and Valley lakes 26 and 23 % respectively. Lateral Moraine and Blocked lakes contribute less than one percent to the lake area.

Table 10.2.10.1: Major Lakes of Jhelum River basin

S.No. Lake number Type Area (m2) Associated glacier No.

Distance to glacier (m)

1 Jhe_gl 80 Blocked 37565 2 Jhe_gl 30 Cirque 21666 3 Jhe_gl 20 Cirque 22190 4 Jhe_gl 99 Cirque 26107 5 Jhe_gl 27 Cirque 26905 6 Jhe_gl 33 Cirque 27279 7 Jhe_gl 63 Cirque 28501 8 Jhe_gl 68 Cirque 31038 9 Jhe_gl 53 Cirque 33675

10 Jhe_gl 55 Cirque 34087 11 Jhe_gl 87 Cirque 34486 12 Jhe_gl 90 Cirque 38864 13 Jhe_gl 110 Cirque 40750 14 Jhe_gl 29 Cirque 43632

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15 Jhe_gl 18 Cirque 47336 16 Jhe_gl 62 Cirque 49335 17 Jhe_gl 50 Cirque 53126 18 Jhe_gl 65 Cirque 53275 19 Jhe_gl 38 Cirque 55120 20 Jhe_gl 150 Cirque 55649 21 Jhe_gl 149 Cirque 55789 22 Jhe_gl 189 Cirque 88480 23 Jhe_gl 193 Cirque 91487 24 Jhe_gl 113 Cirque 117873 Jhe_gr 200 46825 Jhe_gl 19 Cirque 145414 26 Jhe_gl 54 Cirque 169895 27 Jhe_gl 46 Cirque 199000 28 Jhe_gl 95 Cirque 201474 Jhe_gr 170 24229 Jhe_gl 97 Cirque 202073 30 Jhe_gl 96 Cirque 211592 Jhe_gr 174 48331 Jhe_gl 85 Cirque 215769 32 Jhe_gl 184 Cirque 226043 33 Jhe_gl 134 Cirque 240657 Jhe_gr 315 34 Jhe_gl 89 Cirque 1036592 35 Jhe_gl 56 End Moraine 23713 36 Jhe_gl 127 End Moraine 25279 37 Jhe_gl 22 End Moraine 25333 38 Jhe_gl 186 End Moraine 31287 Jhe_gr 364 16039 Jhe_gl 49 End Moraine 32377 40 Jhe_gl 181 End Moraine 59579 Jhe_gr 362 45941 Jhe_gl 98 End Moraine 62360 42 Jhe_gl 140 End Moraine 117217 43 Jhe_gl 135 End Moraine 151045 44 Jhe_gl 94 End Moraine 206856 45 Jhe_gl 131 End Moraine 713186 Jhe_gr 300 15346 Jhe_gl 15 Erosion 20140 47 Jhe_gl 31 Erosion 20580 48 Jhe_gl 41 Erosion 20806 49 Jhe_gl 17 Erosion 20955 50 Jhe_gl 86 Erosion 21090 Jhe_gr 166 43051 Jhe_gl 58 Erosion 22288 52 Jhe_gl 93 Erosion 22931 53 Jhe_gl 163 Erosion 22992 Jhe_gr 355 42254 Jhe_gl 106 Erosion 27242 55 Jhe_gl 178 Erosion 28375 56 Jhe_gl 34 Erosion 29749 57 Jhe_gl 61 Erosion 29755 58 Jhe_gl 52 Erosion 29955 59 Jhe_gl 36 Erosion 31770 60 Jhe_gl 74 Erosion 33213 Jhe_gr 106 70061 Jhe_gl 152 Erosion 34350 62 Jhe_gl 165 Erosion 34853 Jhe_gr 359 63 Jhe_gl 45 Erosion 37754 64 Jhe_gl 174 Erosion 38873 65 Jhe_gl 120 Erosion 39303

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66 Jhe_gl 145 Erosion 41411 67 Jhe_gl 169 Erosion 42101 Jhe_gr 360 138568 Jhe_gl 157 Erosion 44569 69 Jhe_gl 138 Erosion 48682 Jhe_gr 332 88570 Jhe_gl 116 Erosion 48708 71 Jhe_gl 139 Erosion 49054 Jhe_gr 333 121272 Jhe_gl 24 Erosion 49133 73 Jhe_gl 40 Erosion 50592 74 Jhe_gl 176 Erosion 50672 75 Jhe_gl 88 Erosion 50931 76 Jhe_gl 141 Erosion 51441 Jhe_gr 337 97377 Jhe_gl 28 Erosion 53137 78 Jhe_gl 79 Erosion 55629 Jhe_gr 140 79 Jhe_gl 111 Erosion 59498 80 Jhe_gl 59 Erosion 73048 81 Jhe_gl 107 Erosion 81913 82 Jhe_gl 117 Erosion 106195 Jhe_gr 226 65383 Jhe_gl 132 Erosion 118569 84 Jhe_gl 69 Erosion 123239 85 Jhe_gl 39 Erosion 222837 Jhe_gr 41 64486 Jhe_gl 170 Erosion 791251 87 Jhe_gl 91 Lateral Moraine 27055 88 Jhe_gl 81 Valley 22251 89 Jhe_gl 190 Valley 25005 90 Jhe_gl 164 Valley 29980 91 Jhe_gl 196 Valley 79563 92 Jhe_gl 101 Valley 304392 93 Jhe_gl 73 Valley 443447 94 Jhe_gl 185 Valley 669214 95 Jhe_gl 14 Valley 874930

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There are five potentially dangerous lakes in this basin and are mainly concentrated in the central northern part of the basin (Figure 10.2.10.1). Among the 33 major Cirque lakes, three are identified as potentially dangerous lakes (Table 10.2.10.3). The lake Jhe_gl 97 is not in contact with any glacier. The Jhe_gl 134 is associated with a large glacier Jhe_gr 315 and has snow avalanche source. Generally these lakes are in contact with hanging glaciers or large ice masses.

The two potentially dangerous End Moraine lakes are Jhe_gl 131 and Jhe_gl 140. One of these is very near to the hanging glacier source while the other is in contact with the hanging glacier. The potentially dangerous lakes of the basin are shown in Figure 10.2.10.2.

Table 10.2.10.2: Summary of Major Lakes of Jhelum River basin. Area (m2) S. No. Type Number Area

(km2) Largest Smallest 1 Blocked 1 0.038 37565 - 2 Cirque 33 3.925 1036592 21666 3 End Moraine 11 1.448 713186 23713 4 Lateral Moraine 1 2.780 27055 - 5 Erosion 41 0.027 791251 20140 6 Valley 8 2.449 874930 22251

Total 95 10.667

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Figure 10.2.10.1: Distribution of potentially dangerous glacial lakes in Jhelum River basin.

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Table 10.2.10.3: Potentially dangerous glacial lakes in Jhelum River basin.

S.No. Lake type Lake Number

Area (m2)

Associated Glacier

Distance to glacier

(m) Remarks

1 Cirque Jhe_gl 97 202073 - In contact with large glacier

2 Cirque Jhe_gl 113 117873 Jhe_gr 200 In contact with hanging glacier

3 Cirque Jhe_gl 134 240657 Jhe_gr 315 Snow avalanche source 4 End Moraine Jhe_gl 131 713186 Jhe_gr 300 153 Near hanging glacier

5 End Moraine Jhe_gl 140 117217 - In contact with hanging glacier

(a) Cirque lake (Jhe_gl 97) (b) End Moraine (Jhe_gl 131)

Figure 10.2.10.2: Potentially dangerous glacial lakes of Jhelum River basin.

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10.2.11 Summary

In conclusion out of total of 2420 glacial lakes, 1328 lakes are characterized as major lakes (Table 10.2.11.1). Among the total number of lakes more than 77% are contributed by five river basins namely Gilgit, Indus, Shingo, Swat and Jhelum. Shyok and Shigar

River basins have the minimum number of total as well as major lakes. Highest numbers of major lakes are in Gilgit River basin (614) followed by Indus River basin (328). A total of 83% major lakes are contributed by five basins which contribute highest number of total lakes as well. Out of 1,328 major lakes, 52 are characterized as potentially dangerous lakes. Most of them (61%) are identified in Indus (15), Astor (9) and Gilgit (8) river basins. The total lake area follows the pattern of total number of lakes in ten river basins. The largest lake in ten basins is in Gilgit River basin having an area of 2.72 sq. km. The other river basins like Chitral, Shingo, Indus and Jhelum also have large size lakes. The largest lakes of Shigar, Shyok and Hunza river basins are relatively smaller in size compared to other basins.

Among various types of major lakes the highest number is of Erosion type lakes (498) followed by Valley (277) and End Moraine (226). The minimum number (20) is of Block type lakes (Table 10.2.11.2). The Valley, Erosion, End Moraine and Cirque lakes are more common in Gilgit, Indus and Swat River basins. In Swat, Shingo and Jhelum River basins Supraglacial lakes are not present. In Shigar River basin only Blocked, Supraglacial and Valley type major lakes are present.

Table 10.2.11.1: Summary of glacial lakes in selected ten basins

Number of lakes Basins

Total Major DangerousLake Area

(km2) Largest lake

(km2)

Swat 255 163 2 15.862 0.81 Chitral 187 70 1 9.365 1.86 Gilgit 614 380 8 39.17 2.72 Hunza 110 47 1 3.215 0.29 Shigar 54 11 - 1.092 0.24 Shyok 66 31 6 2.682 0.27 Indus 574 328 15 26.063 1.35 Shingo 238 139 5 11.59 1.36 Astor 126 64 9 5.528 0.54 Jhelum 196 95 5 11.786 1.04

Total 2420 1328 52 126.353

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Table 10.2.11.2: Summary of Major Lakes in selected ten basins

River Basins S. No. Type Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum Total

1 Blocked 3 3 1 1 5 1 1 1 3 1 20 2 Cirque 10 5 43 - - 1 51 19 21 33 183 3 Erosion 80 17 140 5 - 7 115 78 15 41 498 4 End 31 12 74 3 - 12 65 14 4 11 226 5

Moraine Dammed Lateral 2 2 27 1 - 2 32 1 1 1 69

6 Supraglacial - 1 2 20 5 1 25 - 1 - 55 7 Valley 37 30 93 17 1 7 39 26 19 8 277

Total 163 70 380 47 11 31 328 139 64 95 1328

Table 10.2.11.3: Summary of Potentially Dangerous Glacial Lakes in selected ten basins

Ten Basins Lake Type

Swat Chitral Gilgit Hunza Shigar Shyok Indus Shingo Astor Jhelum Total

Cirque - - - - - 4 2 5 3 13 End Moraine 2 1 6 1 - 4 10 2 3 2 31 Valley - - 2 - - 2 1 1 1 - 8

Total 2 1 8 1 - 6 15 5 9 5 52

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In ten basins of HKH region of Pakistan among the 1,328 major lakes, a total of 52 are characterized as potentially dangerous lakes based on criteria defined earlier (Table 10.2.11.3). Generally the lakes identified as dangerous lakes belong to Cirque, End Moraine and Valley type lakes. Out of 52 dangerous lakes 31 are End Moraine, 13 Cirque and only 8 Valley type lakes. Dangerous Cirque lakes are present in four southern basins namely Indus, Shingo, Astor and Jhelum. Similarly the dangerous Valley lakes are distributed in these basins along with Gilgit River basin. End Moraine dangerous lakes are present in the entire basin in variable numbers except Shigar River basin.

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Figure 10.2.11.1:Distribution of potentially dangerous glacial lakes in ten river basins

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Chapter 11

Glacial Lake Outburst Flood Mitigation Measures, Monitoring and Early Warning Systems

There are several possible methods for mitigating the impact of glacial lake outburst flood (GLOF) surges, for monitoring, and for early warning systems. The most important mitigation measure for reducing GLOF risk is to reduce the volume of water in the lake in order to reduce the peak surge discharge.

Downstream in GLOF prone areas, measures should be taken to protect infrastructure against the destructive forces of GLOF surge. There should be monitoring systems prior to, during, and after construction of infrastructures and settlements in the downstream area.

Careful evaluation by detailed studies of the lake, mother glaciers, damming materials, and the surrounding conditions are essential in choosing an appropriate method and in starting any mitigation measure. The measures taken must be such that these should not create or increase the risk of a GLOF during and after the mitigation measures are in place. Physical monitoring systems of the dam, lake, mother glacier/s, and the surroundings are necessary at different stages during and after the mitigation process.

11.1 REDUCING THE VOLUME OF LAKE WATER

Possible peak surge discharge from a GLOF could be reduced by reducing the volume of water in the lake. In general, any one or combination of the following methods may be applied for reducing the volume of water in the lake:

• controlled breaching,

• construction of an outlet control structure,

• pumping or siphoning out the water from the lake, and

• making a tunnel through the moraine barrier or under an ice dam.

Controlled Breaching

Controlled breaching can be carried out by blasting, excavation, or even by dropping bombs from an aircraft. One of the successful examples has been reported on Bogatyr Lake in Alatau, Kazakhastan (Nurkadilov et al. 1986). An outflow channel was excavated using explosives and 7 million cubic metres of water was successfully released in a period of two days. These methods, however, can give strong, uncontrolled regressive erosion of the moraine wall causing a fast lowering of the lake level. Liboutry et al. (1977a, b, and c) described a case from Peru of the sudden discharge of 6–10 million cubic meters of water after two years of careful cutting of a trench in the moraine wall.

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For more permanent and precise control of lake outflows, rigid structures made out of stone, concrete, or steel can be used. However, the construction and repairs of the required mitigation works at high elevations, in difficult terrain conditions and in glacial lake areas far from road points and not easily accessed, will cause logistic difficulties. Therefore, preference should be given to construction materials available locally such as boulders and stones. The boulders on the moraine walls can be held in place by wire mesh (‘gabion’) and/or held down by appropriate anchors.

Open cuts in a moraine dam can be excavated during the dry season when a lake’s water level is lower than during the wet season. Such a method is risky as any displacement wave arising from an ice avalanche can rip through the cut and breach the moraine. This method should be attempted where there is no risk of avalanches into the lake.

Pumping or siphoning the water out from the lake

Examples given by Liboutry et al. (1977a, b, and c) from Peru and the pumping programme for the control of Spirit Lake after the eruption of Mount St. Helens in Washington State in the USA are very costly because of the large amount of electricity needed for the powerful pumps. The pumping facility consisted of 20 pumps with a total capacity of 5 m3 s–1 and the cost of the pumping plant including the operation and maintenance for about 30 months was approximately US $11 million (Sager and Chambers 1986).

In the HKH region, there is neither hydroelectric power distribution system at high altitudes nor a simple means for transporting fuel to high elevations. Many of the lakes are higher than the maximum flying altitude of helicopters.

The use of a turbine, propelled by the water force at the outside of the moraine dam, will lower the energy costs. The problems of coupling the turbine and the pumps have to be solved.

Siphons with manageable component size are attractive in that they are readily transportable, relatively easy to install, and can be very effective for smaller size lakes.

Making a tunnel through the moraine dam

Tunneling through moraines or debris barriers, although risky and difficult because of the type of material blocking the lake, has been carried out in several countries. In Peru, Liboutry et al. (1977a, b, and c) reported problems related to tunneling through a moraine dam, which had been severely affected by an earthquake.

Tunneling can only be carried out through competent rock beneath or beside a moraine dam. The costs of such a method are very high. Unfortunately, not all moraine dams are suitable for tunneling.

The construction of tunnels would pose difficulties in the Himalayas due to the high cost of transporting construction materials and equipment to high elevations.

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11.2 PREVENTATIVE MEASURES AROUND THE LAKE AREA

Any existing and potential source of a larger snow and ice avalanche, slide, or rock fall around the lake area, which has a direct impact on the lake and dam, has to be studied in detail. Preventative measures have to be taken such as removing masses of loose rocks to ensure there will be no avalanches into the lake.

11.3 PROTECTING INFRASTRUCTURE AGAINST THE DESTRUCTIVE FORCES OF THE SURGE

The sudden hydrostatic and dynamic forces generated by a rapid moving shock wave can be difficult to accommodate by conventionally designed river structures such as diversion weirs, intakes, bridges, settlements on the river banks, and so on. It will be necessary to build bridges with appropriate flow capacities and spans at elevations higher than those expected under GLOF events. The Nepal–China highway, after reconstruction, has arched bridges well above the 1981 GLOF levels. Also, the road has been moved to higher levels and has gabion protection at the base of the embankments. Settlements should not be built at or near low river terraces but at heights well above the riverbed in an area with GLOF potential. Slopes with potential or old landslides and steep slopes on the banks of the river near settlements should be stabilized. It is essential that appropriate warning devices for GLOF events be developed in such areas.

11.4 MONITORING AND EARLY WARNING SYSTEMS

A programme of monitoring GLOFs throughout the country should be implemented using a multi-stage approach, multi-temporal data sets, and multi-disciplinary professionals. Focus should first be on the known potentially dangerous lakes and the river systems on which infrastructure is developed. Monitoring, mitigation, and early warning system programmes could involve several phases as follow.

• Detailed inventory and development of a spatial and attribute digital database of the glaciers and glacial lakes using reliable medium- to large-scale (1:63,360 to 1:10,000) topographic maps

• Update of the inventory of glaciers and glacial lakes and identification of potentially dangerous lakes using remote-sensing data such as the Land Observation Satellite (LANDSAT) Thematic Mapper (TM) and Enhanced Thematic Mapper plus (ETM+), Indian Remote Sensing Satellite (IRS)1C/D Linear Imaging and Self-scanning Sensor (LISS)3, Système Probatoire d’Observation de la Terre (SPOT) multi-spectral (XS), SPOT panchromatic (PAN) (stereo), IRS1C/D PAN (stereo) images, IKONOS , Quickbird and others.

• Semi-detailed to detailed study of the glacial lakes, identification of potentially dangerous lakes and the possible mechanism of a GLOF using aerial photos

• Annual examination of medium- to high-resolution satellite images, e.g. Landsat TM and ETM+, IRS1D, SPOT, and so on to assess changes in the different parameters of potentially dangerous lakes and the surrounding terrain

• Brief over-flight reconnaissance with small format cameras to view the lakes of concern more closely and to assess their potential for bursting in the near future

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• Field reconnaissance to establish clearly the potential for bursting and to evaluate the need for preventative action

• Detailed studies of the potentially dangerous lakes by multi-disciplinary professionals

• Implementation of appropriate mitigation measure(s) in the highly potentially dangerous lakes

• Regular monitoring of the site during and after the appropriate mitigation measure(s) should be carried out

• Development of a telecommunication and radio broadcasting system integrated with on-site installed hydro-meteorological, geophysical, and other necessary instruments at lakes of concern and downstream as early warning mechanisms for minimising the impact of a GLOF

• Interaction/cooperation among all of the related government departments/ institutions/agencies /broadcasting media, and others for detailed studies, mitigation activities, and preparedness for possible disasters arising from GLOF events.

• In the Hindu Kush-Himalayan-Karakoram region, many rivers flow down from the high Himalayan or Tibetan Plateau to more than one country. Flash floods from landslide dam failure or glacial lake outburst in one country can cause havoc in the downstream areas of other countries. So in the Hindu Kush-Himalayan-Karakoram region, inter-country flood warning systems should be established in the river valleys when more than one country is affected. A mechanism for sharing the costs and benefits of flash flooding mitigation works should be devised.

11.5: EARLY WARNING AND FLOOD FORECASTING SYSTEMS IN PAKISTAN The 1973 floods caused extraordinary damage, revealed that single events could undo years of development, and prompted the first national flood investigation (Harza 1975). A succession of floods in 1975, 1976 and 1978 ensured continuing public attention. Prior to independence, flood protection had been a provincial responsibility; following the 1973 floods the federal government sought to coordinate provincial and national flood protection efforts. This was done by a Central Flood Committee until 1977 when a Federal Flood Commission (FFC) was formed. The lapses and failures identified in the past planning strategies include:

• Flood management was provincial subject and there was lack of coordination between the provinces and federal agencies

• Flood sector was given low priority in the provincial programmes

• Funds for operation and maintenance and flood management were grossly inadequate

• Flood works planned were on basis of local requirement

• No systematic procedure was followed for evaluating protection measures and design never related to level of protection

• Interdependent hydrologic/hydraulic effects were never evaluated

• Modern soil engineering practices were never considered

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So the main function of establishment of Federal Flood Commission (FCC) was to integrate flood management planning from Provincial level to National level and to administer, plan, execute and coordinate the flood management activities at the national level. FFC also has a role to coordinate the government agencies and flood fighting agencies. Since the establishment of FFC, the flood problems are receiving increasing recognition as matters of national concern and greater emphasis is now being given to flood problems in national policies and development plans. Another change in approach has been the growing emphasis upon continuous, rather than with the traditional crisis provoked approach. Prior to the establishment of FFC since January 1977, the Provincial Irrigation Departments and other Federal and Provincial Agencies like Irrigation Departments, Building and Roads, Pakistan Railways, Highway Departments, etc. used to prepare flood plans for their areas of jurisdiction. These plans were essentially non-unified, un-integrated, crisis provoked and piece-meal efforts, as no single institute had the responsibility of flood management planning and co-ordination at the national level. The FFC commissioned a National Flood Protection Plan published in 1979 (NESPAK and Harza, 1979), which was followed by flood protection investment plan in 1987 (NESPAK, 1987). The Asian Development Bank (ADB) financed a major study of flood protection priorities in 1989 (NESPAK, 1989). Today, annual flood damage reports are prepared by the Meteorological Department and detailed flood damage reports are prepared by provincial irrigation departments after major floods, like the 1988 and 1992 events in Punjab. In view of the recent experience of 1992 and 1994-floods, Flood Forecasting and Warning Centre has now been redesigned as the National Flood Forecasting Bureau (NFFB).The Director, NFFB is authorized to call the meeting of the Bureau as and when the serious flood situation occurs or lack of coordination comes to his notice calling for immediate remedial action. Figure 11.1 represents the organizational setup of NFFB. It has taken in hand the dissemination of the flood forecasts/warnings to considerably large number of recipients directly or indirectly concerned with the flood mitigation process, over and above the dissemination being done by the Flood Warning Centre (FWC). Press briefings have been started in the office of Director, NFFB as a regular feature to ensure correct and authentic flood and weather information to the public. Such briefings are arranged through the representative of the Punjab Information Department on duty at the FWC, only when the flood situation is or is likely to become serious enough to call for such briefings. Considerable improvement has been made in the dissemination system since the time that it was initially started in early fifties by FWC. Most of the discrepancies have been removed, keeping in view the past experiences specially that of 1992-Floods. A much better hot line coordination now exists with Federal Flood Commission, Army, WAPDA, Provincial Irrigation, Relief and other related departments by the National Flood Forecasting Bureau. The existing dissemination process has been reviewed and lists of the recipients of flood information have been streamlined. Basically there are two types of flood information required to be provided for use by the appropriate recipients namely; advance flood forecasts and the flood data. Flood forecasts are disseminated by NFFB as well as the FWC, the flood data is disseminated by the FWC only. Colour coded forecasts are issued in three colors to warn the concerned organization of the severity of the forecast (red, blue, yellow). Significant flood forecast is issued in case of Low, Medium,

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and High as well as quantitative flood range which is kept as narrow as possible. Significant flood forecast is the most important flood forecast and thus calls for the immediate action by the concerned authorities. A real inundation forecast is issued only when the exceptionally high flood situation is anticipated (Sheikh www.southasianfloods.org/document/).

Chief Meteorologist

Flood Forecasting Division (FFD),

Pakistan Meteorological Department (PMD)

Head

Director,

National Flood Forecasting Bureau (N.F.F.B) Director

Hydrology, WAPDA

Member

Director Floods, Provincial Irrigation

and Drainage Authority (Punjab)

Member

Representative of Commissioner For

Indus Waters

Member Figure 11.1: Organizational setup of NFFB.

Existing facilities for the flood forecasting system:

These are briefly summarized as under: -

i. Pakistan Meteorological Department has a network of around 72 Meteorological Stations within the country. Meteorological data from the adjoining countries is also collected for the preparation of surface and upper air weather charts to identify and track the flood generating weather systems.

ii. Automatic Picture Transmission (APT) system for receiving cloud pictures from the NOAA Satellites.

iii. A network of Quantitative Precipitation Weather Radars. Pakistan Meteorological Department at present has one 10-cm Radar at Lahore, and five 5-cm Radars installed at Karachi, Rahim Yar Khan, D.I.Khan, Sialkot and Islamabad. The radars at Karachi, Rahim Yar Khan, D.I.Khan and Islamabad are connected to the National Flood Forecasting Bureau through networking for the collection of real-time data from the catchments.

iv. High Frequency (H.F) Radio Communication System: 69 HF Radio Communication sets for various federal as well as provincial departments related to flood mitigation were procured as a part of Flood Protection Sector Project-1 and distributed to various departments.

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v. Flood Forecasting Models: National Flood Forecasting Bureau is presently using the CLS model for rainfall run-off computations and is based upon the concept of unit hydrograph and thresholds. For river flow routing, a simple model which is based on the regression analysis relating the downstream flows to the upstream flows is used. This does not take into account the variable flows in tributaries, breaching of banks etc. Empirical techniques are then used to accommodate such flow conditions.

Flood forecasting models called SAMFIL and SOBEK were developed as a part of Flood Protection Sector Project-I (1978-88). SAMFIL is the rainfall run-off model based on the concept of Sacramento model originally developed by California Department of Water Resources in 1973. It simulates run-off processing by dividing it into land phase and a channel phase. SOBEK is a one-dimensional hydrodynamic river flow simulation model based on the full Saint-Venant equation of unsteady flow. It is developed using the physical description of the geometry of rivers, continuity equation and a balance of forces governing the flow of water in open channels. It can properly accommodate the influence of bridges, barrages and dams on the propagation and attenuation of flood waves. Both the models are still under verification stage.

Efficiency of flood forecasting system:

The system is still not perfect and has some limitations. Data acquisition in the real time particularly in case of big events, lack of perfection in the mathematical models used for flood forecasting and some other problems are still inhibiting the proper use of the flood forecasting system but the efficiency of the system even then is quite good.

The evaluation of the flood forecasts issued after 1990 remained around 90%. Lead times for Mangla Catchment, however, remained mostly less than a day but the qualitative forecasts were issued with a lead-time of 24 to 36 hours.

Future developments:

In 1997, in view of the encouraging results of the First Flood Protection Sector Project (FPSP-1), further enhanced facilities in this sector were planned. These are still under implementation through Asian Development Bank financed loan and include broadly the following: -

• Procurement and installation of a 10-cm weather radar system in Mangla catchment in order to have extended radar coverage over the northern parts of upper catchment areas of river Indus and Jhelum.

• Procurement of High Resolution Picture Transmission (HRPT) for the receipt of high-resolution clouds imageries.

• Extension and strengthening of Automatic Gauging and Telemetric System of WAPDA and of the HF-Radio Communication Network.

• Bathymetric Survey of Indus River and its major tributaries. • Meteorological studies for better quantitative measurement of rainfall. • Study on Mangla Dam operation during flood season to further refine Reservoir's

Flood Management rules.

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• Flood Plain Mapping and Zoning studies for flood prone areas.

Needs within the HKH regional framework:

Despite improvements in FFS carried out in the recent past in Pakistan, shortcoming are still felt which ask for a mutual co-operation of the countries in the HKH region. Immediate and long-term needs are summarized below: -

• Immediate needs:

o Development of HKH-HYCOS The World Hydrological Observing System (WHYCOS) was launched by WMO in1993 with the aim of promoting cooperation in the collection and the exchange of hydrological data and in exchanging products of interest to the participating countries. WHYCOS is being developed through a series of regional HYCOS projects. A HKH-HYCOS needs to be developed in HKH region and the data needs to be made accessible on internet in the real time. Reporting frequency and the products need to be discussed with a mutual consensus of the countries in the region.

o Meteorological data acquisition in real time: All countries in HKH region are interdependent upon each other for the exchange of weather data which is the first and foremost requirement for the preparation of weather charts and consequently for the identification of flood generating weather systems. During big events, data communication links especially at times when the data is needed, get badly disrupted leaving little room for the timely preparation of weather charts and the issuance of flood forecasts in time. Measures to exchange data in real time through regional internet links need to be developed.

o Exchange of research in the field: Whatever research work be done in the hydro-meteorological side, be immediately exchanged through ICIMOD or directly among the countries.

• Long term needs: o Human recourse development: Training courses mutually offered by the

countries in HKH region can go a long way in developing the human resources in the field of flood forecasting in the region. The knowledge and expertise need to be exchanged through academic courses, seminars and workshops.

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Chapter 12 Conclusions The inventory of glaciers and glacial lakes of the Pakistan was carried out. Altogether the study area was divided into ten river basins, which clockwise include; Swat, Chitral, Gilgit, Hunza, Shigar, Shyok, Indus, Shingo, Astor and Jhelum. Using remote sensing data and the topographic maps available at a scale of 1:250,000 and 1:50,000 the inventory was completed. For glacier inventory, the methodology developed by the Temporary Technical Secretary for the World Glacier Inventory (Muller et al. 1977) was followed. For glacial lake inventory, the methodology developed by the LIGG/WECS/ NEA was used with some modifications. The methodology for the compilation of inventories of glaciers and glacial lakes is applied using medium-scale maps.

The inventories of glaciers and glacial lakes can be facilitated by the use of better quality remote sensing data combined with the topographic maps. The integration of visual and digital image analysis with GIS can provide useful tool for the study of glaciers, glacial lakes, and GLOFs.

Analysts’ experiences and adequate field knowledge of the physical characteristics of the glacier, glacial lakes, and their associated features are always necessary for the interpretation of the topographic maps, satellite images, and aerial photographs. Evaluation of spectral responses by different surface cover types in different bands of satellite images is necessary. Different techniques of digital image enhancement and spectral classification of ground features are useful for the study of glaciers and glacial lakes. Different spectral band combinations in False Colour Composite and individual spectral bands were used to study glaciers and glacial lakes using the knowledge of image interpretation keys.

The Digital Elevation Model (DEM) is useful in deciding the rules for discrimination of features and land-cover types in GIS techniques and for better perspective viewing and presentations.

The major sub basins of Indus River in HKH region of Pakistan are of Swat, Chitral, Gilgit, Hunza, Shigar, Shyok, Upper Indus, Shingo, Astor and Jhelum River. Most of the snow and ice reserves are concentrated in the mountain ranges lying in these basins. These river basins contain the glaciated part in northern Pakistan, which forms the headwaters of the main Indus basin. In the first phase, out of 10 sub basins, the inventory of glaciers and glacial lakes of Astor sub basin was completed in 2003 and in the second phase the inventory of glaciers and glacial lakes was completed for Upper Indus, Jhelum, Shingo, Shigar and Shyok basins in 2004. In the third and final phase the inventory of rest of four River basins i.e. Swat, Chitral, Gilgit and Hunza was completed in 2005. In this report the comprehensive data and information has been compiled for all the basins oh HKH region of the country. The geographic area comprising of ten river basins covers about 128,731 sq. km. Among the ten basins, Indus River Basin has the largest area covering about 25 % of the total

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geographic area. Another 55% area is shared by Hunza, Chitral, Swat and Gilgit river basins. Shingo and Astor River basins are the smallest basins. Over the vast track of these ten basins, 5,218 glaciers are identified. These glaciers are mainly distributed in the northern part of HKH region covering higher Karakoram and Hindu Kush ranges. These glaciers are also present at the higher elevations of Himalayas. Maximum number of glaciers (1,098 and 1,050) is in the Indus and Hunza river basins respectively. Among these two basins, the glaciers are larger in size in Hunza River basin. The southern basins like Swat, Shigar, Shyok and Jhelum have relatively less number of glaciers. Astor and Gilgit River basins contribute equal number (11% each) of glaciers. All the ten basins contribute to a total glaciated area of about 15,041 sq. km which is 11.7% of the total area. The Shingo and Jhelum river basins contribute less than one percent to the glaciated area. On contrary only 194 glaciers in Shigar River basin contribute about 15% to the glaciated area and 1,098 glaciers in Indus River basin contribute only about 5% of glaciated area. The total length of glaciers in ten basins is more than 9,718 km. The glacier length in Hunza River basin is the highest (about 2,915 km) followed by Chitral and Gilgit (1,416 and 1,185 km respectively). Shyok and Indus basins have about the same total length of glaciers (around 1,000 km each). The three river basins i.e. Shingo, Jhelum and Swat have glaciers smaller in size as well as length. The total ice reserve estimated in these 10 basins is about 2,738 km3 . Altogether, more than 80% of the ice reserves are contributed collectively by Shyok River basin (32%), Hunza (30%) and Shigar river basin (21%). The Chitral and Gilgit River basins contribute about 9 and 3% respectively. The contribution of southern basins especially Swat, Jhelum and Shingo is extremely low for being 0.74% altogether. The Valley glaciers contribute much of the ice reserves followed by the Mountain glaciers. The distribution of various types of glaciers in ten river basins shows maximum number of glaciers are of Mountain type (1,918) followed by Cirque (1,237) and Niche type (974). The Ice cap and Ice apron type glaciers are low in number (149 and 394 respectively). Among these ten basins, generally the Mountain and sub types of mountain glaciers are higher in number compared to Valley glaciers (546). In the northern basins like Chitral, Hunza and Shigar the number of Valley glaciers is relatively high whereas in the southern basins like Swat, Jhelum and Shingo the number of Valley glaciers are low. Compared to the number of Valley glaciers, the area contribution by the Valley glaciers (about 77%) is higher. The Mountain glaciers contribute 18% to the glaciated area while the subtypes of Mountain glaciers collectively contribute only 7%. Ice cap glaciers are smallest and therefore, contribute the minimum area. In Swat, Shingo, Astor and Jhelum River basins the area coverage of Valley glaciers is less than of Mountain glaciers while in rest of the basins the area of Valley glaciers exceeds that of the Mountain glaciers. In Gilgit and Indus river basins the Mountain glaciers contribute 41 and 31 percent of the area respectively. Overall in the ten basins, maximum glaciers are oriented towards North (959) and Northeast (919). The E, S and NW aspects have the equal percentage of glacier number.

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Each basin behaves differently as far as the orientation of the glaciers in various ordinal directions is concerned. The glaciers in Indus, Jhelum and Shyok River basins are generally oriented towards northern and eastern aspects. In Shyok River basin besides the northern aspects the southern aspects have also higher number of glaciers. The Shigar River basin has glaciers in all direction but predominantly on north and north eastern aspects. In this basin north western aspects also have higher numbers.

A total of 2,420 glacial lakes have been identified in ten river basins of HKH region of Pakistan. The maximum glacial lakes are identified in Gilgit River basin (614), followed by Indus (574), Swat (255) and Shingo (238) River basins. The lowest number of glacial lakes is in Shigar (54) and Shyok (66) River basins. Among various types of lakes the highest number is of Erosion type (1,064) due to the fact that they are present in all the basins except Hunza and Shigar river basins. In Hunza River basin they are low in number and in Shigar they do not exist. These are followed by Valley lakes (412) and End Moraine Dammed (322) lakes. Blocked lakes are lowest in number (51) out of which 21 are present in Shigar River basin while in Shingo and Jhelum river basins these are one each. The Cirque lakes are more common in Gilgit, Indus, Jhelum, Astor and Shingo River basins. Similarly the End Moraine lakes are also common in these basins alongwith Swat River basin while Lateral Moraine lakes are highest in number in Indus and Gilgit River basins. The Supraglacial lakes are common in the basins where there are large size glaciers like Indus, Hunza, and Shigar. Very few Valley lakes are present in the northern basins like Shigar (2) and Shyok (8) River basins.

The trends of distribution of glacial lakes in ten river basins showed that generally the lakes are distributed all over the ten basins but mostly concentrated in different pockets. The maximum concentration is observed in the northern part of Indus River basin and adjoining southern part of Gilgit River basin. One cluster can also be observed in the northeastern part of Swat River basin. In the northern part of Jhelum River basin and eastern part of Shingo River basin boardering the Indus River basin clusters of lakes are found. In the center of Astor River basin the glacial lakes are quite prominent.

A total of 2,420 glacial lakes in HKH region of Pakistan contribute about 126 sq. km of lake area. The maximum lake area is recorded for Gilgit River basin (about 39 sq. km) followed by Indus River basin (26 sq. km). Just like the lower number, the lowest lake area was observed in Shigar and Shyok River basins. The southern basins especially Shingo and Jhelum contribute the equal lake area (about 12 sq. km each). Among the various types of lakes, Valley lakes are the largest and altogether contribute about 33% of the total lake area followed by Erosion (26%) and End Moraine Dammed (18%) lakes. Generally Blocked, Supraglacial and Later Moraine lakes are small in size and contribute very low lake area.

Out of total of 2,420 glacial lakes, 1,328 lakes are characterized as major lakes. Among the total number of lakes more than 77% are contributed by five river basins namely Gilgit, Indus, Shingo, Swat and Jhelum. Shyok and Shigar River basins have the minimum number of total as well as major lakes. Highest numbers of major lakes are in Gilgit River basin (380) followed by Indus River basin (328). A total of 83% major lakes are contributed by five basins which contribute highest number of total lakes as well. Out of 1,328 major lakes, 52 are characterized as potentially dangerous lakes. Most of them (61%) are identified in Indus (15), Astor (9) and Gilgit (8) river basins.

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The total lake area follows the pattern of total number of lakes in ten river basins. The largest lake in ten basins is in Gilgit River basin having an area of 2.72 sq. km. The other river basins like Chitral, Shingo, Indus and Jhelum also have large size lakes. The largest lakes of Shigar, Shyok and Hunza river basins are relatively smaller in size compared to other basins.

Among various types of major lakes the highest number is of Erosion type lakes (498) followed by Valley (277) and End Moraine (226). The minimum number (20) is of Block type lakes. The Valley, Erosion, End Moraine and Cirque lakes are more common in Gilgit, Indus and Swat River basins. In Swat, Shingo and Jhelum River basins Supraglacial lakes are not present. In Shigar River basin only Blocked, Supraglacial and Valley type major lakes are present.

In ten basins of HKH region of Pakistan among the 1,328 major lakes, a total of 52 are characterized as potentially dangerous lakes based on criteria defined earlier. Generally the lakes identified as dangerous lakes belong to Cirque, End Moraine and Valley type lakes. Out of 52 dangerous lakes 31 are End Moraine, 13 Cirque and only 8 Valley type lakes. Dangerous Cirque lakes are present in four southern basins namely Indus, Shingo, Astor and Jhelum. Similarly the dangerous Valley lakes are distributed in these basins alongwith Gilgit River basin. End Moraine dangerous lakes are present in all the basins in variable numbers except Shigar River basin. These identified dangerous lakes especially near the head waters and settlements needs to be monitored regularly.

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