1

Verifying and Refining the GLOF Hazard and Vulnerability Assessments

for Community Based Flood and Glacial Lake Outburst

Risk Reduction Project (CFGORRP)

Final Report

Submitted to

Community Based Flood and Glacial Lake Outburst Risk Reduction

Project (CFGORRP)

Department of Hydrology and Meteorology

Babarmahal, Kathmandu, Nepal

Submitted by:

Satyam Consultant (P) Ltd

Bhainsepati Saibu-2, Lalitpur Nepal

February, 2014

2

Study Team

Narendra Raj Khanal, Team Leader

Pashupati Nepal, Team Member

Dhyanendra Bahadur Rai, Team Member

i

ACKNOWLEDGEMENTS

Study team would like to express our gratitude to Mr. Top Bahadur Khatri, National

Project Manager, Community Based Flood and Glacial Lake Outburst Risk Reduction

Project (CFGORRP), Department of Hydrology and Meteorologyfor entrusting us to

conduct this study. We would like to express our gratitude to Rishi Ram Sharma, the

Director General of Department of Hydrology and Meteorology and Mr. Rajendra

Sharma for their guidance and help. Similarly, we would like to express our thanks to

Satyam Consultant (P) Limited for entrusting us to complete this work.

This work would not be possible without active participation and support from the local

people. We would like to thank all of them.

Narendra Raj Khanal

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TABLE OF CONTENTS

Page No.

Acknowledgements ......................................................................................................... i

Table of Contents ........................................................................................................... ii

List of Tables ................................................................................................................ iv

List of Figuires ............................................................................................................... v

Executive Summary ...................................................................................................... vi

CHAPTER I : INTRODUCTION .............................................................................. 1

1.1 Background ............................................................................................... 1

1.2. Objectives ................................................................................................ 6

1.3. Scope of the work .................................................................................... 6

1.4. Methodology ............................................................................................ 7

1.5. Limitation of the study ............................................................................. 9

CHAPTER II : INTRODUCTION TO STUDY AREA ......................................... 11

2.1 Imja Glacial Lake .................................................................................... 11

2.2 Dudhkoshi Watershed ............................................................................. 12

CHAPTER III : PAST GLOF EVENTS AND EXPOSURE TO POTENTIAL

IMJA GLOF RISK ........................................................................ 14

3.1 GLOF Events and Losses in the Past in Dudhkoshi Watershed ............. 14

3.2 Exposure to Potential Imja GLOF Risk .................................................. 15

3.2.1 People ............................................................................................ 15

3.2.2 Animal ........................................................................................... 21

3.2.3 Land and Crops.............................................................................. 22

3.2.4 Infrastructure ................................................................................. 23

3.2.4.1 Private and Public Building ............................................. 23

3.2.4.2 Roads, Trails and Embankments ...................................... 25

3.2.4.3 Bridges .............................................................................. 26

3.2.4.4 Hydropower, Water Mill and Transmission Line ............. 26

3.2.5 Monetary Value of the Elements Exposed .................................... 28

3.2.6 Increasing Exposure of Future Investment to Potential GLOF

Risk ............................................................................................... 30

3.2.7 Livelihood Support Service ........................................................... 31

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CHAPTER IV : VULNERABILITY AND GLOF RISK REDUCTION ............. 34

4.1 Socio-economic Vulnerability at Watershed Level ................................ 34

4.2 Livelihood Vulnerability at Settlement/Community Level .................... 36

4.3 People’s Perception on GLOF Risk and Its Management ...................... 39

4.4 People’s Expectation of Early Warning System ..................................... 40

CHAPTER V: CONCLUSION AND RECOMMENDATION ............................. 42

5.1 Conclusion ............................................................................................... 42

5.2 Recommendation ..................................................................................... 44

5.3 Summary of Results and Findigns: Scope of Work ................................ 46

References .................................................................................................................... 50

Appendix 1: Checklist.................................................................................................. 54

Appendix 2: Sites and participants of focus group discussion .................................... 63

Appendix 3: List of key informants ............................................................................. 64

Appendix 4: Maximum flow, travel time, and flood depth at various locaitons, Imja 65

Appendix 5: Number of tourists visiting Sagarmatha National Park by year and month

................................................................................................................. 67

Appendix6: Application for the survey license of different sites ................................ 68

Appendix 7: Photographs ............................................. Error! Bookmark not defined.

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LIST OF TABLES

Page No.

Table 1.1: Magnitude and downstream impact of GLOFs in the past .......................... 3

Table 2.1: Geometrical and dam material properties of Imja Glacial Lake ................. 12

Table 3.1: Major GLOF events and damages in Dudhkoshi Watershed ..................... 14

Table 3.2: Household and population exposed to Imja GLOF risk ............................. 16

Table 3.3: Population exposed to Imja GLOF risk by districts ................................... 17

Table 3.4: Population exposed to potential Imja GLOF risk at different level by caste

and ethnicity ............................................................................................... 17

Table 3.5: Household and population in the settlements within 50 km downstream

along Dudhkoshi ........................................................................................ 19

Table 3.6: Minimum, maximum and average flow of tourist between 1998 and 2013

by months ................................................................................................... 20

Table 3.7: Khet and bari land exposed to potential Imja GLOF risk (in ropani) ......... 22

Table 3.8: Crops exposed to potential Imja GLOF risk (MT) ..................................... 23

Table 3.9: Number of pakki and kachhi houses exposed to potential Imja GLOF risk.

.................................................................................................................... 23

Table 3.10: Number of shops, hotels and teashops exposed to potential Imja GLOF

risk.............................................................................................................. 24

Table 3.11: Number of schools, office buildings and temple / Gumba exposed to

potential Imja GLOF risk ........................................................................... 24

Table 3.12: Length of trails, roads and embankment exposed to potential Imja GLOF

(km) ............................................................................................................ 25

Table 3.13 Potential hydropower development along Dudhkoshi river ...................... 28

Table 3.14: Irrigation canal, water mills and transmission line exposed to potential

Imja GLOF risk .......................................................................................... 28

Table 3.15: Monetary value of exposed elements to potential GLOF risk in different

sections in Dudhkoshi basin (USD 000) .................................................... 29

Table 3.16: Estimated amount of money to be invested for hydro-electricity

development along Dudhkoshi river and revenue likely to be generated

(USD 000) .................................................................................................. 30

Table 4.1: Number of households by farm size. ......................................................... 34

Table 4.2: Number of households by level of food sufficiency ................................... 35

Table 4.3: Number of households by size of annual income (Rupees) ....................... 36

Table 4.4: Components and parameters used to calculate livelihood vulnerability

index ........................................................................................................... 37

Table 4.5: Exposure, sensitivity, adaptive capacity and overall vulnerability ............. 38

v

LIST OF FIGUIRES

Page No.

Figure 2.1: Location of Imja Lake ....................................................................................... 11

Figure 2.3: VDCs adjoing Dhudkoshi River ....................................................................... 13

Figure 2.2: Dhudhkoshi Watershed ..................................................................................... 13

Figure 3.1: Settlements likely to be affected in upstream area ............................................ 21

Figure 3.2: Imja Glacial Lake: Bridge exposed to potential GOLFrisk. ............................. 26

Figure 3.3: Imja Glacial Lake: Potential hydropower project exposed to potential GOLF

risk. .................................................................................................................... 27

vi

EXECUTIVE SUMMARY

Glacial lake outburst flood accompanying the huge amount of sediments from moraines

not only causes morphological changes along the river channel but also results the loss

of life and properties at very great distances from the outburst source to

downstream.Altogether 21 GLOF events with large scale damages have been

experienced in Nepal. The risk of GLOF has been increasing as a result of global

warming and consequent melting of snow and ice, retreat of glaciers and expansion of

existing glacial lakes, and emergence of new glacial lakes. The probability of

loss/damage can be substantially reduced and the resilience/restoration capacity can be

enhanced through different interventions.

Imja Glacial Lake was identified as high priority lakes needing immediate attention of

GLOF risk reduction. Realizing the urgent needs to responds to potential GLOF risk,

Community Based Flood and Glacial Lake Outburst Risk Reduction Project

(CFGORRP) has been framed. It is a joint undertaking of the Government of Nepal

(GON), Global Environment Facility (GEF) and the United Nations Development

Programme (UNDP). The project is being implemented by Department of Hydrology

and Meteorology (DHM) under the Ministry of Science, Technology and Environment

(MoSTE) as the lead Implementing Agency. One of the objectives of this project is to

reduce human and material losses from potential Imja Glacier Lake Outburst Flooding

(GLOF) in Solukhumbu district.

The main objective is this work to verify, validate and refine the existing GLOF

vulnerability assessments undertaken by different national and international

organizations by using a participatory vulnerability and risk mapping approach, as a

tool and increase local knowledge about GLOF risks and risk management as envisaged

in National Adaptation Programme of Action (NAPA).

The study area covers the whole reach from Imja Glacier Lake to downstream to the

confluence of Dudhkoshi with Sunkosi near Ghurmi. However, the detailed

participatory field study was carried out in 50 km downstream area from the lake and

the secondary information is used in further downstream area.The method of data

collection consisted of i) collection and review of published and unpublished

documents, ii) consultative meetings with the relevant institutions such as ICIMOD,

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UNDP, DHM, WECS, MoSTE, Practical Action, and others; iii) transect walks and

direct observation from the lake site to downstream area iv) Key Informants Interview

(KII) both in the field and Kathmandu and v) Participatory Focus Group discussion at

community level.A total of nine FGD was organized between the Imja lake to

Thadokoshi within 50 km downstream area along Dudhkoshi river. Similarly, a total of

seven Key Informants were interviewed.

Checklist was prepared to collect information on the potential losses of life and

properties from the Potential GLOFs, local people perception, activities carried out in

order to reduce flood risk, activities needed to implement for the reduction of GLOF

risk and willingness of local people to participate in GLOF risk reduction activities.

Based on the literature so far available from hydrological modeling, it was agreed to

follow two scenario of GLOF in terms of flood height i.e up to 10 m and 10-20 m from

normal water level during the meeting for inception report presentation at DHM.

This is a prefeasibility level study and it is limited to the identification and

quantification of elements at risk and discussion of socio-economic and livelihood

vulnerability. The study does not report on the internal damages arising due to loss of

household and personal property indoor.

Imja Glacial Lake is located in Dudhkoshi watershed. Dudhkoshi watershed has a total

area of 4065 sq. km with a crow fly distance of 109 km and the maximum width of 51

km. The altitude of the basin ranges from only 330 m at the confluence of Dudhkoshi

river with Sunkoshi river near Jortighat to 8848 m, the summit of Mount Everest.

Dudhkoshi watershed lies in three districts – Solukhumbu in the north, Okhaldhunga in

the south west and Khotang in the south east. There are a total of 81 VDCs within this

watershed . Not all the VDCs and settlements within the VDCs are directly affected by

the potential GLOF from Imja Lake, but they are likely to be affected indirectly if the

access to service infrastructure is blocked due to damage of infrastructure such as

bridges, roads, hydropower plants from the potential Imja Lake.

Five VDCs namely Namche, Khumjung, Chaurikharka, Taksinda and Jubing which are

located within 50 km distance downstream Imja Lake are likely to be affected directly

with loss of life and properties. Similarly, 10 VDCS namely Baku, Basa, Kaku, Deusa,

Pawai (Mabe), Lokhim, Makali, Jubu, Kangel and Panchan are located between 50-75

viii

km downstream from Imja Lake which are likely to be affected moderately with

potential loss of life and properties. Other 20 VDCs namely Jaleswori, Ribding

Maheswori, Nechabethghari, Kuibhir, Jyamire, Dharapani, Pokhare, Diyale,

Lamidanda, Bhadaure (Okhaldhunga), Taluwa, Salle, Mangaotar, Moli, Bhadaure

(Khotang), Waksa, Ubu, Chyasmitar, Bahunidanda and Thakle are located between 75-

120 km downstream to the confluence with Sunkoshi river are also likely to be affected

in lesser degree since all these VDCs are located along Dudhkoshi river.

Three GLOF events: Nare in 1977, Dig Cho in 1985 and Tampokhari in 1998 were

experienced in Dudhkoshi watershed. During GLOF event in 1985, 4-5 persons were

swept away and large amount of properties (house, land, crops, trails, bridges,

hydropower plant) was damaged down to Jubing.Traffic flow to Namche bazaar was

blocked for 1-2 months due to damage of trails and bridges.

People living in Dudhkoshi watershed are likely affected directly or indirectly from

potential Imja GLOF with different level. A total of 49,683 household with 222,452

population living in Dudhkoshi watershed are likely to be affected directly (with

potential loss of life and properties) and indirectly (with blockade of access to service

infrastructure and social networking).Out of the total household and population in the

watershed, nearly 19,913 households with 90,791 population is distributed in those

VDCs which are bordered with Dudhkoshi river and those are likely to be affected

directly. A total of 3,278 household with 12,690 populations are located within 50 km

downstream from the Imja Glacial Lake and those are likely to be affected more from

the potential Imja GLOF. Out of a total population exposed to Imja GLOF risk at

watershed level, 45 percent is in Solukhumbu, 33 percent in Khotang, 23 percent in

Okhaldhunga district.

There are a total of 21 settlements/communities located along Dudhkoshi river 50 km

downstream from Imja Lake with a total household of 463 and population of 2, 101.Out

of these total households 105 households are likely to be affected directly living or

having properties within expected flood prone area or areas likely to be affected due to

secondary impacts of the flood i.e. landslides along the bank of the river with a total

population of 483. However, the degree of risk and level of vulnerability in those

settlements depend on the amount of sediment production and transportation and the

extent of scouring of the banks during the GLOF.

ix

Khumbu region is one of the most favorite trekking and expedition area in Nepal.

Annual flow of tourist between 1998 and 2013 ranged from 13,786 to 36,202 with an

annual average of 25,461 tourists.The flow of tourist is likely to be affected. However,

the risk of potential Imja GLOF to tourist visiting the area depends on the timing and

magnitude of flood on the one hand and the number of tourist trekking or staying in the

area prone to flood and landslide hazard on the other.

Another typical phenomenon associated with tourism in Khumbu region is the flow of

porters along the trail from Ghat to Chukkung and Imja Lake.The flow porter remains

more than 100 in a day.These porters are also at the risk of Imja GLOF though the level

of risk is dependent on the timing and magnitude of the flood.

In addition to porter, animals like mule and yak are used to transport goods along

Dudhkoshi river. These are likely to be affected from the potential GLOF risk.

Khet land (irrigated land mainly used for paddy cultivation) at risk of GLOF with

flood height less than 10 m from the normal flow is 3,299 ropani. The total khet area

under higher flood scenario i.e. 10-20 m high from normal flow likely to be damaged

is 3,551 ropani. The size of bari land (mainly used to grow wheat (uwa), potato, maize

and millet) likely to be damaged is less than the size of khet land. Paddy, wheat, maize,

millet, potato and vegetables are the main agricultural crops likely to be damaged. A

total of 122 pakki houses (constructed using modern construction materials such as

cement, tin and slates) and 378 kacchi (made of stone, mud and wood using local

materials) houses are at risk of GLOF with a maximum height of 20 m from the normal

flow. Nearly 43% of these total houses at risk are used for trade and business comprising

teashops, shops and hotels.

There are 4 office buildings, 4 temples and 3 schools at GLOF risk with flood level up

to 20 m. About 35 km of trail length in different reaches is at potential GLOF risk.There

are a total of 28 bridges over Dudhkoshi river in different places.One log-bridge located

near Dingboche, 2 truss bridge (one near Pangboche trail to Cholunche and another at

Phunkithanka) are highly vulnerable to the potential Imja GLOF damage. In addition

to these, one truss bridge over Lobuche Khola on the trail to Dingboche at Churo is also

vulnerable to the debris during potential Imja GLOF. Currently there is no hydropower

project in Dudhkoshi river. However, the power houses of micro-hydro projects in the

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tributaries of Dudhkoshi are located along its bank which is susceptible to GLOF

damages.

Proposal for 16 hydropower projects with generating capacity of about 2512 MW

hydropower within 50 km downstream area from Imja Lake, 296 MW in between 50-

75 km distance downstream and 300 MW in between 75 km to the confluence of

Dudhkoshi with Sunkoshi in the future has been prepared . Once these projects are

implemented they are likely to be affected from potential Imja GLOF.

About 0.5 km length of irrigation canal (Dingboche) and 5 water mills and 10 km of

transmission line are at risk of the potential Imja GLOF with expected flood height up

to 20 m.

The total monetary value of the properties exposed to Imja GLOF ranged from USD

0.51 million in headwater zone between Chukkung and Larja Dobhan to 1.42 million

between Jorsalle and Choubas, 0.60 million between Jubing and the district boundary

between Solukhumbu and Khotang, and 366.5 million in far downstream between

Rabuwa and Sunkoshi under flood scenario of 10 m high. Real Estate ( private land and

buildings) and agriculture sector in combination comprises about 80-90% of the total

amount exposed to GLOF risks. The value of exposed elements increases drastically in

the headwater zone between Chukhung and Larja Dobhan from 0.51 million USD to

9.37 million, and between Jorsalle and Choubas from 1.42 million to 3.41 million with

flood scenario up to 20 m high from the normal flow.

Agriculture, livestock, trade and tourism are the major economic activities of the people

living in Khumbu region. All these livelihood support sectors are likely to be affected

from potential Imja. The flow of people, animal and goods is likely to be blocked due

to damage of trails and bridges.

Overwhelming majority of households living in areas likely to be affected are

indigenous ethnic groups and Dalit. Many families (67%) likely to be affected are small

and marginal farmers with less than 10 ropani of land. About 59.6 percent of the total

family likely to be affected by GLOF produces food only enough for 6 months a year.

They have to import food items from outside in order to meet their food requirement.

Nearly 43.6% families likely to be affected have annual income less than 50,000 rupees.

Such socio-economic characteristics clearly show that the capacity of local people to

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implement structural GLOF risk reduction measures is very limited and it needs

external support to carry out such activities.

In terms of exposure settlements within 50 km distance downstream from Imja Lake

such as Jorsalle, Chhermadin, Ghat, Benkar, Phakding, Chhumawa and Dingboche are

relatively highly exposed to potential Imja GLOF with index value more than 0.3. In

terms of adaptive capacity, Pangboche, Phakding/Rakding, Benkar, Manjo, Toktok,

Thadokoshi, Dingboche, Jamphutta, Gumela, and Chummawa are relatively better than

other communities. Similarly, Chukkung, Dingboche, Orso, Jamphutta, Somare,

Jorsalle, Pangboche, Dingboche, Milingo, and Chhumawa are more sensitive to

potential Imja GLOF risk.

The strategies for effective risk reduction is to limit the investment in those settlement

which are highly exposed with high sensitivity index value and improve adaptive

capacity in those settlements which have relatively low index value.

Lowering of lake level, generation of hydropower from water released from the lake,

regular monitoring and establishment of early warning system are some of the activities

demanded by local people in order to reduce the risk of potential Imja GLOF. They

emphasized on public-private partnership in implementing such activity and they have

shown their willingness to participate and cooperate in such activities.Local people

have also expressed their willingness to contribute in site identification, land purchase,

provide local resources (stone, wood etc.) and free labour for office building

construction and installation of EWS, community mobilisation, awareness raising and

establishing a user committee. Construction of the tower and provision of siren systems

are expected from the project.Recommended sites for the installation of early waring

siren are Chhukung, Dingboche, Pancboche, Phungithanga, Jorsalle, Benkar,

Phakdin+Rakdin, Ghat, Juvin, Demlitar, Rabuwa and Jayaramtar.

Sensitization through intensive interaction with the local community; Formation of

Community Based GLOF risk management committee, Skill development training to

the community, Awareness creation through formal medium such as school education

and informal medium through Lama, Regular monitoring of Glacial Lake and its

outburst risk are some of the activities recommended for project activities in order to

reduce the risk of Imja GLOF risk.

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It is hoped that the lesson learnt from this project would help to formulate and

implement similar types of activities in other areas likely affected from potential GLOF.

The findings of this project can also be incorporated in NAPA and LAPA processes and

climate change policy in the future.

1

CHAPTER I

INTRODUCTION

1.1Background

The Himalayas is the storehouse of fresh water and occupied by snow, ice, glaciers and

glacial lakes. There are a total of 3,252 glaciers and 2,323 glacial lakes with a total area

of 75.7 sq. km situated above an altitude of 3,500 m in Nepal Himalaya (Mool, et al.

2001). Among these glacial lakes, 795 are erosional type, 659 are valley type, 566 are

supra-glacial type, 114 are cirque type, 46 are dammed by tributary glaciers, and 143

are dammed by moraines. Supra glacial lakes and moraine dammed lakes are potentially

dangerous causing catastrophic flooding in downstream direction. Glacial lakes are

highly dynamic. The number and size of glacial lakes vary with time and space. Some

merge into one bigger lake, some disappear and new ones appear. Another study in

2009 by ICIMOD (unpublished report) shows a total of 1,466 glacial lakes in the

country with a total area of 101 sq. km. Though the number of glacial lakes decreased

drastically between 2001 and 2009, the area of glacial lakes has increased

tremendously.

Glacial lake outburst flood accompanying the huge amount of sediments from moraines

not only causes morphological changes along the river channel but also results the loss

of life and properties at very great distances from the outburst source to downstream

(Bajracharya, et al. 2007; Dwivedi, 2000; Watanabe et al. 1998; Khanal, 1996;

Budhathoki et al. 1996; WECS/HMG, 1987; Viuchard and Zimmermann, 1987 and

1986; and Ives, 1986). Altogether 21 GLOF events with large scale damages have been

experienced in Nepal. The records of past GLOF events show that one event occurs in

every 3-10 years with varying degree of socio-economic impacts. Table 1 shows the

magnitude and downstream impact of some of the past GLOF events. The reported

stage of peak discharge ranged from 6m to 23 m depending upon the morphology of

river channel. Flood surge reached downstream to 90 km with a temporary damming at

different reaches up to 35 m high water level. Alteration of erosion and accumulation

activity occurs down to 42 km and most of the eroded materials are re-deposited within

the first 25 km. The lost/damaged elements include human life, animal, house, bridge,

2

trail/road, farmland and crops. Traffic flow is also blocked for several days due to

damage of trail/road and bridges.

An inventory of glacial lakes in Nepal in 2001 had indentified 20 glacial lakes as

potentially dangerous (Mool et al. 2001). Another study in 2009 by ICIMOD

(unpublished report) has reported a total of 21 glacial lakes as potentially dangerous.

Among them, 6 are categorized as high priority lakes needing immediate attention for

GLOF risk reduction, 4 are potentially dangerous needing closer observation and

monitoring and 11 are potentially dangerous.

The risk of GLOF has been increasing as a result of global warming and consequent

melting of snow and ice, retreat of glaciers and expansion of existing glacial lakes, and

emergence of new glacial lakes. In order to reduce the increasing risk of GLOF event,

it is necessary to assess the risk, which includes understanding hazard intensity on the

one hand and the physical and socio-economic vulnerability and risk in downstream on

the other. The determination of the probability and the magnitude of the event, and

assessment of vulnerability and risk provides basis to develop effective strategies for

better preparedness. The probability of loss/damage can be substantially reduced and

the resilience/restoration capacity can be enhanced through different interventions, only

after a proper.

3

Table 1.1: Magnitude and downstream impact of GLOFs in the past

SN Name of

Glacial Lake

Date of

Outburst

Volume &

Discharge

Downstream impact Source

1 Nare,

Dudhkoshi

Sept. 3,

1977

5 million m3; 800

m3/sec

Flood surge down to 90 km

People and infrastructure (3 person, 1 building, 10 bridges) down to 35

km

Khanal,

1996

6 Nagama

(Phucan),

Tamor basin

June 23,

1980

Na Alternatively deposited and eroded river bed down to 23 km

People and infrastructures (8 person, 10 houses, 4 bridges) down to 72

km

Teiji et al.

1998

5 Zhangzanbo,

Bhotekoshi/

Sunkoshii

July 11,

1981

19 million m3;

15920 m3/sec

(peak); bursting

flood for 60

minutes; bursting

water head at 35

m; Peak stage

ranged from 6 to

23 m depending

upon the

morphology of

river channel

Flood surge down to 50 km (16 times larger than the average annual

floods)

Vertical erosion down to 6 km; lateral erosion between 6-20 km; lateral

erosion and deposition between 20-50 km)

Major damages between 20-55 km (5 persons killed, 191 injured; 84

houses; 2 highway bridge; 10 suspension bridges; 27 km road; 1 hydro

dam; 1 km transmission line)

Power supply cut for 31 days; road blocked for 36 days

Estimated loss NRs. 60 million

Road rehabilitation cost US $ 3 million; work lasted for 3 years

Daoming,

1985;

Khanal,

2008

4

2 Dig Cho,

Dudhkoshi

August

4, 1985

1 million m3;

1600-2000

m3/sec; 10-15 m

high surge

Alternation of erosion and accumulation activity down to 42 km; most of

the eroded materials redeposited within the first 25 km

People and infrastructure (4-5 persons, 30 houses, 14 bridges, 1

hydropower plant, 8 km of trails, 20 ha cultivated land) down to 40 km

Damages amounting US $ 4 million

Closer of weekly market for 3 successive Saturday, inflation – 50%

increase in price during closure period

Ives, 1986;

Vuichard

and

Ziimmerman

n, 1986 and

1987

7 Kaligandaki

(lake name not

known)

1987 8500 m3/s Damages down to 80 km (Small hydropower plant, 22 houses and 11

bridges)

Khanal,

1996

4 Chubung,

Tamakoshi

July 12,

1991

Na Houses and cultivated land down to 12 km (Beding village) Khanal,

1996;

3 Tam Pokhari;

Dudhkoshi

Sept. 3,

1998

52 m decrease in

water level in the

lake; 17.66

million m3.

Flood surge reached 35 km down to the confluence with Dudhkoshi and

formed debris dam about 30 m high. Gauging station at Rabuwa (66 km

downstream) was washed away and the water flowed above the 10-m

guage. It reached down to Hampachuwar and Koshi barrage.

The river reverted to its original discharge only after 3 days.

Lateral erosion triggered landslides in many places

A large stretch of trail washed away

2 persons; 3 teashops; 4 suspension bridge; 2 wooden bridge; and farm

land

Estimated damages NRs. 150.66 million (in two districts out of three

districts severely affected)

Mool, et

al.2001;

Dwivedi,,

2000;

Dwivedi, et

al. 1999

5

assessment of the flood magnitude and its impacts under different scenarios. Though a

preliminary assessment of GLOF risk and vulnerability have been carried out in the

country. A few attempts have been made to assess risk and vulnerability of potential

GLOF from some selected Glacial Lakes in Nepal. ICIMOD has carried out risk and

vulnerability assessment of potential GLOF from Imja, Tsho Rolpa, Lumu-Chimi

(located in Tibet, China) in 2008 and 2009 (Khanal 2008, Khanal et al 2009 and Khanal

et al 2013). UNDP also carried out a study for the assessment of risk and vulnerability

of potential GLOF from Tsho Rolpa Glacial Lake in Singati, Bhorle and Suridobhan

villages in Dolakha district in 2010 (Adapt-Nepal, 2010).

Imja Glacial Lake was identified as high priority lakes needing immediate attention of

GLOF risk reduction. Realizing the urgent needs to responds to potential GLOF risk,

Community Based Flood and Glacial Lake Outburst Risk Reduction Project

(CFGORRP) has been framed. It is a joint undertaking of the Government of Nepal

(GON), Global Environment Facility (GEF) and the United Nations Development

Programme (UNDP). The project is being implemented by Department of Hydrology

and Meteorology (DHM) under the Ministry of Science, Technology and Environment

(MoSTE) as the lead Implementing Agency. The project’s working areas include

Solukhumbu in the Mountain for GLOF risk assessment and management and

Mahottari, Siraha, Saptari and Udaypur districts in the Terai for flash flood risk

assessment and management.

The objective of CFGORRP is to reduce human and material losses from Glacier Lake

Outburst Flooding (GLOF) in Solukhumbu district and catastrophic flooding events in

the Terai and Churia Range. For achieving this objective, the Project has been

streamlined into two main Components. Component I is specifically aligned towards

reducing GLOF risks arising from Imja Lake whereas Component II aims to reduce

human and material losses from recurrent flooding events in the four flood prone

districts of Terai.

This proposal is to fulfill the objective under the first Component (Component I) of the

project which aims to reduce GLOF risk from Imja Glacial Lake that threatens the

livelihood of downstream communities. The possible extensive damage is expected to

occur along the entire length of the Imja Khola/Dudh Koshi valleys within 50 km and

6

indirectly downwards towards the confluence of Sunkoshi; an overall distance of about

120 km. Actual loss of life would depend on the timing of event–night or day, trekking

season or off–season.

For this purpose, supplementary data and information is required to verify and refine

the vulnerability assessments and identification and implementation of Component I’s

activities.

1.2 Objectives

The main objective is to verify, validate and refine the existing GLOF vulnerability

assessments undertaken by different national and international organizations by using

a participatory vulnerability and risk mapping approach, as a tool and increase local

knowledge about GLOF risks and risk management as envisaged in National

Adaptation Programme of Action (NAPA).

1.3 Scope of the Work

As per the TOR, the scopes of the work are as follow

Organize consultative meetings with flood–affected communities, VDCs,

CBOs, Local government authorities, line agencies and development partners

to generate information on GLOF vulnerability with special focus on women,

poor and the marginalized.

Consult with key stakeholders (government bodies, line agencies, local

communities, DDCs, VDCs, development partners and practitioners that are

working in the areas of DRR/M, such as UNDP, ICIMOD, DP Net, WWF,

Practical Action, Mercy Corps and Nepal Red Cross etc.) on the lessons,

constraints and challenges on GLOF.

Collate and update information and reports of ICIMOD, DHM, WECS, KU,

HMGWP and other organizations on Imja GLOF hazards in the downstream

valley to assess GLOF vulnerability and its management in the study area.

Verify and refine existing GLOF vulnerability assessments undertaken by

ICIMOD, HMGWP and other institutions by using participatory vulnerability

and risk mapping as a tool for engaging communities and increasing their

knowledge about GLOF risks and management options.

7

Undertake a thorough desk review to collect baseline information of GLOF

prone areas downstream of Imia Lake and conduct rapid physical and socio–

economic vulnerability analysis at study area for assessment and verification of

all relevant scientific information and data to assess GLOF vulnerability and its

consequences.

Review local knowledge on GLOF vulnerability, the existing capacity to

mitigate and respond to GLOF events, identify gaps and recommend capacity

building training and awareness needs at the community / local administration

level.

While undertaking the task, recommend how ecosystem payments services for

instance and other mechanism can build upstream–downstream linkages for the

benefit of the study area.

Review and recommend GLOF vulnerability reduction practices in policy and

planning process and level of preparedness and institutional mechanism that

needs to be put in place.

Identify any other pertinent scope of works that needs to be carried out before

GLOF / Flood risk reduction activities during the tenure of the Project.

Based on the above assessment, prepare a draft report to present the findings to

PMU/DHM, PEB and partners for further comments. Finalize the report

incorporating all the comments and feedbacks and submit final report to PMU

for acceptance.

1.4 Methodology

As mentioned earlier, the study area covers the whole reach from Imja downstream to

the confluence of Dudhkoshi with Sunkoshi near Ghurmi. However, the detailed

participatory field study was carried out about 50 km downstream from the lake and the

secondary information is used in further downstream area.

The method of data collection consisted of i) collection and review of published and

unpublished documents, ii) consultative meetings with the relevant institutions such as

ICIMOD, UNDP, DHM, WECS, MoSTE, Practical Action, and others; iii) transect

walks and direct observation from the lake site to downstream area iv) Key Informants

Interview (KII) both in the field and Kathmandu and v) Participatory Focus Group

discussion at community level. Transect walks and direct observation from the lake site

8

to downstream area were made. Information observed during the field work was

recorded in topographic maps and note books. Key informant interview and group

discussions were carried out in different reaches of the basin. The number of

reaches/sections in each site for Key Informant Interview and Focus Group Discussions

was determined depending upon the knowledge of local people about the elements

exposed within the particular reach length. A total of nine FGD was organized between

the Imja lake to Thadokoshi within 50 km downstream area along Dudhkoshi river. The

size of FGD ranged from 3 to 6 persons.For FGD, local people, school teacher and local

entrepreneur were involved. Attempts were made to involve different caste/ethnic

group and females at the time of group formation as far as possible. Checklist used for

FGD is given in Appendix -1.Participants of focus group discussion are given in

Appendix 2. Similarly, a total of seven Key Informants were interviewed. For KII,

local school teacher, social worker, member of community groups and employee of

government offices were selected. The list of Key Informants interviewed in the field

is given in Appendix 3.

The elements at risk considered were people, buildings, livestock, land, crops including

non-agricultural livelihood options, development projects and public infrastructures.

Checklist was prepared to collect information on the potential losses of life and

properties from the Potential GLOFs, local people perception, activities carried out in

order to reduce flood risk, activities needed to implement for the reduction of GLOF

risk and willingness of local people to participate in GLOF risk reduction activities.

Those checklists were used during focus group discussion and key informants

interview. Attempt was also made to prepare GLOF risk map during focus group

discussion and record the elements exposed to GLOF risk.

This study was carried out under the guidance and supervision of the National Project

Director (NPD) and National Project Manager (NPM) in close coordination with Senior

Technical Advisor and the Project Management Unit (PMU) team. At the field level,

the work was carried out in close coordination with the Sagarmatha National Park

(SNP) Staff and other stakeholders as far as practicable.

A meeting was organized in DHM to discuss on progress work and draft inception

report. During the meeting, team leader presented a summary of draft inception report

9

including some samples of checklist. During discussion, the team was asked to collect

information on the suitable sites for the installation of early warning system as

suggested by local people, collect information on the mode of participation of the

community in the proposed project and encourage the participation of women during

focus group discussion. It was agreed to follow two scenario of GLOF in terms of flood

height i.e up to 10 m and 10-20 m from normal water level since the modeled height is

less than 10 m in all the reaches according to the report submitted to ICIMOD (GISIDC,

2010 and appendix 4). Another study shows an estimated Imja GLOF height of 11.7 m

at the lake outlet site, 15.2 m at Dingboche and 13 m at Phakding about 34 km

downstream from the lake (Somos-Valenzuela, 2013)(Appendix4). It was suggested to

take information about secondary damages i. e from landslides triggered by GLOF. It

was also agreed that the data generated in 2009 by ICIMOD be taken as baseline data

and efforts should be made to verify and update those information.

1.5 Limitation of the Study

This study is limited to the identification and quantification of elements at risk and

estimation and discussion of socio-economic and locational vulnerability. The physical

vulnerability of infrastructure is not discussed. It is very difficult to estimate physical

vulnerability without making detailed assessment of the stress from the potential GLOF

on the one hand and the strength of infrastructure to withstand (for example the strength

of the foundation of the bridge along the river) on the other.

This is a prefeasibility level study. Identification and delineation of different hazard

zones of potential GLOF under different scenario was based on the information

provided by a group of local people during group discussion and Key Informants

Interview. Quantification of the elements exposed to potential GLOF risk was estimated

by the same group. Detailed field investigation for hazard mapping and household

survey for accurately quantification of some of the elements exposed to GLOF risk such

as cultivated land, crops, income etc. are needed.

The study does not report on the internal damages arising due to loss of household and

personal property indoor. For example information on potential internal damages

(property inside the building such as TV set, phone, furniture, jewelry and ornaments,

etc.) could not be collected and hence values are imputed. Internal property can be

10

substantial and can be obtained only through household survey. But due to the

limitation of time and resources, household survey was not carried out. So, there is no

estimate of those damages.

11

CHAPTER II

INTRODUCTION TO STUDY AREA

2.1 Imja Glacial Lake

The Imja glacial lake is located at latitude 27° 59’N and longitude 86° 56’E in the Nepal

Himalayas (Figure 1). The lake is situated at the altitude of 5000 m MSL. The galcier

is mainly norurished by snow-fall, snow –avalanche and snow-drift.

Figure 2.1: Location of Imja Lake

ICIMOD carried out detail field investigation of Imja Glacial Lake in 2009. As per this

survey results, the length of the lake was 2.417 km with the width of 0.5 km. The

accumulation of water was estimated to be 28 million m3. The characteristics of the

lake as reported based on the field investigation in 2009 is given in Table 2.1.

12

Table 2.1: Geometrical and dam material properties of Imja Glacial Lake

S.N. Parameters Value Unit

1 Lake surface area 0.88 Sq. Km

2 Lake maximum depth 96.5 Meter (m)

3 Dam top elevation 5030 Meter (MSL)

4 Dam bottom elevation 5010 Meter (MSL)

5 Dam inside slope 2

6 Dam outside slope 4

7 Dam crest width 50 Meter (m)

8 Dam crest length 275 Meter (m)

9 D50 20 Millimeter (mm)

10 D90/D30 400

11 Unit weight 18 KN/cu.m

12 Porosity 30 Percent

13 Internal friction angle (f) 38 Degree

14 Cohesiveness 0

Source: GISIDC, 2010

2.2 Dudhkoshi Watershed

Imja Glacial Lake is located in Dudhkoshi watershed. Dudhkoshi watershed has a total

area of 4065 sq. km with a crow fly distance of 109 km and the maximum width of 51

km. The altitude of the basin ranges from only 330 m at the confluence of Dudhkoshi

river with Sunkoshi river near Jortighat to 8848 m, the summit of Mount Everest.

Dudhkoshi watershed lies in three districts – Solukhumbu in the north, Okhaldhunga in

the south west and Khotang in the south east. There are a total of 81 VDCs within this

watershed (since the VDC boundary does not follow watershed boundary, some of them

are extended outside the watershed boundary) (Figure 2.2). Not all the VDCs and

settlements within the VDCs are directly affected by the potential GLOF from Imja

Lake, but they are likely to be affected indirectly if the access to service infrastructure

is blocked due to damage of infrastructure such as bridges, roads, hydropower plants

from the potential Imja Lake. There are 35 VDCs which are located along Dudhkoshi

river downstream Imja Lake, these VDCs are likely to be affected directly (loss of life

and properties) from the potential Imja GLOF (Figure 2.3). There are 5 VDCs namely

13

Namche, Khumjung, Chaurikharka, Taksinda and Jubing which are located within 50

km distance downstream Imja Lake joining with Dudhkoshi river. Similarly, other 10

VDCS namely Baku, Basa, Kaku, Deusa, Pawai (Mabe), Lokhim, Makali, Jubu, Kangel

and Panchan are located between 50-75 km downstream from Imja Lake joining

Dhudhkoshi river. The remaining 20 VDCs namely Jaleswori, Ribding Maheswori,

Nachabethghari, Kuibhir, Jyamire, Dharapani, Pokhare, Diyale, Lamidanda, Bhadaure

(Okhaldhunga), Taluwa, Salle, Mangaotar, Moli, Bhadaure (Khotang), Waksa, Ubu,

Chyasmitar, Bahunidanda and Thakle are located between 75-120 km downstream to

the confluence with Sunkoshi river joining with Dudhkoshi river (Figure 2.3).

Figure 2.2: Dhudhkoshi Watershed Figure 2.3: VDCs Adjoing

Dhudkoshi River

14

CHAPTER III

PAST GLOF EVENTS AND EXPOSURE TO POTENTIAL IMJA GLOF RISK

3.1 GLOF Events and Losses in the Past in Dudhkoshi Watershed

Three GLOF events have been reported in Dudhkoshi basin between 1977 and 1998

(Table 3.1). The outburst flood of Nare Glacial Lake in Imja Valley in 1977 swept away

3 persons and 10 bridges between Pangboche and Chhermading. Similarly, Dig Cho

GLOF in 1985 swept away 4-5 persons, 18 houses and 30 bridges. The morphology of

river channel was changed drastically due to erosion along its bank and accumulation

of debris along its bed. Traffic flow to Namche bazaar was blocked for 1-2 months due

to damage of trails and bridges. The local people reported that the Tam Pokhari GLOF

in 1998 swept away 14 workers in road construction near Jayaramtar. Large area of

cultivated land – 1,500 ropani of khet and 151 ropani of bari, 100 ropani of forest area

was damaged. The Dudhkoshi river was partially dammed by the sediments brought by

Tam Pokhari GLOF. The outburst of temporary dam caused massive damages in

downstream area.

Table 3.1: Major GLOF events and damages in Dudhkoshiwatershed

Year River reaches

affected

Losses and damages Remarks

1977 Pangbohe-

Chhermading

3 person, 4 animal, 1 house, 3 ropani of bari,

0.6 MT of potato, 10 bridges

Nare GLOF

1985 Jorsalle-Jubing 4-5 person, 16 animal, 18 houses, 127 ropani of

khet, 234 ropani of bari, 200 ropani of forest,

62 MT of paddy, 50 MT of wheat, 56 MT of

maize, 20 MT of millet, 18 MT of poato, 6 km

of trail, 30 bridges, 1-2 month traffic flow

Dig Cho

GLOF

1998 Tari-

Jayaramtar

14 people, 20 animal, 16 houses, 1500 ropani

of khet, 151 ropani of bari, 100 ropani of

forest, 2688 MT of paddy, 37 MT of maize, 35

MT of millet,16 km of trail, 2 suspension

bridge (though not formally reported local

people told that 14 people were swept away

from Jayaramtar area)

Tam Pokhari

GLOF

Source: Khanal et al., 2009

15

These settlements were severely affected during Dig Cho GLOF in 1985. One house at

Jorsalle, one tea shop at Chhumawa, one house at Bengkar, one house at Phakding, 9

houses and 1 or 2 goths at Ghat were damaged from Dig Cho GLOF (Vuichard and

Zimmermann, 1987).

The peak flood accentuated by the GLOF of Nare Glacial Lake on 3 Sept. 1977 was

recorded at Rabuwa bazaar (Ives, 1986). The Tam Pokhari GLOF of 3 Sept. 1998

washed away hydrological gauging station no. 670 at Rabuwa and one suspension

bridge at Silaurighat. The breach occurred at 5 o’clock in the morning. The flood

reached the confluence of the Inkhu khola with Dudhkoshi river which is about 35 km

downstream from the lake at 7.10 AM. A debris dam about 30 m high was formed in

the Dudhkoshi river. Total estimated damages and loss from this event was NRs 92

million in Solukhumbu and NRs 59 million in Okhaldhunga district. The loss and

damages from Tam Pokhari GLOF in 1998 in Khotang district was not estimated and

reported (Dwivedi et al. 1999). These past experiences of downstream impacts of the

GLOFs clearly show that those settlements located in far downstream areas are likely

to be affected from the potential Imja GLOF.

3.2 Exposure to Potential Imja GLOF Risk

3.2.1 People

People are exposed to potential Imja GLOF risk at different level with different

magnitude of stresses and losses. Those are at personal, household, settlement,

community, VDC and watershed level. For example, tourists, porters and traders are

exposed to potential GLOF risk at personnel level. The household at the settlement,

community, VDC and watershed level are affected differently. The households living

and having properties – land, crops and other household items below the potential flood

height from GLOF are directly affected from GLOF with potential of loss of life and

properties. As the stresses of GLOF decreases with the increase in downstream areas,

people living in near the lake and upstream area are likely to be affected more than

those living in downstream areas. VDCs located at far distance from the river channel

but within the watershed are likely to be affected indirectly due to blockage in enjoying

service infrastructures such as health, education, electricity, market and other social

interaction as the result of the damage of physical infrastructure such as road, trails,

16

bridges, hospital buildings, schools, hydropower plant. Attempt has been made here to

discuss the exposure of people at different level.

Table 3.2 shows the number of household and population exposed to Imja GLOF risk

at watershed level. A total of 49,683 household with 222,452 population living in

Dudhkoshi watershed are likely to be affected directly (with potential loss of life and

properties) and indirectly (with blockade of access to service infrastructure and social

networking). Out of the total household and population in the watershed, nearly 19,913

households with 90,791 populations is distributed in those VDCs which are bordered

with Dudhkoshi river and these are likely to be affected directly. A total of 3,278

household with 12,690 populations are located within 50 km downstream from the Imja

Glacial Lake and those are likely to be affected more from the potential Imja GLOF.

Table 3.2: Household and population exposed to Imja GLOF risk

VDCs,

household

and

population

Adjoining VDCS Other VDCs

in the

watershed

Total

Within 50 km 50-75 km > 75 km Total

No. of

VDCs

5 10 20 35 46 81

Household 3278 6774 9861 19913 29770 49683

Population 12690 31982 46119 90791 131661 222452

Source: CBS, Population Census, 2011

Table 3.3 shows the breakdown exposed population by districts. Out of a total of

222,452 population exposed to Imja GLOF risk at watershed level, 99787 (45 percent)

is in Solukhumbu, 71914 (33 percent) in Khotang, 50751 (23 percent) in Okhaldhunga

district. Similarly, the population living within VDC adjoining with Dudhkoshi river

and likely to be affected directly ranged from 48,403 (53 percent) in Solukhumbu,

22,038 (24 percent) in Khotang and 20,350 (22 percent) in Okhaldhunga district.

17

Table 3.3: Population exposed to Imja GLOF risk by districts

Districts Adjoining

VDCS

VDCs within watershed Total

No Population No Population No Population

Solukhumbu 16 48403 15 51384 31 99787

Khotang 10 22038 20 49876 30 71914

Okhaldhunga 9 20350 11 30401 20 50751

Total 35 90791 46 131661 81 222452

Source: National Population and Housing Census, 2011

Table 3.4 shows the caste/ethnic breakdown of the exposed population in the watershed

and different reaches of Dudhkoshi river. At watershed level, the highest share of

population exposed to potential GLOF is of Rai community followed by Chhetri,

Sherpa, Tamang, Magar, Bahun and Kami. However, at river reach level, within 50 km

distance downstream from Imja lake, the share of Sherpa community is highest (53

percent) followed by Rai, Tamang, Kami, Magar and Chhetri. In downstream area,

between 50-75 km from the lake, the share of Rai is highest followed by Chhetri,

Tamang, Kami and Sherpa. In further downstream area, the share in exposed population

is highest among Rai followed by Chhetri, Magar, Bahun and Newar.

Table 3.4: Population exposed to potential Imja GLOF risk at different level by

caste and ethnicity

Caste/

Ethnicity

Adjoining VDCS Other VDCs

in the

watershed

Total

Within 50

km

50-75 km > 75 km Total

No % No % No % No % No % No %

Brahamin 114 0.9 613 1.9 5159 11.2 5886 6.5 7266 5.5 13152 5.9

Chhetri 319 2.5 4356 13.6 6906 15.0 11581 12.8 20639 15.7 32220 14.5

Sanaysi 15 0.1 661 2.1 713 1.5 1389 1.5 1949 1.5 3338 1.5

Rai 2781 21.9 14806 46.3 16448 35.7 34035 37.5 46452 35.3 80487 36.2

Sherpa 6715 52.9 1685 5.3 19 0.0 8419 9.3 10103 7.7 18522 8.3

Tamang 925 7.3 3822 12.0 1480 3.2 6227 6.9 11118 8.4 17345 7.8

Magar 619 4.9 1047 3.3 6519 14.1 8185 9.0 5634 4.3 13819 6.2

Gharti 15 0.1 659 2.1 732 1.6 1406 1.5 2637 2.0 4043 1.8

18

Gurung 26 0.2 535 1.7 60 0.1 621 0.7 2658 2.0 3279 1.5

Newar 105 0.8 127 0.4 2466 5.3 2698 3.0 7037 5.3 9735 4.4

Majhi 0 0.0 135 0.4 885 1.9 1020 1.1 0 0.0 1020 0.5

Sunuwar 0 0.0 0 0.0 57 0.1 57 0.1 771 0.6 828 0.4

Limbu 0 0.0 0 0.0 0 0.0 0 0.0 74 0.1 74 0.0

Yakha 0 0.0 0 0.0 0 0.0 0 0.0 60 0.0 60 0.0

Kami 735 5.8 2163 6.8 2104 4.6 5002 5.5 6243 4.7 11245 5.1

Damai 89 0.7 651 2.0 1138 2.5 1878 2.1 3542 2.7 5420 2.4

Sarki 0 0.0 273 0.9 871 1.9 1144 1.3 2974 2.3 4118 1.9

Others 232 1.8 449 1.4 562 1.2 1243 1.4 2504 1.9 3747 1.7

Total 12690 100.0 31982 100.0 46119 100.0 90791 100.0 131661 100.0 222452 100.0

Source: National Population and Housing Census, 2011

There are a total of 21 settlements/communities located along Dudhkoshi river

downstream from Imja lake with a total household of 463 and population of 2, 101

(Table 3.5). The location of those settlements is given in Figure 3.1. Out of these total

households 105 households are likely to be affected directly living or having properties

within expected flood prone area or areas likely to be affected due to secondary impacts

of the flood i.e. landslides along the bank of the river with a total population of 483.

Table 3.4 also shows that the proportion of population likely to be directly affected

among those settlements/communities ranged from zero to 87 percent with an average

of 23 percent.

Settlements/communities having more than 50 percent of the total population likely to

be affected directly are Chukkung, Phungithanga, Jorsalle, Tawa, Dugdima and

Chhermadin. However, Dingboche, Jorsalle, Toktok, Phakding/Rakding, Benkar,

Chhermadin, Chhumawa, Ghat, Phungithanga, Dungdima and Chukkung are exposed

more in terms of the size of population likely to be affected directly from the potential

Imja GLOF risk (Table 3.5).

There is no settlement along river valleys between Ghat and Jubing. The settlements

which are likely to be affected in the lower reaches between Jubing and the confluence

of Dudhkoshi with Sunkoshi are Jubing, Tari, Diblibesi, Barkhubesi, Demiltar, Tuintar,

Silauri/ Khatrigaon, Rabuwa, Tirpurabesi, Mahadevbesi, Khokselibesi and Jayaramtar.

The degree of risk and level of vulnerability in those settlements depend on the amount

19

of sediment production and transportation and the extent of scouring of the banks during

the GLOF.

Table 3.5: Household and population in the settlements within 50 km downstream

along Dudhkoshi

S.N. Total

Household

Population Household

likely to be

affected

Population

likely to be

affected

%

Population

likely to be

affected

1 10 46 5 24 52.2

2 90 388 12 55 14.2

3 6 28 2 13 46.4

4 18 80 3 17 21.3

5 65 297 2 9 3.0

6 10 52 0 0 0.0

7 8 35 0 0 0.0

8 6 31 5 27 87.1

9 13 60 11 48 80.0

10 4 21 4 17 81.0

11 28 136 3 15 11.0

12 18 84 7 32 38.1

13 32 148 9 42 28.4

14 30 140 10 46 32.9

15 27 119 0 0 0.0

16 9 41 0 0 0.0

17 42 187 10 45 24.1

18 7 33 5 25 75.8

19 7 31 5 23 74.2

20 27 117 7 27 23.1

21 6 27 1 5 18.5

Total 463 2101 105 483

Source: FGD and KII during field investigation, 2013

Khumbu region is one of the most favorite trekking and expedition area in Nepal. Table

3.6 shows the monthly flow of tourists as recorded at Jorsalle. Annual flow of tourist

20

between 1998 and 2013 ranged from 13,786 to 36,202 with an annual average of 25,461

tourists. The average monthly flow ranged from 183 in July to 7,419 in October (see

Appendix 5 for details). The flow of tourist is likely to be affected. However, the risk

of potential Imja GLOF to tourist visiting the area depends on the timing and magnitude

of flood on the one hand and the number of tourist trekking or staying in the area prone

to flood and landslide hazard on the other.

Table 3.6: Minimum, maximum and average flow of tourist between 1998 and

2013 by months

Month Minimum Maximum Average

Jan 235 827 560

Feb 455 1041 739

Mar 1802 4602 2891

Apr 2313 6657 4231

May 692 2617 1604

Jun 61 466 237

Jul 39 349 183

Aug 126 516 323

Sep 877 2835 1659

Oct 3530 10392 7419

Nov 2488 5883 4272

Dec 866 2183 1447

Total 13786 36202 25461

Source: National Park Office at Jorsalle, December 25, 2013

Another typical phenomenon associated with tourism in Khumbu region is the flow of

porters along the trail from Ghat to Chukkung and Imja lake. Estimated daily flow of

porters in the area between the mid of February to the last of April is 500 and from mid

August to the last of November is 450. Though the flow of porters along the trail in

other months is not so high as the number of tourist visiting in the months is few as

compared to these two seasons. However, the flow remains more than 100 in a day even

in the off season for the tourist and those are engaged in carrying out household goods.

21

Figure 3.1: Settlements likely to be affected in upstream area

These porters are also at the risk of Imja GLOF though the level of risk is dependent

on the timing and magnitude of the flood.

3.2.2 Animal

In addition to porter, animals like mule and yak are used to transport goods along

Dudhkoshi river. Mule is used to transport goods from Salleri to Namche and Yak is

used to transport goods from Namche to Everest Base Camp and Chhukkung whereas

Jhokpyo is used to transport goods from Luckla to Namche. A total of 1300 mule, 300

Yak and 350 Jhokpyo are used in Khumbu region to transport goods. In average about

500 animals are used to transport goods through trails located in the hazard prone area

22

of the potential GLOF. So, these animals are likely to be affected from the potential

GLOF risk.

3.2.3 Land and crops

Considerable size of cultivated and forest area along the Dudhkoshi river is likely to be

destroyed from the GLOF. The reported area of khet land (irrigated land mainly used

for paddy cultivation) at risk of GLOF with flood height less than 10 m from the

normal flow is 3,299 ropani. Because of cold climate and steep slope no khet land for

growing paddy is located in the upper part of the watershed. The total khet area under

higher flood scenario i.e. 10-20 m high from normal flow likely to be damaged is 3,551

ropani (Table 3.7). The size of bari land (mainly used to grow wheat (uwa), potato,

maize and millet) likely to be damaged is less than the size of khet land i.e. 1,260 ropani.

Generally, khet land is located on flood plains whereas bari land is located in higher

slope including higher river terraces.

Table 3.7: Khet and Bari land exposed to potential Imja GLOF risk (in ropani)

Area Khet Bari

< 10 m 10-20 m < 10 m 10-20 m

Chukhung-Larja 0 0 38185 444

Jorsalle-Chaubas 0 0 96 321

Jubing-Distbound 367 341 185 175

Rabuwa-Sunkoshi 2932 3010 305 320

Total 3299 3351 624 1260

Source: Khanal et al., 2009 and Field Survey, December 2013

Paddy, wheat, maize, millet, potato and vegetables are the main agricultural crops likely

to be damaged. About 347.5 MT (Metric Ton) of paddy, 64 MT of wheat, 224 MT of

maize, 35 MT of millet, 24 MT of potato and 3 MT of vegetable is likely to be damaged

from GLOF height upto 10 m (Table 3.8). About, 366 MT of paddy, 122 MT of wheat,

235.5 MT of maize, 42 MT of millet, 151 MT of potato and 13 MT of vegetable is

likely to be damaged if the GLOF height reaches 10-20 m from the normal flow.

Wheat/Uwa, potato and vegetable are the major crops likely to be affected in the upper

part of the basin whereas it is paddy, maize and millet in the downstream areas.

23

Table 3.8: Crops exposed to potential Imja GLOF risk (MT)

Crops\area GLOF

scenario

Chukhung

- Larja

Jorsalle -

Chaubas

Jubing -

Distbound

Rabuwa

Sunkoshi

Total

Paddy Up to 10 m 0 0 36 311.5 347.5

10-20 m 0 0 45 321.4 366.4

Wheat Up to 10 m .55 2.2 22.4 38.5 63.65

10-20 m 8.15 50.3 23.1 40.6 122.15

Maize Up to 10 m 0 0 12.7 211.3 224

10-20 m 0 0 20.4 215.1 235.5

Millet Up to 10 m 0 0 11.5 23.3 34.8

10-20 m 0 0 15.4 26.2 41.6

Potato Up to 10 m 6.12 15.3 .2 2.5 24.12

10-20 m 85.22 63.1 .3 2.4 151.02

Vegetables Up to 10 m 0 2.99 .1 0 3.09

10-20 m 1 12.19 .1 0 13.29

Source: Khanal et al., 2009 and Field Survey, December 2013

3.2.4 Infrastructure

3.2.4.1 Private and public building

A total of 122 pakki houses (constructed using modern construction materials such as

cement, tin and slates) and 378 kacchi (made of stone, mud and wood using local

materials) houses are at risk of GLOF with a maximum height of 20 m from the normal

flow (Table 3.9). Nearly 43% of these total houses at risk are used for trade and

business comprising teashops, shops and hotels. The percentage of houses used for

trade and business is about one-third in the upper part from Chaubas to Chukkung.

Among them 15 are teashops, 17 are shops and 91 are hotels between modeled and

maximum flood level (Table 3.10). Many of these are located along the main tourist

trail to Namche and Chukkung. There are 4 office buildings, 4 temples and 3 schools

at GLOF risk with flood level up to 20 m (Table 3.11).

Table 3.9: Number of pakki and kachhi houses exposed to potential Imja GLOF

risk.

Area Pakki Kacchi

24

Up to 10 m 10-20 m Up to 10 m 10-20 m

Chukhung-Larja 4 72 11 135

Jorsalle-Chaubas 23 50 10 82

Jubing-Distbound 0 0 25 41

Rabuwa-Sunkoshi 0 0 130 120

Total 27 122 176 378

Source: Khanal et al., 2009 and Field Survey, December 2013

Table 3.10: Number of shops, hotels and teashops exposed to potential Imja GLOF

risk

Area Shops Hotels Teashops

Up to 10m 10-20 m Up to 10 m 10-20 m Up to 10 m 10-20 m

Chukhung-Larja 0 2 2 30 0 5

Jorsalle-Chaubas 0 0 14 28 7 23

Jubing-Distbound 0 0 2 1 0 0

Rabuwa-Sunkoshi 0 15 8 6 8 12

Total 0 17 26 65 15 40

Source: Khanal et al., 2009 and Field Survey, December 2013

Table 3.11: Number of schools, office buildings and temple / Gumba exposed to

potential Imja GLOF risk

Area Schools Office building Temple

Up to 10 m 10-20 m Up to 10 m 10-20 m Up to 10 m 10-20 m

Chukhung-Larja 0 0 0 1 0 1

Jorsalle-Chaubas 0 1 1 2 0 1

Jubing-

Distbound

0 1 0 0 0 0

Rabuwa-

Sunkoshi

0 1 1 1 2 2

Total 0 3 2 4 2 4

Source: Khanal et al., 2009 and Field Survey, December 2013

25

3.2.4.2 Roads, trails and embankments

The Dudhkoshi valley is yet quite inaccessible. There is no motorable road and the area

is linked by air services to Lukla and Phaplu. Recently earthen road has been

constructed to link Jayaramtar and it is proposed to extend it up to Rabuwa. About 4

km road length near Jayaramtar is at GLOF risk.

The trail from Lukla to Namche is very busy. This trail follows the bank of Dudhkoshi

river from Ghat to Larja Dobhan. The trail from Jorsalle to Larja Dobhan follows river

bed and bank at several places which is vulnerable to GLOF. Similarly the trails

between Malingo to the bridge over Dudhkoshi, near Churo, Dingboche to Chhukung

are also vulnerable to Imja GLOF. The traffic flow was blocked for more than 20 days

after the damage of trails and bridges between Jorsalle to Ghat by the Dig Cho GLOF

in 1985. About 35 km of trail length in different reaches is at potential GLOF risk

(Table 3.12).

Table 3.12: Length of trails, roads and embankment exposed to potential Imja

GLOF (km)

Area Trails Roads Embankment

Up to 10 m 10-20 m Up to 10 m 10-20 m Up to 10 m 10-20 m

Chukhung-Larja 2.10 6.20 0 0 0 0

Jorsalle-Chaubas 3.15 4.0 0 0 0 0

Jubing-Distbound 8.72 9.35 0 0 0 0

Rabuwa-Sunkoshi 14.65 15.20 4.5 4.8 0.6 0.8

Total 28.62 34.75 4.5 4.8 .6 .8

Khanal et al., 2009 and Field Survey, December 2013

26

3.2.4.3 Bridges

There are a total of 28 bridges over

Dudhkoshi river in different places

(Figure 3.2). One log-bridge located

near Dingboche, 2 truss bridge (one near

Pangboche trail to Cholunche and

another at Phunkithanka) are highly

vulnerable to the potential Imja GLOF

damage. In addition to these, one truss

bridge over Lobuche Khola on the trail

to Dingboche at Churo is also vulnerable

to the debris during potential Imja

GLOF. There are 24 suspension bridges

and one motorable bridge over Dudhkoshi river. One suspension bridge was recently

constructed at Larcha Dobhan. The old one is used for mule and newly constructed

bridge is used for people. These suspension bridges are located considerably higher

place than the expected flood level from the GLOF. However, the foundation of many

suspension bridges is likely to be susceptible to lateral erosion during the GLOF. It is

difficult to determine the level of vulnerability of these bridges due to uncertainty in

the estimation of the stress from the GLOF and extent of lateral erosion on the one hand

and the strength of the foundation on the other. Previous GLOF hazard assessment

studies have also revealed that suspension bridges at Jorsalle, Bengkar, Phakding and

Ghat are vulnerable to GLOF damage (Braun and Fiener, 1995 and Bajracharya et al.

2007).

3.2.4.4 Hydropower, water mill and transmission line

Currently there is no hydropower project in Dudhkoshi river. However, the power

houses of micro-hydro projects in the tributaries of Dudhkoshi are located along its

bank which is susceptible to GLOF damages. For example, the generation plant and the

tailrace of the micro-hydropower plant near Pangboche with a generation capacity of

0.015 MW are at risk. Though it is located considerably higher than the expected flood

Figure 3.2

27

level, it could be damaged due to bank cutting during the potential Imja GLOF since it

is located on a highly unstable slope.

Many hydropower projects with potential capacity of about3108 MW are going to be

developed along the Dudhkoshi river as indicated by the applications submitted for

survey license (Table 3.13). Application for survey license for about 2464 MW within

50 km downstream (Khumjung,

Chaurikharka, Jubin) have been

submitted. Similarly, application for 296

MW projects within 50-75 km

downstream and 300 km MW in more

than 75 km down to the confluence of

Dudhkoshi with Sunkoshi have been

submitted. Survey license for generation

of hydropower has been issued for 48

MW project in Taksindu-Jubing area.

Feasibility study for the installation of

300 MW hydropower plant near Rabuwa

(Diyale-Lamidanda VDC) in Khotang

district has already been carried out.

Applications for the survey license in different sites with a total capacity ranging from

46 MW to 450 MW have been submitted(Appendix6). Application has also been

submitted for the survey license of a hydropower plant with a total capacity of 10.50

MW (upper Dudhkoshi in Khumjung VDC) in Dudhkoshi. Similarly, applications for

the survey of 210 MW project in Taksindu-Jubing area, two projects – 250 MW and 46

MW in Basa-Waku area has been submitted (www.doed.gov.np). These proposed

hydropower projects are likely to be affected by the potential GLOF. It is difficult to

determine the extent of changes in river morphology and its impact on hydroelectricity

dam. The past experience show that the channel morphology in different sections from

Jorsalle to Jubing (Chaurikharka and Jubing and Taksindu VDCs) was changed

drastically due to extensive lateral erosion and large amount of debris were eroded,

transported and re-deposited during Dig Cho (Langmoche) GLOF of 1985 (Vuichard

and Zimmermann, 1987).

Figure 3.3

28

Only 0.5 km length of irrigation canal (Dingboche) and 5 water mills and 10 km of

transmission line are at risk of the potential Imja GLOF with expected flood height up

to 20 m (Table 3.14). Transmission lines from mini and micro hydroelectricity project

particularly at Pangboche, Rakding and Phakding area follow river bank and it is at risk

of secondary impacts of GLOF.

Table 3.13 Potential hydropower development along Dudhkoshi river

Name of VDC Application

for survey

license

Survey

license for

generation

Total Zone Capacity

(MW)

Khumjung 10.5 10.5

< 50 km 2512.1

Chaurikharka 2243.6 2243.6

Jubing 210 48 258

Baku 296 296 50-75 km 296

Diyale 300 300 >75 km 300

Total 3060.1 48 3108.1 3108.1

Table 3.14: Irrigation canal, water mills and transmission line exposed to potential

Imja GLOF risk

Area

Irrigation canal (km) Water mills (no) Transmission line (km)

Up to 10 m 10-20 m Up to 10 m 10-20 m Up to 10 m 10-20 m

Chukhung-Larja 0.5 0.5 2 2 1 1.5

Jorsalle-Chaubas 0 0 0 0 4 6.5

Jubing-Distbound 0 0 1 1 0 0

Rabuwa-Sunkoshi 0 0 2 2 0 2

Total 0.5 0.5 5 5 5 10

Khanal et al., 2009 and Field Survey, December 2013

3.2.5 Monetary value of the elements exposed

The monetary value of the elements exposed to potential GLOF risk varies in

downstream direction depending upon the level of flood height. Table 3.15 shows the

estimated values for four different sections along Dudhkoshi river. The total exposed

amount ranged from USD 0.51 million in headwater zone between Chukhung and Larja

Dobhan to 1.42 million between Jorsalle and Choubas, 0.60 million between Jubing

and the district boundary between Solukhumbu and Khotang, and 366.5 million in far

downstream between Rabuwa and Sunkoshi under flood scenario of 10 m high. Real

29

Estate ( private land and buildings) and agriculture sector in combination comprises

about 80-90% of the total amount exposed to GLOF risks in all the sections except

between Jubing and district boundary between Khotang and Solukhumbu under the

flood scenario of up to 10 m from the normal flow. It should be noted that the

downstream areas in Khotang and Okhaldhunga districts were severely affected from

Tam Pokhari GLOF in 1998. The value of exposed elements increases drastically in the

headwater zone between Chukhung and Larja Dobhan from 0.51 million USD to 9.37

million, and between Jorsalle and Choubas from 1.42 million to 3.41 million with flood

scenario up to 20 m high from the normal flow. Such an increase in the amount exposed

to potential GLOF risk under assumed maximum flood level up to 20 m is mainly from

Real Estate and agriculture sector comprising land, house and crops. The number of

exposed hotels and the size of agricultural land increases with the increase in the level

of flood height on the one hand and the replacement cost of buildings and per unit price

of agricultural land are very high in Chukhung, Dingboche, Churo, Somare, Pangboche

and Milingo in headwater zone as compared to other areas in downstream.

Table 3.15: Monetary value of exposed elements to potential GLOF risk in

different sections in Dudhkoshi basin (USD 000)

Sector

Chukhung-Larja Jorsalle-Choubas Jubing-Distbound Rabuwa-

Sunkoshi

Up to 10m 10-20m Up to 10m 10-20 m Up to 10m 10-20 m Up to 10m 10-20

m

Real Estate 451 9121 1105 2844 230 301 2910 3103

Agriculture

Sector

9 200 35 250 90 85 480 420

Public

Infrastructure

50 55 285 312 287 333 275 263

Secondary

Damages

5 3 4 6 0 0 0 0

Total 515 9379 1429 3412 607 719 3665 3786

Source: Khanal et al., 2009 and Field Survey, December 2013

30

3.2.6 Increasing exposure of future investment to potential GLOF risk

As mentioned earlier, many proposals for developing hydroelectricity from

Imja/Dudhkoshi river have been submitted to the Nepal Government and these projects

are likely to be implemented in near future. There is uncertainty when the Imja GLOF

occurs. If it occurs after the implementation of those proposed projects in the future,

the investment on hydroelectricity development and the revenue from it will be at risk.

Table 3.16 shows the estimated amount of money to be invested and the revenue to be

generated from those proposed projects. Nearly a total of USD 8.98 billion will be at

risk if the potential danger of Imja GLOF remains even after the completion of those

proposed hydroelectricity development work.

Table 3.16: Estimated amount of money to be invested for hydro-electricity

development along Dudhkoshi river and revenue likely to be

generated (USD 000)

Potential hydroproject

Chukung-

Larja

Jorsalle-

Choubas

Jubing-

distbound

Rabuwa-

Sunkoshi

Total

License for survey 0 0 0 0 0

Project 0 0 115068 0 115068

Revenue 0 0 23671 0 23671

Application for survey 0 0 0 0 0

Project 25171 5378493 1213014 719178 7335856

Revenue 5178 1106433 249534 147945 1509090

Total 30349 6484926 1601288 867123 8983686

Source: Khanal et al., 2009 and Field Survey, December 2013

Since the study on GLOF vulnerability in 2009 from ICIMOD, a few changes in the

elements exposed to potential Imja GLOF have been reported during focus group

discussion and key informants interview and direct observation by the researcher during

field study. One of the sectors is agriculture. The cropping pattern has been changed

and now the local people have been growing vegetable farming which was in small

scale in 2009. The reason of such change is mainly driven by the increasing number of

tourist visiting in this area. The major vegetables growing in this area are cabbage,

cauliflower, raddish, carrot, garlic and different types of mustard leaf.There has been

increasing trend in animals used for transporting goods. So, the number of animals

31

likely to be affected has been increasing as compared to the number reported in 2009.

Another change so far observed is the shift in ownership in business. Outmigration of

local people (Sherpa) by renting their houses to the people living in the hills is

increasing. Now, other hill ethnic groups such as Brahamin, Tamang and Magar are

involved in hotel business and trekking activities. So, there has been slight shift in the

ethnicity of the people exposed to potential Imja GLOF.

3.2.7 Livelihood support service

Agriculture, livestock, trade and tourism are the major economic activities of the people

living in Khumbu region. Agriculture and livestock sectors are likely to be affected.

Many Sherpa households have agricultural and grazing land along the Imja valley. The

direct access to those fields is likely to be disturbed. As a result, large numbers of people

are likely to be affected from potential GLOF risk. The view expressed by local people

about the increasing risk of potential GLOF is given in Box 1.

Box 1

We are agriculture depended family. Except agriculture, trekking is another source of

income of my family. My husband spends five months in trekking in a year. At that time,

I have to take burdens of all kinds of domestic works. I have to spend more time for grass

cutting, fetching water and collection of fodder, firewood and grazing animals. Not only

me, do most of the women of this village like me. If GLOF events occur, certainly we,

women will be highly vulnerable not only inside the house but outside the house as well.

Chhima Finju Sherpa, Member of Focus Group Discussion, Manjo

A large number of women of this settlement are engaged in hotel and lodge and tea shop

business like me. We frequently do up and down for marketing and other different purposes

in this Lukla - Namche route. Not only in business, we are engaged in agricultural as well

as livestock caring activities. The role and responsibility of women is multiple in this area.

Therefore, any events like GLOF, more likely impacts to women community. So,

awareness creation among women about GLOF risk and mitigation and ensuring

participation of women in every activities of EWS installation is necessary.

Istar Ranamagar - A women key informant, Phakdin

32

The main source of income of the people living in Khumbu is tourism related activities

whereas it is agriculture in the downstream areas. In the past, Dudhkoshi valley is one

of the major routes of Tibetan trade via Nagpa La, Namche, Chaurikharka and Jubing

(Department of Information, 1974). The livelihood of the Sherpa people in Khumbu

region who settled there since 1530s was based on agriculture, livestock and trade

before 1950 when the area was opened to mountaineering and trekking. Since the first

scaling of Mount Everest in 1953, the number of foreign visitors to Everest region has

increased from about 1,400 in 1972/73 to 5,836 in 1980, 11,314 in 1990, 25,291 in

2000, 30,599 in 2008 to 35200 in 2013.

The number of hotels in Khumbu region as increased drastically particularly along the

major tourist trails. The first hotel was opened in Namche in 1971 and it increased to

17 in 1978, 83 in 1991, 157 in 1996 and 380 lodges and Sherpa Village Inns in the

region in 2002. (Sharma,, 2001; Tabei 2001; www.unep_wcmc.org/sites/wh/pdf). The

hotel business has been growing rapidly and people even from outside the region are

also attracted to run hotel business hiring buildings. The annual rent for one hotel

ranged from about NRs. 60,000 to more than 1 million depending upon the types of

building, facilities available and the location. One estimate for 1997 shows that nearly

20,331 people were employed as porters and guides in the Everest region when the

number of tourist visiting Khumbu region was 18,179. Similarly, tourism revenue for

1995 from Khumbu region was estimated to be US$ 0.869 million which is 22.1 percent

of the total revenue from tourism (mountaineering royalty, trekking peak fee, trek

permit fee and park entrance fee) in the country when the number of tourist visiting this

area was 14,997. The park entrance fee for 1995 was about 0.235 million (Sharma,

2001). The number of visitors at present is more than double as compared to 1995, the

employment generation as well as the revenue from tourism might have been doubled.

Weekly haat (market) at Namche is one of the important economic activities creating

employment opportunities and income generating source to large number of people. At

the beginning the haat took place on Saturday. However, as the tourism activities

increased it is also extended for two days- Friday and Saturday. People from far rural

areas of Solukhumbu, Okhaldhunga and Khotang carry heavy loads of goods on back

to sale in this haat following trails along Dudhkoshi river particularly from Ghat to

Larja Dobhan. The major sources of goods such as rice, sugar, kerosene, salt, biscuit,

33

soap, noodles, spice, bitten rice, oil, eggs and liquor are Kathmandu, Jiri/Bhandara

whereas wheat, beans and vegetables are the rural areas of Solukhumbu, Okhaldhunga

and Khotang districts. More than 130 persons are involved in this trade. Their livelihood

support system is likely to be affected for a few weeks from the potential Imja GLOF.

After Dig Cho GLOF in August 1985, those activities were interrupted due to damage

of trails and consequent blockage in the movement of people for several weeks.

All the livelihood options such as tourism, trade and business, agriculture and livestock

are directly or indirectly affected by potential GLOF event. The flow of people, animal

and goods is likely to be blocked due to damage of trails and bridges.

34

CHAPTER IV

VULNERABILITY AND GLOF RISK REDUCTION

4. 1 Socio-economic vulnerability at watershed level

Overwhelming majority of households living in areas likely to be affected are

indigenous ethnic groups and Dalit (Table 3.4). Those are Sherpa, Rai, Tamang, Magar

and Dalit (94%) in the upper most part of the Dudhkoshi, Rai, Tamang, Sherpa, Magar

and Dalit (77%) in the middle and Rai, Magar, Newar, Tamang, Majhi and Dalit (69%)

in the downstream areas. Bahun/ Chhetri caste group comprises very low of total

households compared to ethnic groups likely to be directly affected residing in

downstream areas. Majhi is the highly marginalized ethnic group in the country

whereas Tamangs are marginalized and Rai and Sherpa are disadvantaged groups.

These groups generally have less access to national decision making processes.

Many families (67%) likely to be affected are small and marginal farmers with less than

10 ropani of land. About 9% families are nearly landless with less than 1 ropani of land,

27% are marginal families with landholding size between 1-4 ropani and 33.1% are

small farmers with landholding size between 4-10 ropani (Table 4.1). Though the

number of large farm families is comparatively higher in the upper most part of the

basin, however, the cropping intensity is very low and large part of their farm land is

used to grow fodder.

Table 4.1: Number of households by farm size.

Area Landless Marginal Small Medium Large

Chukhung-Larja 13 95 67 63 21

Jorsalle-Chaubas 15 40 44 18 8

Jubing-Distbound 3 32 42 29 12

Rabuwa-Sunkoshi 37 30 82 81 18

Total 68 203 235 191 59

% 9 27 31.1 25 7.9

Note: Landless having less than 1 ropani of land, marginal having 1-4 ropani of land,

small having 4-10 ropani of land and large having more than 10 ropani of land

(1 ropani=0.0509 ha)

Source: Khanal et al., 2009 and Field Survey, December 2013

35

Table 4.2 shows the number of households by level of food sufficiency. The upper part

of the basin is food deficit area. About 59.6 percent of the total family likely to be

affected by GLOF produces food only enough for 6 months a year. They have to import

food items from outside in order to meet their food requirement. Only about 18%

families are able to fulfill their requirements from their own production.

Table 4.2: Number of households by level of food sufficiency

Area <3month 3-6 month 6-9months 9-12months Surplus/sale

Chukhung-Larja 137 61 22 6

Jorsalle-Chaubas 32 42 50 12 .1

Jubing-Distbound 20 15 42 20 3

Rabuwa-Sunkoshi 71 37 43 76 6

Grand Total 260 155 157 114 10

% 37.3 22.3 22.5 16.4 1.5

Source: Khanal et al., 2009 and Field Survey, December 2013

Table 4.3 shows the number of household by income level. Nearly 43.6% families

likely to be affected have annual income less than 50,000 rupees. The proportion of low

income group families is comparatively higher in downstream areas. Though the

proportion of high income families is comparatively higher in the upstream areas, they

have to spend large amount of money in food imported from other areas. The major

source of income living in upstream area is tourism related activities. Any disturbance

in the flow of tourist in this area affects the income of the local people and hence their

livelihoods. The likely damages of trails and bridges along Imja/Dhudhkoshi river will

certainly disturb tourism development in this region. As a consequence, revenue from

tourism is also likely to be decreased.

36

Table 4.3: Number of households by size of annual income (Rupees)

Area <25000

Rs

25000-

50000

50000-

100000

100000-

150000

150000-

200000

>200000

Chukhung-Larja 3 15 34 55 54 85

Jorsalle-Chaubas 8 21 20 27 21 42

Jubing-Distbound 91 4 6 4 10 1

Rabuwa-

Sunkoshi

135 48 45 13 3

Grand Total 237 88 105 99 88 128

% 31.8 11.8 14.1 13.3 11.8 17.2

Source: Khanal et al., 2009 and Field Survey, December 2013

All the socio-economic parameters discussed above at watershed level clearly shows

that the local capacity to implement structural GLOF risk reduction measures is very

limited and it needs external support to carry out such activities.

4.2 Livelihood Vulnerability at Settlement/Community Level

Attempt has been made here to discuss livelihood vulnerability with the help of

Livelihood Vulnerability Index (LVI) calculated based on data collected from 21

communities/settlements in the watershed 50 km downstream from Imja Lake which

are likely to be affected the most. Livelihood vulnerability approach used by Hahn et

al., (2009) has been adopted using relevant indicators. The list of indicators used in

calculating Livelihood Vulnerability is given in Table 4.4. The livelihood vulnerability

index has been developed using following formula.

Livelihood Vulnerability Index (LVId) = (ed-ad)*sd

where, ed = Exposure index of the community

ad = Adaptive capacity of the community

sd = Sensitivity index of the community

The value of a community were aggregated and normalized to a scale of 0 to 1 range

using the following formula.

Zi,j= (Xi,j – Xi min)/(Xi

max-Ximin)

where, Zi,jis the standardized indicator index of type i of community j,

Xi,jis the unstandardized indicator index of type i of community j,

Ximax is the maximum value of the indicator index over community j, and

Ximin is the minimum value of the indicator index over community j.

37

Table 4.4: Components and parameters used to calculate livelihood vulnerability

index

Components Sub-components Parameters

Adaptive

capacity

Demographic % active population

% literate

Livelihood % household with > 200000 annual income

% household having more than 3 different source

of income

Sensitivity Food % hh with food sufficiency < 6 months

Health Time distance to reach health centre

Transport, market,

education and

communication

Time distance to road head

Time distance to market

Time distance to school

% household with TV/Radio

% household with Telephone

Exposure Loss and damages

from GLOF in the

past

Persons swept away from GLOF

Land lost from the GLOF (value)

Crop lost from the GLOF (value)

Houses lost from the GLOF (value)

Infrastructure lost from the GLOF (value)

Estimated loss from

Potential Imja

GLOF risk

People exposed to GLOF risk

Land exposed to GLOF risk (value)

Crop exposed to GLOF risk (value)

Houses exposed to GLOF risk (value)

Infrastructure exposed to GLOF risk (value)

The index parameter value was averaged to obtain index value of each major sub-

component and the index value of major components was averaged to obtain index

value for each contributing factor i.e. exposure, sensitivity, adaptive capacity and

overall vulnerability. The value is given in Table 4.5.

38

Table 4.5: Exposure, sensitivity, adaptive capacity and overall vulnerability

SN

Settlements

Adaptive capacity Sensitivity Exposure Vulnerability

Demographic

index

Livelihood

index

Adaptive

capacity

index

Food

sufficiency

index

Health facility

index

Access to

transport,

market, health

and

communication

index

Sensitivity

index

Past disaster

loss index

Exposure to

potential Imja

GLOF risk

Exposure Vulnerability

index

1 Chukkung 0.1944 0.4697 0.3321 1.0000 1.0000 0.7624 0.9208 0.0000 0.1307 0.0654 -0.2456

2 Dingboche 0.5000 0.6477 0.5739 0.9455 0.6250 0.6775 0.7493 0.0000 0.6143 0.3071 -0.1999

3 Orso 0.3889 0.1818 0.2854 0.8182 0.5000 0.5977 0.6386 0.0000 0.2558 0.1279 -0.1006

4 Somare 0.2778 0.1742 0.2260 0.8364 0.4375 0.5833 0.6191 0.0000 0.2745 0.1372 -0.0550

5 Pangboche 0.7778 0.8636 0.8207 0.9091 0.3125 0.5750 0.5989 0.0756 0.1454 0.1105 -0.4253

6 Milingo 0.1944 0.2992 0.2468 0.8727 0.2500 0.4719 0.5315 0.0000 0.0267 0.0133 -0.1241

7 Diboche 0.0000 0.5152 0.2576 1.0000 0.2250 0.5618 0.5956 0.0000 0.0331 0.0165 -0.1436

8 Phungithanga 0.2222 0.5152 0.3687 1.0000 0.1250 0.3061 0.4770 0.0201 0.1985 0.1093 -0.1237

9 Jorsalle 0.2222 0.5189 0.3706 0.9091 0.3750 0.5712 0.6184 0.6887 0.5004 0.5946 0.1385

10 Tawa 0.5833 0.3106 0.4470 0.5455 0.4000 0.4121 0.4525 0.1947 0.2536 0.2242 -0.1008

11 Manjo 0.8333 0.4697 0.6515 0.4545 0.4375 0.5215 0.4712 0.2747 0.2746 0.2747 -0.1776

12 Chhumawa 0.9167 0.1780 0.5473 0.5636 0.4750 0.5461 0.5282 0.3592 0.2585 0.3088 -0.1260

13 Benkar 0.6389 0.7348 0.6869 0.4182 0.5000 0.5521 0.4901 0.2462 0.7690 0.5076 -0.0879

14 Toktok 0.5833 0.6894 0.6364 0.3636 0.5625 0.4619 0.4627 0.0324 0.3160 0.1742 -0.2138

15 Gumela 0.7222 0.3750 0.5486 0.2727 0.6000 0.4523 0.4417 0.0000 0.0051 0.0025 -0.2412

16 Jamphutta 0.6667 0.4318 0.5492 0.7818 0.5375 0.5601 0.6265 0.0000 0.0087 0.0043 -0.3414

17 Phakding/Rakding 0.5556 1.0000 0.7778 0.5455 0.3750 0.5083 0.4762 0.1605 0.7790 0.4698 -0.1467

18 Dungdima 0.2500 0.3523 0.3011 0.7273 0.3500 0.4070 0.4948 0.1354 0.1159 0.1257 -0.0868

19 Chhermadin 0.2500 0.3409 0.2955 0.1818 0.2500 0.2982 0.2433 0.4323 0.6534 0.5428 0.0602

20 Ghat 0.5000 0.4280 0.4640 0.0000 0.1250 0.3443 0.1564 0.7303 0.3130 0.5217 0.0090

21 Thadokoshi 0.7222 0.4735 0.5979 0.2727 0.0000 0.2935 0.1887 0.1054 0.2387 0.1721 -0.0804

39

In terms of exposure Jorsalle, Chhermadin, Ghat, Benkar, Phakding, Chhumawa and

Dingboche are relatively highly exposed with index value more than 0.3. In terms of

adaptive capacity, Pangboche, Phakding/Rakding, Benkar, Manjo, Toktok,

Thadokoshi, Dingboche, Jamphutta, Gumela, and Chummuwa are relatively better than

other communities. Similarly, Chukkung, Dingboche, Orso, Jamphutta, Somare,

Jorsalle, Pangboche, Dingboche, Milingo, and Chhumawa are more sensitive to Imja

Imja GLOF risk. The strategies for effective risk reduction is to limit the investment in

those settlement which are highly exposed with high sensitivity index value and

improve adaptive capacity in those settlements which have relatively low index value.

4.3 People’s Perception on GLOF Risk and Its Management

No specific preparedness activity for the reduction of risk of potential GLOF has yet

been carried out in this area though local people do have experiences of past GLOF

events. People living in far downstream area are not aware about glacier lakes and its

potentiality of outburst. Many people living nearby areas of the Imja lake still perceive

that glacial lake is the residence of the god and glacial lake outburst flood is the result

of the anger of the god due to acts of sin (Box 2). Confessing sins to God would help

to stabilize the lake. However, some people are aware with the fact that the risk of

GLOF has been increasing in recent years due to the process of global warming. People

are willing to carry out mitigation measures. During group discussion in Dingboche,

the local people demanded for effective work to lower the lake level in order to reduce

the risk. They had proposed to replicate the lake level lowering model implemented in

Tsho Rolpa Glacial Lake in Imja also. One of the incentives for adopting lake level

lowering model adopted in Tsho Rolpa by the people living in Chukkung and

Dingboche is the hydropower that could be generated and utilized. They had

emphasized on public-private partnership in such activity and they are willing to

participate and cooperate in such activities.

40

4.4 People’s Expectation of Early Warning System

During the focus group discussion and key informants interview, people had shown

their willingness to cooperate in developing early warning system of potential Imja

GLOF. They believe that EWS can reduce casualties and damages to people and

moveable property as well. Local people have expressed their willingness to contribute

in site identification, land purchase, provide local resources (stone, wood etc.) and free

labour for office building construction and installation of EWS, community

mobilisation, awareness raising and establishing a user committee (Box 3).

Construction of the tower and provision of siren systems are expected from the project.

It was suggested to consider the following issues while developing early warning

system.

Box 2

"In my memory, until now, there is no specific preparedness activity has been carried out in

this area for the reduction of risk of potential GLOF. Many people living nearby areas of the

Imja lake still perceive that glacial lake is the outcome of the god and glacial lake outburst

flood is the result of the anger of the god due to acts of sin. Still, there is time to involve

local communities who are at risk in preparedness from the very beginning and provide

training and awareness, particularly to convince people that the impact of natural disasters

can be minimize by collective efforts."

Prem Tenji Sherpa, Key Informant, Banker

"Potential GLOF risk can be reduced by various ways. The most crucial one is to reduce the

risk of a flood from the lake. For this, the volume of water in the lake should be reduced.

There are different ways such as controlled breaching of the moraine dam, construction of

an outlet control structure and generation of hydropower are some important measures to

achieve this that can be used alone or in combination. However, coordinated measures to

protect life and property in the downstream area must also be undertaken."

Focus Group Discussion, Dinboche

41

Communities or individuals need to make responsible for system

management. For this, responsibility of daily management be provided to

the local groups such as Buffer Zone Comittee, Women Groups, etc.

To overcome the problem of insecurity of EWS, EWs be located near the

existing security (army and police) check-post.

The site should be accessible to local people.

The site should be selected keeping in view the enough lead time.

Evacuation routes be developed and minimum service facilities at shelter

place should also be developed.

Local people should be made aware about GLOF and EWS.

During discussion with local people, the following sites have been recommended to

install early waring siren. They are Chhukung, Dingboche, Pancboche, Phungithanga,

Jorsalle, Benkar, Phakdin+Rakdin, Ghat, Juvin, Demlitar, Rabuwa and Jayaramtar.

Box 3

"We community people must work together to help ourselves. For this, concerned

authority who are involved in installation of EWS in Imja Lake and its downstream

area need to involve us not only in implementation stage but also in every stage of

planning i.e. program formulation, implementation, benefit sharing and monitoring.

According to him, local people can contribute insite identification, land purchase,

provide localresources (stone, wood etc.), free labour for office building construction and

installation of EWS,community mobilisation, awareness raising and so on. Though

awareness generation is crucial at those settlements which are likely to be affected

highly from potential GLOF risk, there is a need for coordination with government

and donor agencies so that resources, efforts and participation could go together to

achieve the common goal."

Mingma Chhiring Sherpa, Key Informant, Thadokoshi

42

CHAPTER V

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

Imja Glacial Lake was identified as high priority lakes needing immediate

attention of GLOF risk reduction. In the past three GLOF events: Nare in 1977,

Dig Cho in 1985 and Tampokhari in 1998 were experienced in Dudhkoshi

watershed. During GLOF event in 1985, 4-5 persons were swept away and large

amount of properties (house, land, crops, tails, bridges, hydropower plant) was

damaged down to Jubing. Traffic flow to Namche bazaar was blocked for 1-2

months due to damage of trails and bridges. It clearly shows that potential Imja

flood could affect downstream areas with loss of life and properties along

Dudhkoshi river.

This is a prefeasibility level study and it is limited to the identification and

quantification of elements at risk and discussion of socio-economic and

livelihood vulnerability. The study does not report on the internal damages

arising due to loss of household and personal property indoor.

The potential Imja GLOF could affect local people at different scale – the

watershed, VDCs adjoing Dudhkoshi river and settlement located along the

river and distance from Imja lake to downstream areas. Based on the experience

from the past GLOF events, settlements and VDCs located within 50 km

distance are likely to be affected the most, settlements and VDCs located

between 50-75 km downstream are likely to be affected moderately and

settlements and VDCs located further downstream are likely to be affected less.

VDCs and settlement located along the Dudhkoshi river are likely to be affected

directly whereas other VDCs located in the watershed are likely to be affected

indirectly as the access to service infrastructure is blocked due to damage of

infrastructure such as bridges, roads, hydropower plants from the potential Imja

Lake.

The elements exposed to GLOF risk consists people, tourists, porters, animals,

land, houses, bridges, trails, irrigation canals, hydropower projects,

transmission line and revenue from electricity supply. In the context of

increasing activities for the development of hydroelectricity projects along

43

Dudhkoshi river, the risk of potential Imja GLOF in the future is likely to

increase.

Overwhelming majority of households living in areas likely to be affected are

indigenous ethnic groups and Dalit. Many families likely to be affected are

small and marginal farmers with severe food scarcity and low level of household

income. So their capacity to implement structural GLOF risk reduction

measures is very limited and it needs external support to carry out such

activities.

In terms of exposure settlements within 50 km distance downstream from Imja

Lake such as Jorsalle, Chhermadin, Ghat, Benkar, Phakding, Chhumawa and

Dingboche are relatively highly exposed to potential Imja GLOF. In terms of

adaptive capacity, Pangboche, Phakding/Rakding, Benkar, Manjo, Toktok,

Thadokoshi, Dingboche, Jamphutta, Gumela, and Chummawa are relatively

better than other communities. Similarly, Chukkung, Dingboche, Orso,

Jamphutta, Somare, Jorsalle, Pangboche, Dingboche, Milingo, and Chhumawa

are more sensitive to potential Imja GLOF risk. The strategies for effective risk

reduction are to limit the investment in those settlements which are highly

exposed with high sensitivity and improve adaptive capacity in those

settlements which have relatively low adaptive capacity.

Lowering of lake level, generation of hydropower from water released from the

lake, regular monitoring and establishment of early warning system are some of

the activities demanded by local people in order to reduce the risk of potential

Imja GLOF.

Sensitization through intensive interaction with the local community; Formation

of Community Based GLOF risk management committee, Skill development

training to the community, Awareness creation through formal medium such as

school education and informal medium through Lama, Regular monitoring of

Glacial Lake and its outburst risk are some of the activities recommeded for

project activities in order to reduce the risk of imja GLOF risk.

It is hoped that the lesson learnt from this project would help to formulate and

implement similar types of activities in other areas likely affected from potential

GLOF. The findings of this project can also be incorporated in NAPA and

LAPA processes and climate change policy in the future.

44

One of the uncertainties in assessing GLOF vulnerability is the estimation of

the discharge and flood height in different reaches along the river. Two studies

so far carried out for potential Imja GLOF shows different value of discharge

and flood height. Attempt to study vulnerability of potential Imja GLOF

estimated at 30 m flood height as maximum scenario. However, the dam break

model shows the flood height less than 15 m. Keeping in view the results of

dam break models, it was decided to determine maximum flood height of 20 m

for this study. It is necessary to determine potential GLOF level through in depth

study of the lake, moraines and surrounding environment on the one hand and

flood routing using high resolution DEM so that the differences in channel

geometry could be captured and flood height be estimated accurately. Another

uncertainty is in the estimation of secondary impacts of the GLOF i.e the bank

cutting and initiation of landslides and its likely damages from the potential

GLOF. For this the detail stability analysis of the bank and adjoining hillslope

is necessary.

Slight differences in the types and volume of elements exposed to potential Imja

GLOF have been observed. For example, vegetable farming has been

increasing, the flows of people and animals have been increasing and there has

been change in the ethnicity of people exposed to potential Imja GLOF.

Similarly, the change in the monetary value of the properties exposed to GLOF

risk due to increasing value of commodities was also observed. Such changes

over time demands for regular updating of information on GLOF vulnerability.

5.2 Recommendation

• Sensitization through intensive interaction with the local community so that the

community becomes aware with the risk of potential GLOF, interested to

participate and contribute in risk management activities. For sensitization, it is

necessary to develop leaflets incorporating key information about potential

GLOF risk and give out those leaflets the local people. It is also necessary to

organize community meetings to discuss on the potential GLOF risk and its

management activities

• Formation of community based GLOF risk management committee.

During interaction meeting it is necessary to form a committee for GLOF risk

45

management. The size of committee should be based on the size of the

settlement tentatively 9-11 members including one chairman and one secretary.

It is also necessary to have representation from concerned Ward and Village

Level Committee so that the activities can be developed and monitored with

financial support from VDC in the future with the fund obtained from the

government. Small settlement located in close proximity can be considered one

and only one committee be formed. This committee will be responsible to

identify risk management activities – both structural and non-structural

measures. Structural measures may consists of the construction of retaining

walls in vulnerable sites, bioengineering works at unstable banks, improvement

of trail – alignment above 20 m high from normal flow level avoiding flood

prone area. Similarly non-structural measures consist of limiting/controlling

the investment (development of housing and business stalls) in flood prone area

with the development and enforcement of land use zonation and building codes,

establishment, functioning and maintenance of early warning system,

identification of site for shelter and evacuation route and its development,

capacity improvement through training and skill development and resource

generation and investment. This committee should be responsible to formulate,

implement, monitoring and evaluation of action plans targeted to the reduction

of potential GLOF risk within its community area.

Another alternative as suggested during the discussion in the meeting organized

for the presentation of draft report is to mobilize Buffer Zone Management

Committee within National Park and Forest User Groups in downstream area.

However, further intensive consultation with National Park Officials, Buffer

Zone Management Committees, Forest Users Groups, member of civil society

and VDC secretaries (VDCs located along Dudhkoshi rive) is necessary to form

the risk management committee covering all the settlements that are likely to be

affected directly from potential GLOF risk starting from the lake site to

downstream areas (the confluence of Dudhkoshi with Sunkoshi near Ghurmi

settlement).

• Skill development training to the community. Selected members from each

of the risk management committee should be given training on development of

action plans, its implementation and monitoring, techniques of rescue, relief and

46

rehabilitation activities, and functioning and maintenance of early warning

system. It is also necessary to provide skill development training for the

improvement of their livelihood such as entrepreneurship development.

• Awareness creation: through formal medium such as school education and

informal medium through Lama. As practiced in Singati with the help of UNDP,

it is necessary to develop introductory curricula on GLOF risk assessment and

management and be incorporated in school education. Lamas in local area

should also be made aware with this and they should be involved in making

people aware about the potential GLOF risk.

• Regular monitoring of Glacial Lake and its outburst risk: It is also necessary

for regular monitoring of major glacial lakes and its outburst risk in the whole

Dudhkoshi watershed so that the risk of GLOF not only from Imja but also from

other Glacial Lakes to be managed. Technical support (remote sensing and site

specific surveying) should be provided from outside. The networking and

organization developed through this project could be utilized by extending it up

to Thame, Pheriche, and also in Hongu river.

• Replication of the GLOF risk management modality in other areas: After

successful implementation of this project, the lesson learnt from this project

would help to formulate and implement similar types of activities in other areas

likely affected from potential GLOF. The findings of this project can also be

incorporated in NAPA and LAPA processes and climate change policy in the

future.

5.3 Summary of Results and Findings: Scope of Work

Organize Consultative Meetings with Communities: Researchers visited the field

site for detail investigation between Imja lake and Thadokoshi. A total of 21 settlements

were visited and information for vulnerability analysis were collected through focus

group discussion, key informants inteveiw, observation and discussion with other local

people and communities who are likely to be affected. Name of

settlements/communities and people consulted is given in Table 4.5 and name of

persons attended in focus group discussion and consulted as key informants is given in

Annex 2 and Annex 3. During the field investigation, national park authority and

47

member of buffer zone management committees, forest users group and women were

also consulted. Details are given in section 1.4: Methodology.

Consultation with Key Stakeholders: Consultation meetings were held with the

relavent persons from DHM, ICIMOD, Practical Action, UNDP, WECs and MoSTE.

Collate and Update Information and Reports of the Past:Published articles,

published and unpublished reports and documents were collected and reviewed.

Consulted article/reports/documents are given in the list of reference and their findings

is cited in section 1.1: Background. Detail soci-economic data/information related to

potential Imja GLOF risk covering the whole Dudhkoshi watershed is in ICIMOD’s

2009 report (Khanal et al 2009). Population and ethnicity data was updated using

Population Census of 2011 (Table 3.2-3.4). Information on elements exposed to

potential Imja GLOF risk was updated based on the field survey carried out in 2013 and

results are presented in Chapter 3. Data on the flow volume of tourist was updated based

on the records of the National Park Office. Present study shows that the number of

tourists visiting Khumbu region, number of porters involved to carry loads and number

of animals used to transport goods has been increased in recent years as compared to

the figures given for 2009 in ICIMOD report. Similarly, vegetable farming has been

growing. The elements exposed to the potential Imja GLOF given in this report is not

the same as given in ICIMOD’s report. It is partly due to the change in maximum level

of GLOF scenario and partly due to the change in the price of the properties likely to

be affected. In ICIMOD report the maximum height was fixed as 30 m whereas in this

study, the maximum height was fixed to 20 m based on the results of dam break model

(ICIMOD, 2009 and Somos-Valenzuela et al 2013). It was decided during the

discussion in the inception meeting organized by the project.

Verify and Refine GLOF Vulnerability Assessment: Basically it was decided to

follow the methodology used by ICIMOD in 2009 (Khanal et al, 2009). In addition to

this, the relative value of exposure, sensitivity, adaptive capacity and vulnerability has

been calculated for 21 settlements located 50 km downstream from Imja Lake and

which are likely to be affected the most. Such assessment was not in the ICIMOD’s

2009 report. The parameters and the methods of calculating the value of exposure,

sensitivity, adaptive capacity and vulnerability was adopted with slight modification

from the work done by UNDP for Singati, Bhorle and Suridobhan in Dolakha district (

48

Adapt/Nepal, 2010) (Table 4.5). The data for this was generated during focus group

discussion and key informants interview in which local people including women were

actively participated.

Desk Review: Materials collected for review is given in the list of reference. Besides,

population census data was collected and has been incorporated. Based on the review

work, structured checklist was prepared (Appendix 1) in order to guide focus group

discussion, key informants interview and record data/information. Transect walk and

direct observation by the researchers was carried out in order to probe the information

during consultative meetings with local people and verify the information particularly

on the physical vulnerability of the elements exposed to potential Imja GLOF risk.

Review Local Knowledge: Report on local knowledge on potential Imja GLOF

vulnerability is very scanty. However, attempts were made to collect such information

from the field. Section 4.3 and 4.4 gives the detail on people’s perception on GLOF risk

and its management.

Ecosystem Payments Services: Since the capacity of local people to contribute as cash

for GLOF risk reduction is very low, they are willing to participate in the development

of early warning system and provide free labour for office construction and installation

of EWS (Section 4.4).

Review and Recommend GLOF Vulnerability Reduction Practices in Policy: Local

people specifically from Dingboche and Chhukung have recommended the model of

GLOF risk reduction- lowering lake level, generation of hydropower and establishment

of early warning system as adopted in Tso Rolpa. They are very much eager to take the

opportunity of the development of hydroelectricity utilizing released water from the

lake and use it in tourism development activities and ultimately improving their level

of income. They are also willing to contribute even cash for hydroelectricity

development (Section 4.4). There is no specific institution at local level to carry out

activities for GLOF risk reduction. There are two possibilities for institutionalization

GLOF risk management at local level – formation of new GLOF risk management

committee or strengthen Buffer Zone Management Committee within National Park

area and forest user’s group in downstream areas. Keeping in vewi the existing

institutional mechanism and availability of financial resources, it is necessary to have

representation of VDC in each committee. It has also been recommended to build the

49

capacity by organizing skill development training for relief and rescuoperation (Section

5.2).

Identify any other Pertinent Scope of Work: Awareness creation for wider

participation in the project activities, intensive consultation with National Park

Officials, Members of Buffer Zone Management Committee, Forest Users Group,

member of civil society to form GLOF risk management committee, preparation of

working guidelines including land use guidelines specifically housing and other

infrastructure development and code of conduct of the proposed institution are

necessary.

Draft and Final Report Submission: A meeting was organized at Project office to

discuss on inception report and finalize the methodology. The methodology was

finalized as per the suggestion during the discussion. Draft report was prepared and

submitted to the Project Office and another meeting was organized at Project Office to

present summary of the draft report. The draft report was revised as per the comments

and suggestions so far made during the discussion and submitted to the Project Office.

50

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Nepal. CRWR Online Report 13-06.The University of Texas at Austin and the

Mountain Institute.http://www.crwr.utexas.edu/online.shtml.

Turner II, B. K. (2003). A framework for vulnerability analsis in sutainability science.

Proceedings of the National Academy of Science of the United States of

America 100, (pp. 8074-8079).

Viuchard, D., & Zimmermann, M. (1986).The Langmoche Flash-flood, Khumbu

Himal, Nepal. Mountain Research and Development , 7 (2), pp. 91-110.

Vuichard, D., & Zimmermann, M. (1987). The 1985 catastrophic drainage of moraine-

dammed lake, Khumbu Himal, Nepal: Causes and consequences. Mountain

Research and Development , 7 (2), pp. 91-110.

WECS/HMGN (1987). Preliminary Study of Glacier Lake Outburst Floods (GLOFs)

in the Nepal Himalaya: Phase I Interim Report No. 4/1/200587/1/1. Water and

Energy Commission Secretariat, Ministry of Water Resources, His Majesty’s

Government of Nepal.Kathmandu.

54

Appendix 1: Checklist

A. Background Information

1. Name of the Glacial Lake: …………………………………………………

2. Background for data collection through group discussionPlace:………….;

Date……………………; Time:…………..Group size:……..

Participants:…………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

………………………………………………………………………………………

……………

3. Aerial coverage of information (name of the VDC and length of river reaches)

B. Flood events in the past and losses

4. Information about the GLOF and flash flood in the past

a) Major events

SN Year Description of the event (flood level, timing, causes)

b) Loss and damages

Loss/damages Yr1 Yr2 Yr3 Yr4 Remarks

1. Loss of life

Loss of human life (no)

2. Loss of properties

Loss of animal (no)

Loss of house (no)

Loss of cultivated khet land (ropani)

Loss of cultivated bari land (ropani)

Loss of forest land (ropani)

Loss of paddy (MT)

Loss of wheat (MT)

Loss of maize (MT)

Loss of millet (MT)

Loss of potato (MT)

Loss of other crops – specify (MT)

Loss of fruits (MT)

Loss of biodiversity (plant, animal

and fish species)

Loss/damages Yr1 Yr2 Yr3 Yr4 Remarks

55

3. Loss of infrastructures

Damage of road (length in km)

Damage of trails (length in km)

Damage of Highway bridge (no)

Damage of suspension bridge (no)

Damage of river embankment (km)

Damage of irrigation canal (km)

Damage of school building (no)

Damage of office building (no)

Damage of temples/gomba/mosque

(no)

Damage of hydropower dam (no)

Damage of power house (no)

Damage of water mills (no)

Damage of transmission line (km)

Damage of other infrastructure

(specify)

4. Closing of traffic and trade flow

(no of days)

4. Major Rescue, relief and rehabilitation works carried out during and after the

GLOF/Flash Flood events.

C. Elements exposed to GLOF Risk

5. Elements exposed to GLOF Risk (VHH= Very high hazard where the exposed

elements would be completely and immediately washed out; HH= high hazard where

the element at risk both from immediate primary impacts as well as secondary

impacts such as lateral erosion and landslides; MH= moderate hazard where there is

possibility of overtopping by the GLOF; LH=Low hazard those areas where there is

little chance to do any direct damage but can still be destructive when it cuts across

terraces and induce secondary landslides or low-lying terraces at some distance from

predicted direct path of the GLOF)(Note: delineate different hazard zones in the

toposheet and also draw a sketch map- social mapping- showing details)

Elements Up to 10 m 10-20 m

VHH HH MH LH VHH HH MH LH

1. Household and Population

No. of household within the flood

prone area

No. of household outside the flood

prone area but with properties

inside

No. of people within the flood

prone area

No. of people outside the flood

prone area but with properties

inside

56

2. Animals VHH HH MH LH VHH HH MH LH

No of animal owned by the

households within flood prone

area

3. Houses

No of pakki houses in the flood

prone area

No of kacchi houses in the flood

prone area

4. Land

Area of khet land (ropani)

Area of bari land (ropani)

Area of forest (ropani)

Area under paddy cultivation

(ropani)

Area under wheat cultivation

(ropani)

Area under maize cultivation

(ropani)

Area under millet cultivation

(ropani)

Area under potato cultivation

(ropani)

Area of building plots (Ghaderi)

Other if specify

5. Crops

Paddy (MT)

Wheat (MT)

Maize (MT)

Millet (MT)

Potato (MT)

Other crops if any (specify)

Fruits (MT)

Vegetables (MT)

6. Biodiversity (plant, animal

and fish)

7. Infrastructures

Total road length likely damaged

( km)

Road length likely inundated (km)

Total trails length likely damaged

( km)

Trail length likely inundated (km)

Highway bridge (no)

Suspension bridge (no)

River embankment (km)

Irrigation canal (km)

School building (no)

Office building (no)

57

General shops (no)

Hotel (no)

Tea shop (no)

Temples/gomba/mosque (no)

Hydropower dam (no)

Power house (no)

Water mills (no)

Transmission line (km)

Rafting spots (no)

Rafting reach length (km)

Industries (types and numbers)

Any other infrastructure (specify)

6. Livelihood (within flood prone areas)

Description Number Remarks

1. Families involved in wholesale trade

2. Families involved in retail trade

3. Families involved in hotel business

4. Families involved in industries

5. People employed in transport sector

including porters

6. People employed in government services

including school teachers

7. People employed in tourism and recreation

sector

7. Flow of traffic and volume of trade

a. Traffic flow (average daily flow of vehicle/ people – two way on road/trails exposed

to GLOF)

Vehicle/ people Daily flow

Jeep/pickups

Bus

Minibus

Truck

Local people

Tourist

58

b. Trade (major items of export and import through roads/trails exposed to GLOF)

SN Items Export Import

Volume

(unit)

Value

(Rs)

Volume (unit) Value (Rs)

1

2

3

4

5

6

7

8

9

10

11

12

13

D. Socio-economic vulnerability

8. Number of households and population by ethnicity in flood prone area

SN Ethnicity No. of household Population

1

2

3

4

5

6

7

8

9. Number of households by types of families in flood prone area

Types of families/people No. of household Population

Nuclear

Joint

Non-nuclear (yekal)

Disabled

59

10. Status of education (5 years and above)

Level of education Number

Illiterate

Primary

Secondary

Intermediate/higher secondary

Graduate

11. Number of households by landholding size (flood prone areas)

Land holding size No of Household

Landless (< 1 ropani)(0.05 ha)

Marginal (1- 4 ropani )(0.05-0.2ha)

Small (4-10 ropani (0.2-0.5 ha)

Medium (10-20 ropani) (0.5-1.0 ha)

Large (> 20 ropani) (>1 ha)

12. Number of households by major sources of income (flood prone areas)

Sources of income No. of households

Agriculture

Business and Trade

Wage/ labor

Service in Nepal

Remittances/pension

Other (specify)

13. Number of households by annual income categories (flood prone areas)

Income size (Rs) No of households

Less than 25,000

25000-50000

50000-100000

100000-150000

150000-200000

More than 200000

14. Number of households by the level of food sufficiency (flood prone areas)

Level of food sufficiency from own production No. of households

Less than 3 months

3-6 months

6-9 months

9-12 months

Surplus / Sale

15. Social relation to cope with the flood risk and disasters (pre, during, post disaster)

(when, who, how)

60

16. Local knowledge about rescue, relief, mitigation and rehabilitation activities to

reduce the impact of flash flood (types of activities needed)

17. Participation/Involvement of local people in establishing early warning system

(Cash, labour and materials).

18. Best locations for early warning system

19. Preparedness strategies/activities performed and recommended

SN Management

strategies/activities

Existing situation Recommendation

1 Preparedness plan

2 Land use codes and

guidelines

3 Building codes and

guidelines

4 Rescue operation

5 Relief provisions (food,

cloth, shelter, medicine)

6 Awareness raising activities

7 Flood forecasting and

monitoring

8 Early warning system

including monitoring

9 Networking, community

mobilization and Institutions

10 Skills and technologies

11 Structural measures

including bio-engineering

12 Risk spreading measures

(saghau, mutthi collection,

insurance etc.)

13 Training and skill

development activities

14 Other (specify)

61

20. Formal and informal institutions including local clubs involved in awareness

creation, training and implementation of structural and non-structural measures to

reduce the risk of flash floods.

SN Name of institutions Types of activities Efficiency Problems

21. Future needs for capacity building (policy, legislation, institutions, risk

communication and awareness, training, technology development and transfer, early

warning and advanced planning)

22. Price list

Elements exposed Average unit price

Animal

Pakki houses in the flood prone area

Kacchi houses in the flood prone area

Khet land (ropani)

Bari land (ropani)

Housing/building plots (Ghaderi)

Other if specify

Paddy (MT)

Wheat (MT)

Maize (MT)

Millet (MT)

Potato (MT)

Other crops if any (specify)

Fruits (MT)

Vegetables (MT)

62

Fish (Kg)

Road (km)

Trails (km)

Highway bridge (no)

Suspension bridge (no)

River embankment (km)

Irrigation canal (km)

School building (no)

Office building (no)

General shops (no)

Hotel (no)

Tea shop (no)

Temples/gomba/mosque (no)

Hydropower

Water mills (no)

Transmission line (km)

Industries (numbers)

Any other infrastructure (specify)

Thank you

63

Appendix 2: Sites and Participants of Focus Group Discussion

Sites/Settlements Participants

Dinbuche Mingma Sherpa, Pasang Sherpa, Lakpa Dimi Sherpa, Ramesh

Tamang and Mingma Diki Sherpa

Panboche Pemba Sherpa, Lakpa Sherpa, Phurbu Sherpa, Chhiring Sherpa,

Tendi Sherpa, Shiva Rai

Phungithanga Kiran Sherpa, Ramesh Magar, Bhabisara Rai, Ganesh Rai

Jorsalle Kamal Tamang, Raju Tamang, Bhim Rai

Manjo Chhuki Sherpa (Member of Himalaya Madhyabarti Forest Group),

Lakpa Tamang, Gopi Tamang, Sunita Tamang (First Group).

Gokarna Rai, Pravin K. Rai, Chhima Finju Sherpa, Pasang Rai, Dev

kumara Sharma, Nima Sherpa, Lakpa Gelgen Sherpa, Pema Chhurin

Sherpa

( Local teachers of Yuba Barsa Lower Secondary School, Second

Group)

Phakdin +

Rakdin

Laxmi Sundas, Phurwa Sherpa, ganga Rai, Sushma Sherpa,

Tirsana Nachhiring Rai, jamakala Rai,, Balkumari B. K., Kunti Rai

Ghat Nimdima Sherpa, Lamu Sherpa, Kamal rai, Chhewang Nuru Sherpa

Chhumawa Dan Bahadur Baniya, Shova Baniya, Laxmi Rai, Pema Chhiri sherpa

Tok Tok Nanda Raj Rai, Prabha Rai, Chandra Nachhiring, Suman Rai

64

Appendix 3: List of key informants

Name of the Interviewee Settlements Occupation

Nirman kumar Pokherel Jorsalle Staff, Sagarmatha National Park

Tej Bahadur Magar Jorsalle Staff, Sagarmatha National Park

Pem Tenji Sherpa Banker Member, Bufferzone Committee

Mingma Chhiring Sherpa Thadoshir Member, Thadokoshi Micro Hydro Project

Istar Ranamagar Phakdin+

Rakdin

Hotel and lodge and member of women

group

Khagendra Raj Bastola Chhumawa Local teacher

Durga Rai Ghat Hotel and lodge

65

Appendix 4: Maximum flow, travel time, and flood depth at various locations,

Imja

SN Location Distance

from

dam

(km)

Maximum

flow

(Cu.m/s)

Max.

flood

reaching

time

(hrs)

Maximum

stage

elevation

(m MSL)

Normal

flow

water

elevation

(m MSL)

Normal

flow

depth

(m)

Flood

depth* (m)

1 DAM 0 5708 3.124 4994 4983.2 2.17 11.25

2 Dhusum 4.16 3813 2.989 4704 4698.9 1.1 5.3

3 Dinboche 7.97 3409 3.124 4334 4328 1.97 6.47

4 Orse 11.7 3159 3.259 4047 4040.8 1.11 6.26

5 Panboche 15.7 2965 3.394 3792 3786.9 2.18 5.18

6 Litho Goth 20.7 2766 3.529 3267 3264.3 1.08 2.66

7 Confluence 25.3 2604 3.665 2906 2898.4 1.51 7.43

8 Bengkar 29.2 2493 3.8 2726 2720.5 2.46 5.37

9 Thulo Gumela 32.9 2383 3.935 2595 2590.2 2.03 4.84

10 Ghat 37.3 2264 4.205 2419 2413.1 1.62 6

11 Nakchung 41.2 2192 4.34 2100 2096.4 1.15 3.18

12 Chheubas 44.3 2148 4.34 1784 1778.2 3.24 5.78

13 Buspa 48.2 2102 4.34 1605 1598.4 2.43 6.17

14 Hatemu 53.2 2011 4.745 1418 1412.3 2.32 5.74

15 Lap 57.9 1956 4.88 1237 1228.6 4.07 8.16

16 Phapare 62.7 1894 5.016 1104 1098 3.04 6.37

17 Ramnem 67.8 1835 5.151 943.1 938.21 2.21 4.86

18 Kuwapani 72 1785 5.421 839.1 832.44 3.01 6.61

19 Majhigaun 77.7 1707 5.691 741.5 736.17 2.75 5.34

20 Maiku 82.3 1640 5.961 638.3 635.51 0.94 2.78

21 Tallo Salle 88.6 1551 6.367 533.3 529.21 2.21 4.08

22 Dharapani 93.4 1475 6.772 487.3 483.01 1.73 4.29

23 Rabuwa 100 1328 7.447 446.3 442.62 2.62 3.63

*Above the normal flow depth

Source: GISIDC, 2010

Appendix 2: GLOF Model Results at Selected Cross-Sections in the Imja Khola and

Dudhkoshi

66

Station Distance

from

outlet

(km)

Pre-

GLOF

stage

(m)

Arrival

time

(min)*

Peak

stage

(m)

Relative

Peak

stage

(m)

Peak

Time

(min)*

Peak

Flow

(m3/s)

Imja Lake

outlet

0 4,979 0 4,991 11.7 55 10,022

Dingboche

village (8.4

km)

8.4 4,353 70 4,368 15.2 75 8,383

Phakding

village

33.6 2,619 150 2,632 13 165 4,056

* time after start of breach at 10 minutes

Source: Somos-Valenzuela et al 2013.

67

Appendix 5 :Number of tourists visiting Sagarmatha National Park by year and

month

Year/Mont

h

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

1998 553 708 1863 2784 1108 142 94 195 1103 5987 3964 1513 20014

1999 594 781 2255 3440 1408 115 153 315 1521 7263 4533 2183 24561

2000 474 876 2883 4238 1299 61 39 145 1196 7537 4862 1681 25291

2001 579 682 2540 3834 1313 145 114 203 1160 6440 3479 1081 21570

2002 235 496 1995 2313 692 90 78 126 877 3530 2488 866 13786

2003 427 518 1802 2759 1624 221 77 252 1253 5470 3714 1183 19300

2004 592 751 2696 3914 1301 127 160 183 976 6390 3208 1098 21396

2005 426 524 2343 2458 937 201 204 260 1036 6242 3448 984 19063

2006 486 455 1977 3439 886 110 184 352 1190 6595 3323 1039 20036

2007 566 592 3029 4246 1679 284 209 434 1458 7750 4188 1379 25814

2008 643 852 3688 4661 1986 297 294 450 2135 9260 4830 1503 30599

2009 576 658 3041 4513 1629 298 229 509 2135 8831 4769 1596 28784

2010 721 923 3676 5112 2134 431 349 421 2301 9407 5056 1593 32124

2011 619 923 3318 6651 2395 434 241 403 2374 10392 4968 1853 34571

2012 694 1041 3931 6657 2617 466 266 516 2835 9647 5814 1718 36202

2013 827 1024 4602 6160 2551 318 222 407 2598 8883 5883 1727 35202

Source: National Park Office at Jorsale, December 25, 2013

68

Appendix 6: Application for the survey license of different sites

SN Name of the Project

Capacity

(MW) Places Type

Location

(VDC)

1 Dudh Koshi -V 48 Taksindu-Jubing

Survey License

for Generation Jubing

2 Dudh Koshi-I 425

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

3 Dudh Koshi-II 300

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

4 Dudh Koshi-IV 46 Basa-Waku

Application for

Survey License Baku

5 Dudhkoshi - 1 108

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

6 Dudhkoshi - 2 213

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

7 Dudhkoshi - 3 289

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

8 Dudhkoshi - 4 197

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

9 Dudhkoshi Medium 9.6

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

10 Dudhkoshi(Khotang) 300 Diyale-Lamidanda

Application for

Survey License Diyale

11 Dudhkoshi-3 150

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

12 Dudhkoshi-2 102

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

13

Dudhkoshi-

4(Taksindu) 210 Taksindu-Jubing

Application for

Survey License Jubing

14 Dudhkosi-2 250 Basa-Waku

Application for

Survey License Baku

15 Dudhkosi-3 450

Khumjung-

Chaurikharka

Application for

Survey License Chaurikharka

16 Upper Dudhkoshi 10.5

Khumjung-

Chaurikharka

Application for

Survey License Khumjung