RAPID HAZARD AND RISK ASSESSMENT

POST -FLOOD RETURN ANALYSIS

UNESCO on behalf of OCHA and UNCT, NEPAL Funded by UNDP Supported by ICON/ADAPT Nepal TABLE OF CONTENT

TABLE OF CONTENT...... II LIST OF TABLES...... IV LIST OF FIGURES...... V 1 INTRODUCTION ...... 1

1.1 BACKGROUND ...... 1 1.2 OBJECTIVES /SCOPE OF THE STUDY ...... 2 1.3 METHODOLOGY AND ORGANIZATION OF THE REPORT ...... 3 1.4 LIMITATION ...... 6 1.5 ASSESSMENT TEAM ...... 6 2 RIVER KOSHI AND THE BREACH ...... 8

2.1 INTRODUCTION ...... 8 2.2 RIVER SYSTEM ...... 9 2.2.1 Sunkoshi Basin ...... 10 2.2.2 Arun River Basin ...... 11 2.2.3 Tamur River Basin ...... 12 2.3 KOSHI AREA TOPOGRAPHY ...... 12 2.4 THE KOSHI PROJECT ...... 14 2.5 CHARACTERISTICS OF THE RIVER KOSHI CHANNELS WITH RESPECT TO GEOMORPHIC CONTEXT GENERAL ...... 18 2.6 RIVER CHANNEL CHARACTERISTICS ...... 19 2.6.1 River Channel Geometry and Processes ...... 20 2.6.2 Response of Koshi River in Altered Conditions ...... 23 2.6.3 Historical Records ...... 26 2.6.4 Sediment Load ...... 26 2.6.5 Bed and Flood Profile Slopes ...... 27 2.7 SPUR FAILURE ...... 30 2.8 HYDROL OGICAL ASPECTS ...... 36 2.9 ASSESSMENT OF THE EVENT OF THE EMBANKMENT BREACH FLOOD ON 18 TH AUGUST 2008. 40 3 OBSERVATIONS FROM THE FIELD VISIT...... 44

3.1 AREA AND PEOPLE AFFECTED ...... 44 3.2 PROPERTIES LOST ...... 45 3.3 BREACH REPAIR ...... 52 3.4 CONDITIONS OF THE SPURS AND MAINTENANCE ...... 52 3.5 REHABILITATION WORKS IN PROGRESS ...... 54 3.6 ASSESSMENT OF BREACH FLOOD RISK ...... 54 3.7 EXPOSURES T O POTENTIAL RISK ...... 57 3.8 LOCAL CAPACITY TO COPE WITH FLOOD RISK ...... 63 3.9 FLOOD RISK MANAGEMENT ...... 65 3.9.1 The August 2008 breach flood ...... 65 3.10 PREPAREDNESS ...... 74 3.11 FLOOD FIGHTING AND PREPAREDNESS ( FF&P)...... 75 4 CONCLUSIONS AND KEY ISSUES...... 77

4.1 INTRODUCTION ...... 77 4.2 TECHNICAL ISSUES :...... 77

4.3 INSTITUTIONAL ISSUES :...... 79 4.4 SOCIAL ISSUES ...... 79 4.5 PREPAREDNESS ISSUES :...... 80 5 RECOMMENDATION FOR RISK REDUCTION...... 82

5.1 IMPROVING PREPAREDNESS...... 82 5.2 PREPARATION OF FLOOD STANDING ORDER ...... 83 5.2.1 Nepal-India History of Flood Forecasting Cooperation ...... 84 5.2.2 Review of the existing hydrological and meteorological network ...... 88 5.2.3 Strategy to prepare a Flood Standing Order ...... 90 5.3 ASSESSMENT OF EARLY WARNING SYSTEM (EWS) AND STRATEGY FOR CREATING EWS ..... 91 5.4 MAINTENANCE OF SPURS ...... 95 5.5 COMPREHENSIVE STUDY TO REDESIGN THE SPURS ...... 96 5.6 DAM BREAK ANALYSIS ...... 97 5.7 GENERATING ‘WHAT -IF SCENARIOS ’...... 98 5.8 MONITORING MECHANISM ...... 98 5.9 MANPOWER TRAINING :...... 99 5.10 CONSTRUCTION OF RETIRED EMBANKMENT ...... 99 5.11 LONG TERM ISSUES – CLIMATE CHANGE ...... 100 5.12 RECOMMENDED ACTIVITIES AND RESPONSIBILITIES ...... 101 5.13 MEDIUM TERM PLAN ...... 102 6 REFERENCES...... 103

Rapid Hazard and Risk Assessment iii Final Report: 20 March 2009 Koshi River Embankment Breach

LIST OF TABLES

Table 2.1: Aggradation/Degradation of the River Koshi (GFCC & CBIP, 1986)...... 26 Table 2.2: Hydraulic Parameters of the Koshi River (GFCC & CBIP, 1986)...... 29 Table 2.3: Flood frequency analysis at Chatara ...... 38 Table 3.1: Number of households and population figures for the affected VDCs...... 44 Table 3.2: Number of deaths and injuries...... 45 Table 3.3: Loss of /damage to private properties...... 46 Table 3.4: Extent of damage to cultivated land...... 46 Table 3.5: Number of livestock lost...... 47 Table 3.6: Loss of crops in quintal...... 48 Table 3.7: Loss of fruits in quintal...... 48 Table 3.8: Losses of vegetables in quintal...... 49 Table 3.9: Loss of household goods in number...... 50 Table 3.10: Estimated monetary loss...... 50 Table 3.11: Loss/damage of roads and trails...... 51 Table 3.12: Damage toinfrastructure...... 51 Table 3.13: Number of days when the flow of goods and services were closed...... 52 Table 3.14: Elements exposed to the potential risk of breach flood in Koshi...... 59 Table 3.15: Area under different levels of risk and population...... 60 Table 3.16: Area under different levels of risk by land types...... 61 Table 3.17: Number and percentage of houses located with different levels of flood risk...... 61 Table 3.18: No. and percentage of livestock owned by households with different levels of flood risk...... 62 Table 3.19: Major crops with level of risk...... 62 Table 3.20: Number and percentage of public buildings, industries and structures by the level of flood risk ...... 63 Table 3.21: Number and percentage of items of infrastructure by level of flood risk....63 Table 3.22: Number of households by major occupation...... 64 Table 3.23: Number of households by size of landholding...... 64 Table 3.24: Number of households by annual income category...... 65 Table 3.25: Number of households by level of food sufficiency from own production...... 65 Table 3.26: Number of households and population in vacated camps located on the western bank of Koshi River...... 67 Table 3.27: Number of camps by size of population ...... 68 Table 3.28: Number of people by sex and other status...... 68 Table 3.29: Number of families by ownership of land ...... 69 Table 3.30: Number of household and population living in the camps by the place of origin...... 69 Table 3.31: Number of camps with/without service facilities ...... 70 Table 3.32: One month’s expenditure on different items in the camps...... 70 Table 3.33: Number of camps reporting sufficiency in the distribution of goods and services...... 71 Table 3.34: International/National Agencies Involved in Relief by Sector...... 72 Table 3.35: Number of people willing/not willing to return home ...... 73

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LIST OF FIGURES

Figure 1-1: Assessment Framework...... 4 Figure 1-2: Framework for Analysis...... 5 Figure 2-1: Koshi River Basin...... 9 Figure 2-2: Koshi Topography...... 14 Figure 2-3: Major River Control Structure...... 17 Figure 2-4: Historical Shifting of Koshi River...... 21 Figure 2-5: Satellite Picture of the lateral shifting and Alluvial fan of river Koshi .22 Figure 2-6: Channel Characteristics...... 24 Figure 2-7 Relationship between river discharge and sediment load at Koshi Barrage at Hanuman Nagar (Garde et al., 1990)...... 28 Figure 2-8: Schematic representation of the breach location with respect to the spurs at chainage 12.1 kmand 12.9km (Not to scale)...... 33 Figure 2-9: Google Image 2004 showing concentration of flow...... 34 Figure 2-10: Google Image Showing Breach exactly on the concentrated flow...... 35 Figure 2-11: Mean daily gauge height at Chatara from 12, Aug to 25 Aug, 2008...... 37 Figure 2-12: Average monthly discharge at Chatara...... 37 Figure 2-13: Maximum instantaneous flood discharge in Koshi at Chatara...... 39 Figure 2-14: Mean daily discharge at Chatara and mean daily rainfall for 12 Aug to 18 Aug, 2008...... 39 Figure 3-1: Potential Breach Points and Flow Paths...... 55 Figure 3-2: Google Earth Image showing concentration of flow upstream of the breach (1=Current Breach, 2= Prakashpur, 3= Rajabas and 4=Pulthegaunda)...... 56 Figure 3-3: Area under risk and major ethnic groups...... 58 Figure 3-4: Risk classification of the Koshi Basin below Chatra until the Barrage...60 Figure 3-5: Shelter Camps in the Area...... 67 Figure 3-6: Area Covered by Sand and Water...... 73 Figure 5-1: Conceptual Approach to Koshi Flood Preparedness...... 83 Figure 5-2: Line Diagram of Hydrometric Station on Koshi and its Tributeries in India...... 86 Figure 5-3: Hydrometric and Precipitation Station in Koshi Basin...... 87

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1 INTRODUCTION

1.1 Background

1. Flooding is a common phenomenon in the Himalayan Rivers. Every year floods affect thousands of people in the Himalayan region. Every year the monsoon floods of immense magnitude from the Himalayan Rivers cause huge loss in terms of damage and disruption to economic livelihoods, businesses, infrastructure, services and public health. Long term data on natural disasters suggests that floods are by far the most common cause of natural disasters in this region. This has both an immediate effect such as loss of life by drowning as well as a long term effect such as the spread of disease. Fifty five percent of all people whose lives have been affected by natural disasters are the victims of flooding. Between 1980 and 2008, every year an average of 10 million people suffered flood damage, a statistic which makes floods the most devastating of all natural disasters.

2. Flooding is already one of the most widespread of hydrometeorological hazards, and international panels such as IPCC and ISDR have predicted that it is very likely that flood hazard will continue to increase in many areas of the world, including the Himalayan region, (McCarthy et al ., 2001). Both the number and magnitude of flood risks are increasing. This increase is partly due to an uncertainty in the way that natural phenomena are understood and interpreted, and partly due to the increasing vulnerability of people living in the flood plain or in an area with high exposure to a flood event.

3. The Koshi flood that occurred on the 18 th of August had a devastating impact. The disaster occurred due to the breach of eastern embankment of the Koshi barrage at Kushaha of Sunsari district. The flood entered into the settlements damaging national highways, power transmission lines, communication cables, schools, health posts, village roads and private and public buildings. After the initial rescue and relocation works carried out by the administration, security forces and NGOs, the

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immediate remedial measures for flood control are being carried out to restore the pre-flood situation in the affected district. The objective of ongoing repair and construction works is not only to repair and retrofit the damage caused, but also to create a situation such that it is safe for the internally displaced people (IDP) to return to their homes and farms.

1.2 Objectives/scope of the study

4. Although the Koshi River is now flowing back within the guided embankment, there are several activities that need to be undertaken to ensure that such disasters do not happen again. There was an immediate need to undertake a risk and vulnerability assessment to ascertain :

a. Risk for and vulnerability of the IDPs in returning back to their place of origin vis-à-vis the quality and pace of repair and construction work along the embankment, especially the breach area;

b. Adequacy of flood preparedness and early warning;

c. Likelihood of return of the flood in the area.

5. The broader objective of this assignment was to carry out a rapid assessment of the ongoing remedial measures undertaken for the Koshi Floods in terms of hydraulic and structural effectiveness. More specifically, the objectives of the assignment were::

a. To make a qualitative and quantitative assessment of the immediate vulnerability of the flood affected people of Koshi, especially a risk and vulnerability analysis of the quality and pace of ongoing repair works vis-à-vis the flood displaced community in a participatory manner;

b. To assess the adequacy of flood preparation and the early warning mechanism in the flood prone region;

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c. To assess the likelihood of the scenario of the return of floods of similar magnitude and the potential for disaster.

d. To develop a risk management plan to deal with possible flooding that will facilitate coordination between agencies, including the UN system agencies

e. To prepare a medium term action plan and an implementation plan.

1.3 Methodology and Organization of the report

6. This report was prepared on the basis of a rapid assessment of the disaster stricken area. The team, comprised of senior government officials from Nepal, consultants from both India and Nepal and led by a UN official, visited the breach site and undertook a detailed investigation on the cause of the breach and analyzed the existence of pre-breach hazard and vulnerability in the area. The work was undertaken at the request of UNCT, Nepal.

7. This report is an outcome of 8 days (4 -11 Feb 2009) of extensive fieldwork by experts, 30 days of hydrological data collection and assessment both in Kathmandu and in the field (21 January – 18 February, 2009) and 30 days ( 30 January – 1 March, 2009) of socioeconomic data collection. While the fieldwork of the experts mainly involved high-level interactions and measurements, the latter two involved all three methods of data collection – review of literature, survey at Village Development Committee (VDC) level and observation. Published and unpublished documents, information sheets and maps from relevant institutions were collected and reviewed. All the affected VDCs and those located along the Koshi river bank and its adjoining areas and all the shelter camps and institutions located in local areas were surveyed with the help of structured check lists. The current situation of the river channel morphology, spurs and embankment were observed.

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8. For vulnerability assessment, a total of 17 VDCs were surveyed. Among them 12 VDCs 1 were affected by the flood and the remaining 5 VDCs are adjoining VDCs. Information at VDC level was generated through group discussion. Social mapping was another important aspect in the collection of field information. The group was requested to identify different levels of flood hazard-prone areas within their VDCs, based on their experience/perception and to delineate such areas in the toposheet on the scale of 1:25000. The participants in the group discussion included VDC secretary, ex-chairman, ex-ward chairman, leaders of different political parties, social workers, businessmen etc. The size of the group in most cases ranged from 10-12.

9. Similarly a total of 26 shelter camps were surveyed. Group discussion was organized in each camp. The participants in the group discussion included members of the shelter camp management main and sub- committees, the camp supervisor, the health worker and internally displaced people living in the respective camps.

10. Both the relevant spatial and attribute data so far collected from the field has been integrated with the help of GIS tool (Arcview) for the assessment of damages and potential risk in the future.

Technical Causes

Social Breach Institutional Causes Causes

Figure 1-1: Assessment Framework

1 Only 4 VDCs have been frequently reported as breach flood affected area. Many VDCs in the south east of Sunsari district were also affected by the flood water. However, the loss in those VDCs was negligible.

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11. The report has analyzed the probability of hazards and the existing vulnerabilities along three critical areas which, based on the initial deliberation, the team has identified as the key reason for the breach. The primary causes for breach, broadly grouped as technical, social and institutional complexities, or interplay there of, have been highlighted in the succeeding chapters.

12. The report is written by taking into consideration the Hyugo framework for action.

Figure 1-2: Framework for Analysis

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1.4 Limitation

13. This is a preliminary assessment at the pre-feasibility level. This is limited only to Nepal and only for the eastern bank of the Koshi River, although a cursory visit and observation was also made of the Western Embankment. The level of field information generated for this study is at VDC level, through group discussion. Likewise, the identification of the potential breaching site was done based on the discussion with the key informants and visual observation without making detailed investigation of the properties of the materials used and the sheer strength of the construction.

14. It must be noted that this report has been prepared to facilitate humanitarian assistance and is not an attempt to question any bilateral understanding which exists between India and Nepal . The content of this report is not the view of UN agencies, but solely that of those who were involved in the rapid assessment and how have they interpreted the situation on the ground. Therefore the content of this report should in no way be used as a bilateral negotiation tool.

1.5 Assessment Team

15. The Assessment Team involved senior government officials from Nepal, Experts from Both India and Nepal.

a. Dr. L.P. Devkota, Hon. Member NPC

b. Mr. M. Dangol, Joint Secretary, MOWR

c. Mr. M. Gurung, DG, DWIDP

d. Mr. Adarsha Pokhrel, Former DG, DHM

e. Mr. R. Khadka, Regional Director, DWIDP

f. Prof. Prakash Adhikari, Department of Geology, TU

g. Prof. P.P. Mujumdar, Indian Institute of Science, Bangalore, India

h. Prof. U.C. Kothyari, IIT, Roorkee, India

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i. Mr. D.B.Yadav, Officer In-charge Regional office of DHM, Dharan

j. Prof. Narendra Khanal, Department of Geography, TU.

k. Dr. Sanjeev Shah, Structural Engineer, ICON

l. Mr. Srijan Aryal, Hydrologist, ICON

m. Dr. K.N.Dulal, Hydrologist, Nepal

n. Dr. B.R. Neupane, UNESCO

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2 RIVER KOSHI AND THE BREACH

2.1 Introduction

16. The event proved beyond the reasonable doubt that the burden of loss, of course, is greatest in poor communities, where previous studies have shown that thirteen times more people die from flood events compared to their rich counterparts. Economic losses also tend to be larger as a proportion of the total economy of poorer communities tends to be uninsured. The current flood has also proved that a natural disaster knows no boundaries, economic background or ethnicity and is unbiased in its assault. Koshi disaster impacted on two countries, affected millions and perhaps pushed back the pace of development in the impacted area by several decades, by hitting hard on local economies, health, quality of life, education, politics and perhaps stability of the area.

17. This corroborates the common wisdom on flood management that there is a dire need to share information on existing flood preparedness and adopt practices that are best for the area. Enhanced preparedness is obviously better than cure after the flood has impacted on the area. Understanding the fact that floods can still return, there is a need to undertake unilaterally, bilaterally or multilaterally the design and establishment of an integrated system of flood management and forecasting.

18. Complacency on the part of the authorities regarding existing strategies and actions on monitoring, opted modalities for repair and maintenance, confidence over the existing system of mutual cooperation, reliance on available facilities for flood fighting and lack of emergency preparedness all have played a distinct role in the breach that caused massive damage and destruction and led to about 55 deaths thus far. Having said this, one of the biggest contributors to the disaster is the very limited knowledge of the Koshi River itself, which remains one of the least understood and least studied rivers in Nepal. The information available about this river is

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insufficient in terms of what is normally required to better understand a river.

2.2 River System

Figure 2-1: Koshi River Basin

19. The Koshi River basin is the largest river basin in Nepal (Fig 2.1). It comprises of about 61, 000 sq.km. Out of a total catchment area of 27, 816 sq. km. (45.6%) lies in Nepal and the remaining 33,1845 sq.km. lies in

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Tibet. In addition to the Koshi River basin, the other two major basins are in Nepal namely; the Karnali and Gandaki River basins.

20. The River Koshi also commonly known as Sapta Koshi comprises of seven rivers namely (From west to east); Indrawati, Sunkoshi, Tama Koshi, Likhu, Dudh Koshi, Arun and Tamor. Out of these three major rivers or tributaries originate in Tibet; namely; the Sun Koshi, Tama Koshi and Arun. Broadly, the basin of Koshi can be divided into three major river sub-basins; the Sunkoshi, Arun and Tamor. The Sunkoshi River comprises of the Indarwati, Sunkhoshi, Tama Koshi, Likhu and Dudh Koshi rivers.

2.2.1 Sunkoshi Basin

21. The catchment area of the Sunkoshi basin is about 19,000 Km2. The Sunkoshi River originates in the mountain range east of Barhabise called Kalinchowk, and flows in a westerly direction with steep river gradients of 1:10 to meet the Bhotekoshi at Barhabise. The Bhotekoshi, originates from a glacier on the south slope of Mt. Xixabangma Feng, in the southern part of the Himalayan range in the Tibetan plateau. The catchment area at the confluence point is about 2,375 km2 of which about 2000 km2 lies in Tibet. The average gradient in the upper reach is 1:8, while in the lower reach it is about 1:31.

22. The Sunkoshi flows in a south-east direction up to Dolalghat, the confluence point of the Sunkoshi with the Indrawati River, with an average gradient of 1:130. The Indrawati River, one of the main tributaries of the Sunkoshi River, originates in the Himalayan range and flows in a south, south-east direction to meet with the River Sunkoshi at Dolalghat. The average gradient of this river is about 1:34 in the upper reach and 1:194 in the lower reach. The total catchment area of the Indrawati at the confluence with the Sunkoshi River is about 1,175 km2. The Sunkoshi River, after the confluence with Indrawati River, flows in a south-east direction up to Tribeni with an average gradient of 1:450.

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23. The Tamakoshi River, which originates in the southern part of the Tibetan Plateau of China, flows in a southerly direction through the Rolwalin Himalayan range and enters Nepal. Within Nepal, the river flows in a southern direction through the mountainous and hilly areas with an average gradient of 1:20 in the upper reach and 1:110 in the lower reach to meet with Sunkoshi River at Khurkot. The Tamakoshi River has total drainage area of 4,190 km2 at Khurkot. About 40 km downstream of Khurkot, the Sunkoshi River joins with the Likhu Khola.

24. The Likhu Khola originates in the mountain areas and flows towards the south to meet the Sunkoshi River. The average gradient of Likhu Khola is about 1:54. Its drainage area at the confluence point with the Sunkoshi is 1,070 Km2. The Sunkoshi River after the confluence with Likhu Khola, meets with the Dudhkoshi about 25 km downstream.

25. The Dudhkoshi originates in the Khumbu and Nojumpa Glaciers located on the southern slopes of the Mahalangur Himalaya range and flows directly from north to south resulting in a rapid river gradient. The average gradient is about 1:30 in the upper reach and 1:250 in the lower reach. The total drainage area of the river (at the confluence with the Sunkoshi River) is about 4,140 km2.

26. The Sunkoshi River flows in a south-eastern direction to meet the Arun and Tamur Rivers to form the Saptakoshi at Tribeni. The total length of the river is 330 km. The gradient of the Sunkoshi River is approximately 1:210 through out the entire length of its course in Nepal.

2.2.2 Arun River Basin

27. The Arun River originates from a glacier on the northern slope of Mt. Xixabangma Feng (El.8012m), part of the Himalyan range in the southern part of the Tibetan highland. The river is called Pengqu within Tibet. It flows eastward almost parallel to the Himalyan range in upper reaches for a distance of about 280 km and then makes a sharp turn to the southwest at the junction with its tributary, the Yenuzangbu River (in

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Tibet), forming a big bend. The Arun then flows southward crossing the Himalyan range into Nepal. It continues to flow south and joins the Saptakoshi (Koshi) River at Tribeni. The total length of the river is about 510 km and the total drainage area is about 36,000 km2, out of which 25,310 km2 lies in Tibet. In Tibet it has a gradient of 1:130 and 1:630 in upper and lower reach, respectively. When it enters in Nepal it has a steep slope in the range of 1:30 to 1:50 in upper reach. In the middle reach of Nepal it has a slope of 1: 96 and in lower reaches it has a slope of 1:300 to 1: 400.

2.2.3 Tamur River Basin

28. The river has its source in the High Himalayas. Near its source the Tamur is called Medalung Khola. Before becoming the Tamur River it is joined by a large khola called Yangma Khola. The north boundary of the Tamur catchment lies in high Himalayas and delineates the border between Nepal and Tibet. Similarly the eastern boundary lies in the High Himalayas and delineates the border between Nepal and India. Kanchanjanga (at an elevation of 8586m) the world’s third highest peak lies in this basin. In addition, there are 13 other major peaks in the basin, ranging from 5938 m (Ganbul on northern border of Nepal with Tibet) to 7902 m (Kambachen inside Nepal).

2.3 Koshi Area Topography

29. The altitude of the basin ranges from only 65 m near the Nepal-India border in the south to 8848 m in the north within a short distance of about 150 km. The channel gradient in the north is high, as a result the tributaries are powerful in terms of erosion and transportation. When the river debouches from the mountain areas near Chatra its gradient is decreased and the channel pattern becomes braided. In the south near the border and the barrage area, the relief of the channel bed is only 0.5 - 0.6

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m/km. There are marked differences in the discharge between winter and summer. The minimum recorded discharge is 280m3/s whereas the average flood discharge during the monsoon period is about 11400 m3/s. The long term average discharge in August is 4729 m3/s. The recorded peak discharge was 25878 m3/s in 1968 (Dixit, 2009). Six events of extraordinary flood in the Koshi River have been reported by local people. These were in 1954, 1962, 1969, 1979, 1988 and 1996. One extraordinary flood event usually occurs every 7-10 years. The river is heavily loaded with sediments. It brings about 120 million cubic meters of sediment every year of which about 90% is transported during monsoon period. The major sources of sediment in the mountain areas are landslide, debris flow, rockfall, avalanche, glacial lake outburst, active down cutting of the river bed and bank erosion etc.. Due to such a high sediment load, the river channel in the Terai, south from Chatra, is very dynamic. This river has shifted about 115 km from the east to the west in the last 220 years (Gole and Chitale, 1996 cited in Dixit, 2009). This shifting of the Koshi River in the west is in the reverse topographic gradient associated with the shifting of channel bars, due to excessive sediment concentration in the river. The topography of the Piedmont area has been tilted from north-west to south-east as shown by the contours (Figure 2). There is therefore the possibility of the river shifting eastwards by avulsion, a fact which was realized long ago (Chorely, 1984).

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Figure 2-2: Koshi Topography

2.4 The Koshi Project

30. The Koshi Project was framed with the purpose of flood control, irrigation, generation of hydropower and prevention of erosion. An agreement incorporating all the terms and conditions was signed on the 25 th April, 1954 by the government of Nepal and India. The project components consisted of the construction of a barrage, afflux and flood banks, canals and protective works (Figure 3). A barrage was constructed in Nepal about 15 km upstream from the international boundary between Nepal and India. The construction of the Barrage was completed in 1964. Similarly, embankments and spurs were constructed on both the banks in order to control the flow and floods. A 32 km long embankment and

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spurs on the west bank and a 29 km long embankment with 46 spurs were constructed by the project. The major work for the construction of embankment and spurs was completed in 1959 some years ago when the construction of the barrage was completed. A railway line was constructed along the embankment between the barrage and Chatra/Ghopa for the purpose of transporting construction materials such as stone. After the completion of the construction work of the major structures its operation was stopped and almost all the materials used in the construction of railway line have been stolen.

31. The original agreement of 1954 between Nepal and India was amended in 1966 (GoN, 1975). Some of the provisions of the amended agreement of 1966 are as follows.

a. Any construction work for the project within Nepal is carried out in consultation with the Government of Nepal.

b. Investigations and surveys for the general maintenance and operation of the project are carried out by the Union (Government of India) after due intimation to the Government of Nepal.

c. All the data, specimens, reports and other results of surveys and investigations carried out by the Union are made available to the Government of Nepal freely and without delay. Similarly, relevant data, maps, specimens, reports and other results and surveys and investigations carried out by the Government of Nepal are made available to the Union.

d. The Government of Nepal permits necessary access for the execution of construction works including occupation of necessary land.

e. No customs duty or duty of any kind, during construction and subsequent maintenance, on any article and materials required

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for the purpose and project and work connected therewith, are not to be charged for by the government of Nepal.

f. Compensation for lands required for the execution of various works, submerged lands, houses and other immovable property and loss of land revenue is paid by the Union. Compensation, in every case is tendered by the Union through the Government of Nepal to the owners of the land for all accidents that may have occurred .

g. Assessment of the compensation and the manner of payment is determined jointly by mutual agreement.

h. Preference is given to Nepali labor, personnel and contractors for the construction work where available. .

i. The establishment of a joint Indo-Nepal Koshi Project Commission for the discussion of problems of common interest in connection with the project and for purposes of co-ordination and co-operation between the two governments. Until the joint commission is formed, provision is also made for a temporary coordination committee for the Koshi Project, in order to solve the problems associated with land acquisition, the rehabilitation of displaced people and maintenance of law and order.

j. As per the agreement, the Government of Nepal has established Liaison and Land Acquisition Offices in Biratnagar with 25 staff. These salaries of these staff are paid by the Koshi project. The Liaison Office facilitates the import of construction materials whereas the Land Acquisition Office keeps land records for compensation.

32. The Koshi Project agreement between Nepal and India indicates that the role of the Government of Nepal is limited to facilitation of the project with very limited role in major decision making processes for investigation of the embankment and river control structures and their

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proper maintenance work. Similarly, the involvement of local people and institutions that are likely to be affected by the failure of the flood control structure in carrying out monitoring, maintenance and repair, is rather poor. The perceived ownership by the local people of the protection of the river control structure is very critical. . During the field work it was observed that there was no gabion wire at the surface of almost all the spurs constructed by the project, between 13-29 km lengths of the embankment. However, the spurs constructed by the Sunsari-Morang Irrigation Project during 1978-79 a few kilometers upstream were found with the gabion wire intact.

Figure 2-3: Major River Control Structure

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33. Another major project in the Piedmont area is the Sunsari-Morang Irrigation Project. It was originally implemented as a Chatra Canal Project under grant aid from the Government of India in 1964. The main canal has a length of 53 km with a net total command area of 73,000 hectares (Figure 2.3). The intake site is located near Chatra. During 1978-86, the Koshi river control works were carried out and the embankment and spurs were constructed.

34. The Koshi Tappu Wildlife Reserve between 6-25 km upstream from the Barrage with an area of 175 sq. km, was established in 1976. It was also recognized as Ramsar site in 1987.

2.5 Characteristics of the River Koshi Channels with respect to Geomorphic Context General

35. In general terms, the drainage basin of the Koshi River can be divided into three main zones: an upper erosional zone of sediment production, a middle zone of sediment transport with simultaneous erosion and deposition, and a lower zone of sediment deposition. Flooding is more common in the lower zones where the river overflows frequently onto adjacent agricultural and other areas on both banks.

36. In the case of the Koshi River, the longitudinal profile of the stream system tends to flatten through time by degradation in the upper reaches and aggradation in the lower reaches. As in most of the natural river systems this process is also slow enough to be of little engineering concern; but in the case of the Koshi River the process is remarkable. It has been observed that after the intervention on the Koshi River during 1950, profile flattening has been proceeding at very noticeable rates. The flattening of the longitudinal profile was found to proceed rather dramatically, especially in the lower zones after the construction of an afflux bund for the Koshi Barrage and an embankment for flood protection.

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37. After assessments of the basin and channel system geomorphology including historical maps, aerial photographs, satellite images, hydrological records, geological and soils reports, ground reconnaissance, and consultation with local residents and specialists, it was observed that during the design and implementation of the Koshi Project during the 1950’s, more attention had been given to hydraulic design studies whereas insufficient attention had been given to stability and sedimentation aspects. In other words, stability was addressed to a great extent but insufficient attention was given to long-term effects and responses within and beyond the project area.

2.6 River Channel Characteristics

38. The lower zone of the Koshi River (from the foot hills of Nepal to the downstream section ) comprises of an alluvial fans channel where the river emerges from a mountain valley onto relatively flat land. In this zone, the depositional tendency of the river channel is found to be prominent. Depositional features are usually characterized by quantities of coarse to fine alluvial materials. Similarly, unstable multiple channels subject to frequent shifts or “avulsions” is a common phenomenon in the lower zone of the river. It was also observed that the main channel is often “perched” on the highest ground a number of times. It was observed with the help of historical aerial photographs and through interaction with senior local people, that deposition of sediment is highly noticeable during the historical flood events in the alluvial fan and the stream is eroding into earlier deposits dramatically. In general, the main features of the river in the area of concern are (i.e. lower zone) the formation of multiple channels and coarse deposits which are dynamic in nature. The results of this phenomenon further deteriorate the stability problems of the channel by sudden shifts in channel direction, erratic deposition and degradation in the channel.

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39. Embankments and other structure stability problems on this type of alluvial fan include avulsion of the river at a point upstream of the barrage structure or along river training works, thereby bypassing the structures and infilling of the designed conveyance channel with coarse to fine sediment deposits. Although, it was observed that flood control works have been provided sufficiently far upstream of the barrage and afflux bond stretches, however consideration for trapping or removal of the sediment upstream of the flood control zone has been found lacking.

2.6.1 River Channel Geometry and Processes

40. In general, channel geometry has four main components: planform, cross section, slope (gradient), and bed topography. The term “channel processes” generally refers to natural changes in planform, cross-sectional boundaries, longitudinal profiles, and bed topography.

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Figure 2-4: Historical Shifting of Koshi River

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Figure 2-5: Satellite Picture of the lateral shifting and Alluvial fan of river Koshi

41. The planform has been discussed in river channel characteristics. It was also mentioned in several references to the shifting nature of the Koshi River before construction of the guide bunds during the 1950’s. Therefore, before the implementation of a guide bund on both sides of the river planform of the Koshi River changed frequently due to its shifting nature (Fig 2.4). A satellite picture of the lateral shifting of the river Koshi and its alluvial fan is presented in Fig 2.5. However, now the shifting of the river

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has been restricted within the bund. Relationships between planform and other aspects of geometry and processes of Koshi River are difficult to systematize. In order to establish some relationship of planform and other aspects of geometry and processes, the river has to be vigorously monitored and assessed on a regular basis for the long term.

42. In general the cross section of a natural channel depends on basin runoff, sediment input, and boundary soils and vegetation. Although under natural conditions the average cross section usually does not change much over a period of years, in the case of the Koshi River it was observed that cross sections on the lower zone have been altering frequently and temporarily during medium to severe floods.

43. Further, in the Koshi River channel the process of cross-section enlargement by erosion is prominent on one bank and has been observed by most people. This is mainly because the loss of banks and adjacent properties are much more of a social issue than the shrinkage on the opposite bank. Shrinkage of the cross section varies considerably. The phenomenon of shrinkage of the cross section in the Koshi River is mainly due to significant differences in the rate of deposition and the rate of sedimentation during medium to severe floods.

2.6.2 Response of Koshi River in Altered Conditions

44. Instability and sedimentation have two aspects with respect to construction of the barrage and afflux bund in the Koshi River: the impact of existing processes on the project, and the impact of project changes on the stream system both within and beyond the project length. In the case of the Koshi River, it has been observed that the first aspect has been taken greater care of than the second aspect. It should be noted that, the flooding of adjacent banks and the breaching of the embankment of the Koshi River were due to non-consideration of second aspect. The figure below illustrates concepts for long term formation and the response of the Koshi River. It is clearly illustrated that with the alterations in the

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controlling variables (boundary conditions) of the river, the river will respond by altering the cross section, slope and planform.

Figure 2-6: Channel Characteristics

45. Following are some expected changes in channel characteristics with changes in driving variables or boundary conditions.

a. With an increase in river discharges, the channel width and depth increases, resulting in slope reduction and increased bank erosion. Generally widths vary more or less as the square root of discharge, other things being constant. Widening in response to increased flood discharges can generally be expected. In the case of reduced discharges, ultimate narrowing can be expected if the channel carries enough sediment to deposit on the banks or on side bars.

b. Depths increase with the increase of discharges, but not as much as compared to width. Depths will generally decrease with an increase in bed material inflow, as slopes increase.

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c. Similarly if bed-sediment load increases, the depth is reduced with a remarkable increase in the bed slope, resulting changes in planform, especially by increasing bars and channel splitting. This may increase channel erosion.

46. The most widely known geomorphic relationship embodying slope and the equilibrium concept is known as Lane’s (1955) Principle and can be expressed in the form:

QS ~ Q S D 50 where Q = discharge, ft3/sec S = slope, ft/ft Qs = bed material discharge, tons/day

D50 = median sediment size, ft

47. The periodic devastating floods on the Koshi River can be attributed to the raising of the bed of its embanked channel by sediment brought down from upper catchment, followed by the raising of the banks, whereby the river is forced to flow above the level of the plains. When the river was first embanked during the 1950’s, a considerable space was left between the embankments and its banks on each side, so that sufficient space has been provided to allow deviations in the channel and in consideration of two main aspects; that a large area would be available for the depositing of sediment and that a good width of channel would be available for flood discharge. However it has been observed that the channel keeps on shifting to the either side of the riparian land left within the embankments and exposed to every flood. The boundary of the inner embankments were formed close to the river, thereby greatly confining the flood-waters, and consequently raising the flood-level and the river- bed and therefore exposing these embankments to undermining by merely a moderate change in position of the river channel.

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2.6.3 Historical Records

48. Most of the left bank tributaries of the River Ganga originate in the Himalayas and carry an enormous amount of silt. The problem of bank erosion in these rivers is very common. The Koshi Rver shifted east- wards over a distance of 112 kms in a period of about 225 years. In 1963, the Koshi Project was constructed with a barrage at Hanuman Nagar and with embankments along both the river banks. Earlier a disastrous breach of the eastern embankment had occurred in 1984. An excessive silt load and the consequent aggradation of the river bed are believed to be the main cause of the braiding plan form of river and also that of the shifting tendency of its numerous channels.

49. Detailed studies on the aggradation problem of the Koshi River were carried out earlier (Garde et al., 1990) at IIT Roorkee (formerly the University of Roorkee). The river bed levels were observed to mostly aggrade in different reaches post the construction period of Koshi Project in 1963 as per the table below.

Table 2.1: Aggradation/Degradation of the River Koshi (GFCC & CBIP, 1986)

River reach Bed level variations Bed variation during 1963- Length of during 1955-62 (pre- 74 (Post-barrage) in the reach (in barrage) in mm/yr mm/yr From To km) (-)Scouring; (+) Silting 1 2 3 4 5 Chatra Jalpapur 27 (-) 17.6 (+) 123.4 Jalpapur Bhimnagar 15 (-) 165.6 (+) 107.0 Bhimnagar Dagmara 26 (-) 35.6 (-) 08.3 Dagmara Supaul 34 (-) 03.8 (+) 18.6 Supaul Mahesi 40 (+) 95.6 (+) 63.5 Mahesi Koparia 25 - (+) 120.3

2.6.4 Sediment Load

50. The recorded peak flood discharge of the River Koshi is 25,800 m 3/s. The minimum discharge of the river is about 280 m 3/s and its annual average run off is 5.8 m ha.m. The sediment concentration at the point of debouch

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from the gorge is about 0.2 percent by volume. The river carries little coarse sediment; about 0.02 percent of the total load. The percentage of fine silt in sediment concentration is more than 50%. The average sediment load per 100 km 2 is estimated as about 19 Ha.m. The variation of suspended sediment with river discharge is depicted in the Fig. 3 where d represents the average size of the bed sediment.

2.6.5 Bed and Flood Profile Slopes

51. The recorded (past) values of highest flood levels (HFL), the slope of the HFL and the bed slope of the River Koshi in the different reaches are given in the table below. The distance between the Chatra Gorge to the outfall of the Koshi on the Ganga near Kurushela is about 161 m and the total fall in bed level is about 79.25 m. The slope of the head reach is about 0.95 m per km but it flattens to 0.03 per km in the tail reach.

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CUSECS

Figure 2-7 Relationship between river discharge and sediment load at Koshi Barrage at Hanuman Nagar (Garde et al., 1990)

52. The drastic reduction in bed slope results in the marked reduction of sediment transporting capacity and hence causes significant aggradation. However the observed sediment concentration of the Koshi increases in the head reach up to Hanuman Nagar (Table-2.2). This increase is primarily due to an increase in fine fraction which finds its way into the river due to erosion of the Belka hill face on the head reaches. Beyond Hanuman Nagar, the sediment concentration however progressively reduces and in the final reach of the river, coarse and medium fractions are very small compared to the fine fraction.

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Table 2.2: Hydraulic Parameters of the Koshi River (GFCC & CBIP, 1986)

Suspended HFL sediment load slope (in Bed Sr. Station Distance in terms and HFL (in m per Bed slopes No. (starting (in km) percent of m) km) level (in m per upstream) corresponding (in m) km) values at Barakshetra 1. Chatra 0 109 110.18 - 102.16 - 2. Galpharia 17.71 111 - 0.95 - 0.89 3. Raniganj 41.86 - 70.74 - 65.08 - 4. Hanuman 51.52 141.5 - 0.50 - 0.42 Nagar 5. Bhaptiahi 74.06 - 56.98 0.21 51.79 0.19 6. Saupaul 114.31 - 48.38 - 44.27 - 7. Karahara 123.97 96.5 - 0.12 - 0.23 8. Dhamra 210.91 - 36.25 - 19.58 - Ghat 9. Basua 238.28 27.5 - 0.32 - 0.023 10. Nagchia 296.24 - 33.35 0.074 17.19 0.057 11. Kursela 318.78 24 31.70 - 11.12 -

53. Because of a typical river morphology and huge sediment deposition, the Koshi is characterized by a large number of small, local islands due to braiding. This causes the flow to be constricted in narrow channels with increased velocities. Further, the braids themselves change in shape, size and location depending on the flow and sediment characteristics which therefore adds complexity to flood protection measures for the river system.

54. With these complexities there has to be a paradigm shift in management of the Koshi River floods from ‘river control’ to ‘river management’ which emphasizes an integrated approach and addresses the cause rather than the effect (Brierley and Fryirs, 2005). The river management strategy must include modern approaches such as satellite-based monitoring and system dynamic approaches integrated into user-friendly decision support systems.

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2.7 Spur Failure

55. The Koshi River is one of the typical Himalayan rivers possessing some of its own specific evolutionary history besides the common characteristics that it shares with the others. Generally, a combination of embankments with spurs is provided in flood protection measures. Spurs at regular intervals are provided to protect flood embankments. Spurs generally minimize scouring on the embankment by moving the scour-causing turbulence away from the embankment. Therefore, spurs are necessary to protect the bank and the embankment from which they are projected and deflect the current away from the bank. 56. In general, there are three reasons for embankment breach:

a. Overtopping-high flood, silt deposition

b. Piping- seepage and leakage due to rat holes, inappropriate material and insufficient compaction

c. Scouring-flow concentration, high flood

57. To tame the Koshi River, different river training works have been followed. The most commonly used structures to protect the bank erosion and flood controls in the Koshi River are the construction of marginal embankments and spurs. There are numerous spurs regularly arranged from Chatra to the Koshi Barrage on the eastern (and western) side of the Koshi River. Marginal embankments are constructed parallel to the bank line, which shed regular spurs transversely into the river. The marginal embankments near the Koshi Barrage acts as guided banks as well. The spurs constructed more than 40 years ago are still functioning. The older spurs are constructed ofearthen material; while the recently built spurs in the upper reaches of the fan are of masonry bounded by woven wire nets. Most of the spurs are at right angles to the riverbanks, but a few become oblique due to the later action of river.

58. The marginal embankment along the eastern side of the Koshi River from the Koshi Barrage to Chatra was focused on for the present study. The

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embankment has a dual purpose , one for protecting the eastern area from flooding and the other is serving as an embankment service/village road. The embankment was constructed about 50 years ago, while the embankment around west of Prakashpur and the Chakraghatti area are newer. The older one was constructed using earthen material and the latter was constructed using stone masonry with soil covering. The embankment is about 2 to 3 m in height from the general surface i.e. the bottom of the embankment, (which was more than 5 m above the water surface of the river during the field inspection), and 5 m in width at the top and 7 to 8 m at the bottom. The action of the embankment upstream of the Koshi Barrage becomes evident by noting the elevation difference of the ground on the riverside and the outer side of the embankments. The elevation in some areas reaches up to 2 m or more. The elevation differences become more just downstream of the spurs radiating into the riverward side from embankment.

59. The spurs along the banks of the Koshi River are built to obtain certain objectives, such as:

a. To train the river along the desired courses by attracting, or deflecting the flow in the desired direction. b. To reduce the concentration of flow at a particular point of attack. c. To create the slack zone for silting up the area. d. To protect the bank by keeping the flow away from it. 60. In general, the spurs on the eastern bank of the Koshi River worked satisfactorily to protect the area until the event of 18 th August 2008.

61. The spur has two types of sedimentary processes, erosional and depositional processes on either side, i.e., upstream and downstream sides. The upstream side of the spur represents the site of erosion, and the downstream side is the site of siltation, i.e., site of deposition. By maintaining the good spacing between spurs, the worst effects of erosion on the upstream side can be mitigated. The consequence of improper spacing of the spurs has occurred at some locations. An example of one of

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the worst cases of this occurred near the Salbandi village, Sunsari district..

62. The breaching of the embankment on August 18 2008 took place due to the failure of the upstream and the down stream spurs at the breach point. The successive failure of a downstream spur (12.1 km from the Barrage) and then an upstream spur (12.9 Km) allowed the stream channel to shift from its previous location to the adjacent embankment. The failure was due to the effect of scouring rather than to the magnitude of the flood. The magnitude of the flood on that particular day had been assessed with the help of gauging data at Chatra, which concluded that the flood level was even less than 5 year return period flood in Koshi River.

63. Figure 2.8 below shows a schematic of the breach portion with respect to the spurs at chainage 12.1 km and 12.9 km. The spur at chainage 12.1 km, which had eroded considerably over the last few years and was not restored to its original length, was hit first. The nose portion of the spur – which is the most critical structural part of a spur – failed because of the high velocity of flow. Once the nose portion was eroded, the spur did not have the structural strength and protection to resist further damage and a rapid failure of the spur ensued.

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Embankment Flow direction

Spur at 12.9 KM Local island created by Breach location silt deposition Spur at 12.1 KM

Figure 2-8: Schematic representation of the breach location with respect to the spurs at chainage 12.1 km and 12.9km (Not to scale)

64. After a significant length (about 60%) of the spur at 12.1 km was eroded, the impact was transferred to the spur at 12.9 km and, also being in structurally bad shape already, the spur started giving way. As the two protections gave way, the brunt was borne by the embankment and the breach occurred, as the embankment was structurally not capable of taking the entire impact.

65. The hydraulic/technical reasons for the breach are twofold : (a) The flow has been concentrated near the east bank for several years now, and the formation of local islands due to large amounts of silt deposition has canalized the flow in a narrow funnel leading to increased velocities locally. The Google imageries below show the concentration of the flow in a narrow space around the spurs at 12.1 km and 12.9 kms, for about the last four years and (b) the two spurs were in structurally bad shape, having been insufficiently-maintained over the years, and therefore, although the flood discharge was not very high, the spurs failed.

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Figure 2-9: Google Image 2004 showing concentration of flow.

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Figure 2-10: Google Image Showing Breach exactly on the concentrated flow

66. Therefore, after the collapse of the spurs at 12.1 km and 12.9 km, scour causing turbulence hit the toe and sides of embankment between the stretch (12.1 to 12.9 km) causing embankment failures of even during one of the lowest flood levels in Koshi.

67. Spurs are built either perpendicular to the bank or embankment or at an angle inclined slightly upstream for flood protection. The falling of trees on the river between two constructed spurs generally falls in the downstream direction . The falling of a large number of trees in this fashion, together with grass and other debris, acts as natural spurs causing the scour hole to form closer to the bank and tends to maintain the river current close to the bank, as attracting spurs. Therefore trees falling between the constructed spurs during flood always enhance the chances of attracting the river channel more towards the embankment sides.

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68. Most flood protection and river engineering projects in the Indian subcontinent are based on Lacey’s Theory. According to Lacey’s Theory, scour depth is a function of discharge and silt factor. Generally, in order to determine the level of scour, the river discharge and silt factor have been taken for micro levels (overall flood discharge over full width of river). However, in the case of a river with a splitting tendency, into a number of channels, the scour level of channels adjacent to the bank can be more critical than the overall river scenario during flood. This may be one of the reasons for failure of the spurs.

69. The breach of the spur at 12.1 km occurred over a period of more than 24 hours, and if an early warning system was in place, there was adequate time to issue warnings on the possible breach of the embankment.

2.8 Hydrological aspects

70. The mean flood discharge during August 2008 which contributed to the breach of the embankments was 5120 m 3/sec and occurred on 16 August 2008 (Fig 2.11). On 19 th August this discharge was exceeded and rose to 5190 m 3/sec. Similarly, the area had not experienced any significant rainfall that would have caused this. The breach, however, had already occurred on 18 th August and hence the higher discharge (of 5190 m 3/sec) did not directly contribute to causing the breach.

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Figure 2-11: Mean daily gauge height at Chatra from 12, Aug to 25 Aug, 2008

71. The analysis of the observed flow record at the Chatra gauging station in the Koshi basin shows that the average annual flow is about 1600 m 3/s and the peak flood has generally occurred in June to July where the monsoon rain dominates the river flow regime. About 80% of the total annual rainfall occurs during the monsoon season.

Figure 2-12: Average monthly discharge at Chatra

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72. The extreme flow in the Koshi River at Chatra station was 25879m 3/s in 1968 followed by 24241 m 3/s in 1954 and then about 24000 m 3/s in 1980. The flood flow on 18 August 2008 at Chatra was only about 4250 m 3/s when the flood disaster in the Koshi River was initiated while the mean precipitation was about 2.4mm. The discharges shown in Table XX for the period 12 th August 2008 to 25 th August 2008 are all not significantly high in comparison with the critical flood discharges in the Koshi river. Based on a flood frequency analysis, the discharge of the flood with a five year return period at Chatra is 11578 m 3/sec (with log Pearson III distribution). The design discharge of the Koshi Barrage (located downstream of the breach site) is about 27,000 m 3/sec. The maximum instantaneous flood discharges in previous years have varied from 5630 m3/sec to 24000 m 3/sec. (Figure 2.13)

Table 2.3 : Flood frequency analysis at Chatra Return period Flood (m 3/s) Gumbel (Extreme value I) Log-Pearson type III 5 13703 11578 10 17021 14862 20 20202 18739 30 21835 21336 40 23081 23346 50 24328 25009 60 25051 26438 70 25774 27699 80 26391 28832 90 26903 29864 100 27415 30813

73. Flood frequency analysis at Chatra (Table 2.3) shows that the flood flow on 18 Aug, 2008 is less than the magnitude of the five year return period flood. The return period of flooding in 1980, which was 24000m 3/s, is between 40 to 50 years.

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Figure 2-13: Maximum instantaneous flood discharge in Koshi at Chatra

Figure 2-14: Mean daily discharge at Chatra and mean daily rainfall for 12 Aug to 18 Aug, 2008

74. The breach, therefore, did not occur because of a high flood discharge, but rather because of the concentration of flow in a narrow channel and because of vulnerability due to badly maintained spurs. Discharge at Chatra was 4250 m 3/s (149940 cfs) and at the Barrage 4800 m 3/s (169344 cfs), which is much lower than the flood in 1980 and the design discharge

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of the Barrage, whereas the average daily rainfall on 18 August was 2.4 mm only. The 10 year return period flood is 12,831 m 3/s. From these facts, it can be concluded that the breach was not due to hydrological and meteorological extremes. The embankment was breached due to scouring. The reasons for scouring may be the following :

a. Concentration of flow towards left bank at the breached site for the last few years.

b. Rise in river bed level due to sediment deposition.

c. Drainage congestion due to opening of only 34 gates out of 56 gates on August 18, that contributed to the scouring of spurs.

d. Lack of proper inspection, observations and regular maintenance of the spur and a prompt engineering response recognizing the criticality of the problem.

2.9 Assessment of the Event of the Embankment Breach Flood on 18 th August 2008

75. As noted the Koshi River cut two spurs and an embankment in the east and consequently its flow diverted to further south east on 18 th August 2008, when the discharge was far below the long term average high flow. Complete breaching of the embankment occurred at 12:55 PM. Since, the danger of breaching was realized since the early morning and local people were informed about the potentially dangerous areas, they had decided to evacuate before the breach. The speed of the breach was not so high at the beginning. It took about one and half hours for the flood to reach the highway.

76. The breaching of the embankment was neither due to the overtopping of water over the embankment nor was it due to a seepage of water. It was due to the change in the flow direction to the embankment on the one hand and the weak shearing properties within the embankment on the other. It was also partly due to slackness in regular monitoring, maintenance and repair of the spurs and embankment.

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77. The need for the maintenance and repair of the spurs and embankment was realized one month back before the breaching occurred. The office of the Koshi Tappu Wildlife Reserve was requested for permission to clear trees and bushes along the embankment and to permit entry of construction materials without any obstruction through the office of the Chief District Officer. However no permission was granted until the day of the breaching.

78. There was also a one week bandh (strike) called by Terai Madhes Loktantrik Party between 12-16 August. It was reported that the continuous cutting back of the spur-12.10 by the river was noticed on 15th August but the flood fighting work was hindered due to the combination of different events - evacuation of the area by the army for gun firing on the same day, bargaining for wages by the local laborers, the theft of gabion wire from the project site, attempts to set fire to the Koshi Project officials’ vehicles, delays from the customs office in granting permission for the import of construction materials and desertion of Koshi Project staff from the potential breach site for security reasons at midnight on the 17 th of August. They returned to the breach site only on the 22 August, i.e., four days after the breach when security was ensured for their return.

79. In many places, the spur length has been reduced by 20-80 m due to cutting by the river. However, no attempt has been made to bring them to their original design length. After this flood disaster, the project has considered repairing many spurs but it has only considered extending it by 10 m.

80. Reportedly, a test model is being conducted at the Pune Research Lab and the results of the test will be used as a basis to redesign the spurs and their lengths. It will be a very welcome move to reduce underlying risk on the area.

81. Before 1988 when an earthquake of 6.6 on the Richter scale occurred, with its epicenter in the Udaypur district, the larger portion of water flowing

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was on the western side of the embankment. After this event the flow had diverted to the eastern part, damaging most of the spurs along the eastern embankment.

82. As per the agreement and general practices of the project, the inspection is carried out during the lean season of the river. Reportedly, the maintenance and repair works take place during the lean season, however, the focus is also kept on flood fighting (normally between 15 th June and 15 th October). During this period, most of the spurs and the embankment are covered with bushes and shrubs. As a result access to the spur, embankment and reaches of the river becomes poor. It also hampers the identification of potentially hazardous sites where breaching could occur and in the carrying out of maintenance and repair works.

83. As discussed earlier, shifting of the river channel and diversion of flow by avulsion are common geo-hydrological processes even in a natural braided channel in the Terai. For example, the Sundari – one of the tributaries of Koshi completely changed its channel and flow direction during and after the floods of 1973 (Khanal, 1993). Seven events of flood disaster due to breaching of the embankment have been reported from Bihar and Nepal between 1963 and 1991. Among them, two events – one in 1963 at Dalwa and another in 1991 in Joginiya on the west bank, a few km downstream from the Koshi Barrage have been reported (Mishra, 2006 cited in Dixit, 2009). Flood disasters due to breaching of the embankments have also been reported from other areas of Nepal. Many people were swept away and a huge amount of property was damaged due to the embankment breach flood in the Tinau River near Butwal in 1981 and the Rapti River in the Makawanpur and Chitwan districts in 1993 (Khanal, 1996).

84. The threat of breaching of the embankment after cutting of the spur toe was noticed 17 km from Prakashpur in 1993. However, the breach and the subsequent disaster were averted through active flood-fighting with the active participation of the local people. It is very difficult to say if the

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breach of 2008 could have been averted if similar measures had been taken. However an attitude of complacency about flood recurrence is quite noticeable.

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3 OBSERVATIONS FROM THE FIELD VISIT

3.1 Area and people affected

85. A total of 12 VDCs were affected by the flood of August 2008 (Table 3.1). And within this total of 6183 households about 40% of the households in these VDCs were affected by this flood. The number of households affected differs with the sources of information. One estimate shows a total number of 7306 only in the VDCs of Shreepur, Haripur and Paschim Kusaha. Another source shows a total of 7584 displaced families (CDO Office, Sunsary). Almost all the households in Haripur and Shreepur Jabadi were affected. The percentage of affected households decreases with the increase in the distance from the breach site.

Table 3.1: Number of households and population figures for the affected VDCs

Total number Total Number of of number of household % of affected SN Name of the VDCs households population affected household 1 Haripur 1580 9006 1580 100.0 2 Shreepur Jabadi 2250 13500 2250 100.0 3 Paschim Kusaha 2000 11800 1000 50.0 4 Ghuski 1682 10365 300 17.8 5 Basantapur 668 3941 350 52.4 6 Laukahi 909 4920 68 7.5 7 Narsimha 2835 17689 110 3.9 8 Ramgunj Sinuwari 1639 9991 105 6.4 9 Devangunnj 1650 10725 104 6.3 10 Sahevgunj 705 3873 109 15.5 11 Madyaharsahi 910 5364 55 6.0 12 Kaptangunj 1410 8643 152 10.8 Total 18238 109817 6183 33.9 Source: Field Survey, February, 2009

86. There was only one reported fatality from the flooding. However, the number of deaths reached 55, mostly in the shelter camps (ref: CDO Office, Sunsari). Table 3.2 shows the number of dead and injured people as reported during the discussions in the surveyed VDCs. The number of deaths ranged from 2 in Ghuski VDC to 3 in Paschim Kusaha, 16 in Shreepur Jabadi and 19 in Haripur. Among the reported total of 40

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deaths, 18 were female and 6 were children. Many of them had died due to diarrhea. The total number of injured people were 2350, of whom 898 were female and 816 were children. The number of injured women and children is relatively high.

Table 3.2: Number of deaths and injuries

Name of the Death Injury SN VDCs Male Female Children Total Male Female Children Total 1 Haripur 7 8 4 19 120 150 200 470 2 Shreepur Jabadi 8 6 2 16 500 700 600 1800 3 Paschim Kusaha 0 3 0 3 12 35 6 53 4 Ghuski 1 1 0 2 1 1 0 2 5 Basantapur 0 0 0 0 3 12 10 25 6 Laukahi 0 0 0 0 0 0 0 0 7 Narsimha 0 0 0 0 0 0 0 0 Ramgunj 8 Sinuwari 0 0 0 0 0 0 0 0 9 Devangunnj 0 0 0 0 0 0 0 0 10 Sahevgunj 0 0 0 0 0 0 0 0 11 Madyaharsahi 0 0 0 0 0 0 0 0 12 Kaptangunj 0 0 0 0 0 0 0 0 Total 16 18 6 40 636 898 816 2350 Source: Field Survey, February, 2009

3.2 Properties lost

87. Table 3.3 shows the losses of and damage to property from the flooding. A total of 5985 Bighas of cultivated land, 230 pakki houses and 3167 kachchi houses, 323 ordinary sheds and 89 ponds were destroyed by the flood. Almost all the cultivated land in the three VDCs namely Haripur, Shrepur Japadi and Paschim Kusaha was damaged by the flood. Large parts of cultivated land were covered by a thick layer of sand and gravel.

Rapid Hazard and Risk Assessment 45 Final Report: 20 March 2009 Koshi River Embankment Breach

Table 3.3: Loss of /damage to private properties

Land House (no) SN Name of the VDCs (Bigha) Sheds Pond (no) Pakki Kachchi (no) 1 Haripur 2200 30 400 0 14 2 Shreepur Jabadi 1500 150 1700 0 35 3 Paschim Kusaha 1300 50 880 300 20 4 Ghuski 200 0 54 0 7 5 Basantapur 50 0 25 0 3 6 Laukahi 120 0 0 0 1 7 Narsimha 150 0 0 23 0 8 Ramgunj Sinuwari 75 0 16 0 0 9 Devangunnj 85 0 55 0 2 10 Sahevgunj 130 0 9 0 4 11 Madyaharsahi 65 0 11 0 0 12 Kaptangunj 110 0 17 0 3 Total 5985 230 3167 323 89 Source: Field Survey, February, 2009

88. Another estimate of damage to land shows a much higher area of nearly 8200 Bighas damaged by the flood, in only four VDCs. by only. Nearly 46% of the area was totally damaged and the remaining 54% was partially damaged.

Table 3.4: Extent of damage to cultivated land

Totally damaged Total land area land area in Partially damaged land Name of VDC in Bigha Bigha area in Bigha Paschim Kusaha 2473 477 1996 Laukahi 584 0 584 Haripur 2087 624 1463 Shreepur 3063 2663 400 TOTALS 8207 3764 4443

89. Table 3.5 shows the number of livestock lost due to the flood. The number of deaths of cows, buffalos and goats were 1000, 1180, and 7306, respectively. These were mainly confined to the three VDCs namely; Haripur, Shreepur Jabadi and Paschim Kusaha. Another major loss was

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fish. The loss of fish was considerable even in the downstream areas such as Kaptangunj and Sahebgunj.

Table 3.5: Number of livestock lost

Name of the SN VDCs Cow Buffalo Goat Chicken Duck Pig Fish 1 Haripur 150 100 500 5000 1000 0 5000 2 Shreepur Jabadi 250 280 5000 12000 0 0 200000 3 Paschim Kusaha 600 800 1800 4000 1000 300 15000 4 Ghuski 0 0 0 300 0 0 30000 5 Basantapur 0 0 6 200 0 0 30000 6 Laukahi 0 0 0 0 0 0 10000 7 Narsimha 0 0 0 150 0 0 0 Ramgunj 8 Sinuwari 0 0 0 112 0 0 0 9 Devangunnj 0 0 0 55 0 0 0 10 Sahevgunj 0 0 0 65 0 0 3500 11 Madyaharsahi 0 0 0 50 0 0 0 12 Kaptangunj 0 0 0 115 0 0 10000 Total 1000 1180 7306 22047 2000 300 303500 Source: Field Survey, February, 2009

90. Table 3.6 shows the quantity of standing crops damaged and loss of grain stored in the house because of the floods. The standing crops were paddy, sugarcane and jute. The quantity lost ranged from 39800 quintal of sugarcane to 79214 quintal of rice and 2170 quintal of jute. Similarly, the loss of stored grains ranged from 4940 quintal of wheat to 5427 quintal of maize and 635 quintal of potato.

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Table 3.6: Loss of crops in quintal

SN Name of the VDCs Paddy Wheat Maize Potato Sugarcane Jute 1 Haripur 3744 1085 240 100 25000 1000 2 Shreepur Jabadi 35437 1500 1000 500 350000 200 3 Paschim Kusaha 27850 300 200 0 0 100 4 Ghuski 1020 20 10 6 100 60 5 Basantapur 1200 1000 500 0 3000 200 6 Laukahi 2040 0 0 0 20000 500 7 Narsimha 1845 50 30 0 0 0 8 Ramgunj Sinuwari 1095 32 29 0 0 58 9 Devangunnj 1127 568 3100 0 0 37 10 Sahevgunj 1729 225 213 23 0 0 11 Madyaharsahi 438 45 15 6 0 0 12 Kaptangunj 1689 115 90 0 0 15 Total 79214 4940 5427 635 398100 2170 Source: Field Survey, February, 2009

91. Table 3.7 shows the loss of fruits from the flood. The estimated loss of mangoes, jack fruit, bananas, guavas and litchis is 4620, 2370, 300, 100 and 500 quintal respectively. The loss of fruits is confined to three VDCs, namely Haripur, Shreepur Jabadi and Paschim Kusaha.

Table 3.7: Loss of fruits in quintal

Jack Name of the VDCs Mango fruit Banana Guava Litchi Haripur 200 70 0 0 0 Shreepur Jabadi 3000 1500 0 0 500 Paschim Kusaha 1200 800 300 100 0 Ghuski 70 0 0 0 0 Basantapur 50 0 0 0 0 Laukahi 35 0 0 0 0 Narsimha 3 0 0 0 0 Ramgunj Sinuwari 3 0 0 0 0 Devangunnj 12 0 0 0 0 Sahevgunj 25 0 0 0 0 Madyaharsahi 12 0 0 0 0 Kaptangunj 10 0 0 0 0 Total 4620 2370 300 100 500

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92. Table 3.8 shows the estimates of vegetables damaged by the flood. The estimated loss of pumpkin, bottle gourd, cucumber, pointed gourd, chili, aborigine, okra and arum was 1062, 40219, 102, 31015, 10000, 1200, 10 and 30 quintals. Again, Haripur, Shreepur Jabadi, Paschim Kusaha and Ghuski were affected most.

Table 3.8: Losses of vegetables in quintal

Bottle Pointed Name of the VDCs Pumpkin gourd Cucumber gourd Chili Aborigine Okra Arum Haripur 200 150 80 0 0 0 0 0 Shreepur Jabadi 0 40000 0 30000 10000 0 0 0 Paschim Kusaha 0 0 0 15 0 0 10 30 Ghuski 1400 0 0 1000 0 1200 0 0 Basantapur 0 0 0 0 0 0 0 0 Laukahi 0 0 0 0 0 0 0 0 Narsimha 0.5 0.5 0.5 0 0 0 0 0 Ramgunj Sinuwari 0 0 7 0 0 0 0 0 Devangunnj 0 65 12 0 0 0 0 0 Sahevgunj 0 2 1.5 0 0 0 0 0 Madyaharsahi 0.5 0.5 0.5 0 0 0 0 0 Kaptangunj 0.5 1 0.5 0 0 0 0 0 Total 1601.5 40219 102 31015 10000 1200 10 30 Source: Field Survey, February, 2009

93. Table 3.9 shows the estimated loss of household goods. The estimated total number of losses of, bed, closet, radio, television, cycles and motor bikes was 3288, 1075, 1490, 225, and 3150 respectively. Those losses were confined to three VDCs. In addition to these, 8 rice mills and 23 seller mills were damaged.

Rapid Hazard and Risk Assessment 49 Final Report: 20 March 2009 Koshi River Embankment Breach

Table 3.9: Loss of household goods in number

Name of the VDCs Khat Daraj Radio TV Cycle Motor bike Haripur 75 25 40 10 50 1 Shreepur Jabadi 3000 1000 1400 200 3000 10 Paschim Kusaha 150 50 50 15 100 0 Ghuski 30 0 0 0 0 0 Basantapur 30 0 0 0 0 0 Laukahi 0 0 0 0 0 0 Narsimha 0 0 0 0 0 0 Ramgunj Sinuwari 0 0 0 0 0 0 Devangunnj 0 0 0 0 0 0 Sahevgunj 3 0 0 0 0 0 Madyaharsahi 0 0 0 0 0 0 Kaptangunj 0 0 0 0 0 0 Total 3288 1075 1490 225 3150 11 Source: Field Survey, February, 2009

94. One estimate of the loss/damage incurred in monetary value shows that there was a loss of about 3773.6 million rupees (Table 3.10). Land value comprises nearly 64% of the total loss, followed by livestock, food, crops and houses. This estimate is based on the losses in only four VDCs and did not incorporate the loss of other household goods, infrastructure and services. So, the total loss would seem to exceed this estimate.

Table 3.10 : Estimated monetary loss

Properties Loss in Rs % House and shed 60454080 1.6 Land 2422400375 64.2 Livestock 319247508 8.5 Crops 176641475 4.7 Food 190844448 5.1 Total 3773603836 100.0

95. Table 3.11 shows the estimated loss of infrastructure such as road, bridges and culverts. About 7 km of metalled road, 126 km of graveled road, 131 km of earth road and 82 km of trails were damaged. Similarly, 6 bridges and 67 culverts were also damaged by the flood.

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Table 3.11: Loss/damage of roads and trails

Road (km) Trail Bridge Culvert (km) (no) (no) SN Name of the VDCs Metalled Graveled Earth Total 1 Haripur 4 15 25 44 5 1 12 2 Shreepur Jabadi 3.1 35 20 58.1 10 2 35 3 Paschim Kusaha 0.2 28 15 43.2 8 3 6 4 Ghuski 0 11 15 26 7 0 4 5 Basantapur 0 3 6 9 8 0 2 6 Laukahi 0.1 1.5 2 3.6 0 0 1 7 Narsimha 0 8 8 16 7 0 2 8 Ramgunj Sinuwari 0 3.5 10 13.5 10 0 0 9 Devangunnj 0 14 16 30 9 0 1 10 Sahevgunj 0 2 4 6 4 0 2 11 Madyaharsahi 0 2 3 5 4 0 1 12 Kaptangunj 0 3 7 10 10 0 1 Total 7.4 126 131 264.4 82 6 67 Source: Field Survey, February, 2009

96. Table 3.12 shows the losses of other infrastructure such as transmission lines, canals, public buildings and temples. About 117 km of transmission line, 73 kms of canal, 19 public buildings and 26 temples were damaged by the flood. Transmission lines and canals even in the downstream area in the far south and eastern parts were damaged. Five towers of 132 kv transmission line were damaged by the flood.

Table 3.12: Damage to infrastructure

SN Name of the VDCs Transmission line Canal Public Building Temple 1 Haripur 24 9 4 0 2 Shreepur Jabadi 60 8 12 26 3 Paschim Kusaha 15 8 3 0 4 Ghuski 0 10 0 0 5 Basantapur 0 2 0 0 6 Laukahi 0 2.5 0 0 7 Narsimha 0 6 0 0 8 Ramgunj Sinuwari 6 7 0 0 9 Devangunnj 12 10 0 0 10 Sahevgunj 0 4 0 0 11 Madyaharsahi 0 5 0 0 12 Kaptangunj 0 1.5 0 0 Total 117 73 19 26 Source: Field Survey, February, 2009

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97. The flow of people and goods ceased completely for a period of between 30 to 220 days. Previously more than 3600 vehicles used to shuttle every day on the East-West Highway.. Similarly, the supply of drinking water and electricity was completely stopped for up to 220 days in many places. Industries were closed for up to 220 days (Table 3.13).

Table 3.13: Number of days when the flow of goods and services were closed

Traffic Water SN Name of the VDCs flow supply Electricity Trade Industry 1 Haripur 180 200 220 150 150 2 Shreepur Jabadi 180 200 220 150 220 3 Paschim Kusaha 200 200 200 200 200 4 Ghuski 200 0 20 30 20 5 Basantapur 30 0 15 30 15 6 Laukahi 220 7 30 30 30 7 Narsimha 30 15 15 30 15 8 Ramgunj Sinuwari 45 15 15 30 15 9 Devangunnj 45 15 15 30 15 10 Sahevgunj 40 15 15 30 15 11 Madyaharsahi 40 15 15 30 15 12 Kaptangunj 45 15 15 30 15 Source: Field Survey, February, 2009

3.3 Breach Repair

3.4 Conditions of the Spurs and Maintenance

98. The assessment team undertook a detailed assessment of the embankments and spurs. As per the team’s assessment, spurs from 0.0Km to 10.6 KM 2 from the border, there is a need to bring the spurs to their design length to address the shorter term problem. However, there is a need to develop a physical model to undertake detailed analysis and build spurs. The pitching of the nose is damaged in most of the spurs and the nose protection using gabion-wire boxes filled with boulders are essential.

The breach repair work repair is ongoing between 10.7 km and 13.4 km.

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99. For spurs from 14.1 km and 14.5 km, there is a need to restore the nose, apron and shank slope. There is a need extend the length of the spur to their design length of 150m and providing proper armoring of gabion boxes.

100. On spurs between 14.5 and 15.3 km, there is a need to construct a new spur, possibly extending up to 180 m. It should be noted that this will only be a temporary measure and should be confirmed with detailed model testing. Spur at 16.8 km appears damaged and there is need to extend the spur to its design length, properly armor and construct nose, shank, and launching apron.

101. Spurs from 18.81 km and 19.52 km need urgent attention and these need to be repaired with priority. Procupines are provided but they need to be very urgently repaired before the onset of the monsoon. Several of the nuts and bolts of the porcupines have gone missing. This place preferably the river is diverted away from its current flow direction. There is a need also to provide geo-tubes.

102. The Prakashpur/Rajapur section of spurs (23.1 k m and 23.52 and 24.45 km to 27.1 km) also need to be repaired immediately before the onset of the monsoon. The spurs require laying of geotubes especially along the embayed section in between the spurs. The repair work needs to be carried out without delay and there is no need to wait until the results of the model tests become available. All the spurs need to be extended to their design lengths and efforts should be made to channelize the flow of the Koshi away from the embankment.

103. Construction of new spurs at suitable locations and rehabilitation of damaged spurs is also proposed to protect the existing and the newly- constructed embankments, especially from the two spots that the team has identified as dangerous (along Prakashpur and Rajabas).

104. The western embankment is extensively encroached. At places, local people have constructed animal pass and the spurs are being put in

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various uses. Apparently, the east-ward shifting of the river has made people complacent about the possibility of flood. There is a need to quickly address this situation and remove uses of

3.5 Rehabilitation Works in Progress

105. Following the breach, remedial works have been undertaken to reconstruct the embankment between chainages 12.100 km to 13.400 km. To facilitate this work, the Koshi River has been diverted westwards through the construction of a series of three cofferdams. The river diversion has been very effective.

106. The new embankment between chainages 12.100 km to 12.900 km is designed with a slope of 1:2 on the river side and 1:5 on the country side. Revetments are being placed over geotextiles at the embankment toe on the river side to protect it from scouring. The designed section and protection works for the embankment appear adequate.

3.6 Assessment of Breach Flood Risk

107. It is very difficult to determine the probability of breaching and the direction of the water flow and its magnitude, without making a detailed investigation of the materials and geo-hydrodynamics of the river channel as well as the terrain of the piedmont. However, an attempt has been made to identify potential sites where breaching could occur after a short field observation and discussions with the local people. Three sites – Prakaspur, Rajbas and Pulthegaunda were identified as potential sites for breaching, in the absence of effective protective measures (Figure 3.1).

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Figure 3-1: Potential Breach Points and Flow Paths

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4

3 2

1

3

2

Figure 3-2: Google Earth Image showing concentration of flow upstream of the breach (1=Current Breach, 2= Prakashpur, 3= Rajabas and 4=Pulthegaunda)

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108. The flow path was determined based on the gradient of the terrain as indicated by the contours. Another consideration in determining the flow path, particularly from Pulthegaunda, was the old channel of the Koshi River. The old channel of the Koshi River has been traced to about 35 km east from the Barrage (Gole and Chitale, 1996 cited in Dixit, 2009). It is in this context that the flow is likely to follow the old channel.

109. As can be seen in Figure 3.2 above, similar concentrations of river are clearly visible on the embankment.

3.7 Exposures to Potential Risk

110. Identification and quantification of the elements exposed have been based on two sources of information – topo sheet maps and field surveys at VDC level. The analysis is made at VDC level. The breach floods of 2008 affected 12 VDCs with a total population of 98,680 according to the Population Census of 2005. The number of VDCs likely to be affected from the Prakashpur site are 20 (12+8), which also includes VDCs located in the downstream area with a population of 163,846. Likewise, the number of VDCs likely to be affected due to the breach at Rajbas is 29 with a total population of 259,646. Inaruwa, the district headquarters of Sunsari District is likely to be affected. The number of VDCs likely to be affected due to breaching at Pulthegauda is 54 with a total population of 652,811. Biratnagar is likely to be affected in this scenario (Table 3.1 and Figure 3.14). The cultivated land likely to be affected ranges from 360 sq. km from the potential Prakashpur breach to 436 sq. km from Rajbas and 826 sq. km from Pulthegaunda. The total area likely to be affected ranges from about 44.6 sq km of forest, 14.5 sq. km of plantation area, 25.2 sq. km of grassland and 2.5 sq. km of built up areas. About 677 km of road, including 61 km of highway is likely to be affected. There are more than 100 ethnic groups living in this area. The major ethnic groups in population are Muslim, Tharu, Bahun, Chhetri, Yadav, Koiri, Mushahar,

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Jhagar, Newar, Teli, Dhanuk, Rajbansi, Kewat, Rai, Baniya, Mallaha, Marwadi, Haluwai, Gangai and Bantar (Figure 3.3).

Figure 3-3: Area under risk and major ethnic groups

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Table 3.14 : Elements exposed to the potential risk of breach flood in Koshi

Affected Likely to be affected Elements exposed Prakashpur Rajbas Pulthegauda Total No of VDCs (no) 12 8 9 25 54 Population (no) 98680 65166 95900 393065 652811 Land (sq. km) 192.76 113.52 188.43 478.63 973.34 Cultivated 171.86 88.50 172.46 393.37 826.20 Forest 0.33 3.99 7.68 32.64 44.64 Plantation 3.13 2.30 4.01 5.10 14.54 Bush 0.02 0.23 0.03 0.70 0.98 Grassland 4.01 8.87 0.15 12.12 25.15 Built up area 0.03 0.00 0.38 2.13 2.54 Barren land 0.58 0.08 0.12 3.16 3.95 Sand and gravel 3.83 4.61 0.42 15.80 24.66 Swamp 3.15 0.31 0.20 0.31 3.96 Water body 5.81 4.62 2.98 13.30 26.72 Road (km) 133.94 82.21 70.83 389.79 676.77 Highway 22.75 1.16 3.8 33.23 60.94 Other roads 111.19 81.05 67.03 356.56 615.83 Source: Compiled from different sources – population from Population Census, 2001; landuse and road from topo sheet maps (1:25000) published by the Survey Department, GoN.

111. A survey of 17 village development committees located in areas adjoining stretches of the Koshi River, shows that nearly 41% of the total land area in these VDCs is likely to be severely affected. About 28% area is likely to be moderately affected from the breach floods (Fig 3.3 Table 3.15). Nearly 42% of households and 43% of the population are living in areas which are likely to be severely affected by the flood. The percentage of households and portion of the population living in areas which are likely to be moderately affected is 30% each. There are many settlements on the island within the distributaries of the Koshi River and within the embankments in two of the VDCs- Prakashpur and Manhendranagar. These settlements are located in high risk areas. There are 152 families in Mahendranagar and 350 households in Prakashpur living in a high risk area.

Rapid Hazard and Risk Assessment 59 Final Report: 20 March 2009 Koshi River Embankment Breach

Figure 3-4: Risk classification of the Koshi Basin below Chatra until the Barrage

Table 3.15: Area under different levels of risk and population

Level of Risk Land Household Population Area (Bigha) % Number % Number % Severely 33310 41.0 12651 42.2 75241 43.4 Moderately 22433 27.6 9122 30.4 51853 29.9 Slightly 25446 31.3 8222 27.4 46430 26.8 Total 81189 100.0 29995 100.0 173524 100.0 Source: Field Survey, February, 2009

112. Nearly 40% of the total cultivated land, 38% of vegetable and fruit growing areas and 48% of forest land are likely to be affected severely from the flooding. About 29% of the total cultivated land and 28% of the vegetable and fruit growing areas are likely to be moderately affected. The percentage of cultivated land with slight risk of flood is less than 32% (Table 3.15).

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Table 3.16: Area under different levels of risk by land types

Level of Risk Cultivated land Orchard Forest Bigha % Bigha % Bigha % Severely 26086 39.4 506 37.7 164 48.1 Moderately 19353 29.2 369 27.5 95 27.9 Slightly 20743 31.3 467 34.8 82 24.0 Total 66182 100.0 1342 100.0 341 100.0 Source: Field Survey, February, 2009

113. Table 3.16 clearly shows that nearly 46% of pakki houses and 44% of kachhi houses are located in areas which are likely to be severely affected by the flood. About 33% of pakki houses and 29% of kachchi houses are located in areas which are likely to be moderately affected. Only 21% of pakki houses and 27% of kachhi houses are located in relatively safe areas.

Table 3.17 : Number and percentage of houses located with different levels of flood risk

House Pakki House Kachhi Level of Risk Number % Number % Severely 935 46.2 11310 43.9 Moderately 658 32.5 7474 29.0 Slightly 429 21.2 6967 27.1 Total 2022 100.0 25751 100.0 Source: Field Survey, February, 2009

114. Nearly 37% of cattle, 45% of buffaloes and 46 percent of goats are owned by the households who are living in areas which are likely to be affected severely by the flood. Only 26% of the cattle, 27% of the buffalo and 23% of the goats are reared by households living in relatively safe sites (Table 3.18).

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Table 3.18: No. and percentage of livestock owned by households with different levels of flood risk

Cattle Buffalo Goat Level of Risk Number % Number % Number % Severely 20263 36.7 22282 45.0 27821 45.7 Moderately 20656 37.4 14045 28.4 19002 31.2 Slightly 14301 25.9 13198 26.6 14112 23.2 Total 55220 100.0 49525 100.0 60935 100.0 Source: Field Survey, February, 2009

115. Nearly 41% of the total paddy production, 49% of maize, 49% of wheat and 51% of millet are from areas which are likely to be severely affected by the flood. Only 30% of the total production of paddy, 26% of maize, wheat and millet are from areas which are relatively safe from flood hazard (Table 3.19).

Table 3.19 : Major crops with level of risk

Paddy Maize Wheat Millet Level of Risk Quintal % Quintal % Quintal % Quintal % Severely 403217 41.4 162107 48.7 178813 48.8 8065 50.5 Moderately 274622 28.2 84622 25.4 92290 25.2 3810 23.9 Slightly 296495 30.4 86468 26.0 95031 26.0 4095 25.6 Total 974334 100.0 333197 100.0 366134 100.0 15970 100.0 Source: Field Survey, February, 2009

116. Table 3.20 shows the number and percentage of public buildings and other infrastructure located in areas with different levels of flood risk. Nearly 48% of school buildings, 45% of office buildings, 47% temples, 48% of rice mills and 44% of tube wells are located in areas which are likely to be affected severely by flood hazard. Only 24% of schools, 13% of office buildings, 26% of temples, 29% of rice mills and 24% of tube wells are located in relatively safe sites.

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Table 3.20 : Number and percentage of public buildings, industries and structures by the level of flood risk

Level of Risk Schools Office building Temple Rice mills Tube well Number % Number % Number % Number % Number % Severely 64 48.1 38 44.7 99 47.4 59 48.4 11468 44.2 Moderately 37 27.8 36 42.4 56 26.8 28 23.0 8176 31.5 Slightly 32 24.1 11 12.9 54 25.8 35 28.7 6280 24.2 Total 133 100.0 85 100.0 209 100.0 122 100.0 25924 100.0 Source: Field Survey, February, 2009

117. Table 3.21 shows the distribution of infrastructure in areas with different levels of flood risk. Nearly 67% of bridges, 54% of culverts, 46% of transmission lines, 41% of irrigation canals, 69% of highways and 43% of road networks are located in areas which are likely to be severely affected by flood hazard. Only 16% of bridges, 24% of culverts, 28% of transmission lines, 3% of highway lengths and 29% of the road networks are located in relatively safe sites.

Table 3.21 : Number and percentage of items of infrastructure by level of flood risk

Level of Bridges Culvers Transmission line Canals Highways Other roads Risk Number % Number % km % km % km % km % Severely 4 66.7 114 54.0 226 45.6 131 40.9 22.5 69.2 354 42.8 Moderately 1 16.7 47 22.3 130 26.2 84 26.2 9 27.7 235 28.4 Slightly 1 16.7 50 23.7 139.5 28.2 105.2 32.9 1 3.1 238 28.8 Total 6 100.0 211 100.0 495.5 100.0 320.2 100.0 32.5 100.0 827 100.0 Source: Field Survey, February, 2009

118. It is evident that nearly two thirds of land, property and infrastructure is at high risk of hazardous flooding. This fraction is likely to be lost or damaged by the flood.

3.8 Local capacity to cope with flood risk

119. It is evident that nearly two thirds of land, property and infrastructure is at high risk of hazardous flooding which means that they are likely to be lost or damaged by the flood. Attempts have been made to assess the local capacity to cope with the potential risk of flood based on four

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indicators – major occupation of the household, size of landholding, level of income and food sufficiency. The major source of income of 64% of households is agriculture followed by labor, trade and remittance (Table 3.22)

Table 3.22: Number of households by major occupation

Occupation Household % Agriculture 19698 64.4 Trade 2304 7.5 Labor 6185 20.2 Service 745 2.4 Remittance 1533 5.0 Other 110 0.4 Total 30575 100.0 Source: Field Survey, February, 2009

120. Many households depend on agriculture for their livelihoods. But the size of their land holdings is rather small. Nearly 70% households are either landless or marginal farmers with less than one hectare of cultivated land (Table 3.23). Only 5% of households have a landholding size more than 3 ha and are capable of receiving cash earnings from agricultural products.

Table 3.23: Number of households by size of landholding

Size of landholding Household % Landless 2449 8.0 Marginal (<1ha) 18988 62.1 Small (1-3ha) 7426 24.3 Medium (3-5ha) 1469 4.8 Large (>5ha) 243 0.8 Total 30575 100.0 Source: Field Survey, February, 2009

121. The average annual household income among 15% of households is less than NRs. 25,000 which is about 4 -5000 rupees per person (Table 3.24). More than 75% of households have an annual income of less than 100,000Rs which is about 18,000Rs per person. Only 7 % of households have an annual income of more than 200,000Rs.

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Table 3.24: Number of households by annual income category

Income category (NRs.) Household % <25000 4506 14.7 25000-50000 7782 25.5 50000-100000 10882 35.6 100000-200000 5323 17.4 >200000 2082 6.8 Total 30575 100.0 Source: Field Survey, February, 2009

122. The production generated by a large number of households is not sufficient to fulfill their own food requirements. Nearly 38% of households have their own produce which is sufficient only for six months (Table 3.25). Only 20% of households do have enough production with surplus for sale.

Table 3.25: Number of households by level of food sufficiency from own production Food sufficiency Household % < 3 months 7136 23.3 3-6 months 4618 15.1 6-9 months 5667 18.5 9-12 months 7110 23.3 Surplus/sale 6044 19.8 Total 30575 100.0 Source: Field Survey, February, 2009

123. It is clear from the discussion above that the capacity of local people to cope with flood risk is very low. Because the majority of people are landless, marginal and small farmers, they have a low level of income and they have a severe food deficit.

3.9 Flood Risk Management

3.9.1 The August 2008 breach flood 124. Rescue and relief activities were carried out immediately after the breaching of the embankment. Since the breaching occurred in the daytime at 12.55pm and the potential of risk to the local population was

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communicated early in the morning, people left the area with their belongings before the breach flood reached to their localities. So the number of deaths due directly to the flood was only one. The number of internally displaced families was 7306 with a total population of 41,340. Among these internally displaced families about 72% lived in camps, 3% in host families and the remaining 25% in their original home community. The statistics for the internally displaced people still need verification because of the reporting by members of the same family in different camps on the one hand and non-reporting by many people on the other. The recording and verification work is ongoing.

125. This survey shows that there are 34 camps distributed in different areas (Figure 3.5). Eight camps located by the western bank of the river have been vacated. The Indians living in these camps returned home by taking a sum of Rs. 4,500 provided by the government. However, the displaced Nepalese people have joined other camps located in the Sunsari district. The details of households and population in these abandoned camps are given in Table 3.26.

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Figure 3-5: Shelter Camps in the Area

Table 3.26: Number of households and population in vacated camps located on the western bank of Koshi River. Camp Id Household Population A 463 2993 B 344 1512 c1 373 2000 c2 78 461 c3 102 558 c4 209 1135 d1 641 3781 d2 426 2470 Total 2636 14910 Source: Field Survey, February, 2009

126. A total of 26 existing camps were surveyed during the field work. There are a total of 44466 internally displaced people in these camps. The size of

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camps in terms of the number of displaced people living in the camps, ranged from 395 people to 3487 people, with an average of 1710.There are 8 camps with a population size of less than 1000, 8 between 1000-2000, 9 between 2000-3000, and only one with more than 3000 (Table 3.27).

Table 3.27: Number of camps by size of population

Population size Number of camps Below 1000 8 1000-2000 8 2000-3000 9 > 3000 1 Total 26 Source: Field Survey, February, 2009

127. Table 3.28 shows the demographic characteristics of internally displaced people living in the surveyed camps. The female population exceeds the male population in these camps. Nearly14% are children and 0.3% are disabled.

Table 3.28: Number of people by sex and other status Number % Male 21541 48.4 Female 22925 51.6 Total 44466 100.0 Children 6322 14.2 Disabled 142 0.3 Source: Field Survey, February, 2009

128. Table 3.29 shows the economic status of internally displaced people. Nearly 45% of the total number of families who answered about ownership of land are landless while 55% of families do have their own land. Many families belong to marginal and small farmers. Only 2% families do have a large size of landholding and they rent out their land.

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Table 3.29: Number of families by ownership of land

Status Number % Landless 1355 45.1 Landowner 1651 54.9 Not Stated 4235 58.5 Renters 65 2.2

129. Table 3.30 shows the place of origin of the internally displaced people living in these 26 camps. These places are Haripur, Shreepur, Kusaha and Laukahi VDCs in the Sunsari District in Nepal and nearby areas from India. The average family size of these internally displaced people ranged from only 5.3 to 6.7 members. Out of a total of 44,466 people living in the camps 32% are from Haripur, 47% from Shreepur, 18% from Kusaha and 1.6% from India.

Table 3.30: Number of household and population living in the camps by the place of origin

Household Population Average size % Haripur 2530 13454 5.3 32.7 Shreepur 3611 21459 5.9 46.6 Kusaha 1373 8097 5.9 17.7 Laukai 100 665 6.7 1.3 India 127 791 6.2 1.6 Total 7741 44466 5.7 100.0 Nepal 7614 43675 Source: Field Survey, February, 2009

130. Table 3.31 shows the service infrastructures available in these camps. Drinking water and toilet facilities are available in all the camps. However, there is no health care, child care or education facilities in many of the camps. There is also a lack of provision of security in the majority of the camps. Lack of security for adolescent girls and the fear of women and children being trafficked across the border and fear of communal confrontation are some of the issues associated with the poor security provision in many camps.

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Table 3.31: Number of camps with/without service facilities

SN Type of facilities With Without Total % With 1 Drinking water facility 26 0 26 100.0 2 Toilet facility 26 0 26 100.0 3 Bathroom 23 3 26 88.5 4 Health care service 19 7 26 73.1 5 Child Development Care Centre 17 9 26 65.4 6 Education facility 11 15 26 42.3 7 Security provision 14 12 26 53.8 8 Information Centre 11 15 26 42.3 9 Electricity 2 24 26 7.7 Source: Field Survey, February, 2009

131. An attempt was also made to estimate the value of different major items distributed within the camps. These values were based on the expenditure made during one month before the survey month. Nearly 29% is spent on clothes followed by food, tent construction and maintenance, utensils and training activities (Table 3.32).

Table 3.32: One month’s expenditure on different items in the camps

Items No. of people benefited Value (Rs.) % Value Food 43357 57839911 26.84 Lito (baby cereal) 806 77600 0.04 Cloth 43357 63401143 29.42 Medicine 43357 1439772 0.67 Tent 43357 54763145 25.41 Toilet 24966 5057284 2.35 Chulo 395 156400 0.07 Drinking water 43357 3598665 1.67 Container 2560 18275 0.01 Utensils 43357 11330918 5.26 Training 2195 10286808 4.77 Cash 41732 7548100 3.50 Total 332796 215518021 100.00 Source: Field Survey, February, 2009

132. Table 3.33 shows the sufficiency in the distribution of different items requested by different camps. Food, clothing, tents, utensils and cash are

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not sufficiently distributed in many camps and the supply of drinking water, medicine and training is similarly not wide. People have been suffering from many diseases such as coughs, fever, diarrhea, eye infections, skin diseases, measles and acute respiratory illnesses. More than 80% cases are of diarrhea. It was also reported that the size of clothes and utensils distributed has not been according to their needs. They are either too small or too big.

Table 3.33: Number of camps reporting sufficiency in the distribution of goods and services Items Yes No Food 3 23 Clothing 2 24 Tent 2 24 Medicine 18 8 Utensil 4 22 Drinking water 20 6 Training 24 2 Cash 2 24 Source: Field Survey, February, 2009

133. Many international/national/local institutions are involved in relief and rehabilitation activities for the internally displaced people (Table 3.34) Their efforts are confined to registration, verification and distribution of goods and services. No one is actively involved in the rehabilitation of degraded land by removing sand. The layer of sand over the cultivated land in many places is 3-6 ft. In the season of strong winds, the sand deposited in the cultivated land could create health hazards in the area.

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Table 3.34: International/National Agencies Involved in Relief by Sector

Sector Institutions involved Food WFP, NRCS, SC, LWF, FAO, DEPROSC, Concern, WVI, UNICEF, Clothing Oxfam, KVS, Care Nepal, NRCS, IOM, EV, SC, WEL, LWF, UNICEF, Rotary, WVI, Nepal Paribatan Tent Rotary International, Oxfam, KVs, NRCS, Care Nepal, EU, LWF, UNICEF, WEL, KODEF Nepal, IOM, Action Aid Medicine NRCS, Oxfam, KVS, DPHO, Care Nepal, WEL, UNICEF Utensil NRCS, Care Nepal, KVS, Oxfam, IOM, WEL, Rotary Club Drinking Water DWO, Caritas, RRN, Oxfam, KVS, NRCS, UNICEF, WEL, Paribartan Nepal, CSDC Training Rotary International, DPHO, Oxfam, KVS, NRCS, WASH, WEL, Paribartan Nepal, OHCHR, Plan Nepal, Action Aid Cash District Disaster Committee, CDO Office Chulo Care Nepal Litopitho WFP, DEPROSC, CONCERN, SC Toilet Oxfam, KVS, Sabal Nepal, WEL, NRCS, UNICEF, LWF

CDO=Chief District Office(r) CSDC = Community for Social Development Centre DEPROSC = Development Project Service DPHO=District Public Health Office DWO=District Water Office FAO= Food and Agriculture Organization IOM = International Organization for Migration KVS = Koshi Victim’s Society, LWF = Lutheran World Federation NRCS = Nepal Red Cross Society OHCHR= Office of the High Commissioner for Human Rights SC = Save the Children UNICEF = United Nations Children’s Fund WFP = World Food Programme WVI = World Vision International

134. Table 3.35 shows the willingness of the people living in the camps to return to their homes. Very few people are willing to return to their home. The figure is only 13%. Nearly 87% of the total internally displaced people living in the camps are not willing to return their homes 3. Many of them are landless and marginal farmers. There is still a fear of the danger of breach flooding from the same site. Furthermore there is a wide spread belief that the government will provide compensation. Many families have been maintaining multiple households to take advantage of the free distribution of food and other household items in the camps. They have demanded land and other support for resettlement and identified two areas for resettlement: One is located in Singiya VDC and another is located in Mahendranagar VDC. Both areas are on public land covered with forest.

3 Previous study showed that more than 60% families were willing to return their home.

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Table 3.35: Number of people willing/not willing to return home

Willingness Number % Willing to return home 5708 12.8 Willing to stay in camp 38758 87.2 Total 44466 100.0 Source: Field Survey, February, 2009

Figure 3-6: Area Covered by Sand and Water

135. The Government has classified the internally displaced people into three categories – red, yellow and green. People belonging to the red category are those whose lands are covered with a thick layer of sand or have been scoured by the flood. (fig 3.6) The estimated families in this category are 1500. There are two alternatives for the rehabilitation of this group – the rehabilitation of their land by removing sand or resettlement in other

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areas. No collective or institutional effort has been made in connection with the rehabilitation of damaged land till now. There was an opportunity to rehabilitate the sand deposited area if proper care had been made for cultivation when there was enough moisture in the soil, by providing seeds, fertilizer and technology for the landowners.

136. The government has issued a package of Rs. 50,000 per family to return internally displaced people in the yellow and green category to their homes. However, the demands of internally displaced people including the leaders of many political parties were higher than this. They demanded land for resettlement. The Jhumka Agricultural Farm is another alternative for the resettlement of the internally displaced people. However, the size of land available is too small to accommodate all the displaced people. This issue has been politicized and the large landholders who belong to different political parties have asked others not to leave the camps hoping that they could receive compensation for all their land from the government through their collective voice.

3.10 Preparedness

137. Most of the activities have been focused on rescue and relief activities. Only a few activities have been carried out for rehabilitation and preparedness. The provision of NRs. 50,000 package for Nepalese displaced families and NRs 4,500 for Indians has been made to encourage people to return home. The capacities of many internally displaced people has been improved through different types of training. However no effort has yet been made for the rehabilitation of damaged land and resettlement or other alternatives for those who are unwilling to return home.

138. It has been planned for the maintenance of all those spurs which are shortened due to toe cutting by the river. It was reported that the proposed plan i.e. the addition in length by 100m in the existing spur in many places is not enough to reduce the risk of beach.

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139. Improvement in the road network- 23 km of the Jhumka-Chatra road, 12 km Dharan-Chatra road, Kanchanpur-Fattepur road and the Inaruwa- Jalpapur-Dewangunj road and the provision of a ferry with a maximum capacity of transporting 20 tons at a time, are some of the major activities performed for flood preparedness. Keeping in view the magnitude of the vehicular flow (1800 one way traffic per day), the provision of a ferry is not enough. There is a need to construct a permanent bridge for better preparedness.

140. Local people including political parties at a local level are not well aware of the need of for preparedness activities. They often care for fulfilling immediate needs. During the discussion, it was reported that the investment in improvement in roads is a waste of resources. They demanded that investing that resource for the rehabilitation of displaced people should be a priority rather than spending on road improvement. It is in this context that efforts should be made to make local people aware of the importance of flood preparedness activities and the development of a preparedness plan by involving them, in order to reduce and manage the risk of flood hazard in the future.

3.11 Flood Fighting and Preparedness ( FF&P)

141. The assessment revealed that there is no organization responsible for flood fighting and preparedness. There is no preparedness plan in place. Notwithstanding, there is a mechanism that exists to undertake relief measures after a disaster has already occurred. A large gap exists in terms of organization, especially when it comes to coordination. The Government of Nepal (GoN) has mandated the Department of Water Induced Disaster Prevention (DWIDP) under the Ministry of Water Resources (MoWR) to deal with water induced disasters. In the Koshi case according to the Nepal-India agreement, the Government of India (GoI) is responsible for all infrastructural works including repair and maintenance from Chatra to the Indian Border. This makes DWIDP’s role

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almost none existent in the area from the Chatra confluence to the Barrage. The GoN has mandated the Department of Hydrology and Meteorology (DHM) for hydrological and meteorological data collection, including early warning and flood forecasting on a nation-wide basis, but the DHM has very limited instrumentation in the Koshi river basin. Needless to say the establishment of an Early Warning System (EWS) is one of the prime requirements for flood fighting and a preparedness plan to save lives and properties on n both the Nepali and Indian side. The assessment clearly demanded that a fully- fledged EWS is established on a priority basis as a non-structural measure in the Koshi Basin.

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4 CONCLUSIONS AND KEY ISSUES

4.1 Introduction

142. As requested by UNCT in Nepal, UNESCO fielded a team of government officers from Nepal and experts from both India and Nepal. The Team was assigned to undertake a Rapid Hazard Risk Assessment. The Team has just completed their field work. The following conclusions can be drawn from the team’s findings:

143. The river has been diverted within the course of the designed embankment. A very dry winter in Nepal has helped the breach repair.

144. The construction work is going on satisfactorily and the observation by the team’s structural engineer has been very positive on the quality and pace of construction. The efficiency of the Indian engineers in spearheading the task deserves appreciation.

145. Having said the above, if analysis is made of the pre-breach conditions of 2008, there are several conditions that still exist that indicate the existence of risk. The following paragraphs briefly evaluate these threats:

4.2 Technical Issues:

146. All the spurs along the embankment require major repair work. The rebatement along the sides of the spurs are almost non-existent. Also most of the noses and the aprons of the spurs are eroded. As the Team’s analysis has established that the breach of 2008 had principally occurred due to the spur failure, followed by the embankment failure, there is a need to consider restoring spurs to their original design lengths.

147. The team identified that all spurs have been shortened on average by 20- 70 meters and they need to be restored to their design length and their noses and launching aprons need to be repaired. The repair work falls short of what is considered adequate.

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148. The condition of the spurs and the way they stand is not sufficiently strong to withstand floods of a higher magnitude. As per the Team’s observation the 2008 flood was only about 80 percent of the average high flow in Koshi. It was not one of the critical historical hydrological events which caused breaches.

149. The Teams have identified three places upstream of the current breach requiring immediate attention, as the constricted flow of about 75% of the total flow is flowing only 70 meters away from the embankment. These spots in Rajabas, Prakashpur and Pulthegaunda need immediate attention as a breach in either of these spots could cause massive destruction in the area compared to the 2008 breach.

150. The geomorphology of the river is poorly understood and as the world’s second largest silt carrying river, the role of silt in bank erosion needs further study.

151. The basin is also prone to danger due to GLOF-related events. Although the problem will not be so much about water but about the silt that the GOLF can potentially bring down to the alluvial fan. This can dramatically decrease the cross-section of the river, ultimately leading to possible over-topping of the embankment.

152. The river is still flowing along the eastern embankment in a narrow channel highly prone to erosion. The Google image of 2004 clearly shows the concentration of flow, which still exists.

153. The trees in between the spurs inside the embankment in the Koshi wild life reserve can act as attracting spurs upon their natural felling due to smaller floods.

154. The western embankment is in relatively worse shape and if the river course changes its course towards the western bank, a bigger catastrophe could occur.

155. The use of latest technology and mathematical modeling is lacking (or reportedly on-going), which could alternatively justify constructing

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frequent shorter length spurs. The shorter length flood could facilitate maintenance and flood fighting measures quickly as practiced in the Sunsari Morang command area development.

4.3 Institutional Issues:

156. The maintenance of the embankment is guided by a bilateral treaty and in this treaty it is highly desirable that the role of Nepal should be enhanced. Reportedly, this has lead to deliberate delays and/or obstruction of work.

157. Several forms of communication failures, similar to those that existed before the 2008 breach, still exist amongst the various agencies involved in flood risk reduction.

158. Transparency in monitoring of the embankment and spurs still has room for improvement. Information on regular periodic maintenance and repairs needs to be properly archived. At least on the Nepal side, no such archive exits.

159. The role of the authority that oversees wildlife reserve of Koshi may be looked at again and revisited. Reportedly, the monitoring of spurs was hampered due to indifferent behavior and neglect. This also has a bearing on clearing of trees on the river-side of the embankment.

160. There appears to exist a focus on flood fighting and not so much focus on the repair and maintenance of the spurs. Obviously, the “wait and watch” approach is taking prevalence over prompt repairs and maintenance.

4.4 Social Issues

161. There is a need to look again at the broader picture of the basin and the application of non-structural approaches, such as erosion control at the source of the river upstream are essential.

162. The 2008 breach displaced nearly 7000 families in which majority are landless and poor farmers. Their vulnerability to flood hazard is rather high, thus their exposure to risk is also very high.

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163. People's participation in the embankment repair and maintenance needs to be improved by involving local people in the embankment repair, maintenance and monitoring works.

164. The ownership of the embankment is the key and local people appear not to own the embankment and spurs.

165. The team was informed of several problems regarding labor, which existed just prior to breach. The team interviewed a few labor suppliers and can conclude that such problems are still likely to occur.

166. The area suffers from Bandhs and strikes almost an every alternate day. Such strikes can hamper repairs and maintenance and especially the flood fighting effort, as it did in 2008.

4.5 Preparedness Issues:

167. The team observed that the basin does not have proper data collection, information sharing and archiving arrangements. There is a need for improvement vis-à-vis the application of new technology, real time data collection, information archiving and processing.

168. There is a need to prepare hazard and risk maps and assessments which can pay particular attention to the potential sites of embankment breaching.

169. Since the coping capacity of local people is low, their capacity for risk management needs to be enhanced through capacity development interventions.

170. There is a need to develop a thorough calibrated model, either in HECRAS or in MIKE Flood and the generation of finer resolution DEM, and their application etc.

171. Despite the fact that the area is highly susceptible to flooding, the team found no early warning system or flood warning system in the area.

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172. There is a need to prepare “what-if” scenarios for the river. In this way the flood issue scenarios can be best tackled and flood risk reduction modality properly established.

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5 RECOMMENDATION FOR RISK REDUCTION

5.1 Improving preparedness

173. The embankment failure in the Koshi basin has provided sufficient reason to justify the application of all forms of risk reduction strategies. There is a need to avoid risk; develop people’s ability to live with risk; reduce risk; and develop risk transfer mechanisms and schemes wherever possible.

174. The team used the UN/ISDR strategy to analyse the preparedness of the Koshi region. No programme to reduce physical, social, economic and environmental vulnerability through the enhancement of national and local capabilities prevails in the area at all. People were observed occupying flood plains as their permanent home for short-term economic motivations and because of an over-reliance on the structural efforts put in place. From the governments’ side inconsistencies remain in terms of the attention to short- term emergency relief measures and very little long-term thinking or investment in disaster preparedness, including that for institutional capacity- building. As noted people’s involvement and role in disaster risk reduction strategies is not apparent. Similarly, the broader context of disaster mitigation at the basin scale exists only in concept and currently no solid transboundary and basin-wide initiative exists for Koshi. This includes any development of a participatory process on creating awareness, processing and dissemination and for the development of empirical knowledge of risk.

175. The breach has provided a basis on which to conclude that there is a need to undertake strategic risk preparedness in the area as a national priority with a strong organizational and policy basis for implementation. For this, there is a need to better identify, assess and monitor disaster risks and enhance early warning. Suggested priorities for action could include: completing, updating and disseminating risk maps. There is a need to increase the use of knowledge, innovation and education to build a culture of safety and resilience. Suggested priorities for action may include: providing readily understood information on flood risks and protection options; capitalizing

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upon local and traditional knowledge of flood risk; training key officials on risk reduction; and making use of information and communication technology; etc. This involves taking a very straightforward approach as depicted in figure below:

Figure 5-1: Conceptual Approach to Koshi Flood Preparedness

176. This will further require an immediate review and the creation of a national flood disaster preparedness plan, the establishment and regularly testing of information systems; the promotion of dialogue and cooperative activities, both between emergency management personnel and disaster risk reduction personnel in India and also across the border.

5.2 Preparation of Flood Standing Order

177. This study has demonstrated that there is a need to prepare a detailed standing order to deal with the flood. Floods in Koshi River, as an annual event, regularly cause loss of life, damage to property and infrastructure, and are often the cause of psychological and emotional disturbance. It is the poor, forced by sheer necessity to occupy vulnerable flood prone areas constitute the bulk of victims. It can be safely stated that reducing the flood damage caused by annual Koshi floods increases social and economical prosperity of the people of Koshi River Basin.

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178. Floods can neither be eliminated nor totally controlled and so efforts are to be directed towards reducing flood vulnerability and mitigating the flood impact through improved flood managements. After the emergence of Koshi in the plain area the Koshi embankment has been the main protective device against flooding for the last few decades however, the sustainability and efficacy of massive embankment construction as a permanent flood defense, especially where Koshi carries such a tremendous amount of sediment load is a subject of serious debate and the debate has been aggravated more with the 2008 Koshi breach.

179. A non-structural approach to flood management lies in flood forecasting and early warning system. Because of frequently recurring flood events people have learned to live with these conditions and are inclined to stay with their homes and protect their belongings. With an advance early warning system, a significant reduction in losses can be obtained by taking protective and preventive measures. A timely warning provides time for the disaster services to best deploy their services.

180. The objective of establishing such a system would be to protect the agricultural land and human settlements from flooding along the entire Koshi basin with specific focus on the foothills and the low-lying areas on the either side of the embankment. The value of flood forecasting increases as the lead-time increases and hence effective and timely information dissemination to those responsible for disaster management and then directly to the people affected, would be likely to achieve a successful result.

5.2.1 Nepal-India History of Flood Forecasting Cooperation

181. It was agreed at the secretary level meeting between Nepal and India held in Kathmandu on December 22, 1987 that Nepal and India would expedite the implementation of facilities to be provided for an efficient flood forecasting system on the major tributaries of the Ganga that flow from Nepal into India. It was also agreed that Nepal would implement and maintain the system in its territory and would accept the necessary equipment from India to

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implement the system expeditiously. In pursuance of this meeting, a high level Indian delegation of technical officers, headed by the Member for (River Management), the Central Water Commission, New Delhi, held further discussions with the officers of the Government of Nepal in March 1988 and identified 20 hydro-meteorological and 25 meteorological sites. A list of additional equipment required to make these 45 stations fully operational was also identified.

182. In May 1988 a subsequent secretary level meeting decided to form an expert team to install a real-time data transmission system to India from selected rain gauge and hydrological stations in Nepal. It was also agreed that on a reciprocal basis, India would provide Nepal with hydrological data of rivers entering India from Nepal, at two points downstream of the border. ,. It was envisaged that the real time transmission of rainfall and hydrological data from Nepal would help in increasing the lead time of the flood forecast resulting in enhanced preparation time for evacuation and other preparatory measures. This transmission of data is still continuing but the efficiency, effectiveness and the benefits derived from this system are to be carefully analyzed. The system as it is now carries almost no weight in terms of adding any substantial improvement to the flood forecasting system of both countries.

183. Moreover with the recent development in communication systems, wireless data transmission is almost obsolete. There are several modern technologies available which are automatic and robust and are highly reliable, based on satellite technology and remote sensing systems. Therefore future action should be directed to establishing a full-fledged flood forecasting system for the Koshi Basin. It would consist of optimizing the hydrological and meteorological observation network, ensuring sustainable operation of the system and the establishment of early warning systems equipped with modern technology capable of disseminating reliable flood information.

184. The Nepal-India Committee on Flood Forecasting prepared a draft Flood Forecasting Network for the 7 major river basins of Nepal in July 2002. The

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network for the Koshi River Basin is attached herewith. The line diagram of hydrometric stations on the Koshi River and its tributaries in India is also attached herewith (Figure . 5.1)

Birpur G B Balan H/W Jhanjharpur Basua G D F G F

R. KAMALA R. BALAN Jainagar R. KAMALA-BALAN G D Abbreviations used: G = Gauge D = Discharge

R. DHANS Saulighat B = Base Station for FF Kamtaul GD F = Flood Forecasting Station G D F

R.JHIM R. Sonbarsa G Benibad EkmighatADHWARA G D F G D F R. KOSHI

Hayaghat GDF Baltara

GD GD G D F Kursela Banmankhi Runisaidpu Dhengbridge G F G D

R. FARIYANIDHAR

RIVER GANGA

Figure 5-2: Line Diagram of Hydrometric Station on Koshi and its Tributaries in India

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Figure 5-3: Hydrometric and Precipitation Station in Koshi Basin

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185. The draft observation station network prepared by the above committee needs to be reviewed and optimized in the present context. The Department of Hydrology and Meteorology is to be made responsible for establishing a fully operational flood forecasting and early warning System. A wide dissemination of information must be ensured and a Flood Disaster Preparedness Plan (DPP) is to be put in place. The DPP is to be coordinated by the Ministry of Home Affairs (MoHA) and the members should include the DHM, DWIDP, other relevant central government agencies, local government, local people, and NGO’s and INGO’s related with disasters. The Early Warning System (EWS) is to be constructed in such a way that all the people that come under the flood influence would be informed of the potential danger in a timely manner. Warning Sirens are to be installed in a 1 km by 1 km grid and evacuation plans are to be prepared before the monsoon. Large shelters are to be constructed for settling the evacuated people. These shelters will be on the available highland and could be used by a school or for some other fruitful purpose during the no-flood period.

5.2.2 Review of the existing hydrological and meteorological network

186. The DHM maintains 33 river gauging stations within the basin. Out of these all 33 have a manual staff gauge, 23 have the facilities to make discharge measurements from the cable-way and 14 stations have Automatic Water- Level Recorder (AWLR) in which only 6 are functional. The water level is observed only two times a day in all 33 stations. There are 19 climatological and 55 rain gauge stations. The climatological station includes the observation of temperature, relative humidity, vapor pressure and precipitation. The rain gauge stations have a manual rain gauge which is observed once in 24 hours at 08:45 Nepal time. Biratnagar Airport only has a continuous rainfall recording device.

187. After analysis of the network and the facilities available presently for flood forecasting purposes, the following points are observed and recommended:

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a. The existing network is not designed for flood forecasting purposes. This network has to be tailored in the light of flood forecasting requirements. The present network has only 6 functional AWLRs of which only the Sapta Koshi Chatra station is the most important. Data from the other 5 stations will contribute very little in the Koshi flood forecasting task.

b. The same problem exists with rain gauge stations in the basin. Many rain gauge stations are in the district headquarters and in the Terai area. Being a mountainous catchment and having very little lead-time, the network is to be modified and the rain gauge stations are to be improved by installing automatic rain gauge recorders for real time data transmission.

c. Data collection, analysis and the transmission system are to be modernized

d. A Flood Forecasting Centre (FFC) has to be established at Chatra to facilitate a data hub, an analysis wing and flood forecasting and an early warning release.

e. Real time data transmission from the river gauges and rain-gauge stations is to be fully automated using satellite links or other remote sensing devices so that the FFC could retrieve the data at any time.

f. Himalayan glaciers have become very active resulting in the formation and expansion of glacial lakes. The UNEP and ICIMOD study of 2002 shows that 26 glacial lakes of the Nepalese Himalayas are potentially dangerous and can create Glacial Lake Outburst Flood (GLOF). GLOF of smaller magnitude during the dry season may not influence the Koshi plain area much but, if it is combined with the monsoon rain-fed flood it may cause heavy casualties. Therefore the FFC is to be strongly linked with the GLOF monitoring system.

g. The FFC at Chatra would disseminate flood information and issue warnings. It would also be responsible for raising public awareness.

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h. Additionally, a flood hazard map is to be prepared to identify the risk area in relation to the flood level. It will help in ascertaining flood affected areas and information dissemination to the people.

5.2.3 Strategy to prepare a Flood Standing Order

188. Preparation of status reports for appropriate stretches from the Chatra confluence and identification of the desired level of preparedness associated with each of the stretch. Ideally, there should at least be an ultra sonic technique-based sensor, a staff gauge or radar installed to determine flow. The Joint Koshi High Level Committee could request the Department of Hydrology and Meteorology and Department of Water Induced Disaster Preparedness to carry out the feasibility and install such a system.

189. Re-evaluate and re-design of hydrometric system in the basin: There is a need to reevaluate the sufficiency of the stations that DHM maintains and their effectiveness in relaying the relevant information to processing hubs. There is a need to establish more number gauging stations on the stretch from the confluence at Chatra to the Barrage. Local people may be trained and instructed to provide the reading or any visual observation by phone to the authority. 190. Establishing basic protocol for information collection, processing and dissemination: For this a standard guidebook can be prepared. According to the water level at Chatra and in the AWLR, established in the 42 KM stretch, the flood and

its intensity may be defined as: Minor Flood Level; Major Flood Level;

Dangerous Flood Level and Critical Flood Level.

191. Flood forecasting : The DHM should collect hydrological and meteorological data from all river gauging stations and rainfall stations in the basin. The usual method can be adopted to provide the daily stage heights and rainfall data to the monitoring centre in Chatra (or in any other of the other station before the barrage) at the end of each month. However, when floods are expected during the monsoons, field personnel can be asked to submit the hourly data to the monitoring centre via telephone and radio transceivers. If a

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flood of a very high magnitude is expected, field personnel can be instructed to provide stage heights and rainfall figures hourly. Based on these, runoff figures can be calculated using rating curves and the MIKE 21 or MIKE FLOOD package, and the areas that would be inundated can be made known to the public through radio and television. Simultaneously hourly stage heights can be plotted and using previous experiences, a rough idea of the intensity of the flood could be arrived at.

192. Flood warning : When the water level reaches minor flood level at Chatra or on other established stations with the continuous rainfall in the upper catchment, a minor flood warning can be given. At this time the flood monitoring centre can issue warnings to the public via television, radio, the district office and the police stations, using loudspeakers. This information can simultaneously be shared with people in India. The level and seriousness of the warning may be increased as the water level height increases.

193. List of accountability: An office for the flood committee can be instituted at the Regional DWIDP office in Biratnagar with a mandate to share information with their Indian counterparts. For mitigation of floods in the Koshi, the currently established RRU may be used. This may receive instructions on an ‘as and when needed’ basis, or when notification of a flood of major or dangerous level is received, from the JHLC.

5.3 Assessment of Early Warning System (EWS) and Strategy for creating EWS

194. The Department of Hydrology and Meteorology (DHM), the principal collector and disseminator of hydro-meteorological data of Nepal, has established several hydrological and meteorological stations in Koshi River basin (see section 5.2 for details).

195. The team assessed and categorically states that frequency of discharge measurement for developing rating curve is very low. Not least to note the reliability of rating curve is questionable. That means discharge data

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computed from rating curve and all assessments made thereof are questionable.

196. The team found that high frequency discharge and rainfall data, e.g. hourly data are not available. Daily data is collected and is available to purchase it. Numerical weather forecast for the basin is not available. Similarly no telemetry system is installed to transmit data in real time.

197. As noted earlier, Koshi Basin receives bulk of its waters from the Chinese side. There is no hydrometeorological data exchange agreement between China and Nepal on the basin. This situation is complicated by sparse raingauge network, no data on rainfall intensity, as well as prevailing poor understanding of space and time variability of rainfall. Thus, full hydrological regime can not be represented due to limited number of stream gauging stations. Similarly, there is no systematic snow measurement except in two stations. The available length of record is generally short and only a few variables are being measured.

198. Similarly, continuous records of sediment load data are not available. There is no high resolution DEM that can be accessed and there are no properly surveyed cross-sections. Although DHM has a unit named ‘Flood Forecasting project’, forecasting has not been started yet due to lack of real time data transmission system, forecasting model and dissemination system. Neither there are any solid efforts in place that can change the system hitherto in place anytime soon. There are very few trained hydrologists to produce reliable forecasts.

199. Given the recurrence, importance and huge implications of the Koshi River flooding, it is imperative that an early warning system be developed for the river, spanning over the entire river basin across Nepal and India.

200. The early warning system must use stage data from a Real-Time Data Acquisition System (RTDAS) with electronic sensors to measure river stages.

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201. A few, automatic rain gauges must be installed in the catchment area. Locations for these must be decided based on hydrologic features of the catchment.

202. Simple and computationally fast flood forecasting models must be developed specifically with the real time data likely to be available. For example, use of Artificial Neural Networks (ANNs), that use the rainfall in the catchment area and river stage at several locations in the river on a real time basis may be developed to issue flood forecasts.

203. Separate ‘soft’ warnings may also be issued based on the structural conditions of the embankments and the spurs, even in the absence of a critically high flood forecast.

204. Administratively, a single window should be created for real-time data acquisition (both hydro-meteorological and structural), executing the forecasting models and issuing warnings.

205. Currently improving data collection is the only way forward as it will be key to establish the EWS and thus better the flood preparedness in the downstream stretches.

a. There is a need to develop a concept and reach understanding on data collection protocol between China and India.

b. There is a need to prepare a finer resolution (preferably 5-10 m resolution) DEM of Koshi River. Most analyses appears to have been done based on the high resolution freely available DEM (SRTM 90m DEM). Higher resolution DEM will be needed to get more accurate drainage network, slope, drainage length and cross-sectional parameters, and to produce quality inundation map. There is a need to explore the possibility of generating high resolution DEM from available contour map.

c. As regards hydro-meteorological data, the responsible agency, DHM, is desired improve existing hydro-meteorological network density.

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d. Efforts should be made to automate hydrological and meteorological data recording and collection system and collection of continuous data with short intervals. This may be coupled with real-time communication system to transmit data from field to dedicated forecast offices.

e. Rather than depending on traditional methods of discharge measurement, which is quite tedious and less accurate for large rivers, the possibility of modern methods should be explored. For Example, the measurement of discharge may be done using ultrasonic system (acoustic signal) and the measurement of discharge from space may be enhanced by coupling data collection with satellite-based sensors that can measure hydraulic variables, such as water-surface width, water-surface elevation and slope, and the surface velocity of rivers. Similarly for water level data, measurement of water level may be initiated using radar sensor (microwaves).

f. Much also is needed to improve the data transfer situation. Although communication system has really taken a leap forward in the recent years, existing system still rely on wireless system. Use of internet, CDMA, satellite or other wireless communication system can really enhance the data dissemination.

g. Recently, there have been many breakthroughs on the application of satellite-based rainfall for ungauged or poorly gauged basin and the same technology may be introduced to develop near real time flood forecasting system until a more ground-truthing based approach is established in Koshi. A quick assessment to determine the feasibility of using satellite-based rainfall data is therefore very timely.

h. There is a need to establish a basin-wide hydro-meteorological database and management system or at least develop a barebone structure that can be collectively worked on by the countries that share the basin or are prone to flooding.

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206. The team also suggests that there is a need to simultaneously improve the flood forecasting modeling capability on the part of the authorities. These may be process-based hydrological and hydraulic models (routing models); hydrodynamic model, or soft-computing models.

207. The team suggests application of BTOPMC (Block wise use of Top model with Muskingum-Cunge routing), which is distributed hydrological model developed at the University of Yamanashi, Japan. Given the model is based on freely available DEM and data on soil, land use, and NDVI and CRU climate data (for computing evapotranspiration). The model offers grid by grid computation of flow and also spatial distribution of variables. It is noted however that the model has several calibration difficulties and may take a very high computation time for large basins.

208. Similarly, there may be a staged approach for which universities or research institutions may be contracted. Utilization of lumped conceptual hydrological models like NAM, TANK, UBC, HBV etc. by dividing up the basin into a number of small sub-basins. This will be easy to implement and also be rapidly computation time. However, this can also render difficulties in calibration and may not provide reliable result outside the range of calibration.

5.4 Maintenance of Spurs

209. The existing spurs along the river bank are long and spaced at considerable distances. As the spacing of spurs is a function of the spur length, the existing arrangement of long spurs at large distances is theoretically correct. Longer spurs also keep the river flow substantially away from the embankments. However, the drawback of this arrangement is that damage to any one of the spurs washes out the still water pool and erodes the bank line over the entire distance between that particular spur and the next downstream spur. Thus, the river flow is allowed approach the embankment over a considerably long stretch, resulting in the possibility of toe cutting of embankments and

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possible their breaching. This effect is particularly severe immediately upstream of the next downstream spur. This phenomenon also stresses the downstream spur and can result in a chain reaction whereby

210. In view of the above, it is prudent to build a series of shorter spurs at regular intervals. Though it draws the river flow closer to the bank line, this arrangement minimizes the exposed length of the embankment in case of failure of any one particular spur in the series of spurs. Even in this case, all the problems referred to above may still come into play within the affected span; however, the affected span is localized and is, therefore, not likely to affect most of the downstream spurs. The localization of the problem also eases repair and rehabilitation works. Needless to say, the repair and maintenance of shorter spurs is also easier than that for longer spurs.

211. During the inspection, it was noticed that protection at the spur noses were damaged or completely washed away. As they are most vulnerable to damage during floods, the spur noses should be provided with adequate protection through boulder pitching or placement of gabions or interconnected pre-cast concrete blocks.

212. It appears that the spurs and embankments have not been regularly maintained over the past few years. Therefore, regular inspection and maintenance of the spurs and embankments, particularly before the onset of monsoon, must be made mandatory.

5.5 Comprehensive study to redesign the spurs

213. While it is necessary to treat the Koshi river flooding with an integrated approach, addressing river morphology, hydrology, engineering and socio- economic aspects simultaneously, the designs of the structural measures already in place, (viz., the embankments, the barrage and the spurs) must be revisited and checked for their adequacy in view of the complexities of the problem and the huge implications of structural failures.

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214. The spurs were designed as part of the Koshi project in the late fifties/early sixties. The locations, the length and the structural aspects of the nose and the apron of the spurs should be studied with sophisticated mathematical models using the latest methodologies that consider the hydrodynamics and geomorphology of the river. The end results of such studies should be aimed at providing renewed designs of the spurs – in terms of their location, geometry and structural design.

215. The option of providing a larger number of correctly located spurs which are shorter i.e. smaller in size, both on the east and west banks, must be explored in these studies. The shorter spurs may be easier to maintain and are likely to be less prone to puncturing.

5.6 Dam break analysis

216. Comprehensive dam break analysis with good quality data from both the Nepal and Indian sides, should be carried out. The aim of such analysis should be to assess implications of flooding if a breach occurred again. The analysis should be carried out with different flood discharges and resulting vulnerability maps must be put in place. Typical data required for such an analysis are the flood hydrographs, the channel geometry and hydraulic characteristics, complete mapping of the floodplains, including contour maps, land use patterns and socio-economic data on the settlements in the floodplains. Sophisticated models are now available for carrying out such analyses and must be made use of.

217. The dam break analyses should be carried out with simulated breaches at several potential locations on the embankment and also at locations where river diversion works are in place (e.g., around chainage 23.1 km to 26.9 and at Pulthedunga

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5.7 Generating ‘what-if scenarios’

218. With the dam break analysis and/or otherwise, a number of critical flooding scenarios should be worked out for the river.

219. A well calibrated hydrodynamic model that also considers sediment deposition and river morphology (e.g., the MIKE21 or the HEC-RAS) may be used along with a specialist dam break model to generate the scenarios. The services of academic and research institutes well versed with such modeling must be used for generating the scenarios.

220. A typical non-exhaustive list of the possible scenarios to be generated is:

a. Similar embankment breach occurring in immediate future, with varying discharges;

b. Higher floods and larger breaches; number of breaches occurring simultaneously at several locations.

c. Overtopping floods – the embankment does not breach but gets overtopped, both on eastern and western banks.

d. Flooding on the western side – embankment breach on the western slide Deposition of heavy sediments due to GLOF

e. Simultaneous embankment failure on eastern and western banks

f. Lake formation due to landslides

g. Cloud burst events, resulting in instantaneous high discharges.

5.8 Monitoring mechanism

221. A strict monitoring mechanism must be put in place immediately to help in issuing early warnings.

222. As an important component of monitoring, extensive instrumentation must be put in place to detect scouring at the spurs and at potential locations along the two embankments.

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223. A real-time data acquisition system (RTDAS) may be implemented to monitor a critical rise in water levels at several locations in the river. Such systems typically involve electronic sensors and will be useful in issuing early warnings.

224. Routine general monitoring and periodic maintenance of spurs and embankments must be put in place.

225. Additionally, comprehensive stretch-wise monitoring that includes examining the structural condition of the embankment and the spurs must be taken up periodically.

5.9 Manpower Training:

226. Trained professional manpower is required for flood fighting. Personnel working in EWS need extensive in-house and a practical training (which may be in India for a period of about a month during the flood season) where there is a functional EWS followed with refresher courses. Local people are to be trained in flood fighting and attend periodic awareness-raising program.

5.10 Construction of Retired Embankment

227. The authorities should hasten the existing repair work and also consider constructing additional works, remembering that in spite of proper maintenance, the possibility of a breach in the eastern embankment during high floods in future years, cannot be ignored. An appropriate measure for this purpose appears to be to provide a retired embankment. The location, profile and alignment of the proposed retired embankment shall have to be decided based on detailed hydraulic and hydrological investigations. The third phase would consist of long term planning and would be considering the continued aggradations within embankments rendering the further raising of the embankments, even after long period.

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228. The provision of an additional retired flood embankment is considered as an appropriate provision so that if the existing embankment is breached again, the retired embankment would come into play and provide protection against flooding. This retired embankment can better be compartmentalized by providing cross embankments at intervals so that if and when a breach occurs in the existing embankment, flood water would fill the specific compartment opposite the breach and form a pond. The result of this will stop further development of the breach and closing the breach will become easier, faster and much less expensive.

229. Such a retired embankment will obviously involve high cost but it will be justified considering the colossal damage and cost incurred in flood fighting and flood relief work entailed last year after the breach in the existing embankment. Details investigations of the feasibility of this proposal should be commenced at the earliest opportunity. This shall require detailed hydraulic and hydrological investigations, involving both mathematical and physical modeling, which can be commenced immediately.

5.11 Long term issues – climate change

230. Climate change is likely to have an adverse impact on the intensity, magnitude and frequency of floods, particularly in the snow fed Himalayan Rivers. A systematic study should be taken up to work out the intensity- duration-frequency (IDF) relationship for the Koshi river basin in the face of climate change. These relationships must be used to check the adequacy of the structural designs and to formulate the non-structural responses (such as issuing early warnings).

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5.12 Recommended activities and responsibilities

Sl. Activity Primary Secondary Timeframe Comments No. Responsibility responsibility

1. Disseminate the Rapid RHA UNCT - Immediately Dissemination Report of RHRA 2. Second stage HRA with MOHA/DWIDP/MP OCHA , ADB, Immediately detailed field investigation PW UNESCO, IASC 3. To ensure implementation of MOWR/MPPW/Rele ADB/UNDP/IASC 1-3 years HRA recommendations vant Line Ministries and Department 4. Technical examination, MOWR/WECS DWIDP/ District Continuous Until a rehabilitation, maintenance (through bilateral Authorities permanent and monitoring of Spurs and channels) solution is Embankments reached 5. Establishment and operation DHM/DWIDP ADB, Bilateral agencies 2-5 years Regular of a Koshi Basin Flood Forecasting System 6. Establishment and operation DDRC /DDC UNDP. IAS C 1-3 years 6 months for of a Community-Based Early establishment of Warning System CBDP Unit 7. Awareness creation and DDC/UNDP UNCT 1-2 years capacity enhancement of local people and CBDP unit 8. Formulation of a flood-disaster DDRC/DWIDP/MO NRCS/IASC 6 months response plan fro Koshi WR/UNDP

9. Re deliniation of Koshi Wildlife Ministry of forest, - 6 months – 1 Reserve department of Year wildlife 10. Address possible labor issues Ministry of labor, DDC/CDO/ILO/UN Before the onset district administration DP/ADB of monsoon , representatives of political parties 11. Installation of river monitoring DHM, DWIDP Donor agencies/UNCT 1-2 years devices in the stretch below Chatra 12. Establishment of embankment District MOWR (through Before the onset monitoring committees administration , bilateral negotiations) of next monsoon representatives of political parties, liaison office 13. Preparation of detailed DWDIP/UNCT MPPW 1-2 years standing order for Flood Preparedness 14. Preparation of implementation DDRC/ MPPW/MOHA/UNC 1 year strategy for risk management DWIDP/NDP T/ ADB and other plan bilateral donor agencies 15. Undertake detailed modeled- MOWR (through UNCT 1-5 years Scientific based geomorphology and bilateral negotiation) Investigation for river engineering study Disaster Reduction 16. Rehabilitation of DAO/DDC?FAO UNDP/MOLD/ 1-4 year degraded/damaged land ADB/UNCT

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Sl. Activity Primary Secondary Timeframe Comments No. Responsibility responsibility

17. Resettlement of displaced MoHPP, UNDP/UN 0-2 year families MoLRLM/MoHA/M HABITAT/ OLD/MOAC UNICEF/UNCT/ADB 18. Improvement of alternative DoR/DDC/DDRC ADB/UNDP/WB/WF 1-5 years access roads , with emergency P (under food for management corridors work) 19. Skill development and CTEVT/DAO/DoSCI UNCT, 3 years alternative livelihood for ADB/WB/ADBN displaced people 20. Flood disaster preparedness – MOHA/DDRC/NPC UN habitat, UNDP, 3 years shelter place development and /DDC FAO, IOM, WFP, management, development of NRCS/UNICEF food security system 21. Flood disaster risk MoIC, UNCT, IASC/UNDP 1-3 years communication- preparation DDRC/NPC/DDC/D of posters, pamphlets, audio EO visual broadcast 22. Institutional cap acity building: MOHA/DDRC/DDC UNCT/IASC 1 year central and local bodies /UNDP including NGOs/INGOs through training

5.13 Medium term Plan

231. There is an urgent need to implement the medium term action, which has already been agreed and some funds secured. The RHRA team proposes that it will be most appropriate in the medium term to consolidate the findings of the rapid assessment, develop at least two detailed dam-break analysis, and develop a detailed standing order for flood risk reduction in the confluence below Chatra.

232. The risks do exist but there are enough tools available which can be used to minimize them to make them acceptable risks. Still more research and, most importantly, willingness to work together is needed.

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6 REFERENCES

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Mishra, D.K. 2006. Dui Patan Ke Bich: Koshi Nadi ki Kahani Loka Bigyan. Santhan Dehra Dun. Reineck,H.-E. and Singh, I.B.1980. Depositional Sedimentary Environments with Reference to Terigenous Clastics (second revised and updated edition). Berlin, Heidelberg and New York: Springer-Verlag. UN/GA, 2004, World Conference on Disaster Reduction, Draft Programme Outcome Document, A/CONF.206/PC(II)/4, 13 August 2004, 13 p. Viljoen, M.F., du Plessis, L.A., Booysen, H.J., 2001, Extending flood damage assessment methodology to include sociological and environmental dimensions, in Water SA , Vol.27, No.4, October 2001, 517-521

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