Consultant Report Nepal: Water Resources Project Preparatory Facility

Consultant Report

Project Number: 45206-001 September 2020

Nepal: Water Resources Project Preparatory Facility Feasibility Report: West Rapti Basin

This document is being disclosed to the public in accordance with ADB's Access to Information Policy.

GOVERNMENT OF NEPAL

Ministry of Energy, Water Resources and Irrigation

Department of Water Resources and Irrigation

WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal Feasibility Report: West Rapti Basin

10 October 2019

Mott MacDonald 22 Station Road Cambridge CB1 2JD United Kingdom

T +44 (0)1223 463500 F +44 (0)1223 461007 mottmac.com

WRPPF: Preparation of

1243 124 124 Priorityhttps://mottmac.sharepoint.com/teams/pj-b1549/Shared River Basins Documents/02-Flood Reports/Feasibility Study/West Rapti/West Rapti 101019/West Rapti FS_Final 101019.docx Risk ManagementMott MacDonald Project, Nepal Feasibility Report: West Rapti Basin

10 October 2019

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Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal Feasibility Report: West Rapti Basin

Issue and Revision Record

Revision Date Originator Checker Approver Description 0 22/03/19 Consultants A. Akindiji C. Hetmank 1st submission team 1 17/04/19 Consultants A. Akindiji C. Hetmank 2nd submission team C Eller 2 12/07/19 Consultants A Akindiji C Hetmank 3rd submission (Final) team C Eller E Stanley 3 10/10/19 Consultants A Akindiji C Hetmank 4th submission (Updates to the team P Mawson Economics section of Final ADB Report)

Document reference: 383877 | REP | 0044

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Contents

Executive summary 3

1 Introduction 15 1.1 Project rationale 15 1.2 Objectives of the feasibility study 17 1.3 Purpose of this report 18

2 West Rapti Basin 19 2.1 Location and area 19 2.2 Land use and settlement map 20 2.3 Geology and structure of hill slope catchment 21 2.4 Relief and slope of the upper catchment 23 2.5 Historic flooding events 24

3 Selection of priority works 25 3.1 Introduction 25 3.2 FHRMP Package 3 Output 25 3.2.1 Approach 25 3.2.2 River training structures Package 3 28 3.3 Priority areas included in PPRBFRMP (Package 7) 29 3.4 Structures included in Package 7 31

4 Hydrological and hydrodynamic models 34 4.1 Introduction 34 4.1.1 Hydrological model 34 4.1.2 Hydrodynamic model 36 4.2 Climate change 39 4.3 Modelling results 39 4.4 Analysis 39 4.4.1 Impact hydraulic conditions 39 4.4.2 Velocity distribution 43 4.4.3 100 years return period 44 4.4.4 Protected land 44

5 Designs of hydraulic structures 45 5.1 Introductions 45 5.2 Basis of Development 45 5.2.1 Design strategy 45 5.2.2 Guidelines and standards 47

5.2.3 Climate change 47 5.2.4 Design return period 48 5.2.5 Design life 48 5.2.6 Freeboard 48 5.2.7 Lacey’s wetted perimeter 48 5.3 Room for river 51 5.4 Topographical survey works 51 5.5 Flood protections works 51 5.6 Preliminary designs 55 5.6.1 Innovative and nature-based solutions 55 5.6.2 Morphology assessment 56 5.6.3 Designs 60 5.7 Cost estimates improvement works 64

6 FFEWS and CBDRM 66 6.1 Introduction 66 6.2 Existing and proposed rain gauge network 66 6.3 Proposed hydrometric network installation 68 6.4 Proposed hydrometric equipment 69 6.5 Topographic and asset survey 70 6.6 CBDRM and flood shelters 70 6.6.1 Participatory approach 70 6.6.2 Flood shelters 71 6.6.3 Gender and ethnic group inclusion 73 6.6.4 Number of flood shelters 73 6.7 Cost estimates 75

7 Cost benefit analysis 76 7.1 Basis for the Analysis 76 7.2 Benefits 76 7.3 Costs 77 7.4 Results of the Economic Analysis 77 7.4.1 Key Assumptions 77 7.4.2 Results of the Analysis 78

8 Safeguards 79 8.1 Introduction 79 8.2 Environmental safeguards 79 8.2.1 Project Influence Area 79 8.2.2 Priority Project Activities with Environmental Consequences 79 8.2.3 Baseline Environment 80 8.2.4 Anticipated Environmental Impacts and Mitigation Measures 81 8.2.5 Public Consultation, Institutional Arrangement and Grievance Redress Mechanism 82

8.3 Social safeguards 83 8.3.1 Indigenous Peoples (IP) 83 8.3.2 Involuntary resettlement 87

9 Implementation 91 References 93 Appendices 94

A. Flood maps 95 A.1 Flood maps: Run 1 95 A.2 Flood maps: Run 2 102 A.3 Flood maps: Run 3 109

B. Modelling results 116 B.1 Modelling Results – Run 1 116 B.2 Modelling Results – Run 2 146 B.3 Modelling Results – Run 3 177 B.4 Velocity distribution over cross-section for all runs – 50 year return period 207 B.5 Comparison modelling results 1 per 50 years return period 212

C. Design calculations 217

D. Civil works: BoQ and cost estimates 226

E. Methodology for the Economic Analysis 227 E.1 Background to the Analysis 227 E.2 Approach 228 E.3 Infrastructure and Housing 229 E.4 Agriculture 234 E.5 Human Mortality and Injury 237 E.6 Livestock 239 E.7 Prevention and Coping Mechanisms 240 E.8 Economic Assumptions 241 E.9 241 E.10 Prices 242

F. CBA data West Rapti 244 F.1 Background to the Subproject Area 244 F.2 Subproject Interventions 244 F.3 Beneficiaries 244 Source: Consultants’ flood modelling results; the population in the unprotected areas will be those most benefitting from the FFEWS and CBDRM measures. 245

F.4 Benefits 245 Source: Consultants’ flood modelling results 245 F.5 Total Subproject Benefits 250 F.6 Costs 251 F.7 Results of the Economic Analysis 251 Economic analysis 255

G. IEE 256

H. GESI Action Plan 257

I. Civil works: Preliminary designs 258 I.1 Priority areas 258 I.2 Drawings preliminary design 258

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List of abbreviations

ADB - Asian Development Bank ADCP - Acoustic Current Doppler Profiler BCR - Benefit Cost Ratio CBA - Cost Benefit Analysis CBDRM - Community Based Disaster Risk Management CDMC - Community Disaster Management Committee DEM - Digital Elevation Model DGPS - Differential Global Positioning System DHM - Department of Hydrology and Meteorology DoWRI - Department of Water Resources and Irrigation DP - Displaced People DPR - Detailed Project Report DWIDM - Department of Water Induced Disaster Management EIRR - Economic Internal Rate of Return EMP - Environmental Management Plan FFEWS - Flood Forecasting and Early Warning System FHRMP - Flood Hazard Mapping and Risk Management Project GESI - Gender Equality and Social Inclusion GIS - Geographic Information System GoN - Government of Nepal GPU - Graphical Processing Unit GRM - Grievance Redress Mechanism H&S - Health & Safety HEC-HMS - Hydrologic Engineering Center - Hydrologic Modelling System HEC-RAS - Hydrologic Engineering Center - River Analysis System HPC - Heavily Parallelized Compute IEE - Initial Environmental Examination IP - Indigenous People LARIP - Land Acquisition, Resettlement and Indigenous People LS - Lower Siwaliks masl - Meters Above Sea Level MFT - Main Frontal Thrust MoEWRI - Ministry of Energy, Water Resources and Irrigation MoF - Ministry of Finance MoHA - Ministry of Home Affairs MS - Middle Siwaliks MS1 - Lower Middle Siwaliks MS2 - Upper Middle Siwaliks NFDIN - National Foundation for Development of Indigenous Nationalities NGO - Non-Governmental Organisation NPR - Nepalese Rupee NPV - Net Present Value OHS - Occupational Health and Safety PEP - People Embankment Program PIU - Project Implementation Unit PMU - Project Management Unit PPE - Personal Protection Equipment

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PRTW - Proposed River Training Works Q - Discharge RCP - Representative Concentration Pathways RSG - Remote Sensing Group SCF - Standard conversion factor SERF - Shadow Exchange Rate Factor SWRF - Shadow Wage Rate Factor UK - United Kingdom US - Upper Siwaliks USD - Unites States Dollar VAT - Value Added Tax VDC - Village Development Committee WL - Water level WRPPF - Water Resources Project Preparatory Facility

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Executive summary

Introduction

Nepal is considered one of the most disaster-prone countries in the world. Alongside other natural hazards, such as earthquakes and landslides, flooding poses a recurrent risk to large sections of the population. Flooding has a particular impact on communities residing in the Terai region (lowland region across southern Nepal). Thefigure below indicates affected areas during the monsoon in August 2017.

Figure E1: Monsoon affected districts 11-13 August, 2017 (source: reliefweb.int) The Terai region occupies approximately 17% of the country and is known as the granary of Nepal. Agriculture in the Terai region is dominating the economy in Nepal with production of major crops such as rice, wheat, pulses, sugarcane, jute, tobacco and maize. The Terai region has a long history of floods affecting farmland, crops and livestock, which affect lives, livelihoods and property of poor communities. Critical infrastructure such as embankments, roads, communication infrastructure, power supply and overall development of the region are also significantly affected by floods.

Acknowledging the importance of the Terai region to Nepal, the Government of Nepal, through the Ministry of Energy, Water Resources and Irrigation, is implementing the ‘Priority River Basins Flood Risk Management Project’ in the Southern Nepal Terai region, which is supported by the Asian Development Bank. The project is the continuation of the pre-feasibility study: Package 3: Flood Hazard Mapping and Risk Management Project (FHMRM). The project includes the following river basins:

1. Mohana – Khutiya Basin;

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2. Mawa – Ratuwa Basin; 3. Lakhandei Basin; 4. West Rapti Basin; 5. East Rapti Basin; 6. Bakraha Basin.

This feasibility report is prepared for the West Rapti Basin. Mott MacDonald (the Consultant) has undertook hydrological and hydrodynamic modelling, preparation of preliminary designs of civil works, Flood Forecasting and Early Warning Systems (FFEWS), Community Based Disaster risk managememt (CBDRM), Cost-Benefit Analysis (CBA) and the assessment of social and environmental safeguards under the scope of this feasibility study.

The West Rapti Basin, located in central Nepal in the Terai region (see figure below), is severely affected by floods causing damage to communities, agriculture, public infrastructure. For sustainable development and to mitigate flooding in the West Rapti Basin, structural measures are required.

During the 27 June 2018 meeting between WRPPF, DHM and the Consultant, it was concluded that FFEWS and CBDRM would not be included in the Package 7 project as it was already covered by the project “Establishment of End-to-End Flood Early Warning System In Koshi And West Rapti River Basins To Support And Strengthen Disaster Risk Management”. The project is financed by the World Bank.

During the final ADB review meeting in December 2018, with WRPPF and ADB, it was requested that Package 7 Consultant to include some FFEWS equipment and CBDRM as it was not fully covered by the other project.

The Package 7 project objectives are; to alleviate poverty by protecting residential properties and incomes, to provide an increased range of livelihood opportunities and to mainstream opportunities for women.Project’s interventions will be designed to:

1. Reduce the incidence of severe floods; 2. Protect resident houses and public infrastructure, particularly in urban areas and market centres in the basins, from severe floods; 3. Protect agricultural land by reducing bank scouring and soil erosion; 4. Reduce the loss of life and injuries from flood events.

The objectives of the feasibility study are:

- To confirm economic and financial viability of capital investments which will be implemented within the scope of this project;

- To evaluate the robustness of the economic analysis of the project (sensitivity analysis).

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Figure E2: West Rapti Basin Hydraulic structures (structural measures)

Due to limited budget (approximately 65 million USD for 6 sub-projects), not all structures can be constructed. Under the Package 7 project, the potential locations for structural interventions have been prioritised, in close cooperation with the Water Resources Project Preparatory Facility (WRPPF) and People Embankment Program (PEP) field office. The main inputs to location prioritisation are (i) FHRMP Package 3 (pre-feasibility), (ii) the Detailed Project Reports (DPRs), (iii) site visits undertaken during the early stages of Package 7 to assess the on-ground situation and (iv) discussions with knowledgeable Government staff.

A comparison of structure locations from Package 3 and this Package 7 project was undertaken, as shown in the figure below Package 7 priority locations are consistent with the Package 3 locations of structures.

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Figure E3: Comparisons of proposed structures between Package 3 (top) and Package 7 The hydrological model of Package 3 can be used but the hydrodynamic model has been redeveloped. This is because the DEM used in Package 3 did not represent the actual situation on ground. The redevelopment of the hydrodynamic model is described in the report River Hydrology Assessment: West Rapti Basin.

The hydrological model calculates discharges based on catchment parameters and rainfall values, with and without the impact of climate change. These discharges are used for the hydrodynamic model input. The hydrodynamic model is used to; define the hydraulic design criteria for the preliminary designs, assess the impact of climate change on the hydraulic conditions, and assess the impact of the proposed structures on the hydraulic conditions, to provide input for preparing the flood maps and to define the benefits of the proposed structures. For different return periods (1 in 2 years, 1 in 5 years, 1 in 10 years, 1 in 25 years, 1 in 50 years and 1 in 100 years) the following model runs were made:

· Reference Alternative (Run 1): This is the current situation including the existing structures;

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· Future Alternative 1 (Run 2): This is the Reference Alternative (Run 1) including the impact of climate change;

· Future Alternative 2 (Run 3): This is the Future Alternative 1 (Run 2) including the proposed structures.

The benefits of the project depend on the area that the proposed structures protect in comparison to the situation without the project i.e. comparing Run 2 and Run 3. The table below provides an overview of the protected land.

Table E1: Flood affected and protected areas Return period Description 2 5 10 25 50 100 years years years years years years Run 1: Existing situation without the impact of climate change Affected area by flooding [ha] 7,838 9,866 11,247 12,927 14,092 15,319 Run 2: Run 1 including the impact of climate change Affected area by flooding [ha] 8,650 10,869 11,904 13,539 14,821 15,824 Run 3: Run 2 including the proposed structures Affected area by flooding [ha] 8256 10077 10989 12488 13713 15058 Protected land due to structures (difference of Run 2 and 3) Protected land [ha] 394 792 915 1,051 1,108 766 Note: The above analysis concerns the nine proposed priority structures.

For the preliminary designs, a return period of 1 in 50 years, including the impact of climate change, have been used. For each of the nine priority works (see figure below), preliminary designs have been developed. Important aspects to include in the preliminary designs were: a) sustainability; b) environment-friendly (bio-engineering), c) adaptability; and d) low-cost solutions.

In total, the following structures are to be constructed: 17,640 m of embankments, 18,840 m of revetments and 75 spurs.

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Figure E4: Location of priority works Below a typical cross-section of an embankment with revetment is shown.

Figure E5: Typical cross-section embankment with revetment Gabions are used to construct the revetment and launching apron. Boulders are locally available, which will decrease the construction costs compared to e.g. concrete structures. From sustainability point of view it is important to use locally available materials, which also benefits the maintenance works.

Environment-friendly solutions (bio-engineering), grasses such as Vetiver grass, will be seeded to the area above the design water level. For sustainability and environment-friendly purposes, the crest and inner slopes are also protected with suitable grasses.

The estimated costs for the hydraulic structures are shown in the table below.

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Table E2: Summary cost estimates improvement works (1 USD = 115.08 NPR)

No Description Amount [USD] Amount [NPR] A Civil works A1 - Embankments / revetments 13,290,937 1,529,521,087 A2 - Spurs 3,857,495 443,920,504

Sub-total A 17,148,432 1,973,441,592 B General items General items 77,168 8,880,487

Sub-total B 77,168 8,880,487 C Contingencies Contigenceis 4,287,108 493,360,398

Sub-total C 4,287,108 493,360,398 D VAT VAT (13%) 2,229,296 256,547,407

Sub-total D 2,229,296 256,547,407 Grand total (A+B+C+D) 23,742,005 2,732,229,884 Note: The above cost calculation concerns nine structures. During the CBA some of the structures, due to limited flood benefits while the capital investment costs are high, have been removed from the project in order to make the basin feasible. The removal of structures will be discussed in the CBA section.

The annual maintenance costs are estimated on 3% of the economic prices of the civil works, with are NPR 72.38 million or USD 0.63 million.

Flood Forecasting and Early Warning Systems and CBDRM (non-structural measures)

Below the proposed FFEWS equipment and CBDRM to be implemented under this project are described.

Rain gauge network installation

Five new auto telemetry rain gauge stations have been proposed for installation. West Rapti catchment area is 6,370 km2. There are 25 existing gauging stations by the Department of Hydrology and Meteorology (DHM) within this basin. This will deliver a rain gauge station density aof one rain gauge in every 212 km2.

Hydrometric gauge network installation

Eight hydrometric gauging stations in West Rapti catchments have been proposed. All stations are easily accessible and are located in the neighbourhood of a settlement. Five stations will be used for both discharge and water level measurements. Three stations will only measure water levels.

Hydrometric equipment

Only budget for cableway construction has been considered for this basin. No budget for Acoustic Doppler Current Profiler (ADCP), Differential Global Positioning System (DGPS) and echo- sounder has been considered for this basin.

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Topographic and asset survey

The topographic survey will include river sections, any existing structures, and flood embankment profiles. The survey will be done in West river; 421 cross-sections across 160 km will have to be surveyed. The new survey is proposed as the on-going FFEWS model development by DHM, under World Bank funding, is based on old topo survey. For the topographic survey, no survey equipment has been proposed for purchase as the survey will be done through outsourcing.

CBDRM and flood shelters

Only implementing a FFEWS is insufficient to protect the people living and working in the flood- prone areas. It is important to train community members in how to respond when a warning is given , as it is crucial that people know what to do and where to go. Within the CBDRM component, at the community level, groups of people will be trained to guide the communities in the event of a flood warning and increase their resilience to respond.

CBDRM includes a participatory approach and a flood resilience capacity assessment of the local communities. An inventory of the different houses and buildings in each community should be made to identify the vulnerable and non-vulnerable places. Available schools or government buildings, which are often higher and stronger structures in comparison to houses, can be used as temporary shelters during flood events. In case of the absence of these types of buildings, flood shelters can be constructed. It is recognised that most communities do have some form of “safe house” (often a local school) identified. The assessment process will need to review how appropriate the existing systems are.

Where flood shelters are required, it is important to discuss and decide together with the community where the flood shelter should be constructed. The location of the shelter will need to consider how safe it is (low/high ground), how far it is from those it is serving, and land ownership.

For a return period of 1 in 50 years, it is estimated that 33,465 people would be affected. Taking into account that flood shelters are prepared for 150 – 200 people, a large number of flood shelters would therefore be required. However, existing schools, government buildings and houses that are not vulnerable to flooding as well as a decrease in the number of affected people as a result of future constructed flood mitigating works, less shelters may be required.

During the CBDRM phase, it is also important that together with the national and local government, the most vulnerable areas are identified. This project will not undertake a survey of the existing resources. As mentioned above, a local needs assessment is essentially a participatory process to create local ownership and resilience. At this stage, the project assumes that 10 communities require immediate support and for these communities, 10 new shelters will be needed.

Cost estimates

The estimated capital and operation and maintenance costs for the proposed FFEWS equipment and CBDRM are indicated in the table below.

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Table E3: FFEWS and CBDRM – Capital costs (1 USD = 115.08 NPR) Unit Unit price Capital costs Categories [#] [USD] [USD] [NPR] Development flood forecasting model Topographic cross-section survey 1 84,200 84,200 9,689,736 Total 84,200 9,689,736 Hydro meteorological data networking Rain gauge - Telemetry 5 5,000 25,000 2,877,000 Water level + discharge 150 4,333 650,000 74,802,000 Water level 3 7,000 21,000 2,416,680 Total 696,000 80,095,680 Discharge measurement equipment / station installation Cable-way discharge station (construction costs) 1 95,000 95,000 10,932,600 Total 95,000 10,932,600 CBDRM CBDRM 10 8,060 80,600 9,275,448 Flood Shelter 10 35,000 350,000 40,278,000 Total 430,600 49,553,448 Note: - Discharge measurements are to be carried out fortnightly from mid-May to mid-October; this will be 10 measurements per year, 30 in three years and a total of 150 measurements across five stations. - Discharge measurement cost is a continuous expenditure, like model development cost (and should be considered similar to capital cost); it includes cost for all skilled human resources and the logistics required.

Table E4: FFEWS and CBDRM – Operation and Maintenance costs (1 USD = 115.08 NPR) Costs Costs Categories Remarks [USD] [NPR] Hydro-meteorological data networking Rain gauge - Telemetry 6,000 690,480 For a period of 3 year Water level + discharge 6,000 690,480 For a period of 3 year Water level 6,000 690,480 For a period of 3 year CBDRM CBDRM (10 communities) 44,540 5,125,663 Operational costs for year 2 to year 5 Notes: - Operation and maintenance costs of hydro-meteorological data networking is $2,000 per basin, for all stations, per year; this involves routine site visits, repair and maintenance

Cost benefit analysis

The total projected costs amount to NPR 2,228 million (USD16.83 million) including the costs of infrastructure, FFEWS, CBDRM and land acquisition and the environment management plan. In economic prices, the cost is NPR1,986 million (USD 15.00 million).

Table E6: Costs by Expenditure Category (NPR ‘000) Expenditure Category 2020 2021 2022 2023 2024 2025 2026 Total A. Investment Costs Civil Works 0.00 36.41 410.77 440.36 464.29 441.07 0.00 1,792.89 Equipment 0.00 40.59 42.96 45.45 0.00 0.00 0.00 129.01 Supplies, Materials and 0.55 7.82 8.44 9.06 9.41 9.99 8.73 53.99 Operations Studies and Surveys 0.61 7.93 8.56 8.45 0.00 0.00 0.00 25.56

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Training and Workshops 0.12 1.58 1.70 1.83 1.97 1.94 0.00 9.14 Consulting Services 1.59 20.30 21.63 23.02 24.48 24.39 6.32 121.73 Government Staff 1.08 8.46 16.89 18.19 19.55 19.74 12.17 96.09 Resettlement 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Total (financial prices) 3.95 123.08 510.96 546.37 519.70 497.12 27.22 2,228.40 Total (economic prices) 3.68 111.41 455.00 486.54 462.23 442.31 25.75 1,986.92

Key Assumptions

Numeraire and prices: The analysis uses the domestic price level numeraire, expressed in local currency. The financial prices used were those applied in the market in the third quarter of 2019. To derive economic prices, the foreign component of the price of traded goods is adjusted by the shadow exchange rate factor (SERF), scarce labour is adjusted by the shadow wage rate factor (SWRF) of 0.8, taxes (VAT of 13% and any import duties) are removed from prices and domestic resources are multiplied by a factor of 1 (i.e. the financial prices of domestic resources are equal to the economic prices).

Conversion factors and exchange rate: The standard conversion factor (SCF) of 0.92 (SERF = 1.09) was estimated using import and export data for three years. The exchange rate used throughout the analysis is USD1 = NPR 114.9.

Opportunity cost of capital: The opportunity cost of capital used for the analysis is 9%.

Results of the Analysis

The West Rapti sub-project has an EIRR of 29.1%, above the discount rate of 9% that is the hurdle for confirming economic viability. As may be seen Table E7 the EIRR is resilient to changes in the levels of damage sustained by buildings and public infrastructure during flood events. The prevention of this damage is the main source of benefits for the subproject, and it may therefore be concluded that West Rapti sub-project is economically viable and changes in the key factors measured are unlikely to undermine this conclusion.

Risks may occur in implementation if, for any reason, structures are not completed to the required standard. Another source of risk would be climate change engenders more and larger floods than have so far been predicted.

Table E7: Results of the Economic Analysis NPV Switching % change EIRR (NPR mil.) Value Base case 29.1% 957.1 Investment costs +10% 21.9% 790.1 +57% +20% 17.8% 623.0 Benefits -10% 21.6% 694.4 -36.3% -20% 15.9% 431.6 Buildings affected in flood envelope +10% 48.5% 1,221.6 -36.5% -10% 21.3% 694.1 % buildings damaged/destroyed +10% 46.3% 1,204.2 -39.1% -10% 21.7% 711.1 Public infrastructure affected +10% 30.9% 1.000.8 - -10% 27.7% 917.3 Future growth in infrastructure +10% 29.3% 965.1 -

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-10% 29.0% 949.2 Agricultural area affected +10% 29.7% 960.7 - -10% 29.0% 953,5

Safeguards

Social and environmental surveys have been conducted in the West Rapti Basin.

Environmental safeguards

West Rapti Basin, located in the Terai region of Western Nepal, is categorized as an Environmental Category B. Accordingly an IEE has been prepared as a stand-alone document to accompany this feasibility study. As per the Environmental Protection Regulation of Nepal, because it is proposed that the project will have more than 10 km of flood protection works in this river basin, it also requires IEE report to be prepared and approved by the MoEWRI.

The baseline environmental conditions, the anticipated environmental impacts and mitigating measures have all been defined as part of the environmental assessment undertaken. There will be a nominal additional cost for the implementation of mitigation measures as majority of the mitigation measures are part of the Good Practices in the construction management as well as legally binding requirements that need to be complied with. Expected costs during implementation are 4,200,000 NPR or 36,496 USD (exchange rate: 1 USD = 115.08 NPR).

In addition to publishing the notice in a national newspaper informing communities about the project, a number of consultation meetings were also organised. Impacted local bodies were engaged at these meetings in order to understand the public views about the project, and to obtain suggestions on how to minimise the adverse impacts.

Overall people expressed positive views towards the project and suggested that the river protection works should cover all along the river banks for long-term benefits.

Social safeguards – Indigenous People (IP)

For this subproject, there is potential for a small number of IP households owning land plots at the river banks (i.e. where the embankments will be constructed) to be impacted by loss of land/economic displacement. A land acquisition, resettlement and IP (LARIP) plan is proposed to mitigate these impacts.

Based on the above analysis, the IP risk categorisation in line with ADB criteria and Ministry of Energy, Water Resources and Irrigation (MoEWRI) sector guideline criteria, this subproject is Category B with limited impacts on IPs.

Social safeguards – Involuntary resettlement

For involuntary resettlement, the river basin subproject is a Category B project for ADB because it has involuntary resettlement impacts that are not deemed significant, and Category C/Low risk under the Nepalese Guideline. A LARIP plan is proposed to mitigate the impacts.

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The LARIP will reflect the polices and standards identified in national laws, the ADB’s Safeguard Policy Statement, the MoEWRI sector guidelines on involuntary resettlement and indigenous people, and the project’s Resettlement Framework.

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1 Introduction

1.1 Project rationale Nepal is considered one of the most disaster-prone countries in the world. Alongside other natural hazards, such as earthquakes and landslides, flooding poses a recurrent risk to large sections of the population. Nepal, with over 6,000 rivers, is very rich in water resources, which provides both positive as well as negative impacts to the country. The hydrology in Nepal is primarily monsoon driven with approximately 85% of the yearly rainfall during the monsoon period from June – September. During this period the rainfall and runoff is very high, resulting in floods.

Flooding has a significant impact on communities residing in the Terai region. The Terai region occupies approximately 17% of the country and is known as the granary of Nepal. Agriculture in the Terai region is dominating the economy in Nepal with production of major crops such as rice, wheat, pulses, sugarcane, jute, tobacco and maize. The topography is generally flat with a gentle slope in southward direction. Rivers originating from the mountain and hill areas run through the Terai region in southwards direction and eventually into neighbouring India.

The Terai region has a long history of floods affecting livelihoods and agriculture. Figure 1 shows the large number of districts that were affected by floods during the monsoon in August 2017.

Figure 1: Monsoon affected districts 11-13 August, 2017 (source: reliefweb.int)

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Besides inundating the land, floods also transport large quantities of sediments. gravel and boulders due to the excessive soil erosion in upstream hill areas (e.g. due to landslides and gully erosion). Due to the steep gradient in the hill areas, floods transport large quantities of sediments, gravel and boulders into downstream direction reaches the Terai region, where transported materials will deposit due to gentle slope. Sediment deposition occurs:

- In the river itself, increasing the river bed level, decreasing the discharge capacity and thus increasing the flood risks; - On farmland, negatively affecting agricultural livelihoods and food production.

At several locations, floods cause severe bank erosion, threatening the destruction of settlements, agricultural land and infrastructure.

Floods in the Terai region damage farmland and crops and kill livestock, which is of critical importance to affecting lives, livelihoods and property of poor communities. Flood also affect critical infrastructure such as embankments, roads, communication infrastructure, power supply and overall development of the region. With the Terai region being the granary of Nepal, the floods not only negatively impact on the Terai region but the country as a whole.

Flood risks are likely to increase in the Terai region because of high population growth, increase in urban and infrastructure development as well as due to the impact of climate change in general and changing rainfall patterns in particular.

Acknowledging the importance of the Terai region to Nepal, the Government of Nepal (GoN), through the Ministry of Energy, Water Resources and Irrigation (MoEWRI), is implementing the ‘Priority River Basins Flood Risk Management Project’ in the Southern Nepal Terai region, which is supported by the Asian Development Bank (ADB). The project is a continuation of the pre-feasibility study: Package 3: Flood Hazard Mapping and Risk Management Project (FHRMP). During the pre-feasibility study of the 102 flood prone rivers that flow into the Terai region, 25 river basins were studied.

Mott MacDonald, as appointed by the MoEWRI, executes this ‘Priority River Basins Flood Risk Management Project’, which will draw on the findings of the pre-feasibility study. The key requirements for this project is to ensure that cost beneficial and sustainable infrastructure interventions are robustly identified, duly considering the environmental and social impacts, both positive and negative, that flood protection interventions and river training works can have. The basins included in the ‘Priority River Basins Flood Risk Management Project’ are:

- Mohana – Khutiya Basin; - Mawa – Ratuwa Basin; - West Rapti Basin; - Lakhandei Basin; - East Rapti Basin; - Bakraha Basin.

The locations of all sub-projects are shown in Figure 2. This feasibility report, prepared by Mott MacDonald (the Consultant), concerns the West Rapti Basin, which is located in the west of Nepal. The works comprised hydrological and hydrodynamic modelling, preparation of preliminary designs of civil works, FFEWS, CBDRM, cost-benefit analysis and the assessment of social and environmental safeguards.

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West Rapti River Basins To Support And Strengthen Disaster Risk Management”, which is financed by the World Bank.

During the final ADB review meeting, December 2018, with WRPPF and ADB, it was requested that the Package 7 Consultant would include some equipment (no flood forecasting works) and CBDRM as it was not fully covered by the other project.

Figure 2: Location of sub-projects

1.2 Objectives of the feasibility study The Terai region is severely affected by floods causing damage to communities, agriculture, public infrastructure. For sustainable development and to mitigate flooding in the West Rapti Basin, structural and non-structural measures are required.

With the view to alleviate poverty by protecting residential property and incomes, to provide an increased range of livelihood opportunities and to mainstream opportunities for women, the project’s interventions will be designed to:

The objective of this report is to assess the economic and financial feasibility of capital investments, which will be implemented within the scope of this project. The objectives of the feasibility study are:

- To confirm economic and financial viability of capital investments implemented within the scope of this project;

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- To evaluate the robustness of the economic analysis of the project (sensitivity analysis).

1.3 Purpose of this report The purpose of this report is to confirm the economic and financial viability of the investment for the West Rapti Basin as constructed within the scope of this project. This report includes the preliminary designs as well as the cost-benefit analysis.

The outline of the report is as follows:

Chapter 2 Provides a description of the West Rapti Basin Chapter 3 Describes the methodology for selecting the priority works to be included in this project Chapter 4 Provides the results of the hydrological and hydrodynamic modelling, which are input for the preliminary designs and cost benefit analysis Chapter 5 Provides a description of the designs including basis of development and cost estimates Chapter 6 Provides and overview of the FFEWS and CBDRM works to be implemented under the scope of this project Chapter 7 Describes the results of the Cost Benefit Analysis and sensitivity analysis Chapter 8 Provides a summary of the safeguards Chapter 9 Implementation plan

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2 West Rapti Basin

2.1 Location and area The catchment of the West Rapti river basin lies between Northing 3059764 to 3163502 m N (latitude 27°39'35.85" to 28°34'43.37"N), and between Easting 574652 to 726518 m (longitude 81°45'24.78 to 83°18'57.52 E) in WGS 84, UTM Zone 45 N (see Figure 3). The basin extends from the southern slopes of the Mahabharata Range in the north, Chure Hills (Siwalik Hills, also known as sub-Himalayan hills, at low altitude) in the Deukhuri valley, i.e., Dun (intermontane valley) in the south up to the Terai in Indo-Nepal border.

Figure 3: West Rapti Basin The river originate from the middle mountains of Nepal at Chunwang, then enters the lowlands and finally drains to the Ghagra (Karnali) River, a tributary of the Ganges River. It has several tributaries. Major tributaries are Jhimruk River, Mari River, Arun River, Lungri River, Sit River, Dunduwa River, Sotiya and Gandheli rivulets. Downstream of the confluence of the Jhimruk and Mari Rivers, the river is named the West Rapti River. The source of runoff is due to the monsoon rainfall and groundwater. The basin catchment covers an area of 6,370 km2 in the central Nepal, Province No. 5 and a very small part Province 6 and 4. (Figure 3).

West Rapti River system lies in the lies district of Pyuthan, Rolpa, Salyan, Rukum, Gulmi, Arghakhanchi, Kapilbastu, Dang and Banke. The basin has 4,264 settlements distributed over rural and urban municipalities with a population about 949,100 and 192,550 households (CBS, 2011) Kohalpur (part of it) Gadawa, Lamhi, Bhaluwang, Bijuwar, Khalanga, Libang, and Khilji, Kohalpur (part of it) are the major cities, towns and settlements. West Rapti River basin has two

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well developed valleys, i.e., Madi Valley and Jhimruk valley in the middle mountain catchment, and Deukhuri and lower Rapti Valley in the South bounded by the Siwalik Hills. It has a small part of Terai in the south west.

2.2 Land use and settlement map Land use map and statistics for this basin were extracted from the land use of the Chure Terai- Madhesh Area prepared by Chure Terai Madhes Protection and Management Master Plan, the uncovered part was updated from the land use map prepared by Irrigation Master Plan Preparation team and imageries. The basin has two distinct characteristic land use patterns in the Middle Mountain and Siwalik hills and in the lower part of catchment, i.e., Dun valley and Terai (Figure 4).

The catchments of Middle mountain and Siwalik hills have dominantly non-agricultural land use types, such as forest, shrub and grass, dominating about 58% and 90% of the total area respectively. Much of the cultivated land and settlement lie in the valleys and terraces or gentler foot slopes and gentle to moderately slopes (up to 30°).

Human disturbance in terms of agriculture appears considerable in the Middle Mountain catchment in the north of the West Rapti Valley. The Siwalik Hill catchment in the south of the West Rapti Valley is mostly forested, a large, which is under government jurisdiction or community managed.

This indicates that the ecology is highly disturbed in the Middle mountain catchment. In addition, deforestation, overgrazing and frequent fires on the mountain slopes are likely to exacerbate erosion. Therefore, the impact of land use on sediment production is expected to be high.

The Dun Valley and Terai catchment has also been predominantly used for forest, including riverine type and grass comprising about 71.9% of the total area. The forest area is under government jurisdiction, or community, which is rich in biodiversity and diverse wildlife species. The forest is home to 113 tree species, 107 herbal species and 85 shrubs and climber species and many wild life species such as Bengal Tiger, leopard, rhinoceros, bears, boars, dears and others.

Whereas Agriculture account only for 20.3% in whole of the West Rapti Basin. Comparatively in the middle mountain catchment, land under agriculture is high, i.e., 32.8%. The Siwalik hill constitute only 8.2% of its total area under agricultural land. Low land part of the catchment, Dun valley and Terai comprise 23% of the total area under agriculture. Built-up area comprises about 0.3% of the total land, which is occupied by major cities and towns.

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Source: Mott MacDonald derived this map from Chure Terai Madhesh Protection and Management Master Plan (2016)

Figure 4: Land use

2.3 Geology and structure of hill slope catchment The West Rapti Basin is underlain by the Lesser Himalaya in the north, Siwaliks, the youngest parallel mountain chain in the Himalayan orogen (DMG, 2007) in the middle and south, and by quaternary deposits comprising dun in the middle and Terai in the south.

The Siwalik Ranges from the most tectonically active Himalayan belt, which has resulted in active deformation, dislocation and uplift of rocks, giving rise to a complex geologic structure and unstable and erodible landscape (Nakata, 1989; Lavé and Avouac, 2001).

The stratigraphy of the lesser Himalayas, formed of the metamorphic rocks that consist of Jaljala Group (limestone, quartsz and schsist, Surkhet group (shale and limestone) Dadedhura group (granite), Midland group (quartzite and limestone), and under differentiated Lesser Himalayas (Phyllite, quartzite schist and carboniferous rock). The geology is highly weathered due to and shattered due to tectonics and therefore, landslides are common in all units. However, areas underlain by schist, slate, and phyllites are highly prone to erosion and landslides. Similarly on the fault and thrust zone, rocks are crushed, brittle and cracked and therefore, highly susceptible to slope failure and erosion.

South of the Lesser Himalaya, delineated by the Main Boundary Thrust, lie the Siwaliks Group. Based on lithological characteristics DMG (2007), three broad categories of the Siwalik rocks, i.e., Upper Siwaliks, Middle Siwaliks (MS) and the Lower Siwaliks are found (Figure 5). The US is composed of conglomerates, sandstone and few mudstone beds. The hills south to the West Rapti valley is underlain by US. This unit is characterised by unsorted loose, boulder-sized conglomerate with grey sandstone and mudstone. This unit contains typically the Siwaliks sandstone boulders. The upper Siwaliks rocks are highly erodible and susceptible to gully erosion.

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Numerous gullies, ravines and wide and shallow riverbed containing huge sediment aggradations is found

Within the Siwaliks, the catchment underlain by the MS is comprised of fine to very coarse-grained sand as well as pebbly sandstone, which alternate with mudstone. The proportion of sandstone beds is higher than that of the mudstone. The proportion and coarseness of the sandstone increases towards the upper formation of the MS (DMG 2007). Large and deep seated landslides are common.

Similarly in the areas of LS, adjacent to MS consists of inter-bedding of mudstone and sandstone layers are found. The mudstone is variegated dark grey in colour. The sandstones are fine to coarse grained, and are thin to thickly bedded. The proportion of mudstone is greater than that of sandstone in aggregate. The LS occupies the lower section of the upper catchment.

The Siwaliks is delineated as in Figure 5 from alluvial deposits of the Terai plain by the Main Frontal Thrust (MFT) in the South. It is the most active frontal fault where the LS are thrust over the alluvium in the piedmont zone (Nakata, 1989). Similarly, imbricate thrusts of Main Dun Thrusts run South East-North West between MBT and MFT. The formation of Deukhuri Dun is related to these imprecate thrust (Dhital 2015).

Quaternary deposits consist of recent and post Pleistocene alluvial fan and terrace deposits brought by the rivers draining the upper catchments of Chure hills and other Himalayan belts, which form Deukhuri Dun and smaller valleys further west enclosed by Chure hills. These deposits are composed of boulder, gravel, sand and mud. The Terai part of basin lying in south west, also composed quaternary deposits of recent to quaternary age.

Figure 5: Geology and structure of hill slope catchment

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2.4 Relief and slope of the upper catchment Based on the analysis of elevation contours derived from the Digital Elevation Model (Survey Department, 2002), the relief of the catchment of the West Rapti Basin ranges between 130 and 3,550masl. The average relief in the upper catchment is 1,071masl. The highest point lies in the Peak of Mahabharata Range in Sinkundanda Danda in Rolpa district. The average slope of the upper catchment is 26o; such steep slope indicates high potential for erosive and erodibility in a fragile geological setting. The slope of the upper catchment is predominantly steep, i.e., the area above 25o slope is about 55 %. (Figure 6).

Source: Mott MacDonald derived this map from Chure Terai Madhesh Protection and Management Master Plan (2016)

Figure 6: Slope The gentle slopes (<5o) occupy 8.4 % of the total upper catchment area. In Terai, slope less than 5 degree occupy 93% of the total area. Cultivation above 25o is not desirable due to the unstable slopes of Chure hills. The sub catchment wise statistics of slope gradient is presented in Table 1.

Table 1: Slope gradient in West Rapti Basin Percent area [%] Weighted average Total area slope [%] [km2] Slope [deg] < 5 5-15 15-25 25-35 35-45 >45 Upper catchment 8.7 12.4 23.5 29.6 21.2 4.7 26 5457 (Middle mountain and Siwalik hill catchment) Lower catchment 97.0 2.8 0.2 0.0 0.0 0.0 1 913 (Dun and river valley) Whole 42.8 16.1 15.0 6.2 17.1 2.8 14 2963

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Source: Mott MacDonald (Derived from Survey Department, 2002 DEM)

2.5 Historic flooding events West Rapti River is a perennial river and flooding in this river is characterized as being flashy in the narrow valley and prolonged in the wider plain areas in the downstream reaches. There has been a history of over 60 flood events between 1991 and 2015 of which a significant proportion caused low to moderate damage.

In recent years, the river has experienced high sediment loads often aggravated by landslides in the upper catchment.

Table 2 provides an overview of the historic flood events in West Rapti Basin.

Table 2: High impact flood events (1991 – 2015)

No Description (threshold) West Rapti 1 Reported damage value (> NPR 1 million) 0 2 Reported dead (> 1) 1 3 Reported mission (> 2) 2 4 Reported injuries (> 2) 1 5 Reported affected people (> 500) 3 6 Reported affected households (> 10) 0 7 Reported evacuated households (> 15 people) 0 8 Reported relocated persons (> 50) 1 9 Reported housing destruction (> 10) 7 10 Reported damage housing (> 25) 0 11 Reported livestock loss (> 50) 0 12 Reported land affected (> 20 ha) 4 13 Report other impacts (> 1) 2 Source: Package 3 reports

Note: No detailed data per basin is available for the period after 2015.

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3 Selection of priority works

3.1 Introduction The feasibility study has been carried out to assess the economic and financial feasibility of the proposed investments under the PPRBFRMP (Package 7) project.

Under the Package 7 project the potential locations for structural interventions have been prioritised. The main inputs to location prioritisation are (i) FHRMP Package 3 (pre-feasibility), (ii) the DPR and (iii) discussions with knowledgeable Government staff. The DPR for the West Rapti was not available.

Detailed Project Report (DPR)

The DPR is a document prepared by the People’s Embankments Programme (PEP) field office and includes the required river training works for the whole river basin located in the Terai area, from the bottom of the hills to the border with India. The DPR provides a description of the existing conditions, socio-economic conditions, hydrology, proposed mitigation works, design of mitigation works and an economic evaluation. The works are prioritised based on affected people and economic losses. The DPR is updated yearly, mainly after the monsoon, in order to provide proposed works for the upcoming fiscal year. Once the DPR is approved from the DoWRI, the defined works become part of the integrated works of the department.

Programmes as decided by the National Planning Commission, based on recommendations by MoEWRI, are aligned in a 5 year periodic plan. Based on the available budget provided by the GoN, certain works will be executed. The selection of the works to be executed is done by the PEP field office in coordination with the DoWRI depending of the severity of the existing problems. There is not a set of defined criteria for allocating budget. At present, there is insufficient budget available to execute all the required works.

This section explains the Package 7 prioritisation process and demonstrates the consistency between Package 7 locations and structural interventions proposed for the Package 3 project, which analysed the river basin in a holistic and comprehensive way.

Further, prioritisation of the Package 7 locations for structural interventions was undertaken in close cooperation with the WRPPF and the PEP field offices (Peoples’ Embankment Programme field office), who are familiar with the existing flood-damage related situation in the West Rapti Basin.

3.2 FHRMP Package 3 Output

3.2.1 Approach The starting point of the prioritisation analysis was the output from Package 3 (pre-feasibility), where the river basin was analysed in a holistic and comprehensive way and which identified

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potential priority locations supported by an economic analysis at pre-feasibility level. The main objectives as indicated in the Package 3 final report1 were as follows:

(i) Produce climate change scenario based flood hazard/flood risk maps for the modelled areas in the 25 priority basins;

(ii) Recommend flood risk management interventions in the key priority areas identified in consultation with the Client. These may comprise both structural and non-structural measures to prevent, alleviate or manage flood risk from floods, sedimentation and river bank erosion especially in the densely populated and agriculture productive areas;

(iii) Based on a selection criteria determined in consultation with the Client, and that identified in (ii) above, short list six sub-projects for which the consultants will prepare individual concept notes to a pre-feasibility level. This includes preparing:

a) Pre-feasibility engineering designs based on recommended best-practices and technologies; b) Improved watershed and water distribution management c) Initial assessment of safeguard requirements d) Preliminary economic assessments.

Package 3 final report summarized the approach as following:

- Based on the results of the hydraulic modelling and flood inundation, maximum velocity, flood hazard - flood risk maps were produced to obtain insight into all areas at risk of flooding. Figure 7 shows the hazard map for a return period of 1 in 50 years for West Rapti Basin (source: Package 3 reports);

- Through field visits undertaken by the social team, information on vulnerable communities in the basin, views on the type of interventions being requested, their impact on the community as well as constraints that would inhibit flood intervention measures were collected. These insights provided the basis for the identification of flood mitigation measures and the required social safeguard measures (ADB, 2009);

- Field visits stressed the need for flood protection as the residents spoke of the constant fear during the wet season and the short lead times before their areas were inundated;

- A number of flood mitigation locations and options were identified and considered in discussions with DWIDM based on the modelling results and maps were produced. Thesewere checked in an iterative manner using the models.

Based on a comprehensive analysis of the river basin, Package 3 proposed a number of flood mitigating measures in concept notes covering 6 catchments, which included West Rapti Basin.

Figure 7 and Figure 8 shows respectively the flood hazard maps (1 in 50 years return period) and the locations of proposed structural interventions for West Rapti from Package 3.

1 Package 3: Flood Hazard Mapping and Preliminary Preparation of Flood Risk Management Projects, Final Report – Volume I, May 2016

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Figure 7: Flood hazard map 1 in 50 years (source: Package 3 Reports)

Figure 8: Proposed measures (source: Package 3 Reports)

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3.2.2 River training structures Package 3 It is emphasised that it is not possible to compare designs of the Package 3 and Package 7. The hydrodynamic model, which provides the design criteria, from Package 3 provides a good overview of the flood hazards in the entire basin. However, the exact modelling results from the Package 3 hydrodynamic model cannot be compared with Package 7 hydrodynamic model.

The DEM used in Package 3 does not represent the actual situation. Key issues were the use of the DEM to represent in channel bed levels and the absence of existing hydraulic structures. Package 3 used a DEM from 2009. To develop a suitable hydrodynamic model, actual surveyed cross-sections should be used. River cross-sections were surveyed during Package 7 in 2018 and utilised in the model development. It was concluded that a new hydrodynamic model should be redeveloped in order to have sufficient detail for the feasibility study.

Reviewing the Package 3 structures, only the methodology and approach can be reviewed. Package 3 prepared pre-feasibility designs of embankments and spurs in the downstream area of West Rapti. The pre-feasibility structures have been designed following the DWIDM Pocket Diary 2071 (2014 / 2015) taking into account e.g. a river width of at least three times Lacey’s Perimeter. The designed structures have been checked using the hydrodynamic model.

Table 3 provides a description of the pre-feasibility designs in relation to the expected structures to be designed within Package 7. Check dams are not seen as priority structures at this stage; from a technical perspective, the situation in the hills is very complicated and influenced by many factors, including the impact of the 2015 earthquake as well as man-made interventions. It is suspected that the volume of sediments transported in extreme conditions would impact the check dams. Investigating this would require significantly more investigation of the morphological conditions and sediment transport mechanisms than could be afforded under this project. Therefore, in close consultation with the client, the focus of the design was placed on flood protection measures with a more direct positive impact of protecting people i.e. embankments.

Table 3: Description pre-feasibility designs

Type Description Embankment Earthen structure with 0.5 m of sweet soil on the slopes and crest. The crest is 5 m wide with slopes on each side of 1:2 (V:H). The freeboard, about the High Flood Level (HFL), depends on the discharge. When the discharge is below 3,000 m3/s, the freeboard will be 1.5 m. For discharges above 3,000 m3/s a freeboard of 1.8 m is applied. The embankments are located 1.5 times Lacey’s Perimeter from the river centre line. Embankment with revetment Earthen structure with 0.5 m of sweet soil on the slopes and and launching apron crest. The crest is 5 m wide with slopes on each side of 1:2 (V:H). The freeboard, about the High Flood Level (HFL), depends on the discharge. When the discharge is below 3,000 m3/s, the freeboard will be 1.5 m. For discharges above 3,000 m3/s a freeboard of 1.8 m is applied.

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Type Description The revetment and launching apron are made from gabions. The gabions of the revetment and launching apron have a thickness of 0.30 m and 0.60 m respectively. The embankments are located 1.5 times Lacey’s Perimeter from the river centre line. Spur with launching apron Two types of spurs have been included in the pre-feasibility report, solid and sloping spurs. The solid spurs have a length of 12 m and consists of three layers using gabions. The spacing of the spurs is set on 2 – 2.5 times the effective length of the spur. The sloped spurs have a length of about 15 m and consists of a fill material covered by gabions. The spacing of the spurs is set on 2 – 2.5 times the effective length of the spur. The launching apron is made of gabions.

3.3 Priority areas included in PPRBFRMP (Package 7) The Package 7 priority areas have been defined based on the Package 3 priority locations and discussions with PEP field officers.

Package 3 Final report was completed in May 2016. Since completion the situation on the ground may have changed due to the dynamic character of the river or structures may have been completed following the Peoples’ Embankment Programme or local initiatives from e.g. water user organisations. It is important to assess the actual situation onsite. Discussion were held with PEP field office to assess the on-ground situation in the West Rapti Basin.

The selected Package 7 interventions are supported by the flood maps developed under this Package 7 project.

A comparison of structure locations from Package 3 and this Package 7 project for the West Rapti Basin are shown in Figure 9.

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Figure 9: Comparisons of proposed structures between Package 3 (top) and Package 7 Table 4 provides in detail the linkage between location of the Package 3 and Package 7 proposed structures. Details on the type of proposed structures, reference is made to the design chapter, Chapter 5. In general, the proposed structures are embankments, revetments, spurs and launching aprons.

Table 4: Summary of structural Interventions and their link to Package 3 Structure River Included in Package 3 PRTW.01 West Rapti No Area 2, structure located on the left bank. Has been proposed in the Package 7 works based on recent discussions with PEP field office PRTW.02 West Rapti No Area 2, structure located on the left bank. Has been proposed in the Package 7 works based on recent discussions with PEP field office PRTW.03 West Rapti Yes Area Details on the type of proposed structures, reference is made to the design chapter, Chapter 5. In general, the

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Structure River Included in Package 3 proposed structures are embankments, revetments, spurs and launching aprons.2, structure located on the left bank PRTW.04 West Rapti No Area 2, structure located on the right bank. Has been proposed in the Package 7 works based on recent discussions with PEP field office PRTW.05 West Rapti No Area 2, structure located on the right bank. Has been proposed in the Package 7 works based on recent discussions with PEP field office PRTW.06 West Rapti No Area 2, structure located on the left bank. Has been proposed in the Package 7 works based on recent discussions with PEP field office PRTW.07 West Rapti No Area 3, structure located on the right bank. Has been proposed in the Package 7 works based on recent discussions with PEP field office PRTW.08 West Rapti Yes *1 Area 1, structure located in the left bank PRTW.09 West Rapti Yes *1 Area 1, structure located in the left bank

*1: Area 1 in Package 3 indicates that embankments are required along both banks. The PEP field office manager indicated that the right bank and part of the left bank are included in the Sikta Irrigation project financed by Government of Nepal and do not need to be considered for this project.

Package 7 priority locations are consistent with the Package 3 locations of structures.

3.4 Structures included in Package 7 Figure 10 provides an overview of the priority structures as included in Package 7. Table 5 provides more details per location. Details on the type of proposed structures, reference is made to the design chapter, Chapter 5. In general, the proposed structures are embankments, revetments, spurs and launching aprons. At present, check dams were not seen as priority.

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Figure 10: Location priority works

Table 5: Details location priority works Chainage *1 Length Symbol Location / Purpose Upstream Downstream [m] [m] [m] PRTW.01 Municipality: Gadhawa -2 148,209 146,105 2,340 Tole / village: Jethan Gaon District: Dang River: West Rapti Requirement: Left bank, protection against erosion and flooding. PRTW.02 Municipality: Gadhawa- 3 145,481 143,617 2,100 Tole / village: D/S of Dangali Chhap ISP District: Dang River: West Rapti Requirement: Left bank, protection against erosion and flooding PRTW.03 Municipality: Gadhawa- 5 142,513 136,487 5,770 Tole / village: Takaipur District: Dang River: West Rapti Requirement: Left bank, protection against erosion and flooding. PRTW.04 Municipality: Lamahi- 4 136,936 136,487 500 Tole / village: Butkauwa District: Dang River: West Rapti

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Chainage *1 Length Symbol Location / Purpose Upstream Downstream [m] [m] [m] Requirement: Right bank protection against erosion and flooding PRTW.05 Municipality: Lamahi- 6 132,874 132,403 500 Tole / village: D/S of Balrampur Package District: Dang River: West Rapti Requirement: Right bank, protection against erosion and flooding. PRTW.06 Municipality: Gadhawa -7 133,701 132,929 700 Tole / village: D/S of Kanchhigaon Package District: Dang River: West Rapti Requirement: Left bank, protection against erosion. PRTW.07 Municipality: Rapti Sonari -1 34,889 34,097 820 Tole / village: Kachnapur District: Banke River: West Rapti Requirement: Right bank, protection against erosion and flooding. PRTW.08 Municipality: Rapti Sonari -6 20,348 14,747 5,010 Tole / village: Kachnapur District: Banke River: West Rapti Requirement: Left bank, protection against erosion and flooding. PRTW.09 Municipality: Duduwa- 1 7,233 6,324 1,050 Tole / village: Kurwa District: Banke River: West Rapti Requirement: Left bank, protection against erosion and flooding. *1: Based on the chainage (Station Number) in the modelling. Zero is just downstream

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4 Hydrological and hydrodynamic models

4.1 Introduction This chapter presents an overview of hydrological and hydrodynamic modelling undertaken in this study. The detailed analysis is presented in the River Hydrology Assessment Report: West Rapti Basin2. As part of the assessment, hydrological and hydrodynamic modelling undertaken at the prefeasibility study stage i.e. was also reviewed. The hydrological model of Package 3 has been used in this study. However, the hydrodynamic model from Package 3 was redeveloped for use in this analysis.

4.1.1 Hydrological model HEC-HMS (Hydrologic Engineering Center - Hydrologic Modelling System) software was used for the preparation of the hydrological model. Based on the review of the hydrological model of Package 3, it was concluded that the model can be used for Package 7..

Model and schematisation

The following sub-models were selected within HEC-HMS for computing flow:

· Initial and constant loss model: Interception and depression storage is considered as initial loss. After the initial loss is satisfied, the maximum potential loss of precipitation is constant throughout an event. The constant loss is considered to be ultimate infiltration capacity of the soil. The model has two parameters: initial loss and constant loss rate; · Clark’ s runoff transform model: Clark’ s model derives a watershed Unit Hydrograph by explicitly representing two critical processes, translation and attenuation, in the transformation of excess precipitation to runoff. In this model, linear reservoir represents the aggregated effect of storage. The time of travel is represented by a time area histogram. The model has two parameters: time of concentration and storage coefficient; · Recession base flow model: According to this model, the base flow decays exponentially from the starting flow. The parameter of this model is recession constant; · Lag routing model: According to this model, the outflow hydrograph is simply the inflow hydrograph, but with all ordinates translated (lagged in time) by a specified duration. Lag time is the parameter of this model.

The schematisation of West Rapti Basin into HEC-HMS of consists of 4 sub-basins, 2 junctions, 2 reaches and 1 sink, see Figure 11.

· Sub-basin 1 represents Mari khola tributary; · Sub-basin 2 represents Jhimruk khola tributary; · Sub-basin 3 represents mid part of basin; · Sub-basin 4 represents lower part of basin.

At each junction, the contribution of flow from each tributary is added.

2 River Hydrology Assessment: West Rapti Basin, Mott MacDonald, 2019

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Figure 11: HEC-HMS Model Schematic for West Rapti Rainfall

The final rainfall hyetographs used in Package 3 for the present day and climate change events are provided in Table 6.

Table 6: Final rainfall hyetographs used in Package 3 Time Rainfall (mm) Present Day Rainfall (mm) Climate Change (hr) 2yr 5yr 10yr 25yr 50yr 100yr 2yr 5yr 10yr 25yr 50yr 100yr 0 000000000000 1 112222122222 2 112222122222 3 112222122222 4 233344333444 5 6 7 8 9 9 10 7 8 8 9 10 10 6 18 22 24 26 28 29 20 23 25 27 29 30 7 61 73 79 87 92 97 67 77 83 89 96 101 8 18 22 24 26 28 29 20 23 25 27 29 30 9 6 7 8 9 9 10 7 8 8 9 10 10 10 2 3 3 3 4 4 3 3 3 4 4 4 11 1 1 2 2 2 2 1 2 2 2 2 2 12 1 1 2 2 2 2 1 2 2 2 2 2 13 1 1 2 2 2 2 1 2 2 2 2 2 14 0 0 0 0 0 0 0 0 0 0 0 0

Note: the increase is applied to a duration of rainfall equal to the time of concentration.

Parameter estimation

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West Rapti is a gauged basin. Although Kusum station is the most downstream station, this station has short period of data (after 2003). So, the Jalkundi gauging station located in the mid reach having a longer data record, was used for the calibration of the parameters of the HEC-HMS model. The calibration period was 1990-1999 and the validation period was 2001-2006. The performance of the model for peak flow was found to be satisfactory. For sub-basins downstream of Jalkundi, the upstream sub-basin was taken as a reference for defining model parameters.

The following parameter values have been used for the West Rapti river basin:

· Loss model parameters: Taken based on the calibration at Jalkundi gauging station; · Clark’s model parameters: Time of concentration is computed from topographic data, and storage coefficient from calibration at Jalkundi gauging station; · Recession base flow parameters: Recession constant = 0.95 was taken for all sub- basins; · Lag routing model parameter: Lag time is based on the travel time for the reach (considering length of reach from topographic data and approximate flow velocity).

Table 7 details the parameters used for each sub-basin:

Table 7: Parameters used for each sub-basin Basin Initial deficit Loss rate Time of Storage Recession Lag (mm) (mm/hr) concentration coefficient constant time (h) Sub-basin 1 4 1.6 13 40 0.95 Sub-basin 2 4 1.6 8 32 0.95 Sub-basin 3 5 1.1 10 28 0.95 Sub-basin 4 5 1.1 13 28 0.95 Reach 1 3 Reach 2 4.66

Table 8 shows the peak flow values generated from HEC-HMS for the West Rapti Basin in relation to the schematisation shown in Figure 11.

Table 8: Peak flow generated by HEC-HMS for West Rapti Flow without impact of climate change per return period [m3/s] Location 2yr 5yr 10yr 20yr 50yr 100yr Upstream (Junction1) 1,612 2,499 3,225 4,349 5,125 6,109 Jalkundi (Junction2) 2,947 4,386 5,450 6,952 8,171 9,469 Outlet 3,664 5,414 6,649 8,389 9,752 11,194 Flow with the impact of climate change per return period [m3/s] Location 2yr 5yr 10yr 20yr 50yr 100yr Upstream (Junction1) 2,099 2,893 3,426 4,359 5,300 6,410 Jalkundi (Junction2) 3,482 4,822 5,683 7,279 8,522 10,187 Outlet 4,306 5,971 7,027 8,991 10,532 12,613

4.1.2 Hydrodynamic model The hydrodynamic modelling was carried out by using the HEC-RAS (Hydrologic Engineering Center - River Analysis System). The hydrodynamic model used for Package 3 could not be used

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and required redevelopment. The DEM used in Package 3 does not represent the actual situation. Key issues were;

[1] the use of the DEM to represent in channel bed levels, which are not well picked up given the resolution of the DEM, and [2] the absence of existing hydraulic structures.

It was concluded that a new hydrodynamic model should be developed in order to have sufficient detail for the feasibility study. To develop a suitable hydrodynamic model, actual surveyed cross- sections should be used. River cross-sections were surveyed during Package 7 in 2018 and utilised in the model development. Results from the hydrodynamic model of Package 3 cannot be used for this project.

The redevelopment of the hydrodynamic model is described in the River Hydrology Assessment: West Rapti Basin report.

Schematisation

1. Embankments: Embankments are modelled as lateral structures in HEC-RAS. Embankment crest levels have been picked up during the 2018 topographical surveys and used to define the lateral structures. In some of the 2014 surveyed cross-sections, the crest-level of the embankment was not included. The embankment levels for these sections have been inferred based on the 2018 topographic survey, and the cross- sections modified accordingly. Levee markers are used in HEC-RAS model when the embankments are overtopped and flood passes to the flood plain. 2. Bridges: Bridges have been incorporated into the models using the bridge unit within HEC-RAS. Key data such as number of piers, span between the piers and level of the bridge were taken from 2018 survey and included into the bridge editor. 3. Spurs and Porcupines: No topographical survey has been undertaken for spurs and porcupines, and these have not been considered in the HEC-RAS model. For spurs, the main purpose is to divert the main flow away from the embankments in order to decrease the velocity along the toe of the embankments / revetments to mitigate erosion. Spurs, are relatively small structures that do not cause backwater. During flood conditions, the spurs are submerged and do not have a flood defence purpose. For that reason, the spurs have not been surveyed but only the locations have been identified. Porcupines do not constrict flow but rather stimulate sedimentation by reducing velocities. After a few years due to the accumulation of sedimentation the porcupines can be seen as a solid structure. They are not considered as a structure in 1D model, due to the uncertainty in the potential increase in sedimentation, and the possibility that the accumulated sediment could be washed out during an extreme flood event. Figure 12 shows the schematisation of West Rapti Basin based on new topographic surveys.

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Figure 12: HEC-RAS schematic for West Rapti Flow data

The hydrological model calculates the discharges based on rainfall values with and without the impact of climate change. These discharges are input for the hydrodynamic model. The hydrodynamic model is used to define the hydraulic design criteria for the preliminary designs, assess the impact of climate change on the hydraulic conditions, assess the impact of the proposed structures on the hydraulic conditions, to provide input for preparing the flood maps and to define the benefits of the proposed structures.

Model scenarios

For different return periods (1 in 2 years, 1 in 5 years, 1 in 10 years, 1 in 25 years, 1 in 50 years and 1 in 100 years) the following model runs were made:

· Reference Alternative (Run 1): This is the situation as per today including the existing structures;

· Future Alternative 1 (Run 2): This is the Reference Alternative (Run 1) including the impact of climate change;

· Future Alternative 2 (Run 3): This is the Future Alternative 1 (Run 2) including the proposed structures.

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4.2 Climate change For a sustainable development it is crucial to include the impact of climate change. As described in the report River Hydrology Assessment: West Rapti Basin, the impact of climate change is integrated into the hydrological model by including the projected rainfall following the (Representative Concentration Pathways) RCP4.5 climate change scenario. The climate change scenario of RCP4.5 was selected during Package 3 as it is a moderate scenario. Given the uncertainties in climate change projections, it has been concluded that the climate change model used for Package 3 is suitable to be used for Package 7. The projected rainfall data following the RCP4.5 climate change scenario used for modelling is shown in Table 9.

Table 9: Projected rainfall following the RCP4.5 (Package 3) Return period Historical Rainfall RCP4.5 projected Increase compared to [years] *1 [mm] rainfall *2 [mm] historical rainfall [%] 2 140 154 10.0% 5 167 178 6.6% 10 182 190 4.4% 25 200 205 2.5% 50 212 220 3.8% 100 224 233 4.0% *1: Source of Historical Rainfall: DHM *2: Source of Projected Rainfall: HADGEM2, GCM The output of the hydrological model were discharges for the different return periods with and without the impact of climate change. The discharges are input for the hydrodynamic model.

4.3 Modelling results The result for flood maps and modelling results for the different return periods are included in Appendix A (flood maps) and Appendix B (modelling output) respectively.

Figure 13 to Figure 15 show the flood maps for a return period of 1 in 50 years for all three runs. The flood maps present the latest alignment based on the 2018 survey of the project.

4.4 Analysis The hydrodynamic modelling was carried out for the three runs as indicated in Chapter 4.1 above. The analysis of the results are provided below.

4.4.1 Impact hydraulic conditions The modelling results are compared in Appendix B.5. The purpose of the comparison is to see the impact of the proposed structures on the hydraulic conditions. It is important that the water levels do not increase significantly due to the proposed structures, as this would indicate that the river has been constricted too much.

The main comparison is made between Run 2 (Reference Alternative (Run 1) including the impact of climate change) and Runs 3 (Future Alternative 1 (Run 2) including the proposed structures).

Within this project a maximum rise of water levels of 30 cm is accepted. Based on the comparison it can be seen that the maximum difference is an increase of 23 cm in Run 3 compared to Run 2. This happens only in one cross-section while the other sections show less or no increase in water level. The maximum rise is acceptable.

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Figure 13: Flood maps Run 1, return period of 50 years

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Figure 14: Flood maps Run 2, return period of 50 years

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Figure 15: Flood maps Run 3, return period of 50 years

4.4.2 Velocity distribution In general, the velocity along the banks is on average around 70% lower when compared to the average velocity in the flood way. The velocity distributions in West Rapti river for a return period of 1 per 50 years for the three different runs is shown in Figure 16 and Figure 18 respectively.

WEST RAPTI NOV26 Plan: Plan 24 12/7/2018 West Rapti Upstream 7 Legend

6 Vel Chnl PF 5(50 yr) Vel Right PF 5(50 yr) 5 Vel Left PF 5(50 yr)

Vel Left (m/s), Vel Chnl Vel(m/s), Right (m/s) 0 0 20000 40000 60000 80000 100000 120000140000 160000 180000 Main Channel Distance (m)

Figure 16: Velocity distribution, Run 1 – 1 per 50 years return period

WEST RAPTI NOV26 Plan: Plan 29 12/7/2018 West Rapti Upstream 7 Legend

6 Vel Chnl PF 5(50yr) Vel Right PF 5(50yr) 5 Vel Left PF 5(50yr)

Vel Left (m/s), Vel Chnl (m/s), Vel Right (m/s) 0 0 20000 40000 60000 80000 100000 120000 140000 160000 180000 Main Channel Distance (m)

Figure 17: Velocity distribution, Run 2 – 1 per 50 years return period

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WEST RAPTI NOV26 Plan: Plan 31 12/11/2018 West Rapti Upstream 7 Legend

6 Vel Chnl 50yr Vel Right 50yr 5 Vel Left 50yr

Vel Left (m/s), Vel Chnl (m/s), Vel Right (m/s) 0 0 50000 100000 150000 Main Channel Distance (m)

Figure 18: Velocity distribution, Run 3 – 1 per 50 years return period

4.4.3 100 years return period The designs have been prepared for a return period of 1 in 50 years including the impact of climate change (see Chapter 5.2). However, analysing the hydrodynamic model results, the proposed structures also protect the adjacent areas against a 1 in 100 years flood with climate change.

The reason that areas are still protected during the flood with a 1 in 100 year return period is due to the applied freeboard. The proposed structures have sufficient height to protect against water levels that occur during a flood with a return period of 1 in 100 years.

4.4.4 Protected land The benefits of the project depend on the area that the proposed structure protect compared to the existing situation (reference alternative). Table 10 provides an overview of the protected land.

Table 10: Flood affected and protected areas Return period Description 2 5 10 25 50 100 years years years years years years Run 1: Existing situation without the impact of climate change Affected area by flooding [ha] 7,838 9,866 11,247 12,927 14,092 15,319 Run 2: Run 1 including the impact of climate change Affected area by flooding [ha] 8,650 10,869 11,904 13,539 14,821 15,824 Run 3: Run 2 including the proposed structures Affected area by flooding [ha] 8256 10077 10989 12488 13713 15058 Protected land due to structures (difference of Run 2 and 3) Protected land [ha] 394 792 915 1,051 1,108 766 Note: The above analysis concerns the nine proposed priority structures.

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5 Designs of hydraulic structures

5.1 Introductions This project includes both structural and non-structural flood mitigating works. The non-structural flood mitigating works such as flood forecasting and early warning systems and community based disaster risk management are addressed in Chapter 6.

This chapter addresses the structural flood mitigating works. The preliminary designs are prepared for those structures that will be constructed under the scope of this project. The cost estimates of the preliminary designs are included in the Cost Benefit Analysis (CBA) in order to review the feasibility of the investments.

During the preparation of the preliminary designs the consultant was in close contact with the WRPPF and the PEP field office, to define the priority areas and discuss the designs.

5.2 Basis of Development It is evident that the preliminary design highly depends on the design criteria adopted. At the start of the preliminary design phase, technical notes have been submitted to WRPPF, which included the draft Basis of Development. After discussion with WRPPF, the Basis of Development was updated. The Basis of Development is described below.

5.2.1 Design strategy When preparing the preliminary designs the following design aspects were taken into account:

- Sustainability; - Environment-friendly (bio-engineering); - Adaptability; - Low cost solutions.

Sustainability

It is important that the structures are sustainable. It must be avoided that the structures fail after one flood season. This requires that the implemented structures should be designed appropriately. Concerning embankments, possible overtopping or excessive rainfall can cause erosion / damage to the crest and / or inner slope of the embankment, which could result in failure of the embankment. To avoid this, besides protecting the outer slopes, also the crest and the inner slopes should be protected. Sufficient freeboard should be applied to compensate possible increasing bed levels due to aggradation and changes in climate change projections. It is also important, from a sustainability point of view, to make use of locally available materials, which also benefits the maintenance works.

Environment-friendly (bio-engineering)

The structures must have sufficient resistance and height to mitigate the impact of floods but should also become an integrated part of the surrounding landscape. Large areas of the West Rapti Basin have a rural character. To integrate the structures into the landscape it is preferred to include environment-friendly solutions (bio-engineering) into the designs. An environment- friendly solution is to integrate e.g. Vetiver or other grasses into the structure design.

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Grass such as Vetiver grass is implemented in different countries to protect the embankments (bank stabilisation) against floods and is also available in the Terai region. The root system of Vetiver grass is finely structured and very strong which stabilises the soil making the embankments resistant against the flood waters.

Environment-friendly solutions also have the advantage that they decrease the quantities of required construction materials, which results in lower construction costs.

Environment-friendly solutions are already implemented in the Terai region, see Figure 19.

Figure 19: Example of environment-friendly embankment (bio-engineering) Adaptability

Due to the uncertainties in e.g. climate change, settlement and hydraulic boundary conditions it is important that the structures should be adaptable to future changes. When required, the crest level of the structure should be able to be increased to cope with future changes. For instance, adding another layer of e.g. gabions of soil on top of the existing structure.

Low-cost solutions

Budgets are limited while many areas in the basin require protection against erosion and / or flooding. To minimise the costs, it is important to make use of local available materials. Materials

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such as (reinforced) concrete are more expensive compared to local available materials. This also benefits the maintenance works. Examples of low cost solutions are shown in Figure 20.

Figure 20: Low-cost solutions bamboo porcupine (left) or nylon bags filled with sand to be used as spur (right) Problem with these low-cost solutions is that the design life time is short to approximately 2 - 4 years.

Making use of local material also concerns the use of boulders. Due to the local availability and lower costs compared to other construction materials, structures designed and constructed by the PEP field office engineers include mainly the use of gabions filled with suitable stones and boulders excavated from the river bed.

5.2.2 Guidelines and standards The preliminary design is carried out using appropriate Nepalese Standards and Guidelines for the design of river training works.

If Nepalese Standards and Guidelines are not available, international standards that are commonly used in Nepal will be applied.

Some applied Standards and Guidelines are:

· DWIDM Pocket Diary 2071 (2014 / 2015); · Guidelines for preparation of DPR for flood management works, Government of India, Central Water Commission; · River and channels revetments, a design manual.

5.2.3 Climate change Nepal is a highly vulnerable country to climate change. Change in rainfall patterns, incidence of frequent droughts, floods and heat waves, and the rapid melting of glaciers are major risks in the country. The increase of extreme events such as high intensity rains, can result in an increase of flood events and associated negative impacts.

For sustainable development, the impact of climate change must be included in the design and modelling works.

Chapter 4.2 describes how climate change is incorporated into the project. The RCP4.5 climate change projections for rainfall are integrated into the hydrological model. The output of the hydrological model, discharges, will be input for the hydrodynamic model. The hydrodynamic model is used to define the design criteria for the different structures and input for the preparation of flood maps including the impact of climate change.

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The projected time horizon for climate change is the year 2050, based on the proposed design life of the structures.

5.2.4 Design return period For the preliminary designs a return period of 1 in 50 years including the impact of climate change was used.

5.2.5 Design life The minimum design life time of structures is 25 years.

5.2.6 Freeboard Freeboard, the height between the design water level and crest level, is required in order to:

· Compensate for uncertainties in the hydraulic boundary conditions; · Provide accessibility of the areas during high water; · Prevent wave overtopping; · Sedimentation; and due to · Settlement of the embankment.

There is not a specific value or international agreed value to be used for freeboard. It also depends on the local conditions. Different guidelines provide different values for freeboard as can be seen in Table 11.

Table 11: Indications for freeboard

No Source Criteria Freeboard 1 DWIDM Pocket Diary 2071 - 1.0 – 1.5 m 2 Guidelines for preparation of DPR for Q < 3,000 m3/s 1.5 m flood management works, India *1 Q > 3,000 m3/s 1.8 m 3 Technical Standards and Guidelines Q < 200 m3/s 0.6 m for Planning and Design, Volume I – 200 m3/s < Q < 500 m3/s 0.8 m Flood Control, JICA 500 m3/s < Q < 2,000 m3/s 1.0 m 2,000 m3/s < Q < 5,000 m3/s 1.2 m 5,000 m3/s < Q < 10,000 m3/s 1.5 m Q > 10,000 m3/s 2.0 m *1: Applied in FHRMP

The maximum design discharge, 50 years return period, in West Rapti Basin is 10,532 m3/s. This is very high. Based on Table 11, a freeboard in the range of 1.8 – 2.0 m should be selected.

Within this project, taking into account the adaptability of the structures, a freeboard of 1.5 m is applied for all structures in West Rapti Basin.

5.2.7 Lacey’s wetted perimeter In Nepal the width of the river is often related to the Lacey’s wetted perimeter, which is used for alluvial rivers. Within the project area, this mainly concerns the area downstream of the East –

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West Highway. Upstream the East – West Highway, the bed material is coarse consisting of boulders and gravel. Table 12 shows some examples of guidelines to define the required width of the river.

Table 12: Indications of required river width No Source Criteria River width *2 1 DWIDM Pocket Diary 2071 Lacey’s wetted perimeter (P) 3 – 6 x P 2 Guidelines for preparation of DPR Lacey’s wetted perimeter (P) 3 x P for flood management works, India *1 3 Technical Standards and Q = 300 m3/s 40 – 60 m Guidelines for Planning and Q = 500 m3/s 60 – 80 m Design, Volume I – Flood Control, Q = 1,000 m3/s 90 – 120 m JICA Q = 2,000 m3/s 160 – 220 m Q = 5,000 m3/s 350 – 450 m *1: Applied in FHRMP *2: spacing between flood embankments The values indicated in Table 12 are guidelines. In the DPR of Lakhandei Basin use is made of 2 times the Lacey’s Wetted Perimeter.

It is important that the river has sufficient space also taking into account future climate changes. In the Netherlands, since 2006, the government is implementing the programme “room for river” to provide the river sufficient space in order to address flood management (taking into account climate change), landscaping and the improvement of environmental conditions.

Providing sufficient space, especially in dynamic rivers such as in Nepal, is crucial for a long term development of the river basin. Lacey’s wetted perimeter, as applied in Nepal, is an empirical formula often used to defined the required width of alluvial rivers mainly for irrigation purposes. The defined width is based on the concept to avoid silting and scouring, which is mainly related to normal conditions, the bankfull discharge. Bankfull discharge is determined by the discharge that a river can convey when reaching the level of the flood plain.

Figure 21: Example cross-section. (Source: Pierre Y. Jullien) There is no clear definition of bankfull discharge. Often 1.5 and 2 years return period are used but also mean annual floods, mean annual flows and 5 years return period floods have been used to describe bankfull discharge in alluvial rivers. In Nepal, bankfull discharge is defined as the discharge with a 2 year return period (DWIDM policy 2072).

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Following the guideline of 3 times the Lacey’s wetted perimeter for extreme discharges such as Q50 would result in very wide river. An example for Mohana (PRTW.04) is given below.

At PRTW.04 the width of the river is limited, approximately 70 m. Based on the discharge (Q50), the required width according to 3 times Lacey’s wetted perimeter is about 480 m. Taking into account this value the embankments will be located far inland, not protecting the settlements, infrastructures and agricultural land located between the embankments and the river, see Figure 22.

Figure 22: Example impact Lacey's wetted perimeter Not protecting these settlements will create social unrest and the flood mitigating works will not be accepted by the local residents.

For this location there are three options:

1. The embankments will be located inland following the value of 3 times Lacey’s wetted perimeter. Consequence is that the houses and land between the embankments and the river, the flood plain, are not protected. These areas are often experiencing immediate threats from the river due to erosion and flooding. Resettlement of these people will require additional costs;

2. The embankments will be located along the river bank, not complying with the distance of three times the Lacey’s wetted perimeter. The people are protected but the narrow river will have impact on the hydraulic conditions in the river. Proper erosion protection is required for the embankments during extreme conditions. The impact of the narrow section is included in the hydrodynamic model and appropriate measures can be taken;

3. The river bank is protected using revetments. The level of protection can coincide with a lower return period, e.g. a return period of 1 in 2 years (bankfull discharge). The embankments required to protect the land against a flood with a return period of 1 in 50 years will be located further inward. In this option, the settlement along the river does receive some degree of protection for a lower return period.

It is important to provide sufficient room for the river. However, as also indicated by the PEP experts, it is also important to take the local conditions into account. At some locations with settlements and limited river width, a different approach is required.

Within this project, Option 2 (see above) is implemented. The people already living in these areas are experiencing problems due to flooding and erosion and should be protected. The impact of

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the narrow sections can be assessed using the hydrodynamic models so that appropriate measures can be taken.

Zoning

For the sustainable development of the West Rapti Basin it is recommended to implement zoning. Zoning is already described in the DWIDM Policy 2072. The purpose of zoning is to define an appropriate use, to cope with the flood characteristics in each zone and to define appropriate use and restrictions.

For a sustainable development, it crucial to be aware of the different flood prone areas. Flood prone areas should be developed in such way that damage due to flooding is minimized. Important facilities for the functioning of the district, should not be located in these flood prone areas. Services such as, but not limited to hospitals, police and main infrastructure, should have a high level of protection and thus located in safe areas. It is important that houses and other important facilities such as schools and hospitals are not constructed in the flood prone areas.

Flood maps can be used to support land-use zoning plans, by using the areal coverage of flooding from the main river channel for different return periods. This will enable the identification of the vulnerability category and the corresponding zone.

5.3 Room for river Preparing the preliminary designs, making use of the hydrodynamic model, a 2-step approach is followed:

- Step 1: Run 2, which includes the impact of climate change but without designed structures. This run provides the design criteria for the first preliminary design;

- Step 2: Run 3, which includes the impact of climate change and the designed structures.

It is important to check the impact of the designed structures within the hydrodynamic model. This is in order to assess the impact of the structures (difference between Run 2 and 3). A large increase in water levels would indicate that the river has been constricted too much. Within this project a maximum rise of water level of 30 cm is accepted.

5.4 Topographical survey works Topographical surveys have been conducted in 2018 within the project Package 7: WRPPF: Preparation of Priority River Basins Flood Risk Management Project. Based on the surveys the hydrodynamic models and designs were prepared. The topographical surveys have been submitted to the WRPPF (January 2019). Reference is made to the final report: Feasibility Study (West Rapti and Lakhandei) – Deliverable 2 (December 2018).

5.5 Flood protections works The flood mitigation structures to be considered for the preliminary designs are in general embankments, spurs and guide dams, revetments and launching aprons. Based on the identified priority locations (see Chapter 3), a general description of the different suitable structures is provided below.

Embankments / levees

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Embankment are earthen structures constructed along the river to prevent water from entering adjacent areas that cause damage to crops, settlements, and threaten human life and livestock.

As common practise in Nepal, the crest width of the embankments will be 5 m. This provides the opportunity to access the embankments for inspection and when required maintenance works. For that reason, in Nepal, some of the crests consist of a strip of 0.75 m of grass along each side of the crest and 3.5 m width with compacted gravel.

Revetments Depending on the flow velocities, embankments need to be protected against erosion. Revetments protect the embankments against erosion. The revetments need to be sustainable structures that are environment-friendly and are low-costs solutions. Protection can be done by using hard revetment such as gabions or nature-based solutions such as grass. In the Terai often gabion revetments are used, see Figure 23.

Figure 23: Example of gabion revetments Gabions are suitable because:

- Boulders to fill the gabions are locally available, which will reduce the costs compared to concrete / reinforced concrete;

- Gabion structures are commonly applied in the West Rapti Basin and are familiar to those who maintain the structures. Using similar structures will benefit the maintenance works as all structures require the same type of maintenance;

- Gabions, in comparison to concrete structures, are flexible and adaptable structures. Gabions; 1) can cope with uneven settlements; and 2) can easily be adjusted (e.g. adding another layer of gabions) in case of changing river characteristics.

The cages of the gabions will be machine made using double twisted hexagonal woven heavily coated steel wire. Geotextiles will be used as filter layer under the gabions.

It is possible to protect the entire slope from bed level up to the crest level using gabions. One of the reasons to protect the entire slope with gabions is because the water levels could always be higher compared to the design water level. However, for the environmentally friendly character of the structures and to integrate them in the surrounding landscape, it was chosen to design the area above the design water level as environment-friendly (bio-engineering) and ot with gabions. Often grasses, such as Vetiver, is used to protect the embanjkment above the design water level, see also Chapter 5.2.1.

For the sustainability and safety of the embankments, it proposed to also protect the crest and the inner slope of the embankments, which is required to protect the embankment against erosion due to possible overtopping and / or heavy rainfall. Instability of the inner slope could result in

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failure of the entire embankment. Environmentally friendly solutions such as grasses will be applied. In the preliminary design grasses are used to protect the crest and inner slope. A typical cross-section of a protected embankment is shown in Figure 24.

Figure 24: Typical cross-section embankment with revetment Spurs

Spurs have the function to divert the flow in order to protect the embankments. Sedimentation is expected between the spurs, due to the low flow velocity. Spurs should not be applied at those locations where the diversion of the flow with affect settlements located at the opposite bank. Spurs are mainly proposed in outer bends where the flow directly attacks the banks and cause erosion. Diverting the flows will protect the banks and stimulate sedimentation.

The spurs can be constructed using gabions. A typical cross-section is shown in Figure 25.

Figure 25: Typical cross-section spur During the detailed design, the dimensions of the spurs need to be optimised. This could include e.g. the length of the spur.

Launching apron

The areas with the identified priority works experience erosion threatening existing settlements, agricultural land and infrastructure. At some locations, as can be seen form the hydrodynamic modelling, velocities can increase. Embankment need to be constructed to protect the adjacent areas during flood events. To maintain the stability of the structures (spur, revetment and embankment) it is important to ensure that scouring will not cause failure (instability) of the structure. To protect the structures from scour, launching aprons are constructed. Launching aprons protect the toe of the structures (e.g. spurs and revetments) against erosion, maintaining

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the stability of the entire structure. In Nepal, rectangular and semi-circular launching aprons are implemented, see Figure 26.

Figure 26: Types of launching aprons For the preliminary design rectangular launching aprons are applied, which are easier to construct and to maintain. The dimensions of the launching apron are based on the scouring calculations.

Outlet structure

For the West Rapti Basin, the team and PEP/WRPPF did not do a detailed survey or identify outlets due to this basin not being progressed to detailed design.

Nature-based solutions

Nature-based solutions include the use of grasses to protect embankments against erosion. As indicated earlier, the design of revetments to protect the embankments include environment- friendly aspects by uses vetiver grass or turfing the outer slope above the design water level, the crest and the inner slope.

However, structures mentioned before in this paragraph can also be constructed using cheaper locally available materials such as bamboo. Instead of Gabion spurs to protect against erosion, they can be replaced with e.g. bamboo porcupine structures. Bamboo porcupines structures, can be used as spur or as embankment protection, are permeable structures to reduce flow and trap sediment, see Figure 27. Porcupine structures are seen as emergency measures instead of long- term sustainable solutions.

Figure 27: Examples of bamboo porcupine structures Besides porcupines, bamboo can also be used for e.g. bamboo fencing. The design life of these bamboo structures is limited to about 4 years.

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5.6 Preliminary designs

5.6.1 Innovative and nature-based solutions Innovative solutions need to be explored as an option to further develop flood management capacities in Nepal. Innovative solutions can be found in the applied structures but also in the methodology.

Methodology, an innovative approach for Nepal Making use of hydrological and hydrodynamic models for river basin management is a new approach in Nepal. Traditionally, empirical formulae are used to calculate the required width of the river (e.g. Lacey parameter) and empirical formulae are used to estimate the design flood flow. Using hydrological and hydrodynamic models, a better understanding of the impact of climate change and proposed interventions can be obtained. The impact that proposed interventions may have on water-levels can be assessed and structures which restrict the river too much can be avoided or redesigned. Applying models for river basin management provides the opportunity of a better understanding of the river basin, the impact of climate change and the impact of proposed interventions.

The flood maps provide insight into the impact of floods. This insight can be used for different purposes such as the identification of flood prone areas, explanation to communities about the impact of floods (CBDRM) and land-use planning of the government. Zoning is a non-structural measure for flood management. Flood maps support the land-use zoning, as defined in the DWIDM Policy 2072.

Natural-based solutions for Nepal The Consultant will consider implementing natural-based solutions at all locations. Whether a natural-based solution will be proposed depends on the characteristics of each site;

- Grasses will be used to protect embankments; a) the outer (river-side) slope of the embankment above the design water level; b) the crest of the embankment; and c) the inner (land-side) slope. Further, as mentioned above certain grasses may also be incorporated into the revetment gabion baskets. Some embankments which are setback from the riverbank and are not exposed to high velocities or wave attack may not need gabion protection below the design water level and may be simply protected by grasses; - Integrate Vetiver grass into hard structures in a rural landscape. Vetiver grass can be planted into the top rows of revetment gabions as a pilot project. The Vetiver grass can grow within the gabions making it a stronger structure and more environmentally friendly; - Bamboo porcupines will be considered on a case-by-case basis as a means of protecting river banks from erosion and encouraging sedimentation. It is emphasized that these types of structure do not have the same design life as hard structures and are mainly seen as emergency or temporary works; - Induced meander cut-offs will be considered on a case-by-case basis to straighten the river and avoid the continued river bank erosion which is part of the natural meander evolution process. Meander cut-offs connect the two closest parts of the meander to form a new channel. The steeper drop in gradient will cause the river flow gradually to abandon the old meander which will silt up with sediment from deposition. Cut-offs are a natural based solution since they are a natural part of the evolution of a meandering river, however they are not a permanent riverbank erosion protection solution and if implemented should be monitored after every flood season;

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- Allowing continued erosion and regular monitoring. In certain locations it may be advisable to allow continued erosion to occur, particularly if the adjacent erosion-risk land has low value or low productivity. Erosion is a natural process. In these cases the erosion situation will be monitored after every flood season.

5.6.2 Morphology assessment A morphology assessment of West Rapti Basin3 has been completed. Figure 28 shows the high- level channel aggradation and degradation in the basin. The purpose of the assessment is to understand dynamic river system and to provide support for the designs. Based on the assessment, the proposed structures and sites were analysed from morphology point of view. The associated river process and hazard in the West Rapti River at the different sites is described in the Table 13.

3 Morphology Assessment: West Rapti Basin, Mott MacDonald, 2018

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Figure 28: Aggradation-degradation in the West Rapti River system

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Table 13: Proposed River Training Works and the associated river process and hazard Symbol Location Sediment River process and hazard type PRTW.01 Municipality: Gadhawa 2 Boulder, Bank erosion is active, low bank height, (Dang District) gravel and and potential overtopping. Historical Tole / village: Kothari sand evidences of widening of riverbed, bed River: West Rapti level rise. Morphology is highly instable Requirement: Left bank, due to due huge deposition of boulder and protection against erosion. gravels by several channels flowing from the Upper Siwaliks joining the main channel. Hence, Mitigation measures are necessary. Protective vegetation cover is necessary at the active fans and scroll-bars. PRTW.02 Municipality: Gadhawa 3 Boulder, Bank erosion is active and over topping is (Dang District) gravel and likely. Aggradations and degradation is Tole / village: Balapur sand concurrently high. Evidence of channel River: West Rapti migration in left bank (scrollbars) and Requirement: Left bank, frequent channel avulsion is observed. protection against erosion Mitigating measures of erosion and over and flooding topping is necessary. Morphology is highly instable because of the sediment yield by channel and their tributaries joining at the left bank PRTW.03 Municipality: Gadhawa- 4-5 Boulder, Active bank erosion and past evidence of (Dang District) gravel and channel avulsion are observed at left bank. Tole / village: Khadgpur, sand Aggradations and degradation is Parsiya, Maghar, and concurrently high on the riverbed and fans Dharampur of tributary stream and gullies at their River: West Rapti junction. Bank erosion and flood control Requirement: Left bank, measures are necessary. Morphology is protection against erosion highly instable due to obvious reasons. and flooding. PRTW.04 Municipality: Lamahi- 4 Boulder, Active bank erosion, aggradations and bed (Dang District) gravel and level rise. Evidence of riverbed widening Tole / village: Thulo Ghumna sand channel migration towards left bank. River: West Rapti Proposed mitigation measures with Requirement: Right bank, protective vegetation along the bank and protection against erosion. active fans are necessary. PRTW.05 Municipality: Lamahi- 6 Boulder, Over topping, inundation and bank erosion (Dang District) gravel and hazards obvious from the morphological Tole / village: Dhikpur and sand features of the channel. Historical evidence Langadi Deupur of frequent channel avulsion and River: West Rapti abandonment by 600 m in right bank is Requirement: Left bank, observed. Hence flood and bank erosion protection against erosion control measures are needed. and flooding. PRTW.06 Municipality: Gadhawa-7 Boulder, Potential sites of bank erosion and over (Dang District) gravel and topping at left bank. Bank migration and Tole / village: Jharbaira sand frequent avulsion are observed from the River: West Rapti morphological foot prints and historical Requirement: Left bank, images. The sites are very vulnerable due protection against erosion. to flood in the tributary stream. River training work to reduce the flood risk. Similarly mitigation measures such as plantation are necessary.

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Symbol Location Sediment River process and hazard type PRTW.07 Municipality: Rapti Sonari- 2 Boulder, Potential erosion section, over topping and (Banke District) gravel and avulsion at the outer bend of the channel at Tole / village: Aurahawa, sand right bank. Historical evidences of bank Mahendra Pur migration and avulsion of 250 m at the River: West Rapti current site and about 900 m on the Requirement: Right bank, channel section before the start point. protection against erosion and flooding. PRTW.08 Municipality: Rapti Sonari- Boulder, Active bank erosion, over topping and 6(Banke District) gravel and inundation hazard is observed. Historical Tole / village: Laxmirajpur, sand evidences of the channel avulsion and Shidhanwa, Joraiya(Banke abandonment by 1,000 m and bank District) migration at left bank are seen. Proposed River: West Rapti PRTW Will protect the village and fertile Requirement: Left bank, agricultural land along the bank protection against erosion and flooding. PRTW.09 Municipality: Narainpur- 6, Gravel, sand Flood prone area. Evidences of scroll bars, Duduwa-3 and silt frequent channel avulsions and Tole / village: Chaupheri abandonment by 2,000m. Highly instable River: West Rapti alluvial reach. Mitigation and protection Requirement: Left bank, measures necessary. Vegetation on the protection against erosion scrollbars and frequently flooded flood and flooding. plain is necessary. Geo-morphologically, eight PRTW sites (PRTW 01 - PRTW07) are located in the channel section within the West Rapti valley (Deukhuri Valley) andis bounded by the Siwalik Hills. The valley is formed of flood plain and fans deposits accrued from the rivers originating from the Siwalik Hills. At these sites, sediments are comprised of boulder, gravel and sand. The West Rapti River is braided and riverbed is wide and consists of multiple channels, banks are defined but not stable and frequently change shape at each flood. Bar deposits lead to local bank erosion as the flow is diverted around a bar toward the bank. High aggradations led to bed level rise combined with bank erosion, which facilitates frequent avulsions. Hence, channel is highly instable. The alluvial fans are composed of boulders, gravel and sand laid down by the tributaries joining the river. This is a very dominant morphological feature of the West Rapti River in the studied reach. A very contrasting morphological feature between left and right bank is observed. The right bank is relatively stable because the tributaries joining carry lesser amounts of sediments. The sediments are also relatively fine, i.e., gravel and sand. However, at the left bank, the tributaries which drain the highly erodible loosely packed Upper Siwalik rocks, bring huge amount of sediments as bedload during rainstorm.. These tributaries join the West Rapti River at the toe of their fan. The riverbeds of these tributaries are disproportionately wide compared to catchment area, which indicates high sediment yield and aggradations. Bedload consisting of boulders, cobbles and gravels is very high. Bed level rise, channel shift and bank erosion are therefore, very common river hazard events during rainstorm. The banks of these streams are not defined; hence, the nearby areas are highly vulnerable to flash floods, causing sedimentation and erosion. Morphology is very unstable, therefore in addition to structural measures, non-structural measures such as catchment management (restriction to over grazing and deforestation on the hill slopes, avoiding settlement and infrastructures in active fans and flood prone area) are necessary.

The two PRTW sites (PRTW08 and PRTW09) are located at gravel and sand zone (boulders also in foothills), where the channel emerges out of the valleys to Terai plain in the Banke District.

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Here the morphology gradually changes from braided to wandering type. During high flows, the channel may appear to be of wandering type, and during low flows, channels would appear partially meandering. Alternate bar deposits are observed, which causes the channel to erode or accrete at either of the banks. Bank erosion and meander migration, overtopping and inundation, and avulsion are common river activities. Avulsion may also be due to breaching of bank due to erosion. Remarkable evidences of the channel avulsion are seen.

Hence, from the morphological assessment of the channel segment in various reaches, it can be concluded that the selected sites for PRTW are appropriate and urgent for flood and erosion control measures.

Impact of new river training works

A number of erosion vulnerable river segments have been identified (see report Morphology Assessment: West Rapti Basin). Moreover, the river being alluvial, erosion was noted even at more places than this. Due to proposed new structures, the response on sediment yield has been assessed taking results from the HEC-RAS model for the 50-year return period flood (Scenario 3). The sediment load indicates hardly any influence due to new structures. The energy grade (most sensitive parameter for generating sediment load) demonstrates almost identical slope in with and without project condition for the 1-in-50-year flood. However, we need to emphasise that proposed structures might not have any added effect, as autonomous development of morphology would still continue.

5.6.3 Designs The preliminary designs have been prepared based on site visits, modelling results, discussions with the morphology experts and discussion with the project managers / engineers from WRPPF and the PEP field office.

The structures to be constructed are embankments, revetments, spurs and launching aprons. A general description of the different structures is provided in Table 14. In total it concerns 17,640 m of embankments, 18,840 m of revetments and 75 spurs (Note: Google maps are indicative and not always up to date).

For the design calculations and drawings, reference is made to Appendix C and Appendix I respectively.

Table 14: Structures to be constructed Symbol / overview (indicative) Details PRTW.01 River: West Rapti Start structure Latitude 27°49'3.96"N Longitude 82°39'41.21"E End structure Latitude 27°48'56.09"N Longitude 82°38'18.80"E Chainage *1 Upstream [m] 148,209 Downstream [m] 146,105 Description: Located along the left bank providing protection against erosion and inundation. Structures: · Earthen embankment with gabion revetment. The total length is 2,340 m;

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Symbol / overview (indicative) Details · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also, the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 13 spurs; · Launching aprons to protect the toe of the revetment and spurs. PRTW.02 River: West Rapti Start structure Latitude 27°48'51.90"N Longitude 82°38'2.34"E End structure Latitude 27°49'9.36"N Longitude 82°36'49.62"E Chainage *1 Upstream [m] 145,481 Downstream [m] 143,617 Located along the left bank providing protection against inundation and erosion. Structures: · Earthen embankment with gabion revetment. The total length is 2,100 m out of which first 1,200 m is revetment (A in the picture) only and remaining 900 m (B in the picture) is embankment with gabion revetment; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also, the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 9 spurs; · Launching aprons to protect the toe of the revetment and spurs. PRTW.03 River: West Rapti Start structure Latitude 27°49'34.51"N Longitude 82°36'12.54"E End structure Latitude 27°49'45.73"N Longitude 82°32'46.46"E Chainage *1 Upstream [m] 142,513 Downstream [m] 136,487 Located along the left bank providing protection against inundation and erosion. Structures: · Earthen embankment protected by a gabion revetment. The total length is 5,770 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 10 spurs; · Launching aprons to protect the toe of the revetment and spurs. PRTW.04 River: West Rapti Start structure Latitude 27°50'22.05"N Longitude 82°32'55.13"E End structure Latitude 27°50'14.45"N Longitude 82°32'39.11"E Chainage *1 Upstream [m] 136,936

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Symbol / overview (indicative) Details

Downstream [m] 136,487

Located along the right bank providing protection against inundation and erosion. Structures: · Earthen embankment protected with a gabion revetment. The total length is 500 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · Launching aprons to protect the toe of the revetment.

PRTW.05 River: West Rapti Start structure Latitude 27°50'55.88"N Longitude 82°30'56.11"E End structure Latitude 27°50'51.38"N Longitude 82°30'38.47"E Chainage *1 Upstream [m] 132,874 Downstream [m] 132,403 Located along the right bank providing protection against erosion and inundation. Structures: · Earthen embankment protected with a gabion revetment. The total length is 500 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freebaord is 1.5 m; · 4 spurs; · Launching aprons to protect the toe of the revetment and spurs.

PRTW.06 River: West Rapti Start structure Latitude 27°49'54.38"N Longitude 82°31'12.46"E End structure Latitude 27°50'6.10"N Longitude 82°30'49.23"E Chainage *1 Upstream [m] 133,701 Downstream [m] 132,929

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Symbol / overview (indicative) Details Located along the left bank providing protection against erosion and inundation. Structures: · Earthen embankment protected with a gabion revetment. The total length is 750 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 4 spurs; · Launching aprons to protect the toe of the revetment and spurs.

PRTW.07 River: West Rapti Start structure Latitude 28° 4'37.65"N Longitude 81°49'20.66"E End structure Latitude 28° 4'58.48"N Longitude 81°49'9.61"E Chainage *1 Upstream [m] 34,889 Downstream [m] 34,097 Located along the right bank providing protection against inundation and erosion. Structures: · Earthen embankment protected with a gabion revetment on top of existing embankment. The total length is 820 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 9 spurs; · Launching aprons to protect the toe of the revetment and spurs. PRTW.08 River: West Rapti Start structure Latitude 28° 3'52.69"N Longitude 81°43'35.35"E End structure Latitude 28° 1'36.53"N Longitude 81°45'8.91"E Chainage *1 Upstream [m] 20,348 Downstream [m] 14,747

Located along the left bank providing protection against inundation and erosion. Structures: · Earthen embankment protected with gabion revetment of 5,010 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 18 spurs; · Launching aprons to protect the toe of the revetment and spurs. PRTW.09 River: West Rapti Start structure Latitude 27°57'41.96"N Longitude 81°45'28.87"E End structure

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Symbol / overview (indicative) Details Latitude 27°57'9.16"N Longitude 81°45'37.40"E Chainage *1 Upstream [m] 7,233 Downstream [m] 6,324

Located along the left bank providing protection against inundation and erosion. Structures: · Earthen embankment protected by a gabion revetment. The total length is 1,050 m; · Above the design water level, the outer slope will be protected by using grass (bio- engineering / environment-friendly). Also the crest and inner slope will be protected by using grass. Freeboard is 1.5 m; · 8 spurs; · Launching aprons to protect the toe of the revetment and spurs.

The downstream extent lies about 1km from the Indian border and the adjacent right bank lies within India. The Indian government has already constructed a flood embankment with roads at the adjacent right bank on the Indian side downstream of the proposed structure PRTW.09.

*1: Based on the chainage (Station Number) in the modelling. Zero is just downstream.

5.7 Cost estimates improvement works Table 15 provides a summary of the cost estimates of the civil works. Appendix D includes detailed information on the bill of quantities and cost estimates.

Table 15: Summary cost estimates improvement works (1 USD = 115.08 NPR) No Description Amount [USD] Amount [NPR] A Civil works A1 - Embankments / revetments 13,290,937 1,529,521,087 A2 - Spurs 3,857,495 443,920,504

Sub-total A 17,148,432 1,973,441,592 B General items General items 77,168 8,880,487

Sub-total B 77,168 8,880,487 C Contingencies Contigenceis 4,287,108 493,360,398

Sub-total C 4,287,108 493,360,398 D VAT VAT (13%) 2,229,296 256,547,407

Sub-total D 2,229,296 256,547,407 Grand total (A+B+C+D) 23,742,005 2,732,229,884

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Note: The above cost calculation concerns nine structures. During the CBA some of the structures, due to limited flood benefits while the capital investment costs are high, have been removed from the project in order to make the basin feasible. The removal of structures will be discussed in the CBA section.

The annual maintenance costs are estimated on 3% of the economic prices of the civil works, with are NPR 72.3 million or USD 0.63 million.

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6 FFEWS and CBDRM

6.1 Introduction During the 27th of June 2018 meeting between WRPPF, DHM and the Consultant, it was concluded that FFEWS and CBDRM would not be included in the Package 7 project. This is because it is already being covered by another project “Establishment Of End-to-end Flood Early Warning System In Koshi And West Rapti River Basins To Support And Strengthen Disaster Risk Management”, financed by the World Bank.

During the final ADB review meeting (December 2018), with WRPPF and ADB, it was requested that the Package 7 Consultant should include some FFEWS equipment and CBDRM as it was not fully covered by the other project.

In this chapter the proposed FFEWS equipment for hydrometeorological gauge networking and CBDRM to be implemented under this project is described. CBDRM for West Rapti is include din the larger document on CBDRM4 that is submitted.

6.2 Existing and proposed rain gauge network Five new auto telemetry rain gauge stations have been proposed for installation. Where feasible, new gauges will be installed at bridge locations, for ease of access. West Rapti catchment area is 6,370 km2. There are twenty five existing gauging stations by DHM within this basin. This will deliver a rain gauge station density as one rain gauge in every 212 km2. It is noted here that England has highest gauge density in Europe (one rain gauge in every 60 km2; Allot, 2010). Based on data and model performance evaluation during the FFEWS model operation, further review of gauging density should be carried out and if required, installation of more gauges could be considered. At this stage, considering the maintenance budget (and advice from DHM), only these five new stations are proposed.

The optimum gauge density may be higher, 1 in every 20 to 45 km2, like in mountainous Nepal (Lopez et. al., 2015 and Volkman et al., 2010) considering greater spreads of annual rainfall among mountains, Siwalik and Terai region. Flood prediction in rural and urban areas requires dense spatial gauge networking, one gauge between 10 to 100 km2 and higher temporal measurement frequency between minutes to hour (Berndtsson and Niemczynowicz, 1988). However, considering practicality, management, and with reference to other countries, the five new stations have been proposed. All proposed rain gauges should be stationed in the within the vicinity of a settlement, and ideally be distributed considering the main channels and its tributaries. Accordingly the positions have been selected based on the above criteria, see Table 16 and Figure 29. An X-band radar rain gauge was also considered initially. However, as recommended by ADB, radar rain gauge has been excluded. Figure 29 still includes the potential location of the radar rain gauge in case it is considered in the future.

Table 16: Proposed new auto telemetric rain gauge stations Catchment / Rain gauge ID Name of nearest Station coordinates basin name settlement Longitude, Latitude, N E [deg] [deg] West Rapti WR_Rain_01 Baghsalgoth 81.836 28.211 WR_Rain_02 Tallo Khairikhuti 81.925 28.150

4 Community Based Disaster Risk Management, Mott MacDonald, 2018

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Catchment / Rain gauge ID Name of nearest Station coordinates basin name settlement Longitude, Latitude, N E [deg] [deg] WR_Rain_03 Kharibang 82.766 28.007 WR_Rain_04 Hanjabang 82.450 28.334 WR_Rain_05 Kudar 82.632 28.423

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Figure 29: Existing and proposed rain gauge stations

6.3 Proposed hydrometric network installation Eight hydrometric gauging stations in West Rapti catchments have been proposed (see Table 17 and Figure 30). All stations are easily accessible and are located within the vicinity of a settlement. Where feasible, new gauges will be installed at bridge locations, for ease of access. All stations have access to GSM (DHM, 2018).

The locations have been carefully chosen, to enable calibration of run-off from hydrological model and calibration of river levels in hydrodynamic model. There are five water level (WL) and discharge (Q) stations (both parameters at same station), and three WL only (no Q) stations. At all eight hydrometric stations, bed material samples shall be collected and in five discharge stations, suspended sediment samples shall be collected. Bed material shall be collected from mid-channel, and from bed near the banks. Concentration samples of suspended sediment shall be collected from three positions as minimum over the cross-section. If river depth is high (>3m), we recommend collecting concentration over several vertical positions (e.g. 02d, 0.6d and 0.8d; d is total water depth) at each position. If the depth is shallow (<3m), only one sample at 0.5d is recommended.

The distribution of WL and Q stations will allow for a considerably dense network for calibration of the hydrodynamic model. Such dense network should be considered as essential given the relatively steep slope in upper basin and mild slope in lower basin of the terrain .

Table 17: Proposed water level and discharge stations River name Water level Gauge type Name of Station coordinates and nearest Longitude, Latitude, N discharge settlement E [deg] [deg] gauge ID West Rapti WR_G_01 Water Level Aurahawa 81.813 28.081 WR_G_02 Water Level Rajpur 82.314 27.902 WR_G_03 Water Level Chhingatpur 82.603 27.834 WR_GD_04 Water Level Nawalpur 81.931 28.043 and Discharge WR_GD_05 Water Level Banghusarikh 82.463 27.861 and uti Discharge WR_GD_06 Water Level Tallo Lape 82.788 27.848 and Discharge WR_GD_07 Water Level Takura 82.705 28.168 and Discharge WR_GD_08 Water Level Chyandanda 82.585 28.298 and Discharge

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Figure 30: Existing water level and discharge station and proposed stations

6.4 Proposed hydrometric equipment Only budget for Cableway construction has been considered for this basin. No budget for ADCP, DGPS and echo-sounder has been considered for this basin.

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We recommend the cableway discharge station at Tallo Lape on the West Rapti River.

6.5 Topographic and asset survey Topographic survey will include river section, existing structures and flood embankment profile.. It is proposed that a total of 160 km and 421 cross-sections will have to be surveyed in the West Rapti river. Given that the on-going FFEWS model development by DHM under World Bank funding is based on old topo survey, new topographic surveys are proposed. No satellite imagery purchase has been considered as the on-going FFEWS model has no 2d model development component. No survey equipment has been proposed for purchase. Survey will be done through outsourcing.

All cross-sections will cover the river, bank to bank and will be extended into the floodplain to sufficiently high ground of highest historic flood water mark. Horizontal projection for survey will be WGS 84 / UTM zone 45N. Ground elevation will be relative to metre above mean sea level (masl) for controlling vertical datum. All cross-sections shall be connected to Nepal National permanent bench mark for horizontal and vertical datum control. Temporary bench marks shall also be established for cross-verification of data. All cross-sections, in a basin, shall be surveyed during dry season, prior to or after monsoon so that cross-sections are stable without much morphological change. All cross-section shall be surveyed in one season. This should not be done that half volume of total survey prior to monsoon, and the rest after the monsoon

Ground elevation (vertical position) in cross-section/topographic survey shall have the following level of accuracy

· better than 20mm in case of level survey, and · better than 50mm in case of echo-sounder depth survey. · Horizontal position accuracy should be better than 1m.

There should be enough vertical points to sufficiently represent a cross-section shape, dense points about 0.5 to 1m apart at scoured part of the cross-section, and less points over shallow sand bars, about 1 to 5m interval.

6.6 CBDRM and flood shelters Only implementing a FFEWS (World Bank Project) is insufficient to protect the people living and carrying out their livelihoods in the flood prone areas. It is important to train community members on how to respond when a warning is given. During the final review mission in December 2018, WRPPF and ADB requested this project to include CBDRM. Within the CBDRM component, at the community level, groups of people will be trained to guide the communities in the event of a flood warning and increase their resilience to respond. It is crucial that people know what to do and where to go in the event of flood warnings. The below paragraphs are part of a more comprehensive document on CBDRM.5

6.6.1 Participatory approach CBDRM includes a participatory approach and a flood resilience capacity assessment with the local communities. An inventory of the different houses and buildings in each community should be made to identify the vulnerable and non-vulnerable places. Available schools or government buildings, which are most of the time higher and stronger structures when compared to houses, can be used for temporary shelter during flood events. In the absence of these kind of buildings, flood shelters can be constructed. It is recognised that most communities do have some form of

5 Community Based Disaster Risk Management, Mott MacDonald, 2018

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“safe house” (often a local school) identified, and the assessment process will need to review how appropriate the existing systems are.

In case flood shelters are required, it is important to discuss and decide together with the community where the flood shelter should be constructed. The location of the shelter will need to consider how safe it is (low/high ground), how far it is from those it is serving, and land ownership.

In other programmes, such as Practical Action in Karnali, there were no land acquisition costs for flood shelters. Their common practise has been that either the local government or a local private land owner voluntary donates land (approximately one Katha is required, which is about 338.63 m2). In the latter case, the land is legally transferred to community ownership through e.g. the forest groups or water users groups, which are legally registered groups. The CDMC is not a legally registered group and cannot have ownership.

Besides the training of what to do during emergencies, CBDRM should also look to the future when the different communities will further development and expand. This should include:

- Undertaking village level planning to identify “no go” zones and creating awareness not to construct houses or other important building in flood-prone areas. This process will contribute to ensure that the structures are located further away from the dangerous areas. Guidelines would be the flood zoning as indicated in the DWIDM Policy 2072;

- Construct housing in such way that they are more protected from floods. This means that the houses are adapted to the local conditions. Houses can be e.g. built on stilts, where living is done on the first floor while the ground floor can cope with flooding or to increase the ground floor above the existing ground level based on the historic floods data. This concept is applied in many countries such as Vietnam, see Figure 31.

Figure 31: Living on the first floor, above flood level

6.6.2 Flood shelters The information on flood shelters is based on the experience gained from the implementation of the NGO Practical Action in Nepal. One of the projects of Practical Action Nepal, is the construction of 12 flood shelters in the Karnali river basin.

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Despite training and warnings, it is known that people will evacuate their houses always at the last possible moment. That would mean that flood shelters should be located close to the communities. Practical Action uses a rule of thumb of a 15 minute walk to the flood shelters, which is about 1 km in distance.

There are no standard designs for flood shelters as it is dependent on the local conditions, e.g. available land and number of people, will influence the designs. These shelters are mainly for emergency support and are not to be used for longer periods. Shelters are used for a maximum of 3 days, but more often only a few hours. Basic requirements are that a flood shelter should have:

1. The ground flood should be constructed above the measured highest flood level. In practise, Practical Action designs the flood shelters about 1.2 m (4 foot) above the ground level. A ramp will be constructed to allow disabled and elderly to access the ground floor easily;

2. Safety of people is important. As this is an emergency evacuation the people need to be safe at all times. This is e.g. earth quake resistant, strong hand rails along the stairs and wider staircases so that elderly and disabled can receive support from others when going to the first floor;

3. Besides an open common area, the first floor of the shelter should have at least 4 rooms: 1 x room with toilets for women; 1 x room with toilets for men; 1 x changing room; and 1 x storage room.

An example of a flood shelter is provided in Figure 32. It is noted that flood shelters are only used during a short period of year. During the dry season the flood shelter can be used for other community activities such as training or community meetings. The shelter below constructed in 2015 costs approximately 25.000 - 30.000 USD. One flood shelter is used by 150 – 160 people, maximum 200 people.

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Figure 32: Flood shelter Nangapur (source: Practical Action)

6.6.3 Gender and ethnic group inclusion It is important is to understand the situation within the community concerning available groups (e.g. gender, pregnant women, single women, disabled and ethnic), which will make use of the same shelter. Based on a Red Cross official in a district of the Mohana – Khutiya Basin: during shelter the users are treated equally. They are all considered shelter users, only one caste during that period.

Practical Action indicated that there are Shelter Management Guidelines (Nepalese language) for the flood shelters. These Shelter Management Guidelines indicates that there are separate rooms for women and men, preferably on opposite sides.

6.6.4 Number of flood shelters Flooding in West Rapti Basin affects a large number of people. Table 18 provides an estimate of the flood affected people, after construction of the structures as included within the scope of this project.

Table 18: Estimation of flood affected people per return period Return period Description 2 5 10 25 50 100 years years years years years years Run 1 - Existing situation without the impact of climate change Flooded Area [ha] 7,838 9,866 11,247 12,927 14,092 15,319 Flood affected households [#] 1,915 2,776 3,587 4,430 5,013 5,764 Flood affected people [#] 11,490 16,657 21,520 26,583 30,081 34,584 Run 2 - Existing situation with the impact of climate change Flooded Area [ha] 8,650 10,869 11,904 13,539 14,821 15,824 Flood affected households [#] 2,233 3,309 3,955 4,870 5,578 6,447 Flood affected people [#] 13,396 19,852 23,729 29,218 33,465 38,679 Run 3 - Run 2 including the proposed structures Flooded Area [ha] 8256 10077 10989 12488 13713 15058 Flood affected households [#] 1740 2637 3121 3918 4593 5502 Flood affected people [#] 10439 15824 18728 23507 27555 33010 Note: The above analysis concerns the nine proposed priority structures.

Taking into account that flood shelters are prepared for 150 – 200 people, a large number of flood shelters will therefore be required. However, existing schools, government buildings and those houses that are not vulnerable to flooding, as well as future constructed flood mitigating works will decrease the number of affected people that require flood shelters.

During the CBDRM phase, it is important that together with the national and local government, the most vulnerable areas are identified. For these areas a detailed survey needs to be conducted to identify which are the vulnerable houses and which houses / buildings / structures can be used for shelter. This project needs to work at the local level to address areas where flood protection service provision needs reinforcement based on community priorities, and without duplication of the efforts and support provided by others.

This project will not undertake a survey of the existing resources. At this stage, the project assumes that 10 communities require immediate support and also require flood shelters. The indicative locations are shown in Figure 33.

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Figure 33: Indicative location of flood shelters West Rapti basin

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6.7 Cost estimates The capital costs are indicated in Table 19. Costs for operation and maintenance are shown in Table 20.

Table 19: Cost estimate FFEWS and CBDRM – Capital costs (1 USD = 115.08 NPR) Unit Unit price Capital costs Categories [#] [USD] [USD] [NPR] Development flood forecasting model Topographic cross-section survey 1 84,200 84,200 9,689,736 Total 84,200 9,689,736 Hydro meteorological data networking Rain gauge - Telemetry 5 5,000 25,000 2,877,000 Water level + discharge 150 4,333 650,000 74,802,000 Water level 3 7,000 21,000 2,416,680 Total 696,000 80,095,680 Discharge measurement equipment / station installation Cable-way discharge station (construction costs) 1 95,000 95,000 10,932,600 Total 95,000 10,932,600 CBDRM CBDRM 10 8,060 80,600 9,275,448 Flood Shelter 10 35,000 350,000 40,278,000 Total 430,600 49,553,448 Note: - Discharge measurement to be carried out fortnightly from mid-May to mid-October; this will be 10 measurements per year, 30 in 3 years and total 150 measurements in 5 stations. - Discharge measurement cost is a continuous expenditure, like model development cost (and should be considered similar to capital cost); it includes cost for all skilled human resources and the logistics required.

Table 20: Cost estimate FFEWS and CBDRM – Operation and maintenance Costs Costs Categories Remarks [USD] [NPR] Hydro-meteorological data networking Rain gauge - Telemetry 6,000 690,480 For a period of 3 year Water level + discharge 6,000 690,480 For a period of 3 year Water level 6,000 690,480 For a period of 3 year CBDRM CBDRM (10 communities) 44,540 5,125,663 Operational costs for year 2 to year 5 Notes: - Operation and maintenance cost of hydro-meteorological data networking is $2,000 per basin for all station per year; this involves routine site visits, repair and maintenance

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7 Cost benefit analysis

7.1 Basis for the Analysis Pre-feasibility studies for the priority basins were carried out in 2015/16. The methodology used in the economic analysis prepared for these studies was detailed and comprehensive, particularly with regard to the factors contributing to project benefits. The present feasibility analysis uses the benefit estimation methodology and models prepared for the prefeasibility studies. Particularly with regard to estimates of housing classes and the extent of damage to buildings and infrastructure for each flood return period. The input data the cost benefit analysis was updated based on the results of the redeveloped hydrodynamic models and flood maps. Prices for infrastructure, agriculture and livestock are also updated to third quarter 2019 prices for the subproject area and inputs and outputs in the agricultural crop budgets, for estimating the value of flood damage to crops, have been modified to bring them into line with current conditions.

Costs for the feasibility level designs have been updated in accordance with the current district unit costs for the subproject districts.

The methodology for the economic analysis is presented in Appendix E. The detailed data required for the CBA for West Rapti Basin is presented in Appendix F.

The economic analysis has been conducted based on the ADB’s Guidelines for Economic Analysis of Projects.

7.2 Benefits Benefits come from the avoided losses accruing with implementation of the flood protection measures. Direct benefits quantified for the analysis are avoided damage and destruction of buildings and public infrastructure, avoided damage to monsoon season crops, prevented human injury and mortality, avoided livestock deaths and the avoided costs of repairing buildings, bunds and other field infrastructure and addressing the effects of sedimentation. Indirect benefits include the value of increases in private and public infrastructure and increases in agricultural productivity and production inside the flood protected area that are induced by the increased security from flood damage.

The areas protected by the subproject physical interventions have significant benefit streams from the avoidance of loss and damage to houses and infrastructure, agriculture, livestock and human mortality as well as benefitting from the FFEWS and CBDRM. Those areas that benefit only from the implementation of the FFEWS and CBDRM will still have real benefits from the project from the protection of lives, livestock and movable assets.

The benefits are the differences between avoided losses in the without and with project situation, plus indirect benefits obtained as a result of the proposed project. Avoided losses are weighted by the probability of their future occurrence and benefits independent of flood events are scheduled with reference to the project flood management time frame. The discounted benefits are shown in Table 21.

Table 21: Discounted Benefits (financial prices) NPV of Benefit Stream Source of Benefits % Total Benefits (NPR million) Direct infrastructure avoided losses 2,190.4 85.1

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Indirect infrastructure benefit 81.9 3.2 Direct agriculture avoided losses 22.7 0.88 Indirect agriculture benefit 8.81 0.34 Direct livestock avoided losses 1) 107.6 4.2 Direct funeral and injury expenses avoided 1) 3.2 0.12 Direct and indirect avoided prevention & coping costs 158.1 6.1 TOTAL BENEFITS 2,572.7 100

Note: 1) Include avoided losses in flood affected area (outside protected area) due to implementation of the FFEWS.

7.3 Costs The total projected costs amount to NPR 2,228 million (USD16.83 million) including the costs of infrastructure, FFEWS, CBDRM and land acquisition and the environment management plan. In economic prices, the cost is NPR1,986 million (USD 15.00 million).

Table 22: Costs by Expenditure Category (NPR ‘000)

Expenditure Category 2020 2021 2022 2023 2024 2025 2026 Total A. Investment Costs Civil Works 0.00 36.41 410.77 440.36 464.29 441.07 0.00 1,792.89 Equipment 0.00 40.59 42.96 45.45 0.00 0.00 0.00 129.01 Supplies, Materials and 0.55 7.82 8.44 9.06 9.41 9.99 8.73 53.99 Operations Studies and Surveys 0.61 7.93 8.56 8.45 0.00 0.00 0.00 25.56 Training and Workshops 0.12 1.58 1.70 1.83 1.97 1.94 0.00 9.14 Consulting Services 1.59 20.30 21.63 23.02 24.48 24.39 6.32 121.73 Government Staff 1.08 8.46 16.89 18.19 19.55 19.74 12.17 96.09 Resettlement 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Total (financial prices) 3.95 123.08 510.96 546.37 519.70 497.12 27.22 2,228.40 Total (economic prices) 3.68 111.41 455.00 486.54 462.23 442.31 25.75 1,986.92 Note: Including contingencies but excluding financing costs

7.4 Results of the Economic Analysis

7.4.1 Key Assumptions Numeraire and prices: The analysis uses the domestic price level numeraire, expressed in local currency. The financial prices used are those applying in the market in the third quarter of 2019. To derive economic prices the foreign component of the price of traded goods is adjusted by the shadow exchange rate factor (SERF), scarce labour is adjusted by the shadow wage rate factor (SWRF) of 0.8, taxes (VAT of 13% and any import duties) are removed from prices and domestic resources are multiplied by a factor of 1 (i.e. the financial prices of domestic resources are equal to the economic prices).

Conversion factors and exchange rate: The standard conversion factor (SCF) of 0.92 (SERF = 1.09) was estimated using import and export data for most recent five fiscal years. The exchange rate used throughout the analysis is USD 1 = NPR 114.9.6

6 Rate of end of August 2019

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Opportunity cost of capital: The opportunity cost of capital used for the analysis is 9%.

7.4.2 Results of the Analysis The West Rapti sub-project has an EIRR of 29.1%, above the discount rate of 9% that is the hurdle for confirming economic viability. As may be seen Table 23 the EIRR is resilient to changes in the levels of damage sustained by buildings and public infrastructure during flood events. The prevention of this damage is the main source of benefits for the subproject, and it may therefore be concluded that West Rapti sub-project is economically viable and changes in the key factors measured are unlikely to undermine this conclusion.

Table 23: Results of the Economic Analysis NPV Switching % change EIRR (NPR mil.) Value Base case 29.1% 957.1 Investment costs +10% 21.9% 790.1 +57% +20% 17.8% 623.0 Benefits -10% 21.6% 694.4 -36.3% -20% 15.9% 431.6 Buildings affected in flood envelope +10% 48.5% 1,221.6 -36.5% -10% 21.3% 694.1 % buildings damaged/destroyed +10% 46.3% 1,204.2 -39.1% -10% 21.7% 711.1 Public infrastructure affected +10% 30.9% 1.000.8 - -10% 27.7% 917.3 Future growth in infrastructure +10% 29.3% 965.1 - -10% 29.0% 949.2 Agricultural area affected +10% 29.7% 960.7 - -10% 29.0% 953,5

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8 Safeguards

8.1 Introduction Social and environmental surveys have been conducted in the West Rapti Basin. In this chapter a summary of the results is presented.

8.2 Environmental safeguards The sub-project on West Rapti river basin, located in the Terai of Western Nepal, is categorized as an Environmental Category B. and accordingly an IEE has been prepared as a stand-alone document to accompany this feasibility study. As per the Environmental Protection Regulation of Nepal, this project with more than 10 km of flood protection works in this river basin, it also requires IEE report to be prepared and approved by the MoWRI.

8.2.1 Project Influence Area The West Rapti rises south of a prominent east-west ridgeline midway between the western Dhaulagiri Himalaya and the Mahabharat Range in the north western part of Rolpa District. The River descends south from rugged highlands of Rolpa District and crosses into Pyuthan. After the confluence with Jhimruk and Madi, the river is called West Rapti River. The West Rapti flows for a short distance towards the south west and makes a turn and flows due North West, parallel to the Churia (Siwalik) range till Shamserganj in Banke district. Here it makes a turn and flows due south east. It joins Ghagra (Karnali) River in India. The prioritized flood protection works in this basin are in Dang and Banke districts and the directly influenced municipalities and rural municipalities by the prioritized flood protection works are Gadhawa Rural Municipality and Lamahi Municipality in Dang District and Narainpur and Rapti Sonari Rural Municipalities in Banke District.

8.2.2 Priority Project Activities with Environmental Consequences This sub-project will not only provide flood control and river training infrastructures, it also has the component on training programme for CBDRM. While designing the flood protection structures, 1 in 50 years return period is used. Although, the modelling to identify the priority areas for protection works covers a total length of around 160 km in West Rapti river, the selection of priority works was done in close cooperation with the WRPPF and PEP field office.

Figure 13 till Figure 15 shows the flood maps for a return period of once every 50 years, and Figure 10 and Table 5 show the defined 9 priority areas for the West Rapti basin. In total 18,840 m of revetments, 17,640 m of embankments and 75 spurs are planned for construction. In addition to this, 10 new flood shelters (Figure 33) are envisaged to be constructed in the basin.

Construction activities at river beds, operation of heavy construction machineries, and movement of heavy vehicles for transporting the boulders and other construction materials will all have environmental consequences that need to be mitigated. Further, the FFEWS will add five new auto telemetry rain gauge stations, and eight hydrometric gauging stations (see Chapter 6).

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8.2.3 Baseline Environment Physical Environment

The river originates from the middle mountains of Nepal, then enters the lowlands and finally drains to the Ghagra (Karnali) River, a tributary of the Ganges River in India. Major tributaries are Jhimruk, Mari, Arun, Lungri, Sit, Dunduwa, Sotiya and Gandheli. The average slope of the basin is 16.8%. The catchment area is almost 5200 square km. While the upper West Rapti River basin has a temperate climate, the lower basin including the Banke district has a tropical to subtropical climate. The temperature reaches upto 46°C in summer in the lower part of the basin and falls below 2°C during winter in the upper part of the basin. The study area receives summer monsoon rainfall extending from June to September, accounting about 80% of the total annual precipitation. The average rainfall for West Rapti River Basin is about 1,500 mm. The air quality along the river basin is quite clean, however, near to the four crusher plant and in areas with traffic particularly in dusty and unpaved road, the ambient air quality is slightly polluted with particulate pollutants. Movement of vehicles and trucks also are the sources for occasional high level of noise along the roads. Excavation of sand and stones from the river body as well as discharges of sewages in the river bodies from Lamahi city makes the river water quality polluted.

Figure 34: Crusher plant Biological Environment

There are no protected areas such as national parks, wildlife reserves, hunting reserves, conservation area and their buffer zones in the sub-project sites. However, the surrounding environment of the Sub-Project area contains sparse vegetation with common species of the area like Sal (Shorea robusta), Sahaj (Borassus flabellifer), Sissoo (Dalbergia sisoo), Bamboo (Bambusa vulgaris), and other common species of Terai. Wildlife like Pate Bagh(Panthera tigris), Syal (Canis aureus), Deer (Muntiacus muntjak), Rabbit (Caprolagus hispidus), Monkey(Macaca mulatta), Badel (Sus scrofa), and occasionally Elephant (Elephus maxima), leopard (Panthera pardus) are seen in the forested areas. The commonly found birds in the sub-project area are Maina ( Gracula religiosa), Suga (Psittacula kramen), Kag (Corvus splendens), Jureli (Hypsipetes leucocephalus), Bhagera (Passer domesticus), Giant hornbill (Buceros bicornis) Laughing Dove (Streptopelia senegalensis) Cattle egret (Bubulcus ibis) etc. West Rapti River have some fish species like Sidra (Puntius sps.), Rohu (Labeo rohita), Silver fish (Hypophthalmichthys molitrix), Thedd (Labeo angra), Catla (Catla catla) etc. Commonly found Herpetofauna in the area are Lizard (Hemidactylus frenatus), Frog (Rana tigrina), Sun Gohoro, Land tortoise (Testudinidae species), and Common rat snake (Ptyas mucosus) etc.

Socio-Economic and Cultural Environment

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According to the 2011 census, the total population in the municipalities and rural municipalities within the project influence area was 98, 157 with female population of 51.61% and male 48.39%. In Banke district, Muslims are the most populous caste group i.e. 19 %. Indigenous group of people such as Tharu (16%), Magar (6%), Kami (5%), Yadav (5%), Thakuri (4%), Kurmi (2%) are resident of Banke district with Brahman- Hill (7%), Chhetri (15%) and others (23%). Similarly, in Dang district, Tharu are the most populous caste group i.e. 30 % followed by Chhetri (25%) and Brahman- Hill (10%). Indigenous group of people such as Magar (14%), Kami (5%), Damai / Doli (3%), Dashnami / Sanyasi (2%), Sarki (2%), Kurmi (2%) and others (7%) are also the resident of this district. There is no industrial area within the periphery of the project influence area, however small and cottage type of industries are in Lamahi city, and some crusher industries in other local bodies as well. As Terai is regarded as the granary of Nepal, majority of people in the area depend on agriculture. The affected area in the West Rapti River Basin based on 1 in 50 years return period with climate change is estimated around 14,891 ha. For the same return period, the flood affected people in the basin are about 31,304 people (5,217 households).

8.2.4 Anticipated Environmental Impacts and Mitigation Measures Impact on Air Quality and Mitigation

Operation of heavy equipment for excavation in the river banks, and movements of heavy trucks along the dusty village roads for transporting construction materials mainly the stones/boulders is expected to increase the dust/smokes in the ambient air with possibility of air borne diseases to people living near to the roads and construction sites. This is a very short term localized impacts and with simple measures like covering the trucks with loose materials, ensuring that the equipment and trucks comply with national standards and are properly maintained as per manufacturer’s specification, limiting the truck speeds below 20 km/hour in dusty road, and spraying water in dusty roads, the impacts can be minimized. The source for stones/boulders to be used in the project are from the river basin itself with permission from local bodies.

Impact on Noise Quality and Mitigation

Above mentioned activities can also generate noise in the construction site and along the road particularly if the trucks move in night time. Maintenance of equipment and vehicles as per the manufacturer’s specification, no use of pressure horns, and restriction in the movement of trucks after 6 pm to 6 am can minimize the impacts.

Impact on River Water Quality and Mitigation

Excavation works and possibility of leakage from equipment can pollute the river water quality. Use of coffer dams and maintenance of equipment as recommended above can minimize the water pollution.

Impact on Vegetation and Aquatic Life

The project does not require to remove any forest land or even the privately grown trees are not found along the river bank in the area where the works are planned. Make sure that the workers do not use illegal techniques like use of electric wires for fishing in the river.

Occupational Health and Safety

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In order to minimize the risk of injuries, impact of dusts/smokes and high noise level in the health of people, the project must ensure the compliance with the OHS standards of Nepal and workers and people in the work places always use the PPE (personal protection equipment).

Socio-Economic Impacts

Social safeguards issues are presented in the next heading of this chapter. As compared to the above mentioned short-term localized adverse impacts that can be minimized just by following the good practices in construction management, the project will result with significant positive impacts. Local peoples will get employment opportunities, start of small business, and good price for the agriculture products during the construction phase. After the completion of the project, it will significantly reduce the risk of damage to human life and properties from floods, make the area attractive for investments, and remove the fear from the mind of people during rainy days. It is estimated that 1,528 ha of area in the basin will be protected benefitting directly to 7,082 people or 1,180 households.

Mitigation Cost

There will be a nominal additional cost for the implementation of above mentioned mitigation measures as majority of the mitigation measures are part of the Good Practices in the construction management as well as legally binding requirements that need to be complied with. Expected costs during implementation are 4,200,000 NPR or 36,496 USD (exchange rate: 1 USD = 115.08 NPR).

8.2.5 Public Consultation, Institutional Arrangement and Grievance Redress Mechanism In addition to publishing the notice on national paper informing communities above the project, a number of consultation meetings were organized covering the impacted local bodies to understand the public views about project and suggestions to minimize the impacts. People expressed happiness towards project and suggest that river protection works should cover all along the river banks for long-term benefits.

Peoples Embankment Program (Field Office in Dang) will assign one civil engineer with experience on environment management as Environmental Liaison Office to ensure the compliance with the EMP. In addition, the environmental officers working in the Municipalities will ensure that the companies collecting stones and sands from riverbed in the area comply with the standards.

In order to address the complaints of the people, a three step GRM is proposed. In the beginning the people can complain to the Environmental Liaison Officer. If the complaints are not resolved within 5 days, they can make the complaints to the Coordination Committee of Local Authorities, and if they also could not resolve within 5 days, they can complain to the Department of Environment. Environmental Act of Nepal also has the provision for appeal in the court.

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8.3 Social safeguards The West Rapti river basin is part of the Terai plains, which act as an international border with India in the south part of Nepal.

The sections below consider the categorisation to be used for indigenous peoples and involuntary resettlement, and indicates how these issues will be dealt with in the project documentation. The social survey team visited the river basin to interview community households, including with questions about knowledge of resettlement programs and interest in providing land voluntarily.

8.3.1 Indigenous Peoples (IP) Nepal is a multi-ethnic, multi-lingual, multi-religious, multi-cultural country with diverse regional characteristics. The Terai region is recognised as being home to indigenous nationalities (Adivasi Janajati). Indigenous nationalities are categorised as being endangered, highly marginalised, marginalised, disadvantaged and advanced. Households in the subproject area are fairly homogenous. In the survey of 103 beneficiary households, 91 were Tharu (a marginalised IP group), one was Tamang, and the rest identified by religion as Muslim, Chhetri, Brahmin. Four households identified as Dalit, a caste group that is generally considered disadvantaged.

The Tharu are the principal inhabitants, rulers, common mass and landlords of the Terai region and have been living there for many centuries. Dahit (2017) identifies that Tharus were the principal inhabitants of the Chitwan and Dang valleys, held independent control of land prior to national land reform in the1950s and early 1960s, and cultivated their land themselves. The traditional profession of the Tharu is agriculture on the Terai plains and inner Terai. Dahit (2017) states that with the mass migration of hill people and plan dwellers into the Terai area, Tharus gradually became poorer, lost power, and began working for others, which affected their self- respect, dignity, identity and sovereignty, such that the Tharu became ruled by others. During the site visit in August 2018, a representative of the Tharu Nagarik Samaj (Tharu Citizens Group – a group started more than 70 years ago and registered 27 years ago) indicated that they do have some organisations but leadership with decision making powers on behalf of Tharu negligible. The Tharu have their own language that is recognised as maintaining continuity. In addition to being recognised as an IP nationality by the National foundation for Development of Indigenous Nationalities (NFDIN), the Tharu meet ADB’s IP criteria. Table 24 presents the IP screening results.

Table 24: Subproject IP screening results KEY CONCERNS NOT (Please provide elaborations YES NO Remarks KNOWN on the Remarks column) A. Indigenous Peoples Identification

1. Are there socio-cultural groups The wider project area is mostly present in or use the project area who comprised of Tharu people, a may be considered as "tribes" (hill X group that is considered an tribes, schedules tribes, tribal indigenous nationality. peoples), "minorities" (ethnic or national minorities), or "indigenous communities" in the project area?

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KEY CONCERNS NOT (Please provide elaborations YES NO Remarks KNOWN on the Remarks column) 2. Are there national or local laws or The government recognises the policies as well as anthropological Tharu as a marginalised IP researches/studies that consider these X nationality. groups present in or using the project area as belonging to "ethnic minorities", scheduled tribes, tribal peoples, national minorities, or cultural communities?

3. Do such groups self-identify as People belonging to the Tharu IP being part of a distinct social and group identify as such. cultural group? X

4. Do such groups maintain collective The National Foundation for attachments to distinct habitats or Development of Indigenous ancestral territories and/or to the X Nationalities (NFDIN) identify natural resources in these habitats and Tharu as being from Terai. territories?

5. Do such groups maintain cultural, X A Tharu NGO representative economic, social, and political said they do not have decision institutions distinct from the dominant making institutions separate society and culture? from dominant society.

6. Do such groups speak a distinct X language or dialect?

The Tharu are recognised by the 7. Has such groups been historically, X NFDIN as marginalised, and socially and economically there are publications by marginalised, disempowered, researchers that also document excluded, and/or discriminated that the Tharu as a group have against? been disempowered.

8. Are such groups represented as X "Indigenous Peoples" or as "ethnic minorities" or "scheduled tribes" or "tribal populations" in any formal decision-making bodies at the national or local levels?

B. Identification of Potential Impacts

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KEY CONCERNS NOT (Please provide elaborations YES NO Remarks KNOWN on the Remarks column) X The Tharu and other ethnic and caste households living in the project area will be beneficiaries of the intended interventions for structural flood protection, early 9. Will the project directly or indirectly warning systems and benefit or target Indigenous Peoples? community based natural resource management, A small number of households will be directly impacted by minor amounts of land acquisitions required for embankments.

X No land used for IP group 10. Will the project directly or indirectly cultural purposes has yet been affect Indigenous Peoples' traditional identified as directly or indirectly socio-cultural and belief practices? impacted. There will be no direct (e.g. child-rearing, health, education, impact on IP practices related to arts, and governance) health, education, arts or governance.

11. Will the project affect the livelihood X The improved embankments will systems of Indigenous Peoples? (e.g., support farming endeavours, food production system, natural including for IP and caste resource management, crafts and households currently using land trade, employment status) close to the riverbanks.

X Land ownership in the area is 12. Will the project be in an area (land considered to be by household. Some IP households will be or territory) occupied, owned, or used directly impacted by land by Indigenous Peoples, and/or acquisition. claimed as ancestral domain?

C. Identification of Special Requirements Will the project activities include:

13. Commercial development of the X cultural resources and knowledge of Indigenous Peoples?

14. Physical displacement from X traditional or customary lands?

15. Commercial development of X natural resources (such as minerals, hydrocarbons, forests, water, hunting or fishing grounds) within customary lands under use that would impact the livelihoods or the cultural, ceremonial, spiritual uses that define the identity and community of Indigenous Peoples?

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KEY CONCERNS NOT (Please provide elaborations YES NO Remarks KNOWN on the Remarks column) 16. Establishing legal recognition of X rights to lands and territories that are traditionally owned or customarily used, occupied or claimed by indigenous peoples?

X No land claimed by an IP group will be acquired. A small number of individual IP households will 17. Acquisition of lands that are lose small portions of their total traditionally owned or customarily landholdings for embankments. used, occupied or claimed by Their losses will be mitigated indigenous peoples? through the production and implementation of a resettlement plan.

Table 25 presents a summary of the IP impacts, based on information known to date about the sites.

Table 25: Anticipated project impacts on Indigenous Peoples

Project output Anticipated positive effect Anticipated negative effect

Hydraulic structures for improved General protection of communities A small number of individual IP flood control established from the physical effects of households will lose small portions flooding, in particular for IP and of their total landholdings for caste households using land close embankments. to the river bank edge.

Flood risk management capacity All community members, There is no indication that IPs will improved regardless of ethnicity or caste, will not benefit or be excluded from potentially benefit from this these benefits. intervention.

For this subproject, there is potential for a small number of IP households who have their land plots at the river banks where the embankments will be constructed to be impacted by loss of land/economic displacement. A land acquisition, resettlement and IP (LARIP) plan is proposed to mitigate these impacts.

IP groups will benefit from the project interventions for CBDRM, in a similar fashion to non-IP groups. The benefits will accrue to those living closer to the proposed structured locations, those who participate in flood risk management training, and those living within user distance of the flood shelters. The GESI action plan (see Appendix H), in particular the social inclusion part, will address ways to ensure that IP and caste groups benefit in an equitable manner as non-IPs. For instance, by ensuring culturally appropriate communication campaigns and community development processes are undertaken.

Based on the above analysis, the IP risk categorisation in line with ADB criteria and MoEWRI sector guideline criteria, this subproject is Category B with limited impacts on IPs.

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8.3.2 Involuntary resettlement The river training component, namely embankments and physical structures, will entail land acquisition. Table 26 provides an indicative picture of the proposed structures and a description of their expected impact on land acquisition.

Table 26: Type of structure and land acquisition implications

Existing similar structure from project area Name of structure and land acquisition implications

Spurs - are river engineering elements used to protect river banks from erosion and to concentrate flow to the river axis. They are built within the river bed. They require no permanent land acquisition and only temporary use of a small amount of river bank for placing equipment and materials during their civil works.

Revetment - a retaining, sloping structures placed on river to absorb the energy of incoming water. They slope and have different widths depending on the design and morphology. This picture is typical of the revetments likely to be needed, i.e. a swath of land from 3-7 metres. The embankments proposed for this subproject range from 300m to 2,200m long. Revetments can be built within the riverbed or as part of the embankment on the river bank. When built within the riverbed, land take will be above as per the description of spurs. If built on the river bank, the land acquisition will be similar to on land embankments described below.

Embankment – is a wall or bank of earth or stone built to prevent a river flooding an area. The embankment crest is usually around 5m wide. The sides are designed for stability. For every meter of height of the embankment, both sides of the embankment need 2m of horizontal land. The swathes of land for this subproject will be the embankment crest plus two sides total width running parallel to the river, for a length of 300m to 2,200m. Depending on the specific location the embankment may be constructed in the river bed or on land starting on or close to the river bank edge. If the former, the land take on the river bank will only be temporary for placing material and equipment during civil works. If the latter, swathes of land will be

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Existing similar structure from project area Name of structure and land acquisition implications acquired from any land owners and land users with plots adjacent to the river edge. These swathes for the embankment will be permanently lost to other uses, and small areas of land around the design may be used temporarily during the civil works for construction materials and equipment.

For the flood shelters, the experience from Karnali River is that usually one kattha (0.03 ha) of land is sufficient. Practical Action has built 12 flood shelters on that river, and in all cases the land for the flood shelters was donated by a government entity or a private land owner who deemed it important for community safety.

Table 27 presents a summary of the land acquisition requirements.

Table 27: Land acquisition requirements

Outputs Land requirements Involuntary resettlement

Hydraulic structures for Embankments – 13,580 m 7 Surveys of DPs have not yet improved flood control total length X 17m wide = been undertaken. Based on established 23.086 ha or 681.73 katthas8. other river basins, it is possible that around 25% of the land is Temporary land use during privately owned. construction – dependent on contractor strategy

Flood forecasting early warning River gauges = 6 X 5m2 = 30m2 None – government land system enhanced (less than 0.01 ha) anticipated to be used

Flood risk management Flood shelters = 10 X 1 one Locations (and therefore any capacity improved kattha (0.03 ha) = 10 katthas DPs) unknown. Could be (0.30ha) government or privately-owned land that is donated or compensated.

The social survey found that 76% of the community households interviewed were willing to provide land voluntarily with no compensation. Their reasoning is that providing small portions of their total landholding with protect the rest of their plot for cultivation. Table 28 presents the involuntary resettlement screening checklist for the subproject.

Table 28: Subproject involuntary resettlement screening checklist results

Probable Involuntary Resettlement Yes No Not known Remarks Effects

Involuntary Acquisition of Land

X Yes, some of the embankment 1. Will there be land acquisition? structures will require land.

7 This is excluding the embankments of the excluded strucures (see Chapter 2) 8 1ha = 29.53 katthas

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Probable Involuntary Resettlement Yes No Not known Remarks Effects

X The feasibility study for the 2. Is the site for land acquisition subproject proposes the location for known? the embankments.

X The social survey team visited the 3. Is the ownership status and site prior to detailed design being current usage of land to be acquired available. known?

X The Ministry of Irrigation has zones 4. Will easement be utilised within an of ROWs that identify approved land existing Right of Way (ROW)? uses that are not enforced. Generally, farmers are already using a setback area prior to their cultivations. Most of the existing embankments are in the buffer area provided by farmers with the farmers’ permission.

X The technical survey team did not 5. Will there be loss of shelter and identify any shelters or residential residential land due to land land that will be impacted. acquisition?

X Some of the embankment 6. Will there be loss of agricultural structures, and may directly impact and other productive assets due land under cultivation. to land acquisition?

X There could be some crops, trees 7. Will there be losses of crops, trees, and fences that will be lost. and fixed assets due to land acquisition?

X 8. Will there be loss of businesses or enterprises due to land acquisition?

X Some crops that are used for 9. Will there be loss of income subsistence or selling may be lost. sources and means of livelihoods due to land acquisition?

Involuntary restrictions on land use or on access to legally designated parks and protected areas

X Public land that is lost, if similar to 10. Will people lose other river basins, it not being used access to natural for ecosystem services. No resources, communal structures or services are in the area facilities and services? to be acquired.

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Probable Involuntary Resettlement Yes No Not known Remarks Effects

X No, currently this is not anticipated. 11. If land use is changed, will it To the contrary, the embankments have an adverse impact on social are aimed at protecting land so it can and economic activities? be cultivated.

X Currently this is not anticipated 12. Will access to land and resources owned communally or by the state be restricted?

Information on Displaced Persons:

Any estimate of the likely number of persons that will be displaced by the Project? [X] No [ ]

If yes, approximately how many

Are any of them poor, female-heads of households, or vulnerable to poverty risks?[ ] No [ ] Yes

Are any displaced persons from indigenous or ethnic minority groups?[ ] No [ ] Yes

Source: Mott MacDonald using ADB involuntary resettlement screening checklist For involuntary resettlement, the river basin subproject is a Category B project for ADB because it has involuntary resettlement impacts that are not deemed significant, and Category C/Low risk under the Nepalese Guideline. A land acquisition, resettlement and IP (LARIP) plan is proposed to mitigate the impacts.

The resettlement plan will reflect the polices and standards identified in national laws, the ADB’s Safeguard Policy Statement, the MoEWRI sector guidelines on involuntary resettlement and indigenous people, and the project’s Resettlement Framework.

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9 Implementation

The executing agency of the project will be the MoEWRI and the implementing agency will be the DoWRI.

The implementation of the Project will be monitored by the Project Steering Committee at MoEWRI. This shall be the apex body chaired by the Secretary, MoEWRI. The other members of the Steering Committee shall be Joint Secretaries from MoF, DoWRI, DHM, representatives from Ministry of Home Affairs.

DoWRI will establish a Project Management Unit (PMU) at Jawalakhel, Lalitpur headed by Project Director from DoWRI and Deputy Project Director from DHM with appropriate staff besides Engineer (Design), Engineer (Procurement), Engineer (Implementation and Execution), Sociologist Officer, Environmental Officer and staff for Administration and support. The activities related to FFEWS shall be monitored by Deputy Project Director of PMU. There will be Project Implementation Units (PIU) in six People Embankment Program field offices located in respective sub-project areas in the Districts Jhapa, Morang, Sarlahi, Makwanpur, Dang, Kailali for the sole purpose of implementing the Project. The PIU will be headed by a Project Manager and appropriately staffed.

The PMU shall have its advisory sections comprising: (i) a committee that will review designs and documents, and advise as necessary; (ii) an environment safeguards and Social Monitoring and Evaluation Section that will monitor, evaluate and report on required safeguard and social activities; (iii) an Accounts and Finance Section that will be responsible for effective accounts and financial management; (iv) a Communications Section who will lead communication activities; and (v) a Procurement Section that will be responsible for obtaining approvals and issuing bid documents, managing bidding processes and bid evaluation until package award, and contract management including review and approval of contract variations.

Local Bodies will interact at Field level with respective PIU only.

The anticipated time schedule is provided in Figure 35. For details reference is made to the Project Administration Manual. The loan agreement is expected to be signed in 2019. In 2019 the procurement of the Project Implementation Consultant will commence.

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Figure 35: Implementation schedule

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References

[1] DWIDM Pocket Diary – 2071 (2014 / 2015), Department of Water Induced Disaster Management;

[2] Package 3: Flood Hazard Mapping and Preliminary Preparation of Flood Risk Management Projects, Final Report – VOLUME 1, Prepared by Lahmeyer International in association with Total Management Services, May 2016;

[3] Guidelines for preparation of DPR for flood management works, Government of India, Central Water Commission, April 2018;

[4] River and channels revetments - A design manual, Manuela Escarameia, 1998;

[5] Morphology Assessment: West Rapti Basin, Package 7: WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal, Mott MacDonald, 2019;

[6] River Hydrology Assessment: West Rapti Basin, Package 7: WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal, Mott MacDonald, 2019;

[7] Community Based Disaster Risk Management, Package 7: WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal, Mott MacDonald, 2019

[8] Vegetation structures for stabilising highway slopes. A manual for Nepal, Department of Road (Nepal) assisted by Overseas Development Administration (UK) March 1991;

[9] Vetiver grass, a thin green line against erosion, Board of Science and Technology for International Development, National Research Council, 1993;

[10] Downstream Hydraulic Geometry of Alluvial Rivers, Pierre Y. Julien, 2014;

[11] Flood control measures, Best practises report, An approach for community based flood control measures in the Terai, 2000, GIZ;

[12] Resource Manual on Flash Flood Risk Management, Module 3: Structural Measures, 2012, ICIMOD;

[13] WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Topographical Survey and Social Survey Watersheds, Feasibility Study (West Rapti and Lakhandei) – Deliverable 2; Engineering and Educational Services Pvt. Ltd.; December 2018.

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Appendices

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A. Flood maps

In this appendix the different flood maps are included for all runs and all return periods. The flood map presents the latest alignment based on the 2018 survey of the project. The following is included:

- Appendix A.1: Reference Alternative (Run 1): This is the situation as per today including the existing structures;

- Appendix A.2: Future Alternative 1 (Run 2): This is the Reference Alternative (Run 1) including the impact of climate change but without the proposed structures;

- Appendix A.3: Future Alternative 2 (Run 3): This is the Future Alternative 1 (Run 2) including the proposed structures and the impact of climate change.

A.1 Flood maps: Run 1 The following flood maps are included:

- Return period of 2 years: Run 1; - Return period of 5 years: Run 1; - Return period of 10 years: Run 1; - Return period of 25 years: Run 1; - Return period of 50 years: Run 1; - Return period of 100 years: Run 1.

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Figure 36: Return period 2 years: Run 1

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Figure 37: Return period 5 years: Run 1

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Figure 38: Return period 10 years: Run 1

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Figure 39: Return period 25 years: Run 1

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Figure 40: Return period 50 years: Run 1

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Figure 41: Return period 100 years: Run 1

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A.2 Flood maps: Run 2 The following flood maps are included:

- Return period of 2 years: Run 2; - Return period of 5 years: Run 2; - Return period of 10 years: Run 2; - Return period of 25 years: Run 2; - Return period of 50 years: Run 2; - Return period of 100 years: Run 2.

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Figure 42: Return period 2 years: Run 2

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Figure 43: Return period 5 years: Run 2

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Figure 44: Return period 10 years: Run 2

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Figure 45: Return period 25 years: Run 2

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Figure 46: Return period 50 years: Run 2

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Figure 47: Return period 100 years: Run 2

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A.3 Flood maps: Run 3 The following flood maps are included:

- Return period of 2 years: Run 3; - Return period of 5 years: Run 3; - Return period of 10 years: Run 3; - Return period of 25 years: Run 3; - Return period of 50 years: Run 3; - Return period of 100 years: Run 3.

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Figure 48: Return period 2 years: Run 3

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Figure 49: Return period 5 years: Run 3

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Figure 50: Return period 10 years: Run 3

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 113 Feasibility Report: West Rapti Basin

Figure 51: Return period 25 years: Run 3

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 114 Feasibility Report: West Rapti Basin

Figure 52: Return period 50 years: Run 3

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 115 Feasibility Report: West Rapti Basin

Figure 53: Return period 100 years: Run 3

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 116 Feasibility Report: West Rapti Basin

B. Modelling results

In this appendix the modelling results consisting hydraulic modelling results and the velocity distribution in the cross-section. This is submitted for all runs and all return periods. The following is included:

- Appendix B.1: Hydraulic modelling results of the Reference Alternative (Run 1). This is the situation as per today including the existing structures;

- Appendix B.2: Hydraulic modelling results of the Future Alternative 1 (Run 2). This is the Reference Alternative (Run 1) including the impact of climate change but without the proposed structures;

- Appendix B.3: Hydraulic modelling results of the Future Alternative 2 (Run 3): This is the Future Alternative 1 (Run 2) including the proposed structures and the impact of climate change;

- Appendix B.4: Velocity distribution over the cross-sections for all the three runs for the 50 year return period;

- Appendix B.5: Provides a comparison of the modelling results of the different runs for the 50 year return period.

B.1 Modelling Results – Run 1

Table 29: Hydraulic modelling results – Run 1 Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 160985 PF 1 (2yr) 1612 300.13 303.87 0.004981 3.38 477.45 277.56 0.82 160985 PF 2(5 yr) 2499 300.13 304.63 0.004279 3.48 717.72 355.54 0.78 160985 PF 3(10 yr) 3225 300.13 305.13 0.003606 3.57 905.09 387.30 0.74 160985 PF 4(25 yr) 4349 300.13 305.82 0.002834 3.71 1182.75 415.49 0.68 160985 PF 5(50 yr) 5125 300.13 306.27 0.002457 3.79 1374.57 432.34 0.65 160985 PF 6(100 yr) 6109 300.13 306.85 0.002080 3.86 1627.18 453.59 0.61

160118 PF 1 (2yr) 1612 298.76 302.80 0.000756 1.82 887.38 331.84 0.35 160118 PF 2(5 yr) 2499 298.76 303.69 0.000695 2.10 1283.64 491.04 0.35 160118 PF 3(10 yr) 3225 298.76 304.29 0.000661 2.26 1587.88 518.19 0.35 160118 PF 4(25 yr) 4349 298.76 305.12 0.000614 2.45 2035.34 553.16 0.35 160118 PF 5(50 yr) 5125 298.76 305.66 0.000585 2.56 2337.23 575.24 0.34 160118 PF 6(100 yr) 6109 298.76 306.29 0.000565 2.70 2722.81 645.34 0.34

159301 PF 1 (2yr) 1612 297.22 300.85 0.004835 3.96 407.40 182.31 0.85 159301 PF 2(5 yr) 2499 297.22 301.66 0.004677 4.40 567.34 210.72 0.86 159301 PF 3(10 yr) 3225 297.22 302.20 0.004457 4.70 685.73 222.71 0.86 159301 PF 4(25 yr) 4349 297.22 302.90 0.004088 5.16 843.32 234.06 0.85 159301 PF 5(50 yr) 5125 297.22 303.31 0.004035 5.49 944.01 263.80 0.86 159301 PF 6(100 yr) 6109 297.22 303.76 0.004042 5.88 1070.09 296.84 0.87

159088 PF 1 (2yr) 1612 297.21 300.73 0.001267 2.41 668.55 230.11 0.45

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 117 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 159088 PF 2(5 yr) 2499 297.21 301.58 0.001300 2.87 885.56 282.33 0.48 159088 PF 3(10 yr) 3225 297.21 302.17 0.001306 3.17 1060.20 316.08 0.49 159088 PF 4(25 yr) 4349 297.21 302.97 0.001291 3.53 1329.18 363.02 0.50 159088 PF 5(50 yr) 5125 297.21 303.45 0.001285 3.75 1520.42 417.40 0.51 159088 PF 6(100 yr) 6109 297.21 304.01 0.001272 3.97 1760.14 446.02 0.51

158876 Bridge

158639 PF 1 (2yr) 1612 295.84 299.94 0.000762 1.87 861.60 296.96 0.35 158639 PF 2(5 yr) 2499 295.84 300.41 0.001122 2.50 1001.48 300.61 0.44 158639 PF 3(10 yr) 3225 295.84 300.82 0.001254 2.85 1156.98 344.96 0.47 158639 PF 4(25 yr) 4349 295.84 301.33 0.001475 3.36 1333.26 350.00 0.52 158639 PF 5(50 yr) 5125 295.84 301.64 0.001609 3.68 1441.87 353.07 0.55 158639 PF 6(100 yr) 6109 295.84 302.00 0.001760 4.05 1570.93 366.90 0.58

158463 PF 1 (2yr) 1612 295.29 299.59 0.002549 2.41 667.65 388.23 0.59 158463 PF 2(5 yr) 2499 295.29 299.76 0.004442 3.39 736.45 389.81 0.79 158463 PF 3(10 yr) 3225 295.29 300.25 0.003456 3.48 927.05 391.20 0.72 158463 PF 4(25 yr) 4349 295.29 300.69 0.003562 3.95 1100.52 391.91 0.75 158463 PF 5(50 yr) 5125 295.29 300.96 0.003681 4.26 1203.38 392.34 0.78 158463 PF 6(100 yr) 6109 295.29 301.27 0.003786 4.60 1326.91 392.85 0.80

157563 PF 1 (2yr) 1612 292.67 295.35 0.007524 3.98 405.31 251.05 1.00 157563 PF 2(5 yr) 2499 292.67 295.99 0.003886 3.38 926.13 619.16 0.75 157563 PF 3(10 yr) 3225 292.67 296.06 0.005720 4.17 968.42 623.16 0.91 157563 PF 4(25 yr) 4349 292.67 296.40 0.005920 4.59 1183.85 643.18 0.95 157563 PF 5(50 yr) 5125 292.67 296.62 0.005956 4.82 1325.73 656.02 0.96 157563 PF 6(100 yr) 6109 292.67 296.87 0.006042 5.09 1490.93 670.67 0.98

156720 PF 1 (2yr) 1612 289.52 291.25 0.002970 1.91 843.42 781.31 0.59 156720 PF 2(5 yr) 2499 289.52 291.56 0.003169 2.30 1084.39 796.53 0.63 156720 PF 3(10 yr) 3225 289.52 291.77 0.003314 2.57 1255.98 811.06 0.66 156720 PF 4(25 yr) 4349 289.52 292.08 0.003365 2.88 1511.33 832.21 0.68 156720 PF 5(50 yr) 5125 289.52 292.29 0.003367 3.04 1684.58 853.57 0.69 156720 PF 6(100 yr) 6109 289.52 292.54 0.003342 3.21 1902.21 883.69 0.70

155824 PF 1 (2yr) 1612 287.01 288.56 0.003024 1.93 835.51 773.58 0.59 155824 PF 2(5 yr) 2499 287.01 288.94 0.002727 2.22 1124.10 778.62 0.59 155824 PF 3(10 yr) 3225 287.01 289.21 0.002567 2.41 1336.46 782.31 0.59 155824 PF 4(25 yr) 4349 287.01 289.58 0.002448 2.67 1626.32 787.31 0.59 155824 PF 5(50 yr) 5125 287.01 289.81 0.002396 2.83 1809.22 790.45 0.60 155824 PF 6(100 yr) 6109 287.01 290.07 0.002384 3.03 2016.83 794.00 0.61

154466 PF 1 (2yr) 1612 283.89 286.46 0.000986 1.34 1201.22 827.20 0.36 154466 PF 2(5 yr) 2499 283.89 286.92 0.001001 1.57 1590.68 874.67 0.37 154466 PF 3(10 yr) 3225 283.89 287.24 0.001007 1.72 1879.44 909.49 0.38 154466 PF 4(25 yr) 4349 283.89 287.71 0.000977 1.88 2318.88 960.06 0.39 154466 PF 5(50 yr) 5125 283.89 287.96 0.000986 2.00 2564.28 1001.48 0.39 154466 PF 6(100 yr) 6109 283.89 288.26 0.000981 2.14 2871.49 1058.99 0.40

153554 PF 1 (2yr) 1612 281.62 284.45 0.005482 2.45 659.21 667.82 0.79

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 118 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 153554 PF 2(5 yr) 2499 281.62 284.73 0.005894 2.96 842.90 675.26 0.85 153554 PF 3(10 yr) 3225 281.62 284.91 0.006291 3.34 965.40 679.01 0.89 153554 PF 4(25 yr) 4349 281.62 285.10 0.007542 3.97 1094.60 679.94 1.00 153554 PF 5(50 yr) 5125 281.62 285.29 0.007216 4.18 1224.79 680.88 1.00 153554 PF 6(100 yr) 6109 281.62 285.51 0.007038 4.45 1372.12 682.02 1.00

153004 PF 1 (2yr) 1612 279.14 280.45 0.009518 2.81 574.51 716.70 1.00 153004 PF 2(5 yr) 2499 279.14 280.72 0.008753 3.24 770.84 727.14 1.01 153004 PF 3(10 yr) 3225 279.14 280.93 0.008161 3.50 921.22 734.74 1.00 153004 PF 4(25 yr) 4349 279.14 281.28 0.006556 3.67 1184.88 746.91 0.93 153004 PF 5(50 yr) 5125 279.14 281.53 0.005691 3.74 1370.42 755.36 0.89 153004 PF 6(100 yr) 6109 279.14 281.60 0.007130 4.29 1425.02 757.83 1.00

151861 PF 1 (2yr) 1612 275.31 278.25 0.000800 1.33 1212.19 722.96 0.33 151861 PF 2(5 yr) 2499 275.31 278.76 0.000794 1.58 1586.49 730.31 0.34 151861 PF 3(10 yr) 3225 275.31 279.13 0.000793 1.74 1854.83 735.53 0.35 151861 PF 4(25 yr) 4349 275.31 279.64 0.000791 1.95 2230.13 742.78 0.36 151861 PF 5(50 yr) 5125 275.31 279.95 0.000791 2.08 2467.09 747.31 0.37 151861 PF 6(100 yr) 6109 275.31 280.16 0.000548 1.77 3878.02 1210.15 0.31

150753 PF 1 (2yr) 1612 273.95 276.82 0.001929 1.96 824.20 533.59 0.50 150753 PF 2(5 yr) 2499 273.95 277.26 0.002017 2.35 1064.41 541.70 0.53 150753 PF 3(10 yr) 3225 273.95 277.57 0.002091 2.62 1231.76 546.83 0.56 150753 PF 4(25 yr) 4349 273.95 277.98 0.002188 2.98 1459.13 551.76 0.59 150753 PF 5(50 yr) 5125 273.95 278.24 0.002249 3.20 1600.50 554.80 0.60 150753 PF 6(100 yr) 6109 273.95 278.56 0.002269 3.43 1778.61 558.61 0.61

149802 PF 1 (2yr) 1612 272.02 274.33 0.003568 2.20 732.96 630.78 0.65 149802 PF 2(5 yr) 2499 272.02 274.68 0.003590 2.61 955.87 637.53 0.68 149802 PF 3(10 yr) 3225 272.02 274.94 0.003561 2.88 1120.16 642.45 0.70 149802 PF 4(25 yr) 4349 272.02 275.29 0.003530 3.22 1349.57 649.27 0.71 149802 PF 5(50 yr) 5125 272.02 275.52 0.003505 3.42 1496.51 653.59 0.72 149802 PF 6(100 yr) 6109 272.02 275.74 0.003667 3.71 1644.87 657.93 0.75

149495 PF 1 (2yr) 1612 270.30 273.57 0.002079 1.77 912.10 726.79 0.50 149495 PF 2(5 yr) 2499 270.30 273.97 0.001972 2.07 1206.86 728.77 0.51 149495 PF 3(10 yr) 3225 270.30 274.27 0.001904 2.27 1422.32 729.84 0.52 149495 PF 4(25 yr) 4349 270.30 274.65 0.001924 2.56 1698.01 731.54 0.54 149495 PF 5(50 yr) 5125 270.30 274.90 0.001900 2.72 1881.61 733.49 0.54 149495 PF 6(100 yr) 6109 270.30 274.94 0.002569 3.20 1910.16 733.79 0.63

149173.* PF 1 (2yr) 1612 269.87 272.93 0.001929 1.78 907.23 678.00 0.49 149173.* PF 2(5 yr) 2499 269.87 273.36 0.001816 2.08 1203.15 679.91 0.50 149173.* PF 3(10 yr) 3225 269.87 273.68 0.001759 2.28 1417.15 681.47 0.50 149173.* PF 4(25 yr) 4349 269.87 273.95 0.002128 2.71 1604.05 684.33 0.57 149173.* PF 5(50 yr) 5125 269.87 274.20 0.002125 2.89 1773.89 688.32 0.57 149173.* PF 6(100 yr) 6109 269.87 274.38 0.001798 2.77 2548.62 1165.71 0.53

148852.* PF 1 (2yr) 1612 269.44 272.34 0.001737 1.77 908.75 629.48 0.47 148852.* PF 2(5 yr) 2499 269.44 272.80 0.001692 2.09 1194.12 632.91 0.49 148852.* PF 3(10 yr) 3225 269.44 273.12 0.001684 2.31 1397.61 639.97 0.50

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 119 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 148852.* PF 4(25 yr) 4349 269.44 273.60 0.001096 2.12 2455.14 1242.47 0.41 148852.* PF 5(50 yr) 5125 269.44 273.90 0.001016 2.19 2830.64 1283.39 0.41 148852.* PF 6(100 yr) 6109 269.44 273.90 0.001431 2.61 2839.57 1284.35 0.48

148530.* PF 1 (2yr) 1612 269.01 271.81 0.001589 1.76 922.75 633.41 0.45 148530.* PF 2(5 yr) 2499 269.01 272.27 0.001594 2.08 1218.72 661.18 0.48 148530.* PF 3(10 yr) 3225 269.01 272.59 0.001584 2.29 1435.81 677.37 0.49 148530.* PF 4(25 yr) 4349 269.01 273.04 0.001584 2.57 1739.06 699.35 0.50 148530.* PF 5(50 yr) 5125 269.01 273.32 0.001576 2.74 1936.72 713.32 0.51 148530.* PF 6(100 yr) 6109 269.01 273.58 0.000985 2.29 3284.30 1318.28 0.41

148209 PF 1 (2yr) 1612 268.58 270.88 0.004214 2.39 674.57 581.08 0.71 148209 PF 2(5 yr) 2499 268.58 271.13 0.005403 3.05 818.81 588.74 0.83 148209 PF 3(10 yr) 3225 268.58 271.31 0.006129 3.50 922.18 594.18 0.90 148209 PF 4(25 yr) 4349 268.58 271.57 0.006668 4.03 1080.09 605.03 0.96 148209 PF 5(50 yr) 5125 268.58 271.73 0.007011 4.36 1175.98 614.00 1.00 148209 PF 6(100 yr) 6109 268.58 271.98 0.006666 4.61 1331.83 628.30 0.99

147709 PF 1 (2yr) 1612 267.11 268.60 0.005105 2.23 723.61 799.84 0.75 147709 PF 2(5 yr) 2499 267.11 268.98 0.003913 2.43 1042.38 912.04 0.69 147709 PF 3(10 yr) 3225 267.11 269.23 0.003519 2.59 1282.25 988.35 0.68 147709 PF 4(25 yr) 4349 267.11 269.52 0.003459 2.88 1579.17 1043.88 0.69 147709 PF 5(50 yr) 5125 267.11 269.71 0.003358 3.04 1784.10 1073.91 0.69 147709 PF 6(100 yr) 6109 267.11 269.94 0.003259 3.21 2028.89 1092.98 0.69

147309 PF 1 (2yr) 1612 266.13 267.93 0.001041 1.32 1222.26 899.65 0.36 147309 PF 2(5 yr) 2499 266.13 268.35 0.001107 1.55 1616.98 982.49 0.38 147309 PF 3(10 yr) 3225 266.13 268.62 0.001138 1.70 1894.56 1022.69 0.40 PRTW.01 147309 PF 4(25 yr) 4349 266.13 268.93 0.001178 1.92 2378.34 1290.37 0.42 147309 PF 5(50 yr) 5125 266.13 269.14 0.001187 2.05 2657.84 1365.69 0.42 147309 PF 6(100 yr) 6109 266.13 269.39 0.001193 2.19 3019.18 1598.05 0.43

146660 PF 1 (2yr) 1612 264.10 266.04 0.009442 2.88 562.19 689.57 1.00 146660 PF 2(5 yr) 2499 264.10 266.33 0.008398 3.28 769.60 728.97 0.99 146660 PF 3(10 yr) 3225 264.10 266.55 0.007778 3.53 929.91 758.01 0.98 146660 PF 4(25 yr) 4349 264.10 266.85 0.006681 3.75 1236.31 925.00 0.94 146660 PF 5(50 yr) 5125 264.10 267.02 0.006492 3.96 1393.89 935.39 0.94 146660 PF 6(100 yr) 6109 264.10 267.23 0.006271 4.18 1584.92 947.82 0.95

146105 PF 1 (2yr) 1612 262.15 264.13 0.001542 1.52 1061.92 850.03 0.43 146105 PF 2(5 yr) 2499 262.15 264.50 0.001566 1.81 1383.63 863.35 0.46 146105 PF 3(10 yr) 3225 262.15 264.76 0.001570 1.98 1706.59 1214.44 0.47 146105 PF 4(25 yr) 4349 262.15 265.09 0.001570 2.22 2133.04 1358.76 0.48 146105 PF 5(50 yr) 5125 262.15 265.30 0.001569 2.35 2422.01 1471.36 0.49 146105 PF 6(100 yr) 6109 262.15 265.53 0.001563 2.50 2780.46 1561.77 0.49

145481 PF 1 (2yr) 1612 260.58 262.87 0.002622 1.64 984.65 1048.21 0.54 145481 PF 2(5 yr) 2499 260.58 263.09 0.003287 2.05 1219.28 1109.42 0.62 PRTW.02 145481 PF 3(10 yr) 3225 260.58 263.23 0.003686 2.34 1383.59 1140.83 0.67 145481 PF 4(25 yr) 4349 260.58 263.41 0.004358 2.76 1584.46 1170.10 0.74 145481 PF 5(50 yr) 5125 260.58 263.52 0.004673 3.01 1716.79 1184.74 0.78

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 120 Feasibility Report: West Rapti Basin

145087 PF 1 (2yr) 1612 259.80 261.38 0.005545 1.84 875.38 1369.82 0.74 145087 PF 2(5 yr) 2499 259.80 261.66 0.004086 1.97 1274.16 1500.88 0.67 145087 PF 3(10 yr) 3225 259.80 261.85 0.003517 2.08 1571.95 1592.31 0.64 145087 PF 4(25 yr) 4349 259.80 262.13 0.002900 2.20 2040.05 1726.27 0.60 145087 PF 5(50 yr) 5125 259.80 262.31 0.002651 2.28 2349.89 1809.50 0.59 145087 PF 6(100 yr) 6109 259.80 262.52 0.002394 2.36 2746.43 1910.72 0.57

144542 PF 1 (2yr) 1612 258.16 260.16 0.001278 1.35 1192.60 986.88 0.39 144542 PF 2(5 yr) 2499 258.16 260.53 0.001337 1.60 1560.62 1036.59 0.42 144542 PF 3(10 yr) 3225 258.16 260.77 0.001347 1.78 1830.82 1150.61 0.43 144542 PF 4(25 yr) 4349 258.16 261.04 0.001510 2.07 2146.21 1195.38 0.46 144542 PF 5(50 yr) 5125 258.16 261.21 0.001591 2.24 2352.29 1223.75 0.48 144542 PF 6(100 yr) 6109 258.16 261.43 0.001641 2.42 2642.61 1400.44 0.50

144083 PF 1 (2yr) 1612 257.14 258.56 0.009996 2.77 581.34 765.83 1.02 144083 PF 2(5 yr) 2499 257.14 258.83 0.009146 3.16 791.39 802.60 1.02 144083 PF 3(10 yr) 3225 257.14 259.02 0.008666 3.40 948.75 827.38 1.01 144083 PF 4(25 yr) 4349 257.14 259.46 0.005693 3.29 1321.52 883.33 0.86 144083 PF 5(50 yr) 5125 257.14 259.72 0.004641 3.30 1558.53 940.69 0.80 144083 PF 6(100 yr) 6109 257.14 260.01 0.003937 3.37 1844.01 1056.14 0.75

143617 PF 1 (2yr) 1612 255.52 258.22 0.000221 0.75 2145.20 1148.04 0.18 143617 PF 2(5 yr) 2499 255.52 258.64 0.000277 0.95 2638.63 1183.95 0.20 143617 PF 3(10 yr) 3225 255.52 258.95 0.000316 1.07 3005.74 1233.72 0.22 143617 PF 4(25 yr) 4349 255.52 259.36 0.000363 1.23 3525.00 1300.88 0.24 143617 PF 5(50 yr) 5125 255.52 259.61 0.000390 1.33 3852.07 1341.45 0.25 143617 PF 6(100 yr) 6109 255.52 259.89 0.000420 1.44 4246.12 1412.20 0.26

142933 PF 1 (2yr) 1612 254.01 257.60 0.005137 2.05 787.26 990.56 0.73 142933 PF 2(5 yr) 2499 254.01 257.97 0.003539 2.17 1152.36 1006.03 0.65 142933 PF 3(10 yr) 3225 254.01 258.23 0.003027 2.28 1413.25 1016.53 0.62 142933 PF 4(25 yr) 4349 254.01 258.57 0.002687 2.47 1763.41 1032.39 0.60 142933 PF 5(50 yr) 5125 254.01 258.77 0.002609 2.60 1970.19 1041.65 0.60 142933 PF 6(100 yr) 6109 254.01 259.00 0.002563 2.76 2209.91 1052.27 0.61

142513 PF 1 (2yr) 1612 253.96 257.03 0.000777 1.17 1380.17 978.40 0.31 142513 PF 2(5 yr) 2499 253.96 257.43 0.000833 1.40 1785.03 1016.28 0.34 142513 PF 3(10 yr) 3225 253.96 257.69 0.000910 1.58 2046.90 1054.12 0.36 142513 PF 4(25 yr) 4349 253.96 258.01 0.001020 1.82 2405.31 1140.58 0.39 142513 PF 5(50 yr) 5125 253.96 258.20 0.001081 1.97 2622.17 1186.79 0.41 142513 PF 6(100 yr) 6109 253.96 258.42 0.001142 2.15 2932.79 1474.10 0.42

141711 PF 1 (2yr) 1612 253.45 255.14 0.009243 2.87 561.49 662.15 1.00 141711 PF 2(5 yr) 2499 253.45 255.46 0.007942 3.17 812.84 895.37 0.96 141711 PF 3(10 yr) 3225 253.45 255.74 0.006351 3.17 1125.62 1350.68 0.89 141711 PF 4(25 yr) 4349 253.45 256.02 0.005616 3.29 1600.10 1831.30 0.85 141711 PF 5(50 yr) 5125 253.45 256.17 0.005381 3.42 1875.36 1984.18 0.85 141711 PF 6(100 yr) 6109 253.45 256.32 0.005310 3.60 2189.45 2145.35 0.86

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 121 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 141107 PF 1 (2yr) 1612 251.56 254.15 0.000569 1.01 1901.90 2025.53 0.27 141107 PF 2(5 yr) 2499 251.56 254.68 0.000389 1.03 3050.65 2300.26 0.23 141107 PF 3(10 yr) 3225 251.56 255.03 0.000328 1.06 3893.22 2427.89 0.22 141107 PF 4(25 yr) 4349 251.56 255.40 0.000330 1.17 4811.49 2559.76 0.23 141107 PF 5(50 yr) 5125 251.56 255.66 0.000318 1.22 5475.28 2651.01 0.23 141107 PF 6(100 yr) 6109 251.56 255.96 0.000305 1.28 6294.91 2759.51 0.23

140216 PF 1 (2yr) 1612 250.70 253.47 0.000879 1.43 1126.09 645.60 0.35 140216 PF 2(5 yr) 2499 250.70 254.13 0.000739 1.59 1599.90 848.21 0.33 140216 PF 3(10 yr) 3225 250.70 254.50 0.000735 1.75 1936.63 951.50 0.34 140216 PF 4(25 yr) 4349 250.70 254.88 0.000693 1.86 2901.13 1630.46 0.34 140216 PF 5(50 yr) 5125 250.70 255.13 0.000698 1.96 3326.21 1774.70 0.34 140216 PF 6(100 yr) 6109 250.70 255.43 0.000694 2.08 3901.79 2067.01 0.35

139579 PF 1 (2yr) 1612 249.22 251.50 0.006872 3.91 412.06 244.32 0.96 139579 PF 2(5 yr) 2499 249.22 252.06 0.006912 4.49 556.54 269.48 1.00 139579 PF 3(10 yr) 3225 249.22 252.80 0.007953 3.71 868.69 628.25 1.00 139579 PF 4(25 yr) 4349 249.22 253.13 0.006992 4.02 1102.93 757.84 0.97 139579 PF 5(50 yr) 5125 249.22 253.35 0.006424 4.17 1278.44 827.02 0.95 139579 PF 6(100 yr) 6109 249.22 253.58 0.006255 4.42 1468.69 894.36 0.96

138812 PF 1 (2yr) 1612 248.01 250.49 0.000922 1.05 1533.37 1482.60 0.33 138812 PF 2(5 yr) 2499 248.01 250.85 0.000840 1.22 2096.10 1701.97 0.33 138812 PF 3(10 yr) 3225 248.01 251.11 0.000781 1.31 2564.45 1899.70 0.32 138812 PF 4(25 yr) 4349 248.01 251.46 0.000717 1.43 3288.79 2182.12 0.32 PRTW.03 138812 PF 5(50 yr) 5125 248.01 251.69 0.000681 1.50 3793.87 2332.30 0.32 138812 PF 6(100 yr) 6109 248.01 251.95 0.000647 1.57 4418.42 2495.32 0.32

138099 PF 1 (2yr) 1612 247.20 248.49 0.009031 3.13 514.90 524.05 1.01 138099 PF 2(5 yr) 2499 247.20 248.84 0.008221 3.55 704.34 553.70 1.00 138099 PF 3(10 yr) 3225 247.20 249.09 0.007883 3.82 843.57 574.51 1.01 138099 PF 4(25 yr) 4349 247.20 249.44 0.007249 4.14 1056.29 665.25 1.00 138099 PF 5(50 yr) 5125 247.20 249.68 0.006535 4.27 1231.33 784.75 0.97 138099 PF 6(100 yr) 6109 247.20 249.96 0.005856 4.41 1468.54 912.76 0.93

137644 PF 1 (2yr) 1612 244.45 246.76 0.001228 1.50 1080.51 785.35 0.40 137644 PF 2(5 yr) 2499 244.45 247.17 0.001264 1.80 1419.00 845.33 0.42 137644 PF 3(10 yr) 3225 244.45 247.44 0.001322 2.02 1654.43 884.65 0.44 137644 PF 4(25 yr) 4349 244.45 247.80 0.001414 2.31 1980.52 963.66 0.47 137644 PF 5(50 yr) 5125 244.45 248.01 0.001499 2.51 2190.86 1101.34 0.49 137644 PF 6(100 yr) 6109 244.45 248.24 0.001563 2.71 2585.94 1645.58 0.50

137467.* PF 1 (2yr) 1612 244.15 246.54 0.001216 1.47 1105.28 825.98 0.39 137467.* PF 2(5 yr) 2499 244.15 246.96 0.001229 1.75 1461.42 895.99 0.41 137467.* PF 3(10 yr) 3225 244.15 247.22 0.001294 1.96 1702.61 941.81 0.43 137467.* PF 4(25 yr) 4349 244.15 247.56 0.001411 2.27 2041.57 1130.16 0.46 137467.* PF 5(50 yr) 5125 244.15 247.76 0.001464 2.43 2359.26 1578.35 0.48 137467.* PF 6(100 yr) 6109 244.15 247.99 0.001498 2.60 2746.98 1766.61 0.49

137290.* PF 1 (2yr) 1612 243.85 246.32 0.001308 1.44 1120.72 865.83 0.40 137290.* PF 2(5 yr) 2499 243.85 246.75 0.001275 1.67 1503.85 953.95 0.41

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 122 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 137290.* PF 3(10 yr) 3225 243.85 247.00 0.001308 1.86 1756.58 1010.64 0.43 137290.* PF 4(25 yr) 4349 243.85 247.34 0.001363 2.12 2188.92 1475.93 0.45 137290.* PF 5(50 yr) 5125 243.85 247.54 0.001378 2.25 2500.92 1596.33 0.46 137290.* PF 6(100 yr) 6109 243.85 247.77 0.001395 2.41 2887.35 1748.01 0.47

137113.* PF 1 (2yr) 1612 243.55 246.08 0.001415 1.45 1113.22 896.94 0.42 137113.* PF 2(5 yr) 2499 243.55 246.53 0.001257 1.64 1538.77 1023.77 0.41 137113.* PF 3(10 yr) 3225 243.55 246.78 0.001276 1.82 1836.66 1348.96 0.42 137113.* PF 4(25 yr) 4349 243.55 247.11 0.001293 2.04 2317.97 1539.18 0.44 137113.* PF 5(50 yr) 5125 243.55 247.32 0.001295 2.16 2645.03 1662.03 0.44 137113.* PF 6(100 yr) 6109 243.55 247.55 0.001303 2.31 3046.31 1801.47 0.45

136936 PF 1 (2yr) 1612 243.25 245.80 0.001623 1.50 1071.32 903.17 0.44 136936 PF 2(5 yr) 2499 243.25 246.27 0.001689 1.62 1542.60 1226.83 0.46 136936 PF 3(10 yr) 3225 243.25 246.55 0.001515 1.71 1908.25 1386.77 0.44 136936 PF 4(25 yr) 4349 243.25 246.91 0.001334 1.85 2435.45 1560.80 0.43 136936 PF 5(50 yr) 5125 243.25 247.12 0.001269 1.94 2782.25 1665.50 0.43 136936 PF 6(100 yr) 6109 243.25 247.36 0.001228 2.05 3193.71 1774.53 0.43

136745 PF 1 (2yr) 1612 243.26 244.81 0.009081 3.02 533.98 576.28 1.00 136745 PF 2(5 yr) 2499 243.26 245.13 0.008235 3.47 719.42 584.51 1.00 136745 PF 3(10 yr) 3225 243.26 245.38 0.007954 3.71 870.43 625.51 1.00 136745 PF 4(25 yr) 4349 243.26 245.76 0.007645 3.86 1126.15 738.19 1.00 136745 PF 5(50 yr) 5125 243.26 245.98 0.006981 3.95 1317.74 1003.82 0.97 136745 PF 6(100 yr) 6109 243.26 246.22 0.006222 4.07 1571.41 1073.93 0.94

136487 PF 1 (2yr) 1612 242.34 244.74 0.000151 0.61 4018.94 3504.42 0.14 136487 PF 2(5 yr) 2499 242.34 245.13 0.000153 0.70 5393.10 3659.37 0.15 136487 PF 3(10 yr) 3225 242.34 245.39 0.000157 0.76 6353.30 3763.86 0.15 136487 PF 4(25 yr) 4349 242.34 245.73 0.000163 0.85 7670.57 3902.65 0.16 136487 PF 5(50 yr) 5125 242.34 245.94 0.000168 0.90 8490.27 3986.58 0.17 136487 PF 6(100 yr) 6109 242.34 246.18 0.000174 0.97 9455.43 4083.19 0.17

136227 PF 1 (2yr) 1612 241.97 244.40 0.000706 1.19 1622.67 1655.28 0.30 136227 PF 2(5 yr) 2499 241.97 244.76 0.000732 1.39 2244.38 1781.46 0.32 136227 PF 3(10 yr) 3225 241.97 245.00 0.000758 1.53 2673.65 1843.54 0.33 136227 PF 4(25 yr) 4349 241.97 245.30 0.000800 1.72 3252.66 1918.59 0.35 136227 PF 5(50 yr) 5125 241.97 245.49 0.000829 1.84 3611.27 1961.20 0.36 136227 PF 6(100 yr) 6109 241.97 245.70 0.000864 1.97 4028.86 2009.17 0.37

135825 Bridge

135708 PF 1 (2yr) 1612 241.22 243.94 0.001266 1.37 1237.66 1398.75 0.39 135708 PF 2(5 yr) 2499 241.22 244.27 0.001240 1.59 1809.45 1838.89 0.40 135708 PF 3(10 yr) 3225 241.22 244.49 0.001228 1.73 2232.07 1974.53 0.41 135708 PF 4(25 yr) 4349 241.22 244.77 0.001249 1.92 2807.91 2136.39 0.42 135708 PF 5(50 yr) 5125 241.22 244.94 0.001267 2.03 3174.04 2233.21 0.43 135708 PF 6(100 yr) 6109 241.22 245.13 0.001292 2.17 3610.08 2343.31 0.44

135187.* PF 1 (2yr) 1612 240.71 243.29 0.001261 1.30 1237.74 1116.07 0.39 135187.* PF 2(5 yr) 2499 240.71 243.62 0.001289 1.56 1680.32 1661.68 0.41

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 123 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 135187.* PF 3(10 yr) 3225 240.71 243.81 0.001368 1.74 2049.87 2076.43 0.43 135187.* PF 4(25 yr) 4349 240.71 244.06 0.001448 1.97 2595.42 2298.12 0.45 135187.* PF 5(50 yr) 5125 240.71 244.21 0.001497 2.10 2943.12 2427.48 0.47 135187.* PF 6(100 yr) 6109 240.71 244.38 0.001532 2.24 3379.04 2580.53 0.48

134926.* PF 1 (2yr) 1612 240.57 243.07 0.000716 1.06 1525.20 1182.27 0.30 134926.* PF 2(5 yr) 2499 240.57 243.37 0.000881 1.32 1947.48 1701.52 0.34 134926.* PF 3(10 yr) 3225 240.57 243.53 0.001004 1.50 2331.14 2296.85 0.37 134926.* PF 4(25 yr) 4349 240.57 243.75 0.001149 1.74 2856.27 2512.11 0.40 134926.* PF 5(50 yr) 5125 240.57 243.88 0.001228 1.88 3195.56 2640.64 0.42 134926.* PF 6(100 yr) 6109 240.57 244.05 0.001280 2.03 3643.54 2801.32 0.43

133880 PF 1 (2yr) 1612 240.02 241.98 0.001663 1.02 1599.82 2559.86 0.40 133880 PF 2(5 yr) 2499 240.02 242.20 0.001478 1.17 2179.32 2639.57 0.40 133880 PF 3(10 yr) 3225 240.02 242.39 0.001280 1.24 2675.85 2706.00 0.38 133880 PF 4(25 yr) 4349 240.02 242.68 0.001010 1.30 3487.26 2811.18 0.36 133880 PF 5(50 yr) 5125 240.02 242.89 0.000854 1.31 4087.47 2886.52 0.34 133880 PF 6(100 yr) 6109 240.02 243.13 0.000745 1.35 4785.74 2971.76 0.32

133790.* PF 1 (2yr) 1612 239.87 241.83 0.001602 1.03 1588.55 2456.98 0.40 133790.* PF 2(5 yr) 2499 239.87 242.08 0.001361 1.16 2194.78 2528.45 0.39 133790.* PF 3(10 yr) 3225 239.87 242.28 0.001145 1.22 2719.45 2600.87 0.37 133790.* PF 4(25 yr) 4349 239.87 242.60 0.000888 1.27 3566.96 2717.54 0.34 133790.* PF 5(50 yr) 5125 239.87 242.82 0.000751 1.28 4184.46 2798.07 0.32 133790.* PF 6(100 yr) 6109 239.87 243.07 0.000671 1.32 4887.35 2942.66 0.31

133701.* PF 1 (2yr) 1612 239.72 241.69 0.001557 1.03 1573.15 2360.01 0.40 133701.* PF 2(5 yr) 2499 239.72 241.96 0.001234 1.14 2221.30 2424.20 0.37 133701.* PF 3(10 yr) 3225 239.72 242.19 0.001011 1.19 2776.06 2501.19 0.35 133701.* PF 4(25 yr) 4349 239.72 242.53 0.000780 1.24 3650.33 2627.58 0.32 133701.* PF 5(50 yr) 5125 239.72 242.76 0.000668 1.25 4278.00 2731.48 0.30 133701.* PF 6(100 yr) 6109 239.72 243.02 0.000600 1.29 4993.84 2888.71 0.29

133611.* PF 1 (2yr) 1612 239.56 241.55 0.001534 1.05 1550.17 2265.97 0.39 133611.* PF 2(5 yr) 2499 239.56 241.86 0.001106 1.13 2257.35 2332.40 0.36 133611.* PF 3(10 yr) 3225 239.56 242.11 0.000888 1.16 2838.90 2405.71 0.33 133611.* PF 4(25 yr) 4349 239.56 242.47 0.000690 1.21 3729.32 2544.33 0.30 133611.* PF 5(50 yr) 5125 239.56 242.71 0.000598 1.23 4374.04 2706.10 0.29 PRTW.06 133611.* PF 6(100 yr) 6109 239.56 242.97 0.000540 1.28 5087.86 2813.93 0.28

133254 PF 1 (2yr) 1612 238.95 241.12 0.001021 1.03 1572.06 1664.08 0.34 133254 PF 2(5 yr) 2499 238.95 241.54 0.000747 1.07 2341.42 1998.24 0.30 133254 PF 3(10 yr) 3225 238.95 241.85 0.000592 1.11 2986.25 2120.63 0.28 133254 PF 4(25 yr) 4349 238.95 242.27 0.000488 1.17 3893.19 2294.93 0.26 133254 PF 5(50 yr) 5125 238.95 242.53 0.000437 1.20 4522.24 2402.04 0.26 133254 PF 6(100 yr) 6109 238.95 242.80 0.000417 1.27 5186.51 2509.76 0.25

132929 PF 1 (2yr) 1612 238.60 240.93 0.000404 0.77 2094.78 1701.92 0.22 132929 PF 2(5 yr) 2499 238.60 241.39 0.000358 0.86 2912.67 1834.37 0.22 132929 PF 3(10 yr) 3225 238.60 241.73 0.000314 0.90 3680.61 2336.88 0.21 132929 PF 4(25 yr) 4349 238.60 242.16 0.000278 0.97 4759.64 2688.78 0.20

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 124 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 132929 PF 5(50 yr) 5125 238.60 242.44 0.000257 1.01 5546.34 2971.13 0.20 132929 PF 6(100 yr) 6109 238.60 242.72 0.000252 1.07 6402.22 3240.08 0.20

132874.* PF 1 (2yr) 1612 238.43 240.90 0.000492 0.83 1933.73 1616.40 0.24 132874.* PF 2(5 yr) 2499 238.43 241.37 0.000423 0.92 2713.47 1773.96 0.24 132874.* PF 3(10 yr) 3225 238.43 241.71 0.000360 0.97 3423.17 2256.19 0.22 132874.* PF 4(25 yr) 4349 238.43 242.14 0.000317 1.04 4503.37 2736.18 0.22 132874.* PF 5(50 yr) 5125 238.43 242.42 0.000290 1.08 5311.13 2999.70 0.21 132874.* PF 6(100 yr) 6109 238.43 242.70 0.000282 1.13 6164.71 3199.05 0.21

132819.* PF 1 (2yr) 1612 238.25 240.87 0.000620 0.92 1759.78 1517.90 0.27 132819.* PF 2(5 yr) 2499 238.25 241.33 0.000498 1.00 2537.55 1933.97 0.26 132819.* PF 3(10 yr) 3225 238.25 241.68 0.000414 1.04 3265.58 2313.82 0.24 PRTW.05 132819.* PF 4(25 yr) 4349 238.25 242.12 0.000355 1.10 4384.15 2762.53 0.23 132819.* PF 5(50 yr) 5125 238.25 242.40 0.000320 1.13 5192.98 2957.43 0.22 132819.* PF 6(100 yr) 6109 238.25 242.67 0.000309 1.19 6035.05 3142.17 0.22

132656 PF 1 (2yr) 1612 237.73 240.65 0.001692 1.35 1230.13 1500.86 0.44 132656 PF 2(5 yr) 2499 237.73 241.21 0.000793 1.25 2304.15 2205.44 0.32 132656 PF 3(10 yr) 3225 237.73 241.59 0.000557 1.21 3170.37 2356.60 0.28 132656 PF 4(25 yr) 4349 237.73 242.04 0.000440 1.24 4293.10 2582.29 0.26 132656 PF 5(50 yr) 5125 237.73 242.33 0.000389 1.26 5071.60 2776.20 0.25 132656 PF 6(100 yr) 6109 237.73 242.61 0.000373 1.32 5868.45 2950.44 0.25

132403 PF 1 (2yr) 1612 237.25 240.53 0.000335 0.88 1840.85 1088.05 0.21 132403 PF 2(5 yr) 2499 237.25 241.11 0.000300 1.00 2650.84 1788.34 0.21 132403 PF 3(10 yr) 3225 237.25 241.50 0.000276 1.07 3387.17 1939.87 0.21 132403 PF 4(25 yr) 4349 237.25 241.96 0.000273 1.18 4314.28 2115.91 0.21 132403 PF 5(50 yr) 5125 237.25 242.25 0.000267 1.24 4951.82 2231.46 0.21 132403 PF 6(100 yr) 6109 237.25 242.52 0.000279 1.33 5571.99 2316.21 0.22

131465 PF 1 (2yr) 1612 235.79 239.95 0.000962 1.48 1085.65 630.39 0.36 131465 PF 2(5 yr) 2499 235.79 240.54 0.000956 1.68 1484.35 710.48 0.37 131465 PF 3(10 yr) 3225 235.79 240.94 0.000946 1.81 1805.31 948.28 0.38 131465 PF 4(25 yr) 4349 235.79 241.36 0.000976 2.05 2209.43 984.88 0.39 131465 PF 5(50 yr) 5125 235.79 241.64 0.000968 2.17 2486.17 1009.17 0.40 131465 PF 6(100 yr) 6109 235.79 241.95 0.000846 2.15 3337.15 1473.72 0.38

130224 PF 1 (2yr) 1612 234.09 236.79 0.007587 3.51 459.64 346.13 0.97 130224 PF 2(5 yr) 2499 234.09 237.24 0.007379 4.02 621.79 373.77 1.00 130224 PF 3(10 yr) 3225 234.09 237.61 0.007244 4.19 770.48 429.80 1.00 130224 PF 4(25 yr) 4349 234.09 238.05 0.006189 4.42 1027.95 555.92 0.95 130224 PF 5(50 yr) 5125 234.09 238.30 0.005959 4.64 1164.66 566.14 0.95 130224 PF 6(100 yr) 6109 234.09 238.63 0.005358 4.79 1382.63 750.73 0.92

129806 PF 1 (2yr) 1612 233.80 236.73 0.000420 1.05 1765.91 1245.62 0.24 129806 PF 2(5 yr) 2499 233.80 237.21 0.000430 1.24 2390.25 1351.51 0.26 129806 PF 3(10 yr) 3225 233.80 237.54 0.000439 1.36 2846.38 1430.55 0.26 129806 PF 4(25 yr) 4349 233.80 237.98 0.000450 1.52 3496.36 1534.21 0.27 129806 PF 5(50 yr) 5125 233.80 238.24 0.000461 1.63 3903.89 1594.12 0.28 129806 PF 6(100 yr) 6109 233.80 238.54 0.000471 1.74 4400.03 1664.15 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 125 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

127967 PF 1 (2yr) 1612 232.67 235.44 0.000937 1.35 1194.19 795.98 0.35 127967 PF 2(5 yr) 2499 232.67 235.91 0.000910 1.58 1644.50 1090.30 0.36 127967 PF 3(10 yr) 3225 232.67 236.29 0.000816 1.68 2065.44 1158.08 0.35 127967 PF 4(25 yr) 4349 232.67 236.70 0.000834 1.87 2558.25 1306.70 0.36 127967 PF 5(50 yr) 5125 232.67 236.94 0.000834 1.98 2941.50 1534.05 0.37 127967 PF 6(100 yr) 6109 232.67 237.23 0.000838 2.11 3451.72 1741.05 0.37

127727 PF 1 (2yr) 1612 232.05 235.15 0.001096 1.67 1033.32 698.07 0.39 127727 PF 2(5 yr) 2499 232.05 235.56 0.001311 2.06 1327.47 733.44 0.44 127727 PF 3(10 yr) 3225 232.05 235.92 0.001456 2.22 1621.61 895.00 0.47 127727 PF 4(25 yr) 4349 232.05 236.28 0.001561 2.53 1967.36 1002.02 0.50 127727 PF 5(50 yr) 5125 232.05 236.49 0.001625 2.72 2181.12 1030.43 0.51 127727 PF 6(100 yr) 6109 232.05 236.74 0.001690 2.93 2438.57 1063.64 0.53

125768 PF 1 (2yr) 1612 230.17 232.15 0.002384 1.47 1096.17 1276.37 0.51 125768 PF 2(5 yr) 2499 230.17 232.45 0.002086 1.68 1491.71 1292.22 0.50 125768 PF 3(10 yr) 3225 230.17 232.65 0.002071 1.85 1747.75 1302.38 0.51 125768 PF 4(25 yr) 4349 230.17 232.92 0.002052 2.07 2105.76 1316.45 0.52 125768 PF 5(50 yr) 5125 230.17 233.10 0.002036 2.19 2335.89 1353.78 0.53 125768 PF 6(100 yr) 6109 230.17 233.30 0.002033 2.35 2617.36 1448.92 0.54

125245.* PF 1 (2yr) 1612 229.50 231.29 0.001240 1.23 1311.93 1224.87 0.38 125245.* PF 2(5 yr) 2499 229.50 231.65 0.001285 1.37 1826.42 1490.20 0.39 125245.* PF 3(10 yr) 3225 229.50 231.87 0.001229 1.49 2168.11 1509.94 0.40 125245.* PF 4(25 yr) 4349 229.50 232.18 0.001200 1.65 2630.51 1544.93 0.40 125245.* PF 5(50 yr) 5125 229.50 232.36 0.001185 1.76 2923.36 1616.18 0.41 125245.* PF 6(100 yr) 6109 229.50 232.56 0.001204 1.89 3252.38 1682.37 0.42

124723.* PF 1 (2yr) 1612 228.82 231.05 0.000300 0.70 2296.33 1712.68 0.19 124723.* PF 2(5 yr) 2499 228.82 231.36 0.000370 0.88 2838.27 1794.94 0.22 124723.* PF 3(10 yr) 3225 228.82 231.58 0.000406 1.00 3245.28 1962.34 0.24 124723.* PF 4(25 yr) 4349 228.82 231.87 0.000444 1.16 3848.01 2149.06 0.25 124723.* PF 5(50 yr) 5125 228.82 232.05 0.000463 1.25 4251.91 2259.71 0.26 124723.* PF 6(100 yr) 6109 228.82 232.24 0.000503 1.37 4681.81 2437.49 0.28

124201 PF 1 (2yr) 1612 228.15 230.98 0.000087 0.45 3742.71 2381.58 0.11 124201 PF 2(5 yr) 2499 228.15 231.27 0.000123 0.59 4456.56 2561.43 0.13 124201 PF 3(10 yr) 3225 228.15 231.48 0.000147 0.69 4996.76 2704.78 0.15 124201 PF 4(25 yr) 4349 228.15 231.76 0.000176 0.82 5774.36 2818.71 0.16 124201 PF 5(50 yr) 5125 228.15 231.93 0.000192 0.89 6276.73 2879.46 0.17 124201 PF 6(100 yr) 6109 228.15 232.11 0.000218 0.99 6778.04 2938.83 0.19

123840 PF 1 (2yr) 1612 228.10 230.60 0.010935 2.24 719.34 1394.92 1.00 123840 PF 2(5 yr) 2499 228.10 230.78 0.010282 2.54 984.59 1512.43 1.00 123840 PF 3(10 yr) 3225 228.10 230.90 0.009805 2.77 1164.16 1513.46 1.01 123840 PF 4(25 yr) 4349 228.10 231.08 0.008875 3.03 1435.83 1515.02 0.99 123840 PF 5(50 yr) 5125 228.10 231.19 0.008721 3.20 1601.00 1534.55 1.00 123840 PF 6(100 yr) 6109 228.10 231.34 0.008546 3.22 1897.64 1776.46 0.99

122539 PF 1 (2yr) 1612 226.03 228.61 0.000354 0.85 1904.00 1214.79 0.22

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 126 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 122539 PF 2(5 yr) 2499 226.03 229.41 0.000243 0.84 3008.40 1599.46 0.19 122539 PF 3(10 yr) 3225 226.03 229.76 0.000213 0.85 4320.31 2624.82 0.18 122539 PF 4(25 yr) 4349 226.03 230.23 0.000192 0.92 5612.40 2852.22 0.18 122539 PF 5(50 yr) 5125 226.03 230.50 0.000188 0.96 6387.21 2977.65 0.18 122539 PF 6(100 yr) 6109 226.03 230.78 0.000191 1.03 7239.34 3109.74 0.18

120519 PF 1 (2yr) 1612 223.70 227.93 0.000296 1.11 1448.45 534.69 0.22 120519 PF 2(5 yr) 2499 223.70 228.67 0.000505 1.27 1971.61 933.97 0.27 120519 PF 3(10 yr) 3225 223.70 229.07 0.000488 1.38 2372.67 1070.97 0.28 120519 PF 4(25 yr) 4349 223.70 229.56 0.000496 1.55 2964.65 1510.97 0.28 120519 PF 5(50 yr) 5125 223.70 229.83 0.000497 1.64 3728.55 3106.65 0.29 120519 PF 6(100 yr) 6109 223.70 230.12 0.000481 1.70 4640.87 3151.66 0.29

120272.* PF 1 (2yr) 1612 223.63 227.85 0.000340 1.13 1425.22 570.76 0.23 120272.* PF 2(5 yr) 2499 223.63 228.54 0.000556 1.30 1927.21 908.63 0.28 120272.* PF 3(10 yr) 3225 223.63 228.94 0.000566 1.40 2307.97 986.45 0.29 120272.* PF 4(25 yr) 4349 223.63 229.42 0.000603 1.55 2806.25 1077.08 0.31 120272.* PF 5(50 yr) 5125 223.63 229.69 0.000616 1.64 3403.88 2958.76 0.31 120272.* PF 6(100 yr) 6109 223.63 229.99 0.000579 1.69 4295.27 3006.42 0.31

120026.* PF 1 (2yr) 1612 223.56 227.76 0.000391 1.15 1403.84 610.69 0.24 120026.* PF 2(5 yr) 2499 223.56 228.39 0.000657 1.30 1920.15 1020.56 0.30 120026.* PF 3(10 yr) 3225 223.56 228.79 0.000729 1.35 2395.22 1308.67 0.32 120026.* PF 4(25 yr) 4349 223.56 229.29 0.000608 1.42 3065.26 1393.93 0.30 120026.* PF 5(50 yr) 5125 223.56 229.56 0.000584 1.49 3497.21 1922.06 0.30 120026.* PF 6(100 yr) 6109 223.56 229.86 0.000560 1.57 4109.35 2117.46 0.30

119287.* PF 1 (2yr) 1612 223.36 227.39 0.000691 1.08 1496.28 1096.87 0.29 119287.* PF 2(5 yr) 2499 223.36 227.97 0.000532 1.17 2141.50 1144.84 0.27 119287.* PF 3(10 yr) 3225 223.36 228.36 0.000486 1.24 2602.09 1187.65 0.27 119287.* PF 4(25 yr) 4349 223.36 228.92 0.000442 1.33 3291.76 1385.03 0.26 119287.* PF 5(50 yr) 5125 223.36 229.19 0.000437 1.41 3743.94 1923.82 0.27 119287.* PF 6(100 yr) 6109 223.36 229.52 0.000414 1.47 4567.71 2391.03 0.26

118056 PF 1 (2yr) 1612 223.02 226.87 0.000298 0.93 1730.37 839.79 0.21 118056 PF 2(5 yr) 2499 223.02 227.46 0.000333 1.11 2251.77 913.64 0.23 118056 PF 3(10 yr) 3225 223.02 227.85 0.000367 1.23 2652.45 1185.37 0.24 118056 PF 4(25 yr) 4349 223.02 228.37 0.000439 1.35 3400.03 1799.33 0.26 118056 PF 5(50 yr) 5125 223.02 228.69 0.000394 1.37 4295.65 2551.62 0.25 118056 PF 6(100 yr) 6109 223.02 229.07 0.000344 1.39 5297.32 2707.05 0.24

117747.* PF 1 (2yr) 1612 222.75 226.74 0.000452 1.09 1474.47 769.75 0.25 117747.* PF 2(5 yr) 2499 222.75 227.31 0.000550 1.26 1999.06 1166.22 0.28 117747.* PF 3(10 yr) 3225 222.75 227.70 0.000497 1.35 2568.93 1695.63 0.28 117747.* PF 4(25 yr) 4349 222.75 228.23 0.000424 1.42 3610.85 2149.37 0.26 117747.* PF 5(50 yr) 5125 222.75 228.57 0.000381 1.44 4358.69 2323.26 0.25 117747.* PF 6(100 yr) 6109 222.75 228.96 0.000338 1.47 5309.12 2491.06 0.24

117438.* PF 1 (2yr) 1612 222.48 226.52 0.000982 1.26 1282.90 972.24 0.35 117438.* PF 2(5 yr) 2499 222.48 227.11 0.000726 1.32 1920.34 1284.17 0.32 117438.* PF 3(10 yr) 3225 222.48 227.54 0.000564 1.34 2584.11 1733.99 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 127 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 117438.* PF 4(25 yr) 4349 222.48 228.10 0.000435 1.37 3624.38 1933.57 0.26 117438.* PF 5(50 yr) 5125 222.48 228.45 0.000384 1.39 4340.83 2127.37 0.25 117438.* PF 6(100 yr) 6109 222.48 228.86 0.000333 1.41 5220.23 2170.77 0.24

117129 PF 1 (2yr) 1612 222.22 226.06 0.001823 1.57 1025.30 881.94 0.47 117129 PF 2(5 yr) 2499 222.22 226.86 0.000788 1.41 1835.38 1271.66 0.33 117129 PF 3(10 yr) 3225 222.22 227.36 0.000555 1.39 2554.86 1550.78 0.29 117129 PF 4(25 yr) 4349 222.22 227.97 0.000425 1.41 3566.89 1777.96 0.26 117129 PF 5(50 yr) 5125 222.22 228.33 0.000375 1.43 4223.83 1827.33 0.25 117129 PF 6(100 yr) 6109 222.22 228.75 0.000335 1.47 5002.45 1890.55 0.24

116874 PF 1 (2yr) 1612 222.12 226.07 0.000101 0.62 2794.51 1674.94 0.13 116874 PF 2(5 yr) 2499 222.12 226.87 0.000086 0.69 4309.72 2127.77 0.12 116874 PF 3(10 yr) 3225 222.12 227.37 0.000081 0.74 5404.27 2251.85 0.12 116874 PF 4(25 yr) 4349 222.12 227.97 0.000081 0.81 6812.75 2402.10 0.12 116874 PF 5(50 yr) 5125 222.12 228.34 0.000081 0.86 7704.39 2492.54 0.12 116874 PF 6(100 yr) 6109 222.12 228.76 0.000082 0.91 8774.92 2596.98 0.13

115068 PF 1 (2yr) 1612 221.92 225.44 0.000920 2.07 778.60 265.23 0.39 115068 PF 2(5 yr) 2499 221.92 226.14 0.001418 2.52 991.51 347.95 0.48 115068 PF 3(10 yr) 3225 221.92 226.55 0.002026 2.80 1150.76 450.14 0.56 115068 PF 4(25 yr) 4349 221.92 227.08 0.002280 3.06 1455.21 742.76 0.60 115068 PF 5(50 yr) 5125 221.92 227.43 0.002077 3.13 1755.17 907.27 0.58 115068 PF 6(100 yr) 6109 221.92 227.90 0.001714 3.10 2280.42 1249.74 0.54

113718 PF 1 (2yr) 1612 220.70 224.98 0.000253 0.83 1930.79 977.96 0.19 113718 PF 2(5 yr) 2499 220.70 225.68 0.000245 0.92 2840.90 1606.39 0.19 113718 PF 3(10 yr) 3225 220.70 226.16 0.000207 0.96 3776.19 2272.79 0.18 113718 PF 4(25 yr) 4349 220.70 226.84 0.000159 0.97 5436.21 2554.44 0.17 113718 PF 5(50 yr) 5125 220.70 227.29 0.000135 0.97 6592.66 2676.26 0.16 113718 PF 6(100 yr) 6109 220.70 227.81 0.000116 0.97 8017.58 2821.25 0.15

112544 PF 1 (2yr) 1612 220.66 224.75 0.000164 0.64 2555.82 1590.71 0.15 112544 PF 2(5 yr) 2499 220.66 225.49 0.000126 0.68 3936.71 2148.82 0.14 112544 PF 3(10 yr) 3225 220.66 226.01 0.000104 0.71 5081.30 2272.08 0.13 112544 PF 4(25 yr) 4349 220.66 226.73 0.000085 0.74 6769.43 2442.55 0.12 112544 PF 5(50 yr) 5125 220.66 227.18 0.000076 0.75 7909.48 2551.24 0.12 112544 PF 6(100 yr) 6109 220.66 227.71 0.000069 0.78 9298.64 2677.72 0.11

111259 PF 1 (2yr) 1612 220.30 224.23 0.000825 1.62 996.76 453.86 0.35 111259 PF 2(5 yr) 2499 220.30 224.99 0.000797 1.84 1362.26 504.27 0.35 111259 PF 3(10 yr) 3225 220.30 225.54 0.000724 1.97 1668.11 623.46 0.35 111259 PF 4(25 yr) 4349 220.30 226.27 0.000647 2.13 2164.32 709.57 0.34 111259 PF 5(50 yr) 5125 220.30 226.72 0.000615 2.23 2515.07 880.66 0.34 111259 PF 6(100 yr) 6109 220.30 227.27 0.000563 2.30 3011.23 932.04 0.33

109410 PF 1 (2yr) 1612 219.12 223.74 0.000155 0.84 2037.37 921.74 0.16 109410 PF 2(5 yr) 2499 219.12 224.53 0.000155 0.98 2862.34 1179.22 0.16 109410 PF 3(10 yr) 3225 219.12 225.13 0.000144 1.05 3618.67 1378.54 0.16 109410 PF 4(25 yr) 4349 219.12 225.95 0.000124 1.10 5062.89 1765.22 0.16 109410 PF 5(50 yr) 5125 219.12 226.45 0.000116 1.13 5963.78 1849.30 0.15

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 128 Feasibility Report: West Rapti Basin

108799.* PF 1 (2yr) 1612 218.93 223.63 0.000183 0.96 1883.40 878.83 0.17 108799.* PF 2(5 yr) 2499 218.93 224.41 0.000188 1.13 2648.61 1115.41 0.18 108799.* PF 3(10 yr) 3225 218.93 225.02 0.000175 1.20 3485.21 1553.15 0.18 108799.* PF 4(25 yr) 4349 218.93 225.86 0.000148 1.23 4843.68 1693.75 0.17 108799.* PF 5(50 yr) 5125 218.93 226.36 0.000136 1.26 5725.49 1793.63 0.17 108799.* PF 6(100 yr) 6109 218.93 226.95 0.000125 1.29 6811.41 1909.47 0.16

108188.* PF 1 (2yr) 1612 218.74 223.50 0.000261 0.95 1740.62 861.47 0.20 108188.* PF 2(5 yr) 2499 218.74 224.29 0.000227 1.07 2535.91 1171.36 0.19 108188.* PF 3(10 yr) 3225 218.74 224.91 0.000191 1.11 3362.47 1436.94 0.18 108188.* PF 4(25 yr) 4349 218.74 225.77 0.000154 1.14 4667.46 1609.85 0.17 108188.* PF 5(50 yr) 5125 218.74 226.28 0.000139 1.17 5516.10 1697.14 0.16 108188.* PF 6(100 yr) 6109 218.74 226.87 0.000127 1.20 6553.05 1799.25 0.16

107577.* PF 1 (2yr) 1612 218.55 223.31 0.000327 1.03 1603.36 887.76 0.22 107577.* PF 2(5 yr) 2499 218.55 224.14 0.000257 1.13 2446.75 1130.06 0.21 107577.* PF 3(10 yr) 3225 218.55 224.79 0.000208 1.15 3262.11 1352.86 0.19 107577.* PF 4(25 yr) 4349 218.55 225.66 0.000164 1.18 4523.52 1508.97 0.18 107577.* PF 5(50 yr) 5125 218.55 226.19 0.000148 1.21 5334.88 1598.12 0.17 107577.* PF 6(100 yr) 6109 218.55 226.79 0.000135 1.24 6324.80 1697.32 0.17

106966.* PF 1 (2yr) 1612 218.36 223.06 0.000494 1.11 1461.22 848.33 0.26 106966.* PF 2(5 yr) 2499 218.36 223.97 0.000308 1.10 2368.24 1087.52 0.22 106966.* PF 3(10 yr) 3225 218.36 224.66 0.000221 1.09 3193.05 1286.64 0.19 106966.* PF 4(25 yr) 4349 218.36 225.57 0.000164 1.11 4433.48 1426.88 0.17 106966.* PF 5(50 yr) 5125 218.36 226.10 0.000146 1.13 5211.51 1495.68 0.17 106966.* PF 6(100 yr) 6109 218.36 226.71 0.000131 1.16 6146.38 1575.13 0.16

106355 PF 1 (2yr) 1612 218.17 222.73 0.000509 1.25 1315.99 773.91 0.27 106355 PF 2(5 yr) 2499 218.17 223.77 0.000293 1.23 2285.84 1042.01 0.22 106355 PF 3(10 yr) 3225 218.17 224.51 0.000218 1.22 3128.07 1225.64 0.20 106355 PF 4(25 yr) 4349 218.17 225.46 0.000168 1.24 4358.20 1359.45 0.18 106355 PF 5(50 yr) 5125 218.17 226.00 0.000152 1.27 5112.31 1416.34 0.17 106355 PF 6(100 yr) 6109 218.17 226.62 0.000140 1.30 6006.08 1480.94 0.17

104906 PF 1 (2yr) 1612 217.11 221.74 0.000671 2.06 782.60 214.21 0.34 104906 PF 2(5 yr) 2499 217.11 222.93 0.000625 2.38 1106.56 331.32 0.35 104906 PF 3(10 yr) 3225 217.11 223.75 0.000590 2.56 1407.38 410.73 0.34 104906 PF 4(25 yr) 4349 217.11 224.70 0.000587 2.83 1906.34 628.11 0.35 104906 PF 5(50 yr) 5125 217.11 225.25 0.000576 2.96 2283.73 727.57 0.35 104906 PF 6(100 yr) 6109 217.11 225.89 0.000548 3.06 2767.75 786.15 0.35

104562 PF 1 (2yr) 1612 217.05 220.60 0.003985 4.05 398.31 147.78 0.79 104562 PF 2(5 yr) 2499 217.05 221.83 0.002828 4.28 586.15 157.94 0.70 104562 PF 3(10 yr) 3225 217.05 222.49 0.003065 4.66 695.85 181.25 0.74 104562 PF 4(25 yr) 4349 217.05 223.28 0.002953 5.15 920.14 311.49 0.75 104562 PF 5(50 yr) 5125 217.05 223.74 0.002902 5.42 1064.47 319.10 0.75 104562 PF 6(100 yr) 6109 217.05 224.25 0.002882 5.75 1229.50 327.96 0.76

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 129 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 103309 PF 1 (2yr) 1612 214.20 219.12 0.000777 2.28 708.16 183.94 0.37 103309 PF 2(5 yr) 2499 214.20 220.66 0.000733 2.40 1048.50 265.01 0.37 103309 PF 3(10 yr) 3225 214.20 221.36 0.000736 2.65 1250.27 313.68 0.38 103309 PF 4(25 yr) 4349 214.20 222.19 0.000776 3.01 1580.40 459.80 0.40 103309 PF 5(50 yr) 5125 214.20 222.66 0.000803 3.23 1807.52 510.20 0.41 103309 PF 6(100 yr) 6109 214.20 223.18 0.000834 3.47 2128.62 715.73 0.42

102609.* PF 1 (2yr) 1612 213.71 218.58 0.000775 2.25 715.08 188.19 0.37 102609.* PF 2(5 yr) 2499 213.71 220.13 0.000821 2.34 1065.80 276.18 0.38 102609.* PF 3(10 yr) 3225 213.71 220.82 0.000857 2.54 1276.28 326.68 0.40 102609.* PF 4(25 yr) 4349 213.71 221.66 0.000862 2.82 1617.75 473.11 0.41 102609.* PF 5(50 yr) 5125 213.71 222.12 0.000861 2.99 1850.95 523.75 0.41 102609.* PF 6(100 yr) 6109 213.71 222.65 0.000863 3.19 2180.50 731.42 0.42

101909.* PF 1 (2yr) 1612 213.23 218.05 0.000773 2.23 722.23 192.57 0.37 101909.* PF 2(5 yr) 2499 213.23 219.55 0.000843 2.33 1071.41 285.39 0.38 101909.* PF 3(10 yr) 3225 213.23 220.22 0.000871 2.53 1280.84 333.23 0.40 101909.* PF 4(25 yr) 4349 213.23 221.05 0.000868 2.80 1623.72 479.06 0.41 101909.* PF 5(50 yr) 5125 213.23 221.53 0.000859 2.97 1862.90 530.61 0.41 101909.* PF 6(100 yr) 6109 213.23 222.05 0.000860 3.16 2188.60 742.95 0.42

101209.* PF 1 (2yr) 1612 212.74 217.51 0.000770 2.21 729.73 197.09 0.37 101209.* PF 2(5 yr) 2499 212.74 218.95 0.000874 2.33 1071.64 293.52 0.39 101209.* PF 3(10 yr) 3225 212.74 219.60 0.000896 2.53 1279.40 338.15 0.40 101209.* PF 4(25 yr) 4349 212.74 220.45 0.000851 2.79 1630.89 485.05 0.40 101209.* PF 5(50 yr) 5125 212.74 220.94 0.000839 2.95 1877.92 537.95 0.41 101209.* PF 6(100 yr) 6109 212.74 221.46 0.000844 3.14 2199.71 733.07 0.41

100509.* PF 1 (2yr) 1612 212.26 216.98 0.000766 2.19 737.72 201.79 0.36 100509.* PF 2(5 yr) 2499 212.26 218.36 0.000810 2.33 1075.79 301.77 0.38 100509.* PF 3(10 yr) 3225 212.26 218.99 0.000821 2.57 1280.34 343.30 0.39 100509.* PF 4(25 yr) 4349 212.26 219.85 0.000827 2.85 1635.88 490.35 0.40 100509.* PF 5(50 yr) 5125 212.26 220.34 0.000817 3.01 1890.56 544.61 0.41 100509.* PF 6(100 yr) 6109 212.26 220.86 0.000833 3.22 2203.22 712.85 0.42

99809.9* PF 1 (2yr) 1612 211.77 216.45 0.000760 2.16 746.48 206.69 0.36 99809.9* PF 2(5 yr) 2499 211.77 217.80 0.000800 2.30 1089.82 308.98 0.38 99809.9* PF 3(10 yr) 3225 211.77 218.43 0.000807 2.54 1297.53 351.32 0.39 99809.9* PF 4(25 yr) 4349 211.77 219.25 0.000909 2.83 1642.32 495.64 0.42 99809.9* PF 5(50 yr) 5125 211.77 219.74 0.000965 2.95 1896.34 549.73 0.43 99809.9* PF 6(100 yr) 6109 211.77 220.26 0.000948 3.11 2213.85 702.56 0.43

99110.1* PF 1 (2yr) 1612 211.29 215.92 0.000751 2.13 756.75 211.90 0.36 99110.1* PF 2(5 yr) 2499 211.29 217.21 0.000887 2.28 1095.61 313.97 0.39 99110.1* PF 3(10 yr) 3225 211.29 217.84 0.000898 2.48 1307.24 357.94 0.40 99110.1* PF 4(25 yr) 4349 211.29 218.64 0.000888 2.75 1640.33 492.01 0.41 99110.1* PF 5(50 yr) 5125 211.29 219.10 0.000874 2.91 1884.79 551.15 0.41 99110.1* PF 6(100 yr) 6109 211.29 219.63 0.000867 3.09 2197.58 681.73 0.42

98410.3* PF 1 (2yr) 1612 210.80 215.40 0.000747 2.10 768.56 219.49 0.36 98410.3* PF 2(5 yr) 2499 210.80 216.62 0.000806 2.28 1098.90 318.11 0.38

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 130 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 98410.3* PF 3(10 yr) 3225 210.80 217.24 0.000801 2.52 1309.45 363.13 0.38 98410.3* PF 4(25 yr) 4349 210.80 218.01 0.000824 2.85 1634.76 482.73 0.40 98410.3* PF 5(50 yr) 5125 210.80 218.47 0.000835 3.04 1875.25 552.64 0.41 98410.3* PF 6(100 yr) 6109 210.80 218.99 0.000847 3.24 2181.06 642.27 0.42

97710.5* PF 1 (2yr) 1612 210.32 214.88 0.000772 2.07 780.59 234.08 0.36 97710.5* PF 2(5 yr) 2499 210.32 216.03 0.000886 2.27 1103.19 322.22 0.39 97710.5* PF 3(10 yr) 3225 210.32 216.66 0.000896 2.46 1319.16 369.73 0.40 97710.5* PF 4(25 yr) 4349 210.32 217.44 0.000869 2.74 1655.13 489.25 0.41 97710.5* PF 5(50 yr) 5125 210.32 217.90 0.000859 2.90 1900.98 561.20 0.41 97710.5* PF 6(100 yr) 6109 210.32 218.42 0.000856 3.09 2212.74 649.99 0.42

97010.7* PF 1 (2yr) 1612 209.83 214.33 0.000802 2.04 790.32 248.36 0.37 97010.7* PF 2(5 yr) 2499 209.83 215.44 0.000809 2.27 1105.71 325.54 0.38 97010.7* PF 3(10 yr) 3225 209.83 216.05 0.000812 2.50 1319.39 374.51 0.39 97010.7* PF 4(25 yr) 4349 209.83 216.83 0.000821 2.81 1657.93 491.57 0.40 97010.7* PF 5(50 yr) 5125 209.83 217.29 0.000829 2.99 1901.50 564.16 0.41 97010.7* PF 6(100 yr) 6109 209.83 217.81 0.000839 3.19 2212.18 660.57 0.42

96310.9* PF 1 (2yr) 1612 209.35 213.77 0.000796 2.02 798.90 253.81 0.36 96310.9* PF 2(5 yr) 2499 209.35 214.89 0.000794 2.24 1120.00 331.84 0.37 96310.9* PF 3(10 yr) 3225 209.35 215.50 0.000793 2.47 1338.69 383.23 0.38 96310.9* PF 4(25 yr) 4349 209.35 216.27 0.000801 2.77 1685.09 500.90 0.39 96310.9* PF 5(50 yr) 5125 209.35 216.73 0.000810 2.95 1929.56 572.59 0.40 96310.9* PF 6(100 yr) 6109 209.35 217.24 0.000822 3.15 2239.19 655.57 0.41

95611.0* PF 1 (2yr) 1612 208.86 213.22 0.000786 1.99 809.10 259.44 0.36 95611.0* PF 2(5 yr) 2499 208.86 214.34 0.000768 2.20 1139.56 339.73 0.37 95611.0* PF 3(10 yr) 3225 208.86 214.96 0.000764 2.42 1365.29 395.74 0.37 95611.0* PF 4(25 yr) 4349 208.86 215.73 0.000791 2.71 1719.45 512.04 0.39 95611.0* PF 5(50 yr) 5125 208.86 216.18 0.000798 2.89 1966.26 582.56 0.40 95611.0* PF 6(100 yr) 6109 208.86 216.68 0.000809 3.09 2278.20 665.88 0.41

94911.2* PF 1 (2yr) 1612 208.38 212.68 0.000767 1.96 822.61 265.68 0.36 94911.2* PF 2(5 yr) 2499 208.38 213.83 0.000724 2.15 1169.33 350.77 0.36 94911.2* PF 3(10 yr) 3225 208.38 214.45 0.000718 2.36 1405.41 420.00 0.36 94911.2* PF 4(25 yr) 4349 208.38 215.21 0.000734 2.66 1766.75 525.91 0.38 94911.2* PF 5(50 yr) 5125 208.38 215.65 0.000748 2.84 2015.45 594.88 0.39 94911.2* PF 6(100 yr) 6109 208.38 216.14 0.000767 3.05 2327.70 678.79 0.40

94211.4* PF 1 (2yr) 1612 207.89 212.16 0.000737 1.92 841.35 272.84 0.35 94211.4* PF 2(5 yr) 2499 207.89 213.31 0.000798 2.09 1196.80 361.70 0.37 94211.4* PF 3(10 yr) 3225 207.89 213.96 0.000750 2.24 1454.15 448.27 0.36 94211.4* PF 4(25 yr) 4349 207.89 214.73 0.000725 2.49 1837.45 544.21 0.37 94211.4* PF 5(50 yr) 5125 207.89 215.17 0.000726 2.64 2095.11 614.51 0.38 94211.4* PF 6(100 yr) 6109 207.89 215.66 0.000736 2.83 2415.05 701.14 0.38

93511.6* PF 1 (2yr) 1612 207.41 211.67 0.000691 1.86 868.80 281.59 0.34 93511.6* PF 2(5 yr) 2499 207.41 212.76 0.000782 2.06 1215.32 370.26 0.36 93511.6* PF 3(10 yr) 3225 207.41 213.44 0.000756 2.18 1493.99 466.49 0.36 93511.6* PF 4(25 yr) 4349 207.41 214.24 0.000719 2.38 1908.26 561.53 0.36

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 131 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 93511.6* PF 5(50 yr) 5125 207.41 214.70 0.000703 2.51 2180.81 638.77 0.37 93511.6* PF 6(100 yr) 6109 207.41 215.18 0.000703 2.68 2513.81 724.97 0.37

92811.8* PF 1 (2yr) 1612 206.92 211.22 0.000623 1.77 910.41 292.74 0.32 92811.8* PF 2(5 yr) 2499 206.92 212.28 0.000631 2.00 1259.48 387.03 0.33 92811.8* PF 3(10 yr) 3225 206.92 212.95 0.000659 2.15 1550.62 488.76 0.34 92811.8* PF 4(25 yr) 4349 206.92 213.76 0.000695 2.35 1980.90 579.34 0.36 92811.8* PF 5(50 yr) 5125 206.92 214.23 0.000681 2.46 2272.74 663.51 0.36 92811.8* PF 6(100 yr) 6109 206.92 214.72 0.000673 2.62 2623.43 780.39 0.36

92112.0* PF 1 (2yr) 1612 206.44 210.83 0.000535 1.66 971.32 307.03 0.30 92112.0* PF 2(5 yr) 2499 206.44 211.89 0.000533 1.88 1343.21 412.80 0.31 92112.0* PF 3(10 yr) 3225 206.44 212.53 0.000591 2.04 1645.36 516.70 0.33 92112.0* PF 4(25 yr) 4349 206.44 213.31 0.000625 2.24 2082.00 607.40 0.34 92112.0* PF 5(50 yr) 5125 206.44 213.80 0.000597 2.35 2400.22 696.24 0.34 92112.0* PF 6(100 yr) 6109 206.44 214.30 0.000591 2.49 2778.88 836.29 0.34

91412.2* PF 1 (2yr) 1612 205.95 210.51 0.000434 1.52 1057.65 324.92 0.27 91412.2* PF 2(5 yr) 2499 205.95 211.58 0.000426 1.75 1470.34 479.64 0.28 91412.2* PF 3(10 yr) 3225 205.95 212.20 0.000427 1.93 1793.34 550.77 0.28 91412.2* PF 4(25 yr) 4349 205.95 212.96 0.000448 2.18 2243.71 653.75 0.30 91412.2* PF 5(50 yr) 5125 205.95 213.45 0.000448 2.31 2589.00 742.67 0.30 91412.2* PF 6(100 yr) 6109 205.95 213.95 0.000466 2.49 2995.25 905.34 0.31

90712.4* PF 1 (2yr) 1612 205.47 210.26 0.000345 1.37 1172.39 353.54 0.24 90712.4* PF 2(5 yr) 2499 205.47 211.31 0.000419 1.54 1638.54 526.78 0.27 90712.4* PF 3(10 yr) 3225 205.47 211.94 0.000415 1.65 1992.78 590.79 0.27 90712.4* PF 4(25 yr) 4349 205.47 212.71 0.000407 1.83 2489.04 717.20 0.28 90712.4* PF 5(50 yr) 5125 205.47 213.22 0.000386 1.92 2884.14 859.80 0.27 90712.4* PF 6(100 yr) 6109 205.47 213.71 0.000387 2.05 3355.03 1027.04 0.28

90012.6* PF 1 (2yr) 1612 204.99 210.05 0.000290 1.22 1323.70 420.98 0.22 90012.6* PF 2(5 yr) 2499 204.99 211.07 0.000311 1.38 1843.13 569.51 0.23 90012.6* PF 3(10 yr) 3225 204.99 211.71 0.000308 1.49 2227.02 641.73 0.24 90012.6* PF 4(25 yr) 4349 204.99 212.48 0.000306 1.67 2779.37 784.75 0.24 90012.6* PF 5(50 yr) 5125 204.99 213.00 0.000293 1.75 3245.89 995.02 0.24 90012.6* PF 6(100 yr) 6109 204.99 213.50 0.000296 1.87 3774.73 1105.22 0.25

89312.8* PF 1 (2yr) 1612 204.50 209.89 0.000218 1.06 1529.89 517.94 0.19 89312.8* PF 2(5 yr) 2499 204.50 210.90 0.000222 1.21 2106.03 617.30 0.20 89312.8* PF 3(10 yr) 3225 204.50 211.54 0.000220 1.33 2532.66 725.27 0.20 89312.8* PF 4(25 yr) 4349 204.50 212.32 0.000225 1.50 3166.60 932.72 0.21 89312.8* PF 5(50 yr) 5125 204.50 212.85 0.000217 1.57 3720.52 1109.67 0.21 89312.8* PF 6(100 yr) 6109 204.50 213.35 0.000223 1.68 4304.13 1242.99 0.22

88613 PF 1 (2yr) 2947 204.02 209.52 0.000466 1.87 1652.97 548.01 0.29 88613 PF 2(5 yr) 4386 204.02 210.48 0.000486 2.19 2225.14 639.49 0.31 88613 PF 3(10 yr) 5450 204.02 211.10 0.000494 2.38 2653.31 754.28 0.32 88613 PF 4(25 yr) 6952 204.02 211.85 0.000501 2.61 3293.16 977.74 0.33 88613 PF 5(50 yr) 8171 204.02 212.36 0.000503 2.75 3852.65 1152.85 0.33 88613 PF 6(100 yr) 9469 204.02 212.85 0.000505 2.88 4456.57 1298.14 0.33

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 132 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

87874.0* PF 1 (2yr) 2947 203.54 209.15 0.000543 1.81 1655.08 533.45 0.31 87874.0* PF 2(5 yr) 4386 203.54 210.12 0.000522 2.08 2217.93 629.40 0.31 87874.0* PF 3(10 yr) 5450 203.54 210.74 0.000512 2.25 2641.24 744.51 0.32 87874.0* PF 4(25 yr) 6952 203.54 211.50 0.000503 2.44 3276.61 964.51 0.32 87874.0* PF 5(50 yr) 8171 203.54 212.02 0.000498 2.57 3832.68 1141.19 0.32 87874.0* PF 6(100 yr) 9469 203.54 212.51 0.000495 2.69 4432.11 1285.60 0.33

87135.0* PF 1 (2yr) 2947 203.07 208.75 0.000544 1.82 1635.45 521.09 0.31 87135.0* PF 2(5 yr) 4386 203.07 209.73 0.000528 2.10 2190.03 615.64 0.31 87135.0* PF 3(10 yr) 5450 203.07 210.36 0.000517 2.26 2607.33 727.34 0.32 87135.0* PF 4(25 yr) 6952 203.07 211.12 0.000507 2.46 3233.99 940.06 0.32 87135.0* PF 5(50 yr) 8171 203.07 211.64 0.000503 2.59 3781.80 1124.93 0.33 87135.0* PF 6(100 yr) 9469 203.07 212.13 0.000500 2.71 4373.54 1267.37 0.33

86396.0* PF 1 (2yr) 2947 202.59 208.33 0.000578 1.84 1609.07 508.60 0.31 86396.0* PF 2(5 yr) 4386 202.59 209.33 0.000547 2.10 2159.19 600.40 0.32 86396.0* PF 3(10 yr) 5450 202.59 209.97 0.000527 2.26 2573.70 707.64 0.32 86396.0* PF 4(25 yr) 6952 202.59 210.74 0.000514 2.45 3194.55 927.28 0.32 86396.0* PF 5(50 yr) 8171 202.59 211.27 0.000508 2.58 3736.44 1110.09 0.33 86396.0* PF 6(100 yr) 9469 202.59 211.76 0.000503 2.70 4322.22 1249.79 0.33

85657.0* PF 1 (2yr) 2947 202.12 207.90 0.000581 1.88 1574.24 483.69 0.32 85657.0* PF 2(5 yr) 4386 202.12 208.91 0.000555 2.15 2118.15 581.86 0.32 85657.0* PF 3(10 yr) 5450 202.12 209.57 0.000534 2.31 2529.24 680.84 0.32 85657.0* PF 4(25 yr) 6952 202.12 210.34 0.000523 2.51 3138.32 908.08 0.33 85657.0* PF 5(50 yr) 8171 202.12 210.87 0.000518 2.64 3669.84 1090.15 0.33 85657.0* PF 6(100 yr) 9469 202.12 211.37 0.000515 2.77 4245.73 1227.06 0.33

84918.0* PF 1 (2yr) 2947 201.65 207.43 0.000659 1.93 1527.28 452.95 0.33 84918.0* PF 2(5 yr) 4386 201.65 208.48 0.000593 2.17 2072.57 562.63 0.33 84918.0* PF 3(10 yr) 5450 201.65 209.14 0.000608 2.31 2473.55 657.71 0.34 84918.0* PF 4(25 yr) 6952 201.65 209.94 0.000576 2.47 3079.96 887.05 0.34 84918.0* PF 5(50 yr) 8171 201.65 210.48 0.000556 2.59 3610.15 1072.01 0.34 84918.0* PF 6(100 yr) 9469 201.65 210.99 0.000543 2.70 4184.28 1205.86 0.34

84179.0* PF 1 (2yr) 2947 201.17 206.96 0.000555 2.02 1484.19 431.59 0.32 84179.0* PF 2(5 yr) 4386 201.17 208.02 0.000562 2.34 2008.96 550.37 0.33 84179.0* PF 3(10 yr) 5450 201.17 208.66 0.000568 2.54 2380.65 624.84 0.34 84179.0* PF 4(25 yr) 6952 201.17 209.44 0.000572 2.77 2945.14 822.45 0.35 84179.0* PF 5(50 yr) 8171 201.17 209.98 0.000572 2.93 3440.60 1021.73 0.35 84179.0* PF 6(100 yr) 9469 201.17 210.49 0.000572 3.06 3988.74 1153.47 0.36

83440.0* PF 1 (2yr) 2947 200.70 206.54 0.000567 2.05 1461.14 416.47 0.32 83440.0* PF 2(5 yr) 4386 200.70 207.58 0.000584 2.39 1960.79 539.74 0.34 83440.0* PF 3(10 yr) 5450 200.70 208.21 0.000596 2.59 2317.65 597.66 0.35 83440.0* PF 4(25 yr) 6952 200.70 208.98 0.000606 2.85 2848.64 796.78 0.36 83440.0* PF 5(50 yr) 8171 200.70 209.52 0.000607 3.00 3318.36 967.47 0.36 83440.0* PF 6(100 yr) 9469 200.70 210.02 0.000609 3.15 3841.48 1111.12 0.37

82701.0* PF 1 (2yr) 2947 200.23 206.11 0.000589 2.08 1432.33 401.09 0.33

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 133 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 82701.0* PF 2(5 yr) 4386 200.23 207.12 0.000617 2.45 1899.31 526.09 0.35 82701.0* PF 3(10 yr) 5450 200.23 207.73 0.000636 2.67 2238.25 582.25 0.36 82701.0* PF 4(25 yr) 6952 200.23 208.48 0.000661 2.95 2723.66 766.31 0.37 82701.0* PF 5(50 yr) 8171 200.23 209.01 0.000662 3.11 3163.07 907.84 0.38 82701.0* PF 6(100 yr) 9469 200.23 209.50 0.000668 3.27 3649.17 1065.37 0.38

81962.0* PF 1 (2yr) 2947 199.75 205.65 0.000625 2.13 1394.30 385.05 0.34 81962.0* PF 2(5 yr) 4386 199.75 206.62 0.000673 2.53 1817.74 506.24 0.36 81962.0* PF 3(10 yr) 5450 199.75 207.20 0.000703 2.78 2130.96 563.19 0.38 81962.0* PF 4(25 yr) 6952 199.75 207.92 0.000744 3.08 2560.83 686.65 0.39 81962.0* PF 5(50 yr) 8171 199.75 208.43 0.000755 3.27 2957.09 818.55 0.40 81962.0* PF 6(100 yr) 9469 199.75 208.91 0.000768 3.45 3384.20 987.06 0.41

81223 PF 1 (2yr) 2947 199.28 205.15 0.000689 2.21 1340.82 366.80 0.35 81223 PF 2(5 yr) 4386 199.28 206.05 0.000770 2.66 1708.77 457.06 0.38 81223 PF 3(10 yr) 5450 199.28 206.58 0.000828 2.95 1976.25 533.77 0.40 81223 PF 4(25 yr) 6952 199.28 207.24 0.000888 3.29 2351.33 602.19 0.43 81223 PF 5(50 yr) 8171 199.28 207.70 0.000951 3.56 2650.06 750.95 0.45 81223 PF 6(100 yr) 9469 199.28 208.14 0.000979 3.77 2995.34 822.14 0.46

80609.1* PF 1 (2yr) 2947 198.83 204.69 0.000830 2.14 1374.49 414.79 0.37 80609.1* PF 2(5 yr) 4386 198.83 205.59 0.000827 2.50 1805.67 529.40 0.39 80609.1* PF 3(10 yr) 5450 198.83 206.11 0.000854 2.73 2094.52 579.10 0.40 80609.1* PF 4(25 yr) 6952 198.83 206.76 0.000883 3.02 2519.52 709.91 0.42 80609.1* PF 5(50 yr) 8171 198.83 207.21 0.000901 3.22 2848.07 760.44 0.43 80609.1* PF 6(100 yr) 9469 198.83 207.65 0.000915 3.40 3206.20 888.73 0.44

79995.2* PF 1 (2yr) 2947 198.38 204.16 0.000940 2.09 1412.71 484.12 0.39 79995.2* PF 2(5 yr) 4386 198.38 205.08 0.000931 2.31 1900.09 582.13 0.40 79995.2* PF 3(10 yr) 5450 198.38 205.63 0.000883 2.47 2240.53 660.36 0.40 79995.2* PF 4(25 yr) 6952 198.38 206.29 0.000870 2.67 2700.90 777.66 0.40 79995.2* PF 5(50 yr) 8171 198.38 206.75 0.000849 2.82 3080.81 860.49 0.40 79995.2* PF 6(100 yr) 9469 198.38 207.20 0.000831 2.95 3487.25 941.70 0.41

79381.4* PF 1 (2yr) 2947 197.92 203.59 0.000946 2.06 1427.75 499.46 0.39 79381.4* PF 2(5 yr) 4386 197.92 204.52 0.000939 2.26 1940.45 597.34 0.40 79381.4* PF 3(10 yr) 5450 197.92 205.11 0.000837 2.38 2305.24 626.23 0.39 79381.4* PF 4(25 yr) 6952 197.92 205.80 0.000790 2.57 2757.09 764.75 0.38 79381.4* PF 5(50 yr) 8171 197.92 206.27 0.000772 2.71 3141.27 855.93 0.39 79381.4* PF 6(100 yr) 9469 197.92 206.74 0.000756 2.85 3558.43 932.16 0.39

78767.5* PF 1 (2yr) 2947 197.47 203.00 0.000969 2.06 1428.26 508.63 0.39 78767.5* PF 2(5 yr) 4386 197.47 203.98 0.000833 2.25 1956.42 563.81 0.38 78767.5* PF 3(10 yr) 5450 197.47 204.64 0.000737 2.35 2337.75 591.36 0.37 78767.5* PF 4(25 yr) 6952 197.47 205.33 0.000733 2.55 2794.04 774.42 0.37 78767.5* PF 5(50 yr) 8171 197.47 205.82 0.000719 2.70 3196.12 875.26 0.38 78767.5* PF 6(100 yr) 9469 197.47 206.30 0.000706 2.83 3619.91 913.60 0.38

78153.7* PF 1 (2yr) 2947 197.02 202.37 0.001021 2.15 1373.56 479.75 0.40 78153.7* PF 2(5 yr) 4386 197.02 203.46 0.000794 2.29 1926.31 528.52 0.37 78153.7* PF 3(10 yr) 5450 197.02 204.15 0.000800 2.39 2308.09 605.36 0.38

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 134 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 78153.7* PF 4(25 yr) 6952 197.02 204.88 0.000740 2.57 2821.29 790.56 0.38 78153.7* PF 5(50 yr) 8171 197.02 205.39 0.000714 2.70 3240.88 856.45 0.37 78153.7* PF 6(100 yr) 9469 197.02 205.87 0.000695 2.82 3665.00 888.94 0.38

77539.8* PF 1 (2yr) 2947 196.57 201.77 0.000857 2.26 1305.83 377.63 0.38 77539.8* PF 2(5 yr) 4386 196.57 202.91 0.000861 2.47 1795.96 471.49 0.39 77539.8* PF 3(10 yr) 5450 196.57 203.59 0.000845 2.60 2134.19 577.16 0.40 77539.8* PF 4(25 yr) 6952 196.57 204.35 0.000786 2.79 2673.12 784.34 0.39 77539.8* PF 5(50 yr) 8171 196.57 204.87 0.000760 2.92 3094.43 825.44 0.39 77539.8* PF 6(100 yr) 9469 196.57 205.37 0.000743 3.05 3510.72 853.92 0.39

76926 PF 1 (2yr) 2947 196.12 201.20 0.000842 2.42 1220.57 317.82 0.39 76926 PF 2(5 yr) 4386 196.12 202.26 0.000906 2.83 1569.95 351.56 0.41 76926 PF 3(10 yr) 5450 196.12 202.91 0.000913 3.08 1846.75 591.98 0.42 76926 PF 4(25 yr) 6952 196.12 203.66 0.000908 3.35 2356.86 744.20 0.43 76926 PF 5(50 yr) 8171 196.12 204.18 0.000900 3.52 2757.20 781.45 0.44 76926 PF 6(100 yr) 9469 196.12 204.68 0.000894 3.68 3151.29 806.14 0.44

76392.5* PF 1 (2yr) 2947 195.57 200.74 0.000909 2.39 1231.63 334.40 0.40 76392.5* PF 2(5 yr) 4386 195.57 201.80 0.000913 2.73 1617.41 402.08 0.41 76392.5* PF 3(10 yr) 5450 195.57 202.46 0.000883 2.94 1904.94 473.51 0.41 76392.5* PF 4(25 yr) 6952 195.57 203.20 0.000889 3.23 2343.04 686.07 0.43 76392.5* PF 5(50 yr) 8171 195.57 203.72 0.000889 3.42 2722.08 770.76 0.43 76392.5* PF 6(100 yr) 9469 195.57 204.22 0.000882 3.58 3114.47 798.96 0.44

75859.1* PF 1 (2yr) 2947 195.01 200.25 0.000915 2.41 1237.55 359.15 0.40 75859.1* PF 2(5 yr) 4386 195.01 201.30 0.000958 2.74 1642.88 417.58 0.42 75859.1* PF 3(10 yr) 5450 195.01 201.96 0.001001 2.91 1936.72 464.96 0.43 75859.1* PF 4(25 yr) 6952 195.01 202.73 0.000976 3.15 2328.09 581.22 0.44 75859.1* PF 5(50 yr) 8171 195.01 203.25 0.000963 3.33 2672.77 711.45 0.44 75859.1* PF 6(100 yr) 9469 195.01 203.75 0.000949 3.50 3051.87 783.74 0.44

75325.7* PF 1 (2yr) 2947 194.46 199.75 0.000997 2.36 1247.60 370.50 0.41 75325.7* PF 2(5 yr) 4386 194.46 200.79 0.001016 2.65 1656.38 420.32 0.43 75325.7* PF 3(10 yr) 5450 194.46 201.44 0.001037 2.81 1942.62 459.11 0.44 75325.7* PF 4(25 yr) 6952 194.46 202.22 0.001005 3.00 2325.16 527.97 0.44 75325.7* PF 5(50 yr) 8171 194.46 202.76 0.000969 3.16 2628.70 625.28 0.44 75325.7* PF 6(100 yr) 9469 194.46 203.27 0.000946 3.32 2978.36 730.03 0.44

74792.2* PF 1 (2yr) 2947 193.91 199.21 0.001017 2.37 1244.46 373.89 0.41 74792.2* PF 2(5 yr) 4386 193.91 200.24 0.001019 2.65 1652.35 418.95 0.43 74792.2* PF 3(10 yr) 5450 193.91 200.88 0.001035 2.82 1929.59 451.00 0.44 74792.2* PF 4(25 yr) 6952 193.91 201.67 0.001047 3.02 2301.14 498.16 0.45 74792.2* PF 5(50 yr) 8171 193.91 202.23 0.001023 3.17 2593.61 550.42 0.45 74792.2* PF 6(100 yr) 9469 193.91 202.75 0.000988 3.32 2900.15 637.17 0.45

74258.8* PF 1 (2yr) 2947 193.36 198.66 0.001022 2.38 1238.66 370.83 0.42 74258.8* PF 2(5 yr) 4386 193.36 199.69 0.001032 2.67 1642.22 416.80 0.43 74258.8* PF 3(10 yr) 5450 193.36 200.33 0.000999 2.85 1917.75 445.08 0.43 74258.8* PF 4(25 yr) 6952 193.36 201.11 0.000985 3.08 2277.52 479.50 0.44 74258.8* PF 5(50 yr) 8171 193.36 201.67 0.000965 3.24 2557.97 520.70 0.44

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 135 Feasibility Report: West Rapti Basin

73725.4* PF 1 (2yr) 2947 192.80 198.12 0.001023 2.39 1233.23 367.13 0.42 73725.4* PF 2(5 yr) 4386 192.80 199.13 0.001046 2.70 1625.95 410.43 0.43 73725.4* PF 3(10 yr) 5450 192.80 199.78 0.001048 2.86 1902.51 439.48 0.44 73725.4* PF 4(25 yr) 6952 192.80 200.58 0.001008 3.07 2266.45 471.97 0.44 73725.4* PF 5(50 yr) 8171 192.80 201.15 0.000984 3.23 2545.99 502.60 0.44 73725.4* PF 6(100 yr) 9469 192.80 201.70 0.000955 3.39 2831.71 538.94 0.44

73192 PF 1 (2yr) 2947 192.25 197.57 0.001002 2.40 1229.06 364.28 0.41 73192 PF 2(5 yr) 4386 192.25 198.58 0.000970 2.75 1614.61 404.44 0.42 73192 PF 3(10 yr) 5450 192.25 199.22 0.000959 2.95 1882.46 430.99 0.43 73192 PF 4(25 yr) 6952 192.25 200.01 0.000957 3.21 2238.03 463.90 0.44 73192 PF 5(50 yr) 8171 192.25 200.59 0.000958 3.39 2510.35 486.52 0.44 73192 PF 6(100 yr) 9469 192.25 201.14 0.000945 3.57 2788.43 518.61 0.45

72501.4* PF 1 (2yr) 2947 191.50 196.88 0.001017 2.39 1233.59 365.84 0.42 72501.4* PF 2(5 yr) 4386 191.50 197.90 0.001029 2.70 1627.38 406.31 0.43 72501.4* PF 3(10 yr) 5450 191.50 198.55 0.001032 2.87 1900.40 433.19 0.44 72501.4* PF 4(25 yr) 6952 191.50 199.35 0.001036 3.07 2262.32 466.17 0.45 72501.4* PF 5(50 yr) 8171 191.50 199.94 0.001025 3.22 2541.35 490.49 0.45 72501.4* PF 6(100 yr) 9469 191.50 200.51 0.001023 3.35 2829.74 524.04 0.45

71810.8* PF 1 (2yr) 2947 190.75 196.18 0.001017 2.38 1236.25 367.93 0.42 71810.8* PF 2(5 yr) 4386 190.75 197.19 0.001030 2.69 1628.35 407.16 0.43 71810.8* PF 3(10 yr) 5450 190.75 197.84 0.001033 2.87 1900.74 433.74 0.44 71810.8* PF 4(25 yr) 6952 190.75 198.64 0.001036 3.07 2261.66 465.95 0.45 71810.8* PF 5(50 yr) 8171 190.75 199.23 0.001039 3.21 2542.47 491.03 0.45 71810.8* PF 6(100 yr) 9469 190.75 199.80 0.001038 3.34 2832.74 525.29 0.46

71120.2* PF 1 (2yr) 2947 190.01 195.47 0.001021 2.38 1238.88 370.84 0.42 71120.2* PF 2(5 yr) 4386 190.01 196.48 0.001030 2.69 1629.55 407.98 0.43 71120.2* PF 3(10 yr) 5450 190.01 197.12 0.001035 2.87 1901.05 434.54 0.44 71120.2* PF 4(25 yr) 6952 190.01 197.92 0.001037 3.07 2261.02 465.84 0.45 71120.2* PF 5(50 yr) 8171 190.01 198.50 0.001044 3.22 2539.56 491.24 0.45 71120.2* PF 6(100 yr) 9469 190.01 199.09 0.001014 3.34 2837.00 526.83 0.45

70429.7* PF 1 (2yr) 2947 189.26 194.77 0.001022 2.37 1241.55 373.06 0.42 70429.7* PF 2(5 yr) 4386 189.26 195.77 0.001029 2.69 1631.40 408.70 0.43 70429.7* PF 3(10 yr) 5450 189.26 196.41 0.001034 2.87 1901.80 434.64 0.44 70429.7* PF 4(25 yr) 6952 189.26 197.20 0.001038 3.08 2260.53 465.81 0.45 70429.7* PF 5(50 yr) 8171 189.26 197.78 0.001050 3.22 2534.81 491.23 0.45 70429.7* PF 6(100 yr) 9469 189.26 198.37 0.001067 3.34 2836.92 528.01 0.46

69739.1* PF 1 (2yr) 2947 188.51 194.06 0.001026 2.37 1242.48 374.85 0.42 69739.1* PF 2(5 yr) 4386 188.51 195.06 0.001031 2.69 1632.11 409.65 0.43 69739.1* PF 3(10 yr) 5450 188.51 195.69 0.001035 2.87 1901.25 434.53 0.44 69739.1* PF 4(25 yr) 6952 188.51 196.48 0.001043 3.08 2257.59 465.98 0.45 69739.1* PF 5(50 yr) 8171 188.51 197.05 0.001047 3.23 2528.09 491.19 0.45 69739.1* PF 6(100 yr) 9469 188.51 197.64 0.001037 3.36 2827.29 528.39 0.46

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 136 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 69048.5* PF 1 (2yr) 2947 187.76 193.36 0.001026 2.37 1245.35 377.03 0.42 69048.5* PF 2(5 yr) 4386 187.76 194.34 0.001031 2.68 1634.29 411.08 0.43 69048.5* PF 3(10 yr) 5450 187.76 194.98 0.001032 2.86 1902.87 434.52 0.44 69048.5* PF 4(25 yr) 6952 187.76 195.77 0.001025 3.08 2258.99 466.38 0.44 69048.5* PF 5(50 yr) 8171 187.76 196.34 0.001013 3.24 2530.34 492.28 0.45 69048.5* PF 6(100 yr) 9469 187.76 196.93 0.001013 3.37 2831.28 530.37 0.45

68357.9* PF 1 (2yr) 2947 187.01 192.65 0.001029 2.36 1246.38 378.70 0.42 68357.9* PF 2(5 yr) 4386 187.01 193.63 0.001029 2.68 1635.33 411.22 0.43 68357.9* PF 3(10 yr) 5450 187.01 194.27 0.001032 2.86 1903.31 434.73 0.44 68357.9* PF 4(25 yr) 6952 187.01 195.07 0.001022 3.07 2263.10 467.23 0.44 68357.9* PF 5(50 yr) 8171 187.01 195.65 0.001004 3.22 2541.24 494.77 0.45 68357.9* PF 6(100 yr) 9469 187.01 196.23 0.001006 3.35 2843.63 533.78 0.45

67667.3* PF 1 (2yr) 2947 186.27 191.94 0.001033 2.37 1245.70 379.31 0.42 67667.3* PF 2(5 yr) 4386 186.27 192.92 0.001030 2.68 1635.63 411.65 0.43 67667.3* PF 3(10 yr) 5450 186.27 193.55 0.001035 2.86 1902.56 435.16 0.44 67667.3* PF 4(25 yr) 6952 186.27 194.35 0.001039 3.07 2264.01 468.15 0.45 67667.3* PF 5(50 yr) 8171 186.27 194.94 0.001052 3.21 2545.19 496.67 0.45 67667.3* PF 6(100 yr) 9469 186.27 195.52 0.001079 3.33 2845.06 536.14 0.46

66976.8* PF 1 (2yr) 2947 185.52 191.21 0.001058 2.38 1238.67 380.79 0.42 66976.8* PF 2(5 yr) 4386 185.52 192.21 0.001034 2.68 1634.60 412.13 0.43 66976.8* PF 3(10 yr) 5450 185.52 192.84 0.001041 2.87 1899.57 435.23 0.44 66976.8* PF 4(25 yr) 6952 185.52 193.63 0.001050 3.08 2258.58 468.77 0.45 66976.8* PF 5(50 yr) 8171 185.52 194.20 0.001069 3.23 2533.48 496.90 0.46 66976.8* PF 6(100 yr) 9469 185.52 194.76 0.001091 3.36 2824.04 554.27 0.46

66286.2* PF 1 (2yr) 2947 184.77 190.48 0.001048 2.39 1231.07 372.22 0.42 66286.2* PF 2(5 yr) 4386 184.77 191.49 0.001048 2.69 1629.05 412.74 0.43 66286.2* PF 3(10 yr) 5450 184.77 192.11 0.001056 2.88 1891.15 435.27 0.44 66286.2* PF 4(25 yr) 6952 184.77 192.89 0.001071 3.10 2245.51 468.98 0.45 66286.2* PF 5(50 yr) 8171 184.77 193.44 0.001099 3.26 2510.12 496.03 0.46 66286.2* PF 6(100 yr) 9469 184.77 193.98 0.001110 3.40 2801.15 576.03 0.47

65595.6* PF 1 (2yr) 2947 184.02 189.75 0.001054 2.40 1227.03 370.57 0.42 65595.6* PF 2(5 yr) 4386 184.02 190.76 0.001057 2.70 1625.89 413.32 0.43 65595.6* PF 3(10 yr) 5450 184.02 191.37 0.001069 2.89 1884.07 435.12 0.44 65595.6* PF 4(25 yr) 6952 184.02 192.14 0.001095 3.12 2230.19 468.69 0.46 65595.6* PF 5(50 yr) 8171 184.02 192.67 0.001110 3.29 2488.15 517.38 0.46 65595.6* PF 6(100 yr) 9469 184.02 193.20 0.001116 3.44 2786.16 602.28 0.47

64905.0* PF 1 (2yr) 2947 183.28 189.03 0.001050 2.41 1223.37 366.91 0.42 64905.0* PF 2(5 yr) 4386 183.28 190.01 0.001086 2.72 1612.16 413.04 0.44 64905.0* PF 3(10 yr) 5450 183.28 190.61 0.001104 2.92 1864.19 434.17 0.45 64905.0* PF 4(25 yr) 6952 183.28 191.35 0.001141 3.16 2196.96 472.01 0.47 64905.0* PF 5(50 yr) 8171 183.28 191.87 0.001138 3.34 2460.09 535.88 0.47 64905.0* PF 6(100 yr) 9469 183.28 192.39 0.001161 3.50 2764.15 637.24 0.48

64214.5* PF 1 (2yr) 2947 182.53 188.30 0.001057 2.41 1220.31 366.21 0.42 64214.5* PF 2(5 yr) 4386 182.53 189.29 0.001006 2.75 1609.49 413.17 0.43

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 137 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 64214.5* PF 3(10 yr) 5450 182.53 189.86 0.001003 2.99 1854.22 434.06 0.44 64214.5* PF 4(25 yr) 6952 182.53 190.55 0.001035 3.32 2165.94 490.75 0.45 64214.5* PF 5(50 yr) 8171 182.53 191.04 0.001059 3.56 2422.99 559.29 0.47 64214.5* PF 6(100 yr) 9469 182.53 191.52 0.001078 3.78 2711.88 629.07 0.48

63523.9* PF 1 (2yr) 2947 181.78 187.56 0.001070 2.43 1215.08 365.73 0.42 63523.9* PF 2(5 yr) 4386 181.78 188.56 0.001100 2.72 1611.19 416.25 0.44 63523.9* PF 3(10 yr) 5450 181.78 189.14 0.001114 2.93 1857.81 436.75 0.45 63523.9* PF 4(25 yr) 6952 181.78 189.83 0.001102 3.22 2185.93 523.03 0.46 63523.9* PF 5(50 yr) 8171 181.78 190.32 0.001100 3.43 2464.55 595.11 0.47 63523.9* PF 6(100 yr) 9469 181.78 190.81 0.001093 3.62 2762.91 636.29 0.47

62833.3* PF 1 (2yr) 2947 181.03 186.82 0.001054 2.44 1210.93 364.67 0.42 62833.3* PF 2(5 yr) 4386 181.03 187.79 0.001076 2.79 1590.48 414.93 0.44 62833.3* PF 3(10 yr) 5450 181.03 188.35 0.001097 3.03 1830.42 455.93 0.45 62833.3* PF 4(25 yr) 6952 181.03 189.03 0.001109 3.34 2171.31 562.25 0.47 62833.3* PF 5(50 yr) 8171 181.03 189.52 0.001113 3.55 2456.23 595.55 0.47 62833.3* PF 6(100 yr) 9469 181.03 190.00 0.001119 3.76 2751.14 638.44 0.48

62142.7* PF 1 (2yr) 2947 180.29 186.10 0.001059 2.44 1210.37 364.53 0.42 62142.7* PF 2(5 yr) 4386 180.29 187.04 0.001093 2.80 1579.85 423.24 0.44 62142.7* PF 3(10 yr) 5450 180.29 187.58 0.001099 3.06 1825.74 481.42 0.45 62142.7* PF 4(25 yr) 6952 180.29 188.26 0.001113 3.37 2183.84 567.65 0.47 62142.7* PF 5(50 yr) 8171 180.29 188.74 0.001118 3.58 2468.90 600.56 0.48 62142.7* PF 6(100 yr) 9469 180.29 189.22 0.001125 3.79 2763.21 640.80 0.48

61452.2* PF 1 (2yr) 2947 179.54 185.35 0.001091 2.44 1205.79 363.94 0.43 61452.2* PF 2(5 yr) 4386 179.54 186.27 0.001122 2.82 1568.77 445.87 0.45 61452.2* PF 3(10 yr) 5450 179.54 186.81 0.001123 3.07 1830.48 528.11 0.46 61452.2* PF 4(25 yr) 6952 179.54 187.49 0.001123 3.36 2200.10 572.60 0.47 61452.2* PF 5(50 yr) 8171 179.54 187.97 0.001125 3.57 2487.51 608.41 0.48 61452.2* PF 6(100 yr) 9469 179.54 188.45 0.001130 3.77 2784.10 649.98 0.48

60761.6* PF 1 (2yr) 2947 178.79 184.58 0.001116 2.47 1193.85 362.45 0.43 60761.6* PF 2(5 yr) 4386 178.79 185.48 0.001120 2.87 1555.00 470.07 0.45 60761.6* PF 3(10 yr) 5450 178.79 186.02 0.001124 3.12 1831.94 532.14 0.46 60761.6* PF 4(25 yr) 6952 178.79 186.69 0.001131 3.42 2202.54 579.11 0.47 60761.6* PF 5(50 yr) 8171 178.79 187.17 0.001140 3.64 2490.52 618.30 0.48 60761.6* PF 6(100 yr) 9469 178.79 187.64 0.001152 3.85 2786.17 659.70 0.49

60071.0* PF 1 (2yr) 2947 178.04 183.78 0.001164 2.51 1172.87 361.05 0.44 60071.0* PF 2(5 yr) 4386 178.04 184.69 0.001144 2.91 1554.13 494.22 0.46 60071.0* PF 3(10 yr) 5450 178.04 185.23 0.001139 3.15 1838.71 539.73 0.46 60071.0* PF 4(25 yr) 6952 178.04 185.90 0.001147 3.46 2213.00 590.14 0.48 60071.0* PF 5(50 yr) 8171 178.04 186.37 0.001159 3.68 2502.23 631.42 0.49 60071.0* PF 6(100 yr) 9469 178.04 186.84 0.001157 3.87 2802.61 647.80 0.49

59380.4* PF 1 (2yr) 2947 177.30 182.96 0.001179 2.58 1147.84 367.69 0.45 59380.4* PF 2(5 yr) 4386 177.30 183.89 0.001134 2.96 1558.49 493.75 0.46 59380.4* PF 3(10 yr) 5450 177.30 184.43 0.001140 3.22 1842.66 547.60 0.47 59380.4* PF 4(25 yr) 6952 177.30 185.08 0.001165 3.54 2215.31 602.97 0.48

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 138 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 59380.4* PF 5(50 yr) 8171 177.30 185.55 0.001168 3.74 2506.86 618.82 0.49 59380.4* PF 6(100 yr) 9469 177.30 186.02 0.001168 3.94 2800.57 632.54 0.50

58689.9* PF 1 (2yr) 2947 176.55 182.15 0.001132 2.62 1140.18 376.66 0.44 58689.9* PF 2(5 yr) 4386 176.55 183.07 0.001205 2.99 1560.76 501.94 0.47 58689.9* PF 3(10 yr) 5450 176.55 183.63 0.001186 3.23 1854.93 563.69 0.47 58689.9* PF 4(25 yr) 6952 176.55 184.27 0.001190 3.52 2231.32 591.24 0.48 58689.9* PF 5(50 yr) 8171 176.55 184.75 0.001185 3.72 2517.49 604.73 0.49 58689.9* PF 6(100 yr) 9469 176.55 185.22 0.001180 3.91 2805.80 617.57 0.50

56618.1* PF 1 (2yr) 2947 174.30 179.73 0.001218 2.60 1180.97 449.62 0.45 56618.1* PF 2(5 yr) 4386 174.30 180.55 0.001233 3.02 1572.42 483.89 0.47 56618.1* PF 3(10 yr) 5450 174.30 181.12 0.001246 3.21 1859.40 517.95 0.48 56618.1* PF 4(25 yr) 6952 174.30 181.80 0.001216 3.48 2218.75 547.10 0.49 56618.1* PF 5(50 yr) 8171 174.30 182.29 0.001199 3.67 2492.50 556.56 0.49 56618.1* PF 6(100 yr) 9469 174.30 182.78 0.001185 3.86 2770.01 570.12 0.50

55927.6* PF 1 (2yr) 2947 173.56 178.88 0.001230 2.63 1194.53 465.71 0.46 55927.6* PF 2(5 yr) 4386 173.56 179.69 0.001240 3.04 1577.96 470.50 0.47 55927.6* PF 3(10 yr) 5450 173.56 180.24 0.001261 3.27 1836.17 488.76 0.49 55927.6* PF 4(25 yr) 6952 173.56 180.94 0.001224 3.54 2189.40 521.75 0.49 55927.6* PF 5(50 yr) 8171 173.56 181.44 0.001210 3.74 2458.39 538.76 0.50 55927.6* PF 6(100 yr) 9469 173.56 181.94 0.001200 3.93 2729.95 552.95 0.50

55237.0* PF 1 (2yr) 2947 172.81 178.04 0.001213 2.63 1214.41 452.50 0.45 55237.0* PF 2(5 yr) 4386 172.81 178.83 0.001256 3.07 1575.65 456.80 0.48 55237.0* PF 3(10 yr) 5450 172.81 179.35 0.001271 3.33 1813.80 459.64 0.49 55237.0* PF 4(25 yr) 6952 172.81 180.06 0.001269 3.59 2152.30 496.12 0.50 55237.0* PF 5(50 yr) 8171 172.81 180.57 0.001252 3.80 2412.33 519.81 0.50 55237.0* PF 6(100 yr) 9469 172.81 181.07 0.001242 4.00 2676.07 534.91 0.51

54546.4* PF 1 (2yr) 2947 172.06 177.21 0.001293 2.39 1235.49 439.16 0.45 54546.4* PF 2(5 yr) 4386 172.06 178.01 0.001260 2.76 1587.50 443.53 0.47 54546.4* PF 3(10 yr) 5450 172.06 178.53 0.001233 2.99 1822.14 445.50 0.47 54546.4* PF 4(25 yr) 6952 172.06 179.24 0.001238 3.25 2140.85 471.54 0.48 54546.4* PF 5(50 yr) 8171 172.06 179.79 0.001178 3.41 2406.40 503.66 0.48 54546.4* PF 6(100 yr) 9469 172.06 180.31 0.001146 3.59 2671.77 519.53 0.48

53855.8* PF 1 (2yr) 2947 171.31 176.31 0.001279 2.41 1223.88 425.26 0.45 53855.8* PF 2(5 yr) 4386 171.31 177.14 0.001237 2.78 1575.93 429.30 0.46 53855.8* PF 3(10 yr) 5450 171.31 177.69 0.001208 3.01 1811.55 431.28 0.47 53855.8* PF 4(25 yr) 6952 171.31 178.40 0.001173 3.28 2120.71 433.85 0.47 53855.8* PF 5(50 yr) 8171 171.31 178.98 0.001145 3.44 2383.12 479.25 0.47 53855.8* PF 6(100 yr) 9469 171.31 179.51 0.001116 3.61 2648.99 503.23 0.48

53165.3* PF 1 (2yr) 2947 170.57 175.44 0.001245 2.42 1218.02 411.80 0.45 53165.3* PF 2(5 yr) 4386 170.57 176.30 0.001182 2.79 1574.38 415.19 0.46 53165.3* PF 3(10 yr) 5450 170.57 176.87 0.001147 3.01 1812.57 417.22 0.46 53165.3* PF 4(25 yr) 6952 170.57 177.61 0.001113 3.28 2121.15 419.83 0.46 53165.3* PF 5(50 yr) 8171 170.57 178.18 0.001136 3.46 2363.95 451.47 0.47 53165.3* PF 6(100 yr) 9469 170.57 178.75 0.001094 3.63 2630.96 487.41 0.47

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 139 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

52474.7* PF 1 (2yr) 2947 169.82 174.61 0.001154 2.40 1228.97 398.12 0.44 52474.7* PF 2(5 yr) 4386 169.82 175.52 0.001084 2.75 1593.55 401.31 0.44 52474.7* PF 3(10 yr) 5450 169.82 176.12 0.001056 2.98 1832.66 403.38 0.44 52474.7* PF 4(25 yr) 6952 169.82 176.87 0.001035 3.26 2138.69 406.03 0.45 52474.7* PF 5(50 yr) 8171 169.82 177.43 0.001027 3.46 2366.75 407.99 0.46 52474.7* PF 6(100 yr) 9469 169.82 178.02 0.001007 3.65 2626.40 472.76 0.46

51784.1* PF 1 (2yr) 2947 169.07 173.91 0.000954 2.30 1282.41 384.55 0.40 51784.1* PF 2(5 yr) 4386 169.07 174.85 0.000928 2.67 1646.26 387.80 0.41 51784.1* PF 3(10 yr) 5450 169.07 175.45 0.000926 2.90 1880.50 389.88 0.42 51784.1* PF 4(25 yr) 6952 169.07 176.21 0.000933 3.20 2176.67 392.49 0.43 51784.1* PF 5(50 yr) 8171 169.07 176.77 0.000942 3.42 2395.75 394.41 0.44 51784.1* PF 6(100 yr) 9469 169.07 177.35 0.000936 3.62 2644.70 460.43 0.45

51093.5* PF 1 (2yr) 2947 168.32 173.37 0.000698 2.12 1392.71 372.41 0.35 51093.5* PF 2(5 yr) 4386 168.32 174.29 0.000772 2.53 1736.62 383.80 0.38 51093.5* PF 3(10 yr) 5450 168.32 174.88 0.000804 2.77 1968.03 394.58 0.39 51093.5* PF 4(25 yr) 6952 168.32 175.63 0.000823 3.07 2305.43 511.69 0.41 51093.5* PF 5(50 yr) 8171 168.32 176.20 0.000825 3.26 2602.80 543.77 0.41 51093.5* PF 6(100 yr) 9469 168.32 176.80 0.000839 3.40 2956.46 617.74 0.42

50576.5 Bridge

50403 PF 1 (2yr) 2947 167.58 170.58 0.006696 4.28 688.07 348.94 0.97 50403 PF 2(5 yr) 4386 167.58 171.24 0.005752 4.77 918.93 353.20 0.94 50403 PF 3(10 yr) 5450 167.58 171.63 0.005575 5.15 1058.59 354.53 0.95 50403 PF 4(25 yr) 6952 167.58 172.13 0.005489 5.64 1233.40 356.18 0.97 50403 PF 5(50 yr) 8171 167.58 172.48 0.005506 6.01 1359.81 357.37 0.98 50403 PF 6(100 yr) 9469 167.58 172.84 0.005510 6.37 1487.62 358.57 1.00

50215 PF 1 (2yr) 2947 166.58 170.41 0.001693 2.70 1091.73 395.02 0.52 50215 PF 2(5 yr) 4386 166.58 171.15 0.001720 3.17 1385.57 399.12 0.54 50215 PF 3(10 yr) 5450 166.58 171.59 0.001795 3.49 1562.35 401.57 0.56 50215 PF 4(25 yr) 6952 166.58 172.15 0.001883 3.89 1788.05 404.68 0.59 50215 PF 5(50 yr) 8171 166.58 172.56 0.001947 4.18 1955.06 406.96 0.61 50215 PF 6(100 yr) 9469 166.58 172.97 0.002014 4.47 2119.33 409.19 0.63

48583 PF 1 (2yr) 2947 164.38 167.87 0.001534 2.25 1309.82 578.60 0.48 48583 PF 2(5 yr) 4386 164.38 168.44 0.001744 2.65 1655.97 630.83 0.52 48583 PF 3(10 yr) 5450 164.38 168.80 0.001804 2.89 1884.93 645.61 0.54 48583 PF 4(25 yr) 6952 164.38 169.22 0.001927 3.22 2161.61 663.04 0.57 48583 PF 5(50 yr) 8171 164.38 169.52 0.002039 3.46 2358.68 675.17 0.59 48583 PF 6(100 yr) 9469 164.38 169.78 0.002157 3.73 2553.06 905.76 0.62

47002 PF 1 (2yr) 2947 161.51 165.56 0.001392 2.26 1307.97 552.19 0.46 47002 PF 2(5 yr) 4386 161.51 166.08 0.001354 2.52 2038.08 1035.83 0.47 47002 PF 3(10 yr) 5450 161.51 166.43 0.001354 2.71 2410.66 1105.08 0.48 47002 PF 4(25 yr) 6952 161.51 166.86 0.001319 2.91 3061.23 1502.72 0.48 47002 PF 5(50 yr) 8171 161.51 167.19 0.001281 3.03 3562.71 1607.73 0.48 47002 PF 6(100 yr) 9469 161.51 167.51 0.001230 3.13 4098.61 1684.76 0.48

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 140 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

46382 PF 1 (2yr) 2947 161.14 163.39 0.008055 3.60 818.11 619.03 1.00 46382 PF 2(5 yr) 4386 161.14 163.80 0.007417 4.08 1074.42 633.40 1.00 46382 PF 3(10 yr) 5450 161.14 164.07 0.007088 4.36 1249.53 644.62 1.00 46382 PF 4(25 yr) 6952 161.14 164.43 0.006751 4.69 1481.74 660.56 1.00 46382 PF 5(50 yr) 8171 161.14 164.70 0.006556 4.91 1662.93 676.66 1.00 46382 PF 6(100 yr) 9469 161.14 164.96 0.006482 5.15 1839.36 691.98 1.01

44672 PF 1 (2yr) 2947 157.31 160.10 0.000971 1.30 2275.05 1633.84 0.35 44672 PF 2(5 yr) 4386 157.31 160.54 0.000882 1.47 2986.06 1663.33 0.35 44672 PF 3(10 yr) 5450 157.31 160.82 0.000838 1.58 3461.63 1682.25 0.35 44672 PF 4(25 yr) 6952 157.31 161.19 0.000792 1.71 4087.58 1706.83 0.35 44672 PF 5(50 yr) 8171 157.31 161.47 0.000767 1.80 4562.55 1725.25 0.35 44672 PF 6(100 yr) 9469 157.31 161.74 0.000731 1.88 5193.01 1926.24 0.35

43734 PF 1 (2yr) 2947 155.61 159.52 0.000465 1.02 2889.32 1788.66 0.25 43734 PF 2(5 yr) 4386 155.61 159.98 0.000458 1.19 3732.85 1851.23 0.26 43734 PF 3(10 yr) 5450 155.61 160.29 0.000454 1.29 4296.37 1877.86 0.26 43734 PF 4(25 yr) 6952 155.61 160.68 0.000448 1.41 5036.10 1907.47 0.27 43734 PF 5(50 yr) 8171 155.61 160.97 0.000446 1.50 5590.88 1934.91 0.27 43734 PF 6(100 yr) 9469 155.61 161.25 0.000445 1.59 6151.34 1964.98 0.28

41794 PF 1 (2yr) 2947 155.20 158.69 0.000399 0.97 3101.31 1891.60 0.23 41794 PF 2(5 yr) 4386 155.20 159.18 0.000385 1.12 4046.60 1968.75 0.24 41794 PF 3(10 yr) 5450 155.20 159.49 0.000381 1.22 4669.38 2016.06 0.24 41794 PF 4(25 yr) 6952 155.20 159.89 0.000377 1.33 5487.35 2076.55 0.25 41794 PF 5(50 yr) 8171 155.20 160.19 0.000375 1.41 6104.62 2121.06 0.25 41794 PF 6(100 yr) 9469 155.20 160.47 0.000376 1.50 6724.30 2164.83 0.25

40074 PF 1 (2yr) 2947 153.10 157.33 0.001436 2.17 1606.60 1307.82 0.46 40074 PF 2(5 yr) 4386 153.10 157.94 0.001155 2.29 2524.68 1667.65 0.43 40074 PF 3(10 yr) 5450 153.10 158.30 0.001053 2.37 3149.07 1797.98 0.42 40074 PF 4(25 yr) 6952 153.10 158.75 0.000964 2.47 4000.21 2003.92 0.41 40074 PF 5(50 yr) 8171 153.10 159.07 0.000915 2.54 4666.24 2150.31 0.41 40074 PF 6(100 yr) 9469 153.10 159.38 0.000878 2.62 5353.13 2291.50 0.40

37538 PF 1 (2yr) 2947 150.64 155.50 0.000463 1.47 2132.81 949.28 0.27 37538 PF 2(5 yr) 4386 150.64 156.13 0.000511 1.76 2845.13 1341.81 0.30 37538 PF 3(10 yr) 5450 150.64 156.50 0.000535 1.92 3365.50 1466.39 0.31 37538 PF 4(25 yr) 6952 150.64 156.92 0.000577 2.13 4007.70 1586.61 0.33 37538 PF 5(50 yr) 8171 150.64 157.23 0.000602 2.28 4509.58 1674.56 0.34 37538 PF 6(100 yr) 9469 150.64 157.53 0.000623 2.42 5028.31 1760.85 0.35

35903 PF 1 (2yr) 2947 150.16 154.05 0.001698 2.24 1406.34 875.93 0.50 35903 PF 2(5 yr) 4386 150.16 154.72 0.001370 2.43 2108.51 1288.03 0.47 35903 PF 3(10 yr) 5450 150.16 155.12 0.001236 2.53 2696.83 1619.42 0.45 35903 PF 4(25 yr) 6952 150.16 155.62 0.001071 2.59 3538.44 1759.88 0.43 35903 PF 5(50 yr) 8171 150.16 155.97 0.000996 2.65 4169.29 1865.11 0.42 35903 PF 6(100 yr) 9469 150.16 156.31 0.000937 2.72 4836.02 2004.99 0.42

PRTW.07 34889 PF 1 (2yr) 2947 149.27 153.29 0.000504 1.54 1983.83 822.09 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 141 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 34889 PF 2(5 yr) 4386 149.27 154.00 0.000521 1.80 2614.82 926.96 0.30 34889 PF 3(10 yr) 5450 149.27 154.40 0.000554 1.99 2994.78 967.19 0.32 34889 PF 4(25 yr) 6952 149.27 154.88 0.000601 2.23 3470.58 1013.77 0.34 34889 PF 5(50 yr) 8171 149.27 155.21 0.000646 2.41 3802.72 1044.45 0.35 34889 PF 6(100 yr) 9469 149.27 155.51 0.000693 2.60 4127.26 1073.59 0.37

34467 PF 1 (2yr) 2947 148.83 152.84 0.001183 2.18 1467.33 785.84 0.43 34467 PF 2(5 yr) 4386 148.83 153.55 0.001090 2.43 2078.41 933.59 0.43 34467 PF 3(10 yr) 5450 148.83 153.97 0.001018 2.54 2684.71 1286.78 0.42 34467 PF 4(25 yr) 6952 148.83 154.47 0.000974 2.70 3345.61 1380.52 0.42 34467 PF 5(50 yr) 8171 148.83 154.79 0.000974 2.84 3800.20 1422.09 0.43 34467 PF 6(100 yr) 9469 148.83 155.10 0.000984 2.98 4241.92 1461.35 0.43

34097 PF 1 (2yr) 2947 147.50 151.21 0.007247 4.24 695.55 380.87 1.00 34097 PF 2(5 yr) 4386 147.50 151.82 0.006706 4.69 935.88 415.61 1.00 34097 PF 3(10 yr) 5450 147.50 152.30 0.005633 4.74 1186.18 677.68 0.94 34097 PF 4(25 yr) 6952 147.50 152.80 0.004837 4.94 1559.70 833.91 0.89 34097 PF 5(50 yr) 8171 147.50 153.19 0.004250 5.00 1894.57 899.38 0.85 34097 PF 6(100 yr) 9469 147.50 153.54 0.003872 5.09 2274.16 1093.64 0.83

32686 PF 1 (2yr) 2947 145.26 150.20 0.000363 1.22 2773.33 1376.31 0.24 32686 PF 2(5 yr) 4386 145.26 150.73 0.000409 1.46 3576.70 1621.74 0.26 32686 PF 3(10 yr) 5450 145.26 151.06 0.000428 1.60 4149.33 1794.90 0.27 32686 PF 4(25 yr) 6952 145.26 151.48 0.000447 1.76 4915.81 1888.24 0.28 32686 PF 5(50 yr) 8171 145.26 151.79 0.000457 1.87 5507.70 1952.20 0.29 32686 PF 6(100 yr) 9469 145.26 152.10 0.000464 1.97 6114.99 2013.42 0.30

30075 PF 1 (2yr) 2947 144.58 148.89 0.000753 1.57 2486.12 1857.62 0.33 30075 PF 2(5 yr) 4386 144.58 149.42 0.000682 1.72 3493.41 1966.30 0.33 30075 PF 3(10 yr) 5450 144.58 149.76 0.000646 1.81 4174.72 2036.52 0.33 30075 PF 4(25 yr) 6952 144.58 150.20 0.000608 1.92 5080.91 2126.33 0.32 30075 PF 5(50 yr) 8171 144.58 150.52 0.000585 1.99 5778.75 2192.99 0.32 30075 PF 6(100 yr) 9469 144.58 150.83 0.000572 2.07 6470.54 2257.13 0.32

27652 PF 1 (2yr) 2947 141.57 146.58 0.001150 1.89 1629.25 818.50 0.41 27652 PF 2(5 yr) 4386 141.57 147.12 0.001223 2.22 2090.90 883.81 0.44 27652 PF 3(10 yr) 5450 141.57 147.46 0.001268 2.42 2400.04 924.97 0.45 27652 PF 4(25 yr) 6952 141.57 147.89 0.001320 2.67 2805.73 976.36 0.47 27652 PF 5(50 yr) 8171 141.57 148.20 0.001357 2.84 3114.23 1013.70 0.48 27652 PF 6(100 yr) 9469 141.57 148.50 0.001381 3.02 3426.32 1106.37 0.49

27200.6* PF 1 (2yr) 2947 141.41 146.07 0.001179 1.83 1668.90 889.29 0.41 27200.6* PF 2(5 yr) 4386 141.41 146.58 0.001246 2.14 2145.66 955.08 0.44 27200.6* PF 3(10 yr) 5450 141.41 146.91 0.001281 2.33 2465.29 994.72 0.45 27200.6* PF 4(25 yr) 6952 141.41 147.32 0.001312 2.56 2886.18 1040.64 0.47 27200.6* PF 5(50 yr) 8171 141.41 147.63 0.001333 2.72 3204.68 1071.91 0.48 27200.6* PF 6(100 yr) 9469 141.41 147.92 0.001341 2.89 3522.88 1098.32 0.48

26749.3* PF 1 (2yr) 2947 141.25 145.54 0.001220 1.78 1710.06 974.01 0.41 26749.3* PF 2(5 yr) 4386 141.25 146.04 0.001250 2.06 2216.30 1047.43 0.43 26749.3* PF 3(10 yr) 5450 141.25 146.36 0.001259 2.23 2559.87 1090.54 0.44

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 142 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 26749.3* PF 4(25 yr) 6952 141.25 146.78 0.001248 2.43 3023.91 1140.90 0.45 26749.3* PF 5(50 yr) 8171 141.25 147.08 0.001241 2.58 3378.56 1176.18 0.46 26749.3* PF 6(100 yr) 9469 141.25 147.38 0.001224 2.71 3738.62 1205.91 0.46

26298.0* PF 1 (2yr) 2947 141.09 145.00 0.001237 1.72 1757.84 1068.50 0.41 26298.0* PF 2(5 yr) 4386 141.09 145.51 0.001186 1.96 2338.85 1199.54 0.42 26298.0* PF 3(10 yr) 5450 141.09 145.85 0.001128 2.09 2765.25 1279.83 0.42 26298.0* PF 4(25 yr) 6952 141.09 146.30 0.001051 2.23 3365.56 1383.98 0.41 26298.0* PF 5(50 yr) 8171 141.09 146.63 0.001002 2.33 3835.69 1455.93 0.41 26298.0* PF 6(100 yr) 9469 141.09 146.96 0.000956 2.43 4326.08 1524.63 0.41

25846.6* PF 1 (2yr) 2947 140.93 144.46 0.001189 1.64 1832.32 1145.52 0.40 25846.6* PF 2(5 yr) 4386 140.93 145.05 0.000970 1.79 2531.71 1218.91 0.38 25846.6* PF 3(10 yr) 5450 140.93 145.43 0.000886 1.88 3008.38 1265.40 0.37 25846.6* PF 4(25 yr) 6952 140.93 145.92 0.000804 2.00 3645.12 1321.06 0.36 25846.6* PF 5(50 yr) 8171 140.93 146.28 0.000764 2.10 4117.49 1355.05 0.36 25846.6* PF 6(100 yr) 9469 140.93 146.62 0.000735 2.19 4592.38 1388.62 0.36

25395.3* PF 1 (2yr) 2947 140.77 144.01 0.000921 1.47 2035.46 1238.70 0.35 25395.3* PF 2(5 yr) 4386 140.77 144.73 0.000639 1.53 2967.75 1340.47 0.31 25395.3* PF 3(10 yr) 5450 140.77 145.15 0.000577 1.60 3543.85 1397.76 0.30 25395.3* PF 4(25 yr) 6952 140.77 145.68 0.000522 1.71 4296.62 1459.44 0.30 25395.3* PF 5(50 yr) 8171 140.77 146.05 0.000501 1.79 4842.65 1500.45 0.30 25395.3* PF 6(100 yr) 9469 140.77 146.41 0.000486 1.88 5498.19 1984.31 0.30

24944 PF 1 (2yr) 2947 140.61 143.73 0.000520 1.20 2478.57 1314.84 0.27 24944 PF 2(5 yr) 4386 140.61 144.54 0.000363 1.25 3596.85 1421.49 0.24 24944 PF 3(10 yr) 5450 140.61 144.98 0.000340 1.33 4231.78 1470.10 0.24 24944 PF 4(25 yr) 6952 140.61 145.53 0.000323 1.44 5044.80 1528.44 0.24 24944 PF 5(50 yr) 8171 140.61 145.91 0.000309 1.50 5964.39 1992.43 0.24 24944 PF 6(100 yr) 9469 140.61 146.27 0.000303 1.58 6711.34 2072.69 0.24

23188 PF 1 (2yr) 2947 139.01 143.54 0.000057 0.59 5350.52 1816.06 0.10 23188 PF 2(5 yr) 4386 139.01 144.37 0.000060 0.70 6902.86 1975.69 0.11 23188 PF 3(10 yr) 5450 139.01 144.80 0.000067 0.79 7784.30 2112.88 0.11 23188 PF 4(25 yr) 6952 139.01 145.34 0.000074 0.89 8956.80 2276.33 0.12 23188 PF 5(50 yr) 8171 139.01 145.71 0.000080 0.96 9829.66 2390.76 0.13 23188 PF 6(100 yr) 9469 139.01 146.07 0.000086 1.04 10711.29 2501.03 0.13

21140 PF 1 (2yr) 3664 138.11 143.08 0.000624 1.83 2267.37 1091.49 0.32 21140 PF 2(5 yr) 5414 138.11 143.88 0.000576 2.03 3271.42 1388.91 0.32 21140 PF 3(10 yr) 6649 138.11 144.27 0.000588 2.19 3824.30 1436.52 0.33 21140 PF 4(25 yr) 8389 138.11 144.76 0.000604 2.37 4537.16 1498.48 0.34 21140 PF 5(50 yr) 9752 138.11 145.09 0.000618 2.51 5055.64 1584.34 0.35 21140 PF 6(100 yr) 11194 138.11 145.42 0.000633 2.64 5581.84 1669.18 0.36

20425 Bridge

20348 PF 1 (2yr) 3664 136.98 140.38 0.001926 3.09 1378.04 789.66 0.56 PRTW.08 20348 PF 2(5 yr) 5414 136.98 141.07 0.001780 3.38 2176.14 1358.53 0.56 20348 PF 3(10 yr) 6649 136.98 141.48 0.001652 3.49 2782.51 1617.57 0.55

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 143 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 20348 PF 4(25 yr) 8389 136.98 142.00 0.001472 3.56 3702.84 1945.75 0.53 20348 PF 5(50 yr) 9752 136.98 142.36 0.001353 3.59 4451.84 2176.74 0.51 20348 PF 6(100 yr) 11194 136.98 142.71 0.001249 3.61 5258.14 2400.70 0.50

19845 PF 1 (2yr) 3664 136.03 140.11 0.000588 1.74 2244.38 1085.32 0.31 19845 PF 2(5 yr) 5414 136.03 140.81 0.000604 2.02 3159.10 1497.01 0.33 19845 PF 3(10 yr) 6649 136.03 141.22 0.000608 2.16 3806.82 1701.75 0.33 19845 PF 4(25 yr) 8389 136.03 141.73 0.000604 2.33 4745.34 1986.01 0.34 19845 PF 5(50 yr) 9752 136.03 142.09 0.000595 2.42 5497.71 2190.81 0.34 19845 PF 6(100 yr) 11194 136.03 142.44 0.000585 2.51 6296.41 2387.72 0.34

19296 PF 1 (2yr) 3664 135.18 139.76 0.000589 1.99 2403.11 1298.84 0.32 19296 PF 2(5 yr) 5414 135.18 140.46 0.000608 2.26 3443.70 1657.89 0.34 19296 PF 3(10 yr) 6649 135.18 140.89 0.000596 2.37 4170.47 1779.75 0.34 19296 PF 4(25 yr) 8389 135.18 141.42 0.000579 2.50 5152.04 1931.45 0.34 19296 PF 5(50 yr) 9752 135.18 141.79 0.000569 2.59 5885.64 2035.88 0.34 19296 PF 6(100 yr) 11194 135.18 142.14 0.000562 2.68 6627.90 2136.36 0.34

18840 PF 1 (2yr) 3664 135.10 139.51 0.000585 1.84 2565.53 1596.39 0.32 18840 PF 2(5 yr) 5414 135.10 140.25 0.000526 1.99 3799.91 1770.25 0.31 18840 PF 3(10 yr) 6649 135.10 140.68 0.000502 2.07 4592.71 1873.41 0.31 18840 PF 4(25 yr) 8389 135.10 141.22 0.000479 2.18 5639.95 2001.56 0.31 18840 PF 5(50 yr) 9752 135.10 141.60 0.000469 2.26 6407.73 2090.52 0.31 18840 PF 6(100 yr) 11194 135.10 141.96 0.000463 2.34 7173.61 2175.65 0.31

18406 PF 1 (2yr) 3664 135.06 139.46 0.000185 1.08 4674.98 1995.47 0.18 18406 PF 2(5 yr) 5414 135.06 140.20 0.000184 1.22 6183.76 2095.42 0.18 18406 PF 3(10 yr) 6649 135.06 140.63 0.000187 1.30 7109.61 2154.47 0.19 18406 PF 4(25 yr) 8389 135.06 141.17 0.000191 1.42 8293.69 2227.70 0.19 18406 PF 5(50 yr) 9752 135.06 141.55 0.000196 1.50 9137.76 2278.46 0.20 18406 PF 6(100 yr) 11194 135.06 141.91 0.000201 1.58 9962.06 2326.97 0.20

17785 PF 1 (2yr) 3664 134.42 139.39 0.000102 0.83 5740.03 2279.85 0.13 17785 PF 2(5 yr) 5414 134.42 140.13 0.000109 0.96 7491.10 2477.10 0.14 17785 PF 3(10 yr) 6649 134.42 140.56 0.000113 1.04 8592.73 2593.52 0.15 17785 PF 4(25 yr) 8389 134.42 141.10 0.000119 1.14 10029.71 2737.96 0.15 17785 PF 5(50 yr) 9752 134.42 141.48 0.000123 1.21 11071.19 2838.04 0.16 17785 PF 6(100 yr) 11194 134.42 141.83 0.000128 1.28 12100.63 2933.62 0.16

17069 PF 1 (2yr) 3664 133.91 139.34 0.000066 0.72 6613.63 2358.93 0.11 17069 PF 2(5 yr) 5414 133.91 140.07 0.000076 0.85 8394.73 2513.97 0.12 17069 PF 3(10 yr) 6649 133.91 140.50 0.000081 0.94 9498.63 2605.44 0.13 17069 PF 4(25 yr) 8389 133.91 141.04 0.000089 1.04 10923.09 2718.92 0.14 17069 PF 5(50 yr) 9752 133.91 141.41 0.000094 1.11 11945.20 2797.51 0.14 17069 PF 6(100 yr) 11194 133.91 141.76 0.000099 1.18 12947.47 2872.49 0.15

16550 PF 1 (2yr) 3664 133.78 139.31 0.000053 0.67 7191.98 2249.52 0.10 16550 PF 2(5 yr) 5414 133.78 140.04 0.000064 0.81 8871.73 2379.64 0.11 16550 PF 3(10 yr) 6649 133.78 140.47 0.000071 0.90 9906.57 2456.37 0.12 16550 PF 4(25 yr) 8389 133.78 141.00 0.000080 1.01 11236.10 2551.56 0.13 16550 PF 5(50 yr) 9752 133.78 141.37 0.000086 1.09 12186.04 2617.46 0.14

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 144 Feasibility Report: West Rapti Basin

16053 PF 1 (2yr) 3664 133.51 139.27 0.000127 0.92 6113.17 2633.13 0.15 16053 PF 2(5 yr) 5414 133.51 139.99 0.000128 1.03 8098.23 2857.14 0.16 16053 PF 3(10 yr) 6649 133.51 140.41 0.000130 1.11 9345.35 2989.29 0.16 16053 PF 4(25 yr) 8389 133.51 140.94 0.000133 1.20 10972.70 3153.43 0.16 16053 PF 5(50 yr) 9752 133.51 141.31 0.000136 1.26 12150.48 3267.08 0.17 16053 PF 6(100 yr) 11194 133.51 141.66 0.000139 1.33 13311.57 3375.38 0.17

15483 PF 1 (2yr) 3664 133.30 139.18 0.000146 0.96 5420.98 2234.36 0.16 15483 PF 2(5 yr) 5414 133.30 139.90 0.000151 1.10 7083.28 2390.66 0.17 15483 PF 3(10 yr) 6649 133.30 140.32 0.000155 1.19 8113.60 2482.60 0.17 15483 PF 4(25 yr) 8389 133.30 140.85 0.000161 1.30 9445.95 2596.67 0.18 15483 PF 5(50 yr) 9752 133.30 141.21 0.000166 1.38 10401.67 2675.51 0.18 15483 PF 6(100 yr) 11194 133.30 141.56 0.000172 1.46 11336.70 2750.45 0.19

14747 PF 1 (2yr) 3664 133.27 138.99 0.000338 1.38 4033.25 2444.41 0.24 14747 PF 2(5 yr) 5414 133.27 139.73 0.000273 1.41 5933.94 2662.97 0.22 14747 PF 3(10 yr) 6649 133.27 140.16 0.000254 1.45 7104.19 2780.62 0.22 14747 PF 4(25 yr) 8389 133.27 140.69 0.000239 1.52 8617.68 2925.78 0.22 14747 PF 5(50 yr) 9752 133.27 141.05 0.000233 1.57 9702.49 3025.54 0.22 14747 PF 6(100 yr) 11194 133.27 141.40 0.000231 1.63 10762.57 3119.95 0.22

14000 PF 1 (2yr) 3664 133.01 138.97 0.000031 0.47 9915.50 3016.71 0.08 14000 PF 2(5 yr) 5414 133.01 139.71 0.000039 0.59 12222.58 3291.33 0.09 14000 PF 3(10 yr) 6649 133.01 140.13 0.000044 0.66 13656.32 3449.26 0.09 14000 PF 4(25 yr) 8389 133.01 140.66 0.000049 0.74 15519.38 3628.12 0.10 14000 PF 5(50 yr) 9752 133.01 141.02 0.000053 0.80 16853.11 3742.15 0.10 14000 PF 6(100 yr) 11194 133.01 141.36 0.000057 0.86 18153.24 3850.91 0.11

13016 PF 1 (2yr) 3664 132.90 138.69 0.000761 2.10 2351.10 1319.07 0.36 13016 PF 2(5 yr) 5414 132.90 139.38 0.000735 2.33 3373.63 1629.63 0.37 13016 PF 3(10 yr) 6649 132.90 139.79 0.000716 2.45 4069.87 1778.41 0.37 13016 PF 4(25 yr) 8389 132.90 140.29 0.000711 2.61 5003.29 2002.43 0.37 13016 PF 5(50 yr) 9752 132.90 140.63 0.000710 2.73 5724.71 2197.92 0.38 13016 PF 6(100 yr) 11194 132.90 140.97 0.000689 2.80 6476.54 2294.16 0.37

12081 PF 1 (2yr) 3664 132.60 138.38 0.000256 1.45 3578.64 1614.14 0.22 12081 PF 2(5 yr) 5414 132.60 139.05 0.000291 1.70 4710.52 1777.59 0.24 12081 PF 3(10 yr) 6649 132.60 139.44 0.000311 1.84 5426.59 1873.64 0.25 12081 PF 4(25 yr) 8389 132.60 139.92 0.000335 2.02 6356.19 1991.44 0.26 12081 PF 5(50 yr) 9752 132.60 140.25 0.000348 2.14 7029.48 2040.86 0.27 12081 PF 6(100 yr) 11194 132.60 140.58 0.000360 2.25 7700.66 2087.08 0.28

11157 PF 1 (2yr) 3664 132.40 138.08 0.000397 1.42 2966.88 1538.86 0.26 11157 PF 2(5 yr) 5414 132.40 138.72 0.000414 1.64 3988.03 1650.22 0.27 11157 PF 3(10 yr) 6649 132.40 139.09 0.000427 1.78 4617.47 1710.16 0.28 11157 PF 4(25 yr) 8389 132.40 139.55 0.000445 1.95 5416.18 1783.33 0.29 11157 PF 5(50 yr) 9752 132.40 139.87 0.000460 2.07 5987.16 1833.84 0.30 11157 PF 6(100 yr) 11194 132.40 140.17 0.000475 2.19 6558.78 1883.05 0.31

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 145 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 10061 PF 1 (2yr) 3664 132.21 137.59 0.000468 1.78 3194.23 1558.23 0.29 10061 PF 2(5 yr) 5414 132.21 138.20 0.000509 2.05 4190.14 1707.12 0.31 10061 PF 3(10 yr) 6649 132.21 138.56 0.000535 2.21 4810.20 1790.68 0.32 10061 PF 4(25 yr) 8389 132.21 138.99 0.000572 2.41 5598.99 1891.64 0.34 10061 PF 5(50 yr) 9752 132.21 139.28 0.000600 2.56 6163.53 1960.70 0.35 10061 PF 6(100 yr) 11194 132.21 139.57 0.000625 2.71 6736.52 2028.40 0.36

9077 PF 1 (2yr) 3664 132.21 136.89 0.000832 2.16 2291.12 1475.05 0.38 9077 PF 2(5 yr) 5414 132.21 137.40 0.000948 2.53 3109.51 1738.13 0.41 9077 PF 3(10 yr) 6649 132.21 137.71 0.000992 2.73 3670.77 1897.03 0.43 9077 PF 4(25 yr) 8389 132.21 138.10 0.001017 2.93 4447.89 2068.14 0.44 9077 PF 5(50 yr) 9752 132.21 138.38 0.001013 3.04 5034.28 2130.10 0.44 9077 PF 6(100 yr) 11194 132.21 138.66 0.001005 3.14 5637.02 2191.96 0.44

8282 PF 1 (2yr) 3664 131.87 136.14 0.001133 1.99 2449.26 1844.73 0.41 8282 PF 2(5 yr) 5414 131.87 136.67 0.001002 2.14 3459.15 1944.19 0.40 8282 PF 3(10 yr) 6649 131.87 137.00 0.000944 2.23 4101.89 1992.72 0.40 8282 PF 4(25 yr) 8389 131.87 137.41 0.000893 2.35 4935.22 2053.93 0.39 8282 PF 5(50 yr) 9752 131.87 137.70 0.000869 2.44 5538.72 2097.15 0.39 8282 PF 6(100 yr) 11194 131.87 137.99 0.000847 2.53 6155.17 2140.40 0.39

7734 PF 1 (2yr) 3664 131.12 135.11 0.002328 2.55 1484.85 918.72 0.58 7734 PF 2(5 yr) 5414 131.12 135.55 0.002514 3.02 1917.21 1048.61 0.62 7734 PF 3(10 yr) 6649 131.12 135.80 0.002662 3.32 2193.08 1145.25 0.65 7734 PF 4(25 yr) 8389 131.12 136.10 0.002868 3.70 2556.10 1264.77 0.68 7734 PF 5(50 yr) 9752 131.12 136.31 0.003020 3.97 2824.83 1346.98 0.71 7734 PF 6(100 yr) 11194 131.12 136.50 0.003169 4.23 3097.48 1424.51 0.73

7233 PF 1 (2yr) 3664 130.80 134.46 0.001050 2.05 2474.72 1915.01 0.40 7233 PF 2(5 yr) 5414 130.80 135.00 0.000961 2.22 3593.26 2226.80 0.40 7233 PF 3(10 yr) 6649 130.80 135.28 0.000964 2.36 4251.36 2380.52 0.41 7233 PF 4(25 yr) 8389 130.80 135.63 0.000972 2.52 5105.87 2547.53 0.41 7233 PF 5(50 yr) 9752 130.80 135.87 0.000985 2.65 5723.36 2661.70 0.42 7233 PF 6(100 yr) 11194 130.80 136.10 0.000998 2.76 6346.78 2772.20 0.43

6882 PF 1 (2yr) 3664 130.18 133.77 0.002163 2.58 1487.09 1143.39 0.56 6882 PF 2(5 yr) 5414 130.18 134.35 0.001936 2.75 2410.88 1988.36 0.55 6882 PF 3(10 yr) 6649 130.18 134.67 0.001759 2.84 3098.08 2314.41 0.53 PRTW.09 6882 PF 4(25 yr) 8389 130.18 135.06 0.001564 2.91 4079.42 2673.30 0.51 6882 PF 5(50 yr) 9752 130.18 135.34 0.001437 2.95 4846.15 2858.35 0.50 6882 PF 6(100 yr) 11194 130.18 135.60 0.001345 2.99 5611.46 3010.93 0.49

6324 PF 1 (2yr) 3664 129.27 133.42 0.000533 1.24 2959.12 1449.29 0.28 6324 PF 2(5 yr) 5414 129.27 134.03 0.000512 1.38 3954.46 1823.52 0.28 6324 PF 3(10 yr) 6649 129.27 134.37 0.000502 1.49 4602.80 2062.29 0.28 6324 PF 4(25 yr) 8389 129.27 134.76 0.000504 1.63 5466.18 2313.39 0.29 6324 PF 5(50 yr) 9752 129.27 135.03 0.000509 1.73 6117.71 2479.52 0.30 6324 PF 6(100 yr) 11194 129.27 135.29 0.000519 1.83 6764.31 2631.63 0.30

5153 PF 1 (2yr) 3664 128.13 132.48 0.001064 1.76 2087.13 1073.48 0.39 5153 PF 2(5 yr) 5414 128.13 133.11 0.001028 1.94 2915.46 1614.81 0.40

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 146 Feasibility Report: West Rapti Basin

Return Dis- Bed Water Slope bed Velocity Flow Top Frou- River Structure period charge level level level channel Area Width de Station [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 5153 PF 3(10 yr) 6649 128.13 133.44 0.001034 2.06 3474.64 1776.94 0.40 5153 PF 4(25 yr) 8389 128.13 133.82 0.001063 2.22 4173.22 1921.69 0.41 5153 PF 5(50 yr) 9752 128.13 134.06 0.001099 2.34 4660.17 2016.46 0.43 5153 PF 6(100 yr) 11194 128.13 134.29 0.001118 2.47 5122.10 2103.47 0.43

4302 PF 1 (2yr) 3664 127.32 131.74 0.000786 1.43 2559.52 1376.01 0.33 4302 PF 2(5 yr) 5414 127.32 132.41 0.000758 1.49 3696.13 1979.42 0.33 4302 PF 3(10 yr) 6649 127.32 132.79 0.000696 1.54 4544.84 2573.14 0.32 4302 PF 4(25 yr) 8389 127.32 133.18 0.000670 1.61 5606.18 2794.66 0.32 4302 PF 5(50 yr) 9752 127.32 133.43 0.000656 1.68 6334.05 2920.93 0.32 4302 PF 6(100 yr) 11194 127.32 133.68 0.000637 1.75 7051.44 3024.74 0.32

3229 PF 1 (2yr) 3664 126.01 128.93 0.006263 4.40 832.52 386.25 0.96 3229 PF 2(5 yr) 5414 126.01 130.69 0.002242 3.11 1749.01 762.55 0.60 3229 PF 3(10 yr) 6649 126.01 131.07 0.002272 3.30 2144.01 1167.36 0.61 3229 PF 4(25 yr) 8389 126.01 131.56 0.001985 3.41 2975.41 1951.88 0.58 3229 PF 5(50 yr) 9752 126.01 131.92 0.001745 3.41 3699.09 2114.01 0.56 3229 PF 6(100 yr) 11194 126.01 132.27 0.001546 3.40 4464.35 2272.90 0.53

1812 PF 1 (2yr) 3664 124.12 128.85 0.000173 1.11 3306.07 822.43 0.18 1812 PF 2(5 yr) 5414 124.12 130.46 0.000150 1.05 5832.68 2895.20 0.17 1812 PF 3(10 yr) 6649 124.12 130.86 0.000156 1.14 7026.63 3152.90 0.17 1812 PF 4(25 yr) 8389 124.12 131.35 0.000159 1.23 8660.52 3463.75 0.18 1812 PF 5(50 yr) 9752 124.12 131.70 0.000161 1.29 9901.83 3684.58 0.18 1812 PF 6(100 yr) 11194 124.12 132.04 0.000161 1.35 11198.77 3901.98 0.18

0 PF 1 (2yr) 3664 123.19 127.90 0.001092 2.60 1409.35 388.28 0.44 0 PF 2(5 yr) 5414 123.19 129.69 0.001091 2.13 2567.14 1051.39 0.41 0 PF 3(10 yr) 6649 123.19 130.03 0.001091 2.31 2951.99 1163.22 0.42 0 PF 4(25 yr) 8389 123.19 130.47 0.001091 2.53 3481.44 1262.62 0.43 0 PF 5(50 yr) 9752 123.19 130.78 0.001091 2.67 3880.89 1323.24 0.44 0 PF 6(100 yr) 11194 123.19 131.08 0.001091 2.82 4293.18 1383.03 0.44

B.2 Modelling Results – Run 2

Table 30: Hydraulic modelling results – Run 2 Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 160985 PF 1 (2yr) 2099 300.13 304.31 0.004581 3.45 609.22 322.67 0.80 160985 PF 2(5 yr) 2893 300.13 304.92 0.003934 3.52 822.72 379.06 0.76 160985 PF 3(10 yr) 3426 300.13 305.26 0.003438 3.60 954.69 392.18 0.73 160985 PF 4(25 yr) 4359 300.13 305.83 0.002828 3.71 1185.23 415.71 0.68 160985 PF 5(50 yr) 5300 300.13 306.37 0.002387 3.81 1417.88 436.06 0.64 160985 PF 6(100 yr) 6410 300.13 307.01 0.001997 3.88 1702.54 459.73 0.60

160118 PF 1 (2yr) 2099 298.76 303.32 0.000719 1.99 1105.25 466.53 0.35 160118 PF 2(5 yr) 2893 298.76 304.03 0.000674 2.19 1452.64 506.30 0.35 160118 PF 3(10 yr) 3426 298.76 304.44 0.000653 2.30 1668.51 525.08 0.35

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 147 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 160118 PF 4(25 yr) 4359 298.76 305.13 0.000614 2.46 2039.30 553.45 0.35 160118 PF 5(50 yr) 5300 298.76 305.78 0.000579 2.58 2404.13 580.02 0.34 160118 PF 6(100 yr) 6410 298.76 306.48 0.000559 2.74 2842.83 666.56 0.34

159301 PF 1 (2yr) 2099 297.22 301.31 0.004818 4.24 495.18 199.31 0.86 159301 PF 2(5 yr) 2893 297.22 301.97 0.004614 4.57 633.49 220.53 0.86 159301 PF 3(10 yr) 3426 297.22 302.34 0.004353 4.78 716.15 222.90 0.85 159301 PF 4(25 yr) 4359 297.22 302.91 0.004090 5.17 844.41 234.40 0.85 159301 PF 5(50 yr) 5300 297.22 303.39 0.004031 5.56 966.63 270.03 0.86 159301 PF 6(100 yr) 6410 297.22 303.89 0.004038 5.99 1109.82 306.51 0.88

159088 PF 1 (2yr) 2099 297.21 301.21 0.001309 2.69 784.51 255.09 0.47 159088 PF 2(5 yr) 2893 297.21 301.91 0.001305 3.04 980.31 301.11 0.48 159088 PF 3(10 yr) 3426 297.21 302.32 0.001301 3.24 1109.50 323.79 0.49 159088 PF 4(25 yr) 4359 297.21 302.98 0.001292 3.54 1331.18 363.83 0.50 159088 PF 5(50 yr) 5300 297.21 303.56 0.001282 3.79 1564.04 422.75 0.51 159088 PF 6(100 yr) 6410 297.21 304.17 0.001267 4.03 1833.11 454.37 0.51

158876 Bridge

158639 PF 1 (2yr) 2099 295.84 300.27 0.000907 2.19 960.52 299.55 0.39 158639 PF 2(5 yr) 2893 295.84 300.64 0.001190 2.69 1096.00 343.20 0.45 158639 PF 3(10 yr) 3426 295.84 300.92 0.001298 2.95 1190.07 345.91 0.48 158639 PF 4(25 yr) 4359 295.84 301.33 0.001477 3.36 1334.43 350.03 0.52 158639 PF 5(50 yr) 5300 295.84 301.71 0.001636 3.74 1465.49 353.73 0.56 158639 PF 6(100 yr) 6410 295.84 302.10 0.001801 4.15 1609.55 370.77 0.59

158463 PF 1 (2yr) 2099 295.29 299.89 0.002518 2.67 786.91 390.33 0.60 158463 PF 2(5 yr) 2893 295.29 300.07 0.003642 3.39 854.52 390.89 0.73 158463 PF 3(10 yr) 3426 295.29 300.33 0.003492 3.57 958.53 391.33 0.73 158463 PF 4(25 yr) 4359 295.29 300.69 0.003578 3.96 1100.51 391.91 0.75 158463 PF 5(50 yr) 5300 295.29 301.01 0.003696 4.32 1226.48 392.43 0.78 158463 PF 6(100 yr) 6410 295.29 301.36 0.003814 4.70 1363.15 393.00 0.81

157563 PF 1 (2yr) 2099 292.67 295.69 0.007207 4.27 491.20 264.48 1.00 157563 PF 2(5 yr) 2893 292.67 295.99 0.005208 3.92 926.13 619.16 0.87 157563 PF 3(10 yr) 3426 292.67 296.13 0.005715 4.24 1011.77 627.24 0.92 157563 PF 4(25 yr) 4359 292.67 296.41 0.005885 4.59 1188.28 643.58 0.94 157563 PF 5(50 yr) 5300 292.67 296.66 0.005989 4.87 1354.54 658.60 0.97 157563 PF 6(100 yr) 6410 292.67 296.94 0.006090 5.17 1537.40 674.74 0.99

156720 PF 1 (2yr) 2099 289.52 291.43 0.003076 2.14 980.97 787.65 0.61 156720 PF 2(5 yr) 2893 289.52 291.68 0.003250 2.45 1179.77 804.64 0.65 156720 PF 3(10 yr) 3426 289.52 291.83 0.003324 2.63 1303.77 815.06 0.66 156720 PF 4(25 yr) 4359 289.52 292.09 0.003372 2.88 1512.59 832.32 0.68 156720 PF 5(50 yr) 5300 289.52 292.34 0.003366 3.07 1724.60 860.49 0.69 156720 PF 6(100 yr) 6410 289.52 292.61 0.003329 3.27 1961.39 885.00 0.70

155824 PF 1 (2yr) 2099 287.01 288.77 0.002851 2.10 997.80 776.42 0.59 155824 PF 2(5 yr) 2893 287.01 289.09 0.002630 2.33 1242.08 780.67 0.59 155824 PF 3(10 yr) 3426 287.01 289.28 0.002535 2.46 1391.75 783.26 0.59

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 148 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 155824 PF 4(25 yr) 4359 287.01 289.58 0.002447 2.68 1628.84 787.35 0.59 155824 PF 5(50 yr) 5300 287.01 289.86 0.002392 2.87 1847.40 791.10 0.60 155824 PF 6(100 yr) 6410 287.01 290.15 0.002374 3.08 2079.81 795.07 0.61

154466 PF 1 (2yr) 2099 283.89 286.72 0.000997 1.48 1421.20 854.68 0.37 154466 PF 2(5 yr) 2893 283.89 287.10 0.001006 1.65 1749.34 893.97 0.38 154466 PF 3(10 yr) 3426 283.89 287.33 0.001007 1.75 1956.74 918.59 0.38 154466 PF 4(25 yr) 4359 283.89 287.72 0.000977 1.88 2322.37 960.45 0.39 154466 PF 5(50 yr) 5300 283.89 288.02 0.000984 2.03 2620.14 1012.18 0.39 154466 PF 6(100 yr) 6410 283.89 288.34 0.000984 2.18 2959.10 1074.83 0.40

153554 PF 1 (2yr) 2099 281.62 284.61 0.005691 2.74 765.72 672.14 0.82 153554 PF 2(5 yr) 2893 281.62 284.83 0.006111 3.17 911.87 678.03 0.87 153554 PF 3(10 yr) 3426 281.62 284.95 0.006402 3.44 995.98 679.23 0.91 153554 PF 4(25 yr) 4359 281.62 285.10 0.007544 3.98 1096.06 679.95 1.00 153554 PF 5(50 yr) 5300 281.62 285.32 0.007236 4.24 1248.81 681.05 1.00 153554 PF 6(100 yr) 6410 281.62 285.57 0.006933 4.52 1419.07 682.47 1.00

153004 PF 1 (2yr) 2099 279.14 280.60 0.009080 3.06 684.93 722.59 1.01 153004 PF 2(5 yr) 2893 279.14 280.84 0.008396 3.39 854.26 731.53 1.00 153004 PF 3(10 yr) 3426 279.14 280.98 0.008021 3.56 961.19 736.60 1.00 153004 PF 4(25 yr) 4359 279.14 281.29 0.006543 3.67 1187.28 747.02 0.93 153004 PF 5(50 yr) 5300 279.14 281.58 0.005530 3.75 1411.83 757.23 0.88 153004 PF 6(100 yr) 6410 279.14 281.66 0.007141 4.37 1467.58 759.74 1.00

151861 PF 1 (2yr) 2099 275.31 278.54 0.000797 1.47 1424.98 727.14 0.34 151861 PF 2(5 yr) 2893 275.31 278.96 0.000796 1.67 1733.96 733.18 0.35 151861 PF 3(10 yr) 3426 275.31 279.22 0.000792 1.78 1925.64 736.90 0.35 151861 PF 4(25 yr) 4359 275.31 279.64 0.000791 1.95 2233.26 742.84 0.36 151861 PF 5(50 yr) 5300 275.31 280.02 0.000791 2.10 2518.57 748.30 0.37 151861 PF 6(100 yr) 6410 275.31 280.27 0.000541 1.79 4011.58 1214.07 0.31

150753 PF 1 (2yr) 2099 273.95 277.07 0.001977 2.18 961.91 538.25 0.52 150753 PF 2(5 yr) 2893 273.95 277.43 0.002058 2.50 1157.82 544.83 0.55 150753 PF 3(10 yr) 3426 273.95 277.65 0.002109 2.69 1274.77 547.77 0.56 150753 PF 4(25 yr) 4359 273.95 277.99 0.002189 2.98 1461.02 551.80 0.59 150753 PF 5(50 yr) 5300 273.95 278.29 0.002263 3.25 1630.98 555.46 0.61 150753 PF 6(100 yr) 6410 273.95 278.65 0.002289 3.51 1827.27 559.65 0.62

149802 PF 1 (2yr) 2099 272.02 274.53 0.003604 2.45 858.24 634.58 0.67 149802 PF 2(5 yr) 2893 272.02 274.82 0.003575 2.76 1046.75 640.26 0.69 149802 PF 3(10 yr) 3426 272.02 275.00 0.003558 2.95 1162.74 643.72 0.70 149802 PF 4(25 yr) 4359 272.02 275.30 0.003530 3.23 1351.51 649.32 0.71 149802 PF 5(50 yr) 5300 272.02 275.57 0.003499 3.47 1528.61 654.53 0.72 149802 PF 6(100 yr) 6410 272.02 275.82 0.003682 3.79 1692.48 659.32 0.75

149495 PF 1 (2yr) 2099 270.30 273.80 0.002018 1.95 1079.06 728.13 0.51 149495 PF 2(5 yr) 2893 270.30 274.14 0.001934 2.18 1326.03 729.36 0.52 149495 PF 3(10 yr) 3426 270.30 274.33 0.001954 2.34 1463.61 730.04 0.53 149495 PF 4(25 yr) 4359 270.30 274.65 0.001923 2.56 1700.46 731.57 0.54 149495 PF 5(50 yr) 5300 270.30 274.95 0.001896 2.76 1921.41 733.91 0.54

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 149 Feasibility Report: West Rapti Basin

149173.* PF 1 (2yr) 2099 269.87 273.18 0.001859 1.95 1075.43 679.07 0.50 149173.* PF 2(5 yr) 2893 269.87 273.54 0.001782 2.19 1321.83 680.73 0.50 149173.* PF 3(10 yr) 3426 269.87 273.64 0.002107 2.46 1391.69 681.22 0.55 149173.* PF 4(25 yr) 4359 269.87 273.96 0.002128 2.71 1606.28 684.37 0.57 149173.* PF 5(50 yr) 5300 269.87 274.25 0.002124 2.93 1810.59 689.79 0.58 149173.* PF 6(100 yr) 6410 269.87 274.46 0.001780 2.81 2642.38 1171.44 0.53

148852.* PF 1 (2yr) 2099 269.44 272.60 0.001710 1.96 1070.85 631.06 0.48 148852.* PF 2(5 yr) 2893 269.44 272.97 0.001686 2.21 1307.07 636.84 0.49 148852.* PF 3(10 yr) 3426 269.44 273.22 0.001233 2.03 1962.66 1117.99 0.43 148852.* PF 4(25 yr) 4359 269.44 273.60 0.001095 2.12 2460.02 1243.01 0.41 148852.* PF 5(50 yr) 5300 269.44 273.96 0.001003 2.21 2911.92 1292.07 0.41 148852.* PF 6(100 yr) 6410 269.44 273.99 0.001409 2.64 2953.10 1296.45 0.48

148530.* PF 1 (2yr) 2099 269.01 272.07 0.001586 1.95 1090.02 644.85 0.47 148530.* PF 2(5 yr) 2893 269.01 272.45 0.001587 2.20 1339.10 670.21 0.48 148530.* PF 3(10 yr) 3426 269.01 272.67 0.001595 2.35 1489.18 681.29 0.49 148530.* PF 4(25 yr) 4359 269.01 273.04 0.001584 2.58 1741.65 699.54 0.50 148530.* PF 5(50 yr) 5300 269.01 273.37 0.001581 2.78 1977.50 716.17 0.51 148530.* PF 6(100 yr) 6410 269.01 273.68 0.000975 2.32 3407.59 1330.49 0.41

148209 PF 1 (2yr) 2099 268.58 271.03 0.004876 2.77 758.85 585.57 0.78 148209 PF 2(5 yr) 2893 268.58 271.23 0.005844 3.31 874.93 591.70 0.87 148209 PF 3(10 yr) 3426 268.58 271.37 0.006079 3.57 959.85 596.15 0.90 148209 PF 4(25 yr) 4359 268.58 271.57 0.006672 4.03 1081.37 605.15 0.96 148209 PF 5(50 yr) 5300 268.58 271.77 0.006962 4.41 1203.17 616.52 1.00 148209 PF 6(100 yr) 6410 268.58 272.05 0.006571 4.67 1378.69 632.53 0.99

147709 PF 1 (2yr) 2099 267.11 268.82 0.004302 2.34 902.02 861.59 0.71 147709 PF 2(5 yr) 2893 267.11 269.12 0.003634 2.51 1178.89 958.56 0.68 147709 PF 3(10 yr) 3426 267.11 269.27 0.003608 2.67 1324.42 996.42 0.69 147709 PF 4(25 yr) 4359 267.11 269.52 0.003459 2.89 1581.69 1044.34 0.69 147709 PF 5(50 yr) 5300 267.11 269.75 0.003337 3.07 1828.90 1077.43 0.69 147709 PF 6(100 yr) 6410 267.11 270.00 0.003240 3.26 2099.68 1098.43 0.69

PRTW.01 147309 PF 1 (2yr) 2099 266.13 268.17 0.001089 1.45 1443.05 948.83 0.38 147309 PF 2(5 yr) 2893 266.13 268.51 0.001124 1.63 1778.77 1012.79 0.39 147309 PF 3(10 yr) 3426 266.13 268.68 0.001119 1.72 2062.15 1224.42 0.40 147309 PF 4(25 yr) 4359 266.13 268.93 0.001181 1.92 2379.78 1290.77 0.42 147309 PF 5(50 yr) 5300 266.13 269.19 0.001188 2.08 2720.64 1382.05 0.43 147309 PF 6(100 yr) 6410 266.13 269.46 0.001193 2.23 3135.76 1652.55 0.43

146660 PF 1 (2yr) 2099 264.10 266.21 0.008581 3.09 683.96 712.96 0.99 146660 PF 2(5 yr) 2893 264.10 266.45 0.008125 3.44 854.58 744.50 0.99 146660 PF 3(10 yr) 3426 264.10 266.60 0.007682 3.60 971.17 765.31 0.98 146660 PF 4(25 yr) 4359 264.10 266.86 0.006615 3.75 1242.37 925.40 0.94 146660 PF 5(50 yr) 5300 264.10 267.06 0.006465 4.00 1427.52 937.59 0.95 146660 PF 6(100 yr) 6410 264.10 267.28 0.006225 4.24 1640.21 951.39 0.95

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 150 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 146105 PF 1 (2yr) 2099 262.15 264.35 0.001547 1.68 1247.27 857.73 0.45 146105 PF 2(5 yr) 2893 262.15 264.65 0.001579 1.92 1510.51 868.55 0.46 146105 PF 3(10 yr) 3426 262.15 264.82 0.001562 2.03 1787.33 1216.46 0.47 146105 PF 4(25 yr) 4359 262.15 265.10 0.001570 2.22 2136.86 1360.68 0.48 146105 PF 5(50 yr) 5300 262.15 265.34 0.001571 2.38 2485.04 1487.66 0.49 146105 PF 6(100 yr) 6410 262.15 265.60 0.001567 2.54 2883.43 1586.79 0.50

145481 PF 1 (2yr) 2099 260.58 263.00 0.002989 1.87 1125.29 1091.05 0.59 145481 PF 2(5 yr) 2893 260.58 263.17 0.003531 2.21 1308.30 1126.55 0.65 145481 PF 3(10 yr) 3426 260.58 263.26 0.003866 2.43 1416.68 1147.05 0.69 145481 PF 4(25 yr) 4359 260.58 263.41 0.004362 2.76 1586.18 1170.29 0.74 145481 PF 5(50 yr) 5300 260.58 263.55 0.004736 3.06 1745.79 1187.92 0.79 145481 PF 6(100 yr) 6410 260.58 263.69 0.005165 3.39 1913.88 1206.21 0.83

145087 PF 1 (2yr) 2099 259.80 261.54 0.004630 1.91 1100.90 1445.02 0.69 145087 PF 2(5 yr) 2893 259.80 261.76 0.003752 2.03 1435.78 1551.17 0.65 145087 PF 3(10 yr) 3426 259.80 261.90 0.003384 2.11 1655.63 1617.07 0.63 145087 PF 4(25 yr) 4359 259.80 262.13 0.002896 2.20 2044.13 1727.39 0.60 145087 PF 5(50 yr) 5300 259.80 262.34 0.002606 2.30 2418.53 1827.42 0.59 145087 PF 6(100 yr) 6410 259.80 262.58 0.002341 2.39 2861.67 1939.15 0.57

144542 PF 1 (2yr) 2099 258.16 260.37 0.001319 1.50 1399.60 1014.89 0.41 144542 PF 2(5 yr) 2893 258.16 260.67 0.001339 1.70 1708.90 1118.39 0.42 144542 PF 3(10 yr) 3426 258.16 260.83 0.001364 1.82 1897.05 1160.15 0.43 PRTW.02 144542 PF 4(25 yr) 4359 258.16 261.04 0.001511 2.07 2148.88 1195.75 0.47 144542 PF 5(50 yr) 5300 258.16 261.25 0.001602 2.27 2399.76 1245.29 0.49 144542 PF 6(100 yr) 6410 258.16 261.49 0.001644 2.46 2733.90 1411.05 0.50

144083 PF 1 (2yr) 2099 257.14 258.72 0.009345 2.99 703.10 788.35 1.01 144083 PF 2(5 yr) 2893 257.14 258.93 0.008866 3.29 878.10 816.35 1.01 144083 PF 3(10 yr) 3426 257.14 259.08 0.008344 3.43 998.76 835.11 1.00 144083 PF 4(25 yr) 4359 257.14 259.46 0.005677 3.29 1324.74 883.80 0.86 144083 PF 5(50 yr) 5300 257.14 259.77 0.004477 3.31 1610.25 953.16 0.79 144083 PF 6(100 yr) 6410 257.14 260.09 0.003789 3.39 1933.02 1107.36 0.74

143617 PF 1 (2yr) 2099 255.52 258.46 0.000255 0.87 2424.22 1167.53 0.19 143617 PF 2(5 yr) 2893 255.52 258.81 0.000299 1.02 2842.16 1211.80 0.21 143617 PF 3(10 yr) 3426 255.52 259.03 0.000325 1.10 3102.49 1246.51 0.22 143617 PF 4(25 yr) 4359 255.52 259.36 0.000363 1.24 3529.34 1301.43 0.24 143617 PF 5(50 yr) 5300 255.52 259.66 0.000396 1.35 3923.77 1350.19 0.25 143617 PF 6(100 yr) 6410 255.52 259.97 0.000428 1.47 4362.80 1430.24 0.27

142933 PF 1 (2yr) 2099 254.01 257.81 0.004042 2.11 994.67 999.43 0.68 142933 PF 2(5 yr) 2893 254.01 258.11 0.003199 2.23 1299.66 1011.33 0.63 142933 PF 3(10 yr) 3426 254.01 258.29 0.002932 2.31 1481.40 1019.64 0.61 142933 PF 4(25 yr) 4359 254.01 258.57 0.002685 2.47 1766.20 1032.52 0.60 142933 PF 5(50 yr) 5300 254.01 258.81 0.002594 2.63 2015.26 1043.65 0.60 142933 PF 6(100 yr) 6410 254.01 259.06 0.002561 2.82 2276.86 1054.38 0.61

142513 PF 1 (2yr) 2099 253.96 257.26 0.000809 1.30 1612.91 1001.75 0.33 142513 PF 2(5 yr) 2893 253.96 257.59 0.000849 1.48 1948.58 1029.90 0.34

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 151 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 142513 PF 3(10 yr) 3426 253.96 257.75 0.000935 1.62 2113.92 1073.11 0.37 142513 PF 4(25 yr) 4359 253.96 258.01 0.001021 1.82 2408.30 1141.11 0.39 142513 PF 5(50 yr) 5300 253.96 258.24 0.001091 2.00 2672.09 1201.92 0.41 142513 PF 6(100 yr) 6410 253.96 258.47 0.001168 2.20 3016.69 1496.02 0.43

141711 PF 1 (2yr) 2099 253.45 255.33 0.008418 3.05 697.84 815.48 0.98 141711 PF 2(5 yr) 2893 253.45 255.59 0.007519 3.27 938.04 1099.20 0.95 141711 PF 3(10 yr) 3426 253.45 255.80 0.006190 3.19 1205.35 1409.80 0.88 141711 PF 4(25 yr) 4359 253.45 256.02 0.005614 3.29 1603.44 1833.23 0.85 141711 PF 5(50 yr) 5300 253.45 256.19 0.005389 3.46 1928.56 2012.38 0.85 141711 PF 6(100 yr) 6410 253.45 256.37 0.005192 3.63 2302.23 2200.34 0.85

141107 PF 1 (2yr) 2099 251.56 254.45 0.000451 1.02 2542.46 2219.73 0.25 141107 PF 2(5 yr) 2893 251.56 254.88 0.000349 1.04 3525.38 2373.02 0.23 141107 PF 3(10 yr) 3426 251.56 255.12 0.000319 1.07 4106.14 2459.10 0.22 141107 PF 4(25 yr) 4359 251.56 255.40 0.000330 1.17 4818.92 2560.80 0.23 141107 PF 5(50 yr) 5300 251.56 255.71 0.000316 1.23 5619.02 2670.35 0.23 141107 PF 6(100 yr) 6410 251.56 256.04 0.000305 1.30 6517.89 2788.30 0.23

140216 PF 1 (2yr) 2099 250.70 253.85 0.000791 1.52 1384.54 733.00 0.34 140216 PF 2(5 yr) 2893 250.70 254.35 0.000725 1.68 1794.08 912.23 0.34 140216 PF 3(10 yr) 3426 250.70 254.58 0.000745 1.80 2017.48 973.06 0.34 140216 PF 4(25 yr) 4359 250.70 254.88 0.000694 1.86 2904.86 1631.33 0.34 140216 PF 5(50 yr) 5300 250.70 255.18 0.000700 1.99 3420.49 1809.08 0.34 140216 PF 6(100 yr) 6410 250.70 255.51 0.000698 2.11 4062.16 2117.84 0.35

139579 PF 1 (2yr) 2099 249.22 251.80 0.007137 4.30 487.70 257.79 1.00 139579 PF 2(5 yr) 2893 249.22 252.63 0.007787 3.76 770.26 533.42 1.00 139579 PF 3(10 yr) 3426 249.22 252.86 0.007761 3.78 908.64 652.85 1.00 139579 PF 4(25 yr) 4359 249.22 253.14 0.006937 4.01 1107.76 760.20 0.97 139579 PF 5(50 yr) 5300 249.22 253.40 0.006287 4.19 1320.29 839.97 0.95 PRTW.03 139579 PF 6(100 yr) 6410 249.22 253.66 0.005992 4.44 1549.95 949.02 0.94

138812 PF 1 (2yr) 2099 248.01 250.69 0.000874 1.15 1843.51 1607.21 0.33 138812 PF 2(5 yr) 2893 248.01 250.99 0.000806 1.27 2349.25 1807.40 0.33 138812 PF 3(10 yr) 3426 248.01 251.17 0.000767 1.34 2694.34 1944.86 0.32 138812 PF 4(25 yr) 4359 248.01 251.47 0.000716 1.43 3295.49 2185.59 0.32 138812 PF 5(50 yr) 5300 248.01 251.74 0.000674 1.51 3906.24 2363.11 0.32 138812 PF 6(100 yr) 6410 248.01 252.02 0.000639 1.59 4606.89 2537.57 0.32

138099 PF 1 (2yr) 2099 247.20 248.69 0.008567 3.38 620.65 540.80 1.01 138099 PF 2(5 yr) 2893 247.20 248.98 0.008040 3.71 780.54 565.18 1.01 138099 PF 3(10 yr) 3426 247.20 249.15 0.007798 3.89 880.90 579.97 1.01 138099 PF 4(25 yr) 4359 247.20 249.44 0.007241 4.14 1058.39 666.51 1.00 138099 PF 5(50 yr) 5300 247.20 249.73 0.006399 4.30 1272.23 808.27 0.96 138099 PF 6(100 yr) 6410 247.20 250.04 0.005693 4.45 1543.27 950.68 0.93

137644 PF 1 (2yr) 2099 244.45 247.00 0.001249 1.68 1271.71 819.77 0.41 137644 PF 2(5 yr) 2893 244.45 247.32 0.001298 1.92 1548.72 867.22 0.43 137644 PF 3(10 yr) 3426 244.45 247.51 0.001339 2.07 1715.41 894.55 0.44 137644 PF 4(25 yr) 4359 244.45 247.81 0.001415 2.31 1983.42 964.42 0.47

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 152 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 137644 PF 5(50 yr) 5300 244.45 248.05 0.001519 2.55 2238.60 1141.80 0.49 137644 PF 6(100 yr) 6410 244.45 248.31 0.001575 2.76 2698.44 1700.79 0.51

137467.* PF 1 (2yr) 2099 244.15 246.78 0.001224 1.63 1305.98 866.02 0.41 137467.* PF 2(5 yr) 2893 244.15 247.10 0.001268 1.87 1593.69 921.40 0.42 137467.* PF 3(10 yr) 3426 244.15 247.29 0.001312 2.02 1764.84 953.28 0.44 137467.* PF 4(25 yr) 4359 244.15 247.56 0.001412 2.27 2044.87 1132.58 0.46 137467.* PF 5(50 yr) 5300 244.15 247.80 0.001471 2.47 2427.46 1609.73 0.48 137467.* PF 6(100 yr) 6410 244.15 248.06 0.001504 2.65 2867.19 1824.07 0.49

137290.* PF 1 (2yr) 2099 243.85 246.56 0.001316 1.58 1333.30 914.41 0.41 137290.* PF 2(5 yr) 2893 243.85 246.89 0.001297 1.78 1641.44 985.22 0.42 137290.* PF 3(10 yr) 3426 243.85 247.07 0.001323 1.91 1821.47 1053.19 0.43 137290.* PF 4(25 yr) 4359 243.85 247.34 0.001363 2.12 2193.42 1477.70 0.45 137290.* PF 5(50 yr) 5300 243.85 247.58 0.001383 2.28 2569.01 1624.08 0.46 137290.* PF 6(100 yr) 6410 243.85 247.84 0.001397 2.45 3005.89 1790.34 0.47

137113.* PF 1 (2yr) 2099 243.55 246.33 0.001374 1.57 1340.44 964.09 0.42 137113.* PF 2(5 yr) 2893 243.55 246.66 0.001279 1.74 1687.13 1171.44 0.42 137113.* PF 3(10 yr) 3426 243.55 246.84 0.001283 1.86 1922.50 1385.18 0.43 137113.* PF 4(25 yr) 4359 243.55 247.12 0.001292 2.04 2322.96 1541.03 0.44 137113.* PF 5(50 yr) 5300 243.55 247.36 0.001299 2.19 2715.39 1687.61 0.45 137113.* PF 6(100 yr) 6410 243.55 247.62 0.001302 2.34 3169.48 1838.33 0.45

136936 PF 1 (2yr) 2099 243.25 246.06 0.001633 1.60 1310.70 1011.24 0.45 136936 PF 2(5 yr) 2893 243.25 246.42 0.001608 1.68 1732.72 1328.08 0.45 136936 PF 3(10 yr) 3426 243.25 246.62 0.001475 1.74 2003.18 1419.51 0.44 136936 PF 4(25 yr) 4359 243.25 246.91 0.001331 1.85 2441.18 1562.58 0.43 136936 PF 5(50 yr) 5300 243.25 247.16 0.001263 1.96 2854.50 1686.50 0.43 136936 PF 6(100 yr) 6410 243.25 247.43 0.001217 2.08 3318.55 1804.56 0.43

136745 PF 1 (2yr) 2099 243.26 244.99 0.008571 3.29 638.63 580.94 1.00 136745 PF 2(5 yr) 2893 243.26 245.26 0.007942 3.63 796.69 589.38 1.00 136745 PF 3(10 yr) 3426 243.26 245.46 0.007861 3.73 918.73 648.09 1.00 136745 PF 4(25 yr) 4359 243.26 245.75 0.007681 3.87 1126.12 738.18 1.00 136745 PF 5(50 yr) 5300 243.26 246.03 0.006765 3.96 1368.12 1033.61 0.96 136745 PF 6(100 yr) 6410 243.26 246.29 0.006080 4.11 1642.48 1083.30 0.93

136487 PF 1 (2yr) 2099 242.34 244.97 0.000151 0.66 4810.80 3594.52 0.15 136487 PF 2(5 yr) 2893 242.34 245.27 0.000155 0.73 5928.42 3717.98 0.15 136487 PF 3(10 yr) 3426 242.34 245.45 0.000158 0.78 6599.72 3790.21 0.16 136487 PF 4(25 yr) 4359 242.34 245.73 0.000163 0.85 7681.54 3903.79 0.16 136487 PF 5(50 yr) 5300 242.34 245.98 0.000169 0.91 8667.70 4004.52 0.17 136487 PF 6(100 yr) 6410 242.34 246.25 0.000175 0.98 9736.53 4110.91 0.17

136227 PF 1 (2yr) 2099 241.97 244.61 0.000717 1.31 1982.98 1740.43 0.31 136227 PF 2(5 yr) 2893 241.97 244.89 0.000745 1.47 2484.59 1816.77 0.33 136227 PF 3(10 yr) 3426 241.97 245.05 0.000767 1.57 2782.17 1858.72 0.34 136227 PF 4(25 yr) 4359 241.97 245.31 0.000801 1.72 3257.51 1919.17 0.35 136227 PF 5(50 yr) 5300 241.97 245.53 0.000835 1.86 3688.50 1970.19 0.36 136227 PF 6(100 yr) 6410 241.97 245.76 0.000875 2.01 4149.32 2022.78 0.38

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 153 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

135825 Bridge

135708 PF 1 (2yr) 2099 241.22 244.13 0.001254 1.50 1558.17 1768.12 0.40 135708 PF 2(5 yr) 2893 241.22 244.40 0.001227 1.67 2046.58 1919.48 0.41 135708 PF 3(10 yr) 3426 241.22 244.55 0.001237 1.77 2335.03 2004.43 0.41 135708 PF 4(25 yr) 4359 241.22 244.78 0.001249 1.92 2812.76 2137.70 0.43 135708 PF 5(50 yr) 5300 241.22 244.98 0.001271 2.06 3253.63 2253.71 0.44 135708 PF 6(100 yr) 6410 241.22 245.19 0.001300 2.21 3738.40 2374.73 0.45

135187.* PF 1 (2yr) 2099 240.71 243.49 0.001251 1.44 1481.69 1439.58 0.40 135187.* PF 2(5 yr) 2893 240.71 243.73 0.001339 1.67 1877.79 1988.42 0.42 135187.* PF 3(10 yr) 3426 240.71 243.86 0.001382 1.79 2153.09 2122.17 0.43 135187.* PF 4(25 yr) 4359 240.71 244.06 0.001448 1.97 2600.08 2299.90 0.45 135187.* PF 5(50 yr) 5300 240.71 244.24 0.001505 2.13 3020.74 2455.43 0.47 135187.* PF 6(100 yr) 6410 240.71 244.43 0.001538 2.28 3511.72 2625.34 0.48

134926.* PF 1 (2yr) 2099 240.57 243.25 0.000820 1.20 1757.39 1398.95 0.32 134926.* PF 2(5 yr) 2893 240.57 243.46 0.000949 1.42 2170.45 2181.08 0.36 134926.* PF 3(10 yr) 3426 240.57 243.58 0.001029 1.55 2433.20 2341.99 0.37 134926.* PF 4(25 yr) 4359 240.57 243.75 0.001150 1.75 2860.89 2513.91 0.40 134926.* PF 5(50 yr) 5300 240.57 243.91 0.001241 1.91 3272.76 2669.02 0.42 134926.* PF 6(100 yr) 6410 240.57 244.10 0.001288 2.06 3785.17 2850.23 0.44

133880 PF 1 (2yr) 2099 240.02 242.10 0.001571 1.11 1917.74 2603.89 0.40 133880 PF 2(5 yr) 2893 240.02 242.30 0.001372 1.21 2445.34 2675.37 0.39 133880 PF 3(10 yr) 3426 240.02 242.44 0.001235 1.25 2811.57 2723.88 0.38 133880 PF 4(25 yr) 4359 240.02 242.68 0.001008 1.30 3493.80 2812.01 0.36 133880 PF 5(50 yr) 5300 240.02 242.94 0.000825 1.31 4224.16 2903.40 0.33 133880 PF 6(100 yr) 6410 240.02 243.19 0.000734 1.37 4960.78 2992.75 0.32

133790.* PF 1 (2yr) 2099 239.87 241.97 0.001484 1.11 1916.42 2496.45 0.40 133790.* PF 2(5 yr) 2893 239.87 242.19 0.001243 1.20 2474.55 2567.67 0.38 133790.* PF 3(10 yr) 3426 239.87 242.34 0.001101 1.23 2860.91 2619.83 0.36 133790.* PF 4(25 yr) 4359 239.87 242.60 0.000887 1.27 3573.58 2718.41 0.34 133790.* PF 5(50 yr) 5300 239.87 242.87 0.000726 1.28 4323.73 2815.92 0.31 133790.* PF 6(100 yr) 6410 239.87 243.13 0.000665 1.34 5063.99 2986.36 0.31

133701.* PF 1 (2yr) 2099 239.72 241.84 0.001379 1.11 1924.86 2397.90 0.38 133701.* PF 2(5 yr) 2893 239.72 242.08 0.001109 1.17 2517.83 2464.68 0.36 133701.* PF 3(10 yr) 3426 239.72 242.25 0.000971 1.20 2921.95 2521.05 0.34 133701.* PF 4(25 yr) 4359 239.72 242.53 0.000780 1.24 3656.88 2628.48 0.32 133701.* PF 5(50 yr) 5300 239.72 242.82 0.000651 1.26 4420.16 2789.91 0.30 133701.* PF 6(100 yr) 6410 239.72 243.08 0.000596 1.32 5167.62 2915.21 0.29 PRTW.06 133611.* PF 1 (2yr) 2099 239.56 241.72 0.001264 1.09 1941.47 2304.64 0.37 133611.* PF 2(5 yr) 2893 239.56 241.99 0.000979 1.15 2569.92 2365.80 0.34 133611.* PF 3(10 yr) 3426 239.56 242.17 0.000854 1.18 2987.45 2426.31 0.33 133611.* PF 4(25 yr) 4359 239.56 242.47 0.000690 1.21 3735.80 2546.77 0.30 133611.* PF 5(50 yr) 5300 239.56 242.76 0.000580 1.23 4518.15 2728.11 0.29 133611.* PF 6(100 yr) 6410 239.56 243.03 0.000539 1.30 5257.44 2839.24 0.28

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 154 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

133254 PF 1 (2yr) 2099 238.95 241.36 0.000869 1.05 1992.76 1822.64 0.32 133254 PF 2(5 yr) 2893 238.95 241.72 0.000652 1.09 2694.65 2069.34 0.29 133254 PF 3(10 yr) 3426 238.95 241.92 0.000577 1.12 3134.84 2146.63 0.28 133254 PF 4(25 yr) 4359 238.95 242.27 0.000488 1.17 3899.13 2295.97 0.26 133254 PF 5(50 yr) 5300 238.95 242.59 0.000428 1.21 4660.94 2424.92 0.25 133254 PF 6(100 yr) 6410 238.95 242.86 0.000424 1.30 5333.84 2533.04 0.26

132929 PF 1 (2yr) 2099 238.60 241.20 0.000378 0.82 2552.43 1785.03 0.22 132929 PF 2(5 yr) 2893 238.60 241.58 0.000336 0.88 3337.10 2228.52 0.21 132929 PF 3(10 yr) 3426 238.60 241.80 0.000311 0.92 3850.54 2388.68 0.21 132929 PF 4(25 yr) 4359 238.60 242.17 0.000278 0.97 4766.55 2691.23 0.20 132929 PF 5(50 yr) 5300 238.60 242.50 0.000253 1.02 5724.80 3035.77 0.20 132929 PF 6(100 yr) 6410 238.60 242.77 0.000258 1.10 6588.36 3288.85 0.20

132874.* PF 1 (2yr) 2099 238.43 241.17 0.000451 0.89 2368.44 1690.31 0.24 132874.* PF 2(5 yr) 2893 238.43 241.56 0.000386 0.95 3090.48 2133.65 0.23 132874.* PF 3(10 yr) 3426 238.43 241.78 0.000357 0.99 3587.79 2332.83 0.23 132874.* PF 4(25 yr) 4359 238.43 242.14 0.000317 1.04 4510.35 2739.16 0.22 132874.* PF 5(50 yr) 5300 238.43 242.48 0.000284 1.08 5491.89 3043.01 0.21 132874.* PF 6(100 yr) 6410 238.43 242.75 0.000288 1.16 6346.49 3239.92 0.22

132819.* PF 1 (2yr) 2099 238.25 241.13 0.000556 0.97 2176.47 1641.17 0.26 132819.* PF 2(5 yr) 2893 238.25 241.53 0.000448 1.02 2924.48 2127.34 0.25 132819.* PF 3(10 yr) 3426 238.25 241.75 0.000410 1.06 3434.91 2392.36 0.24 PRTW.05 132819.* PF 4(25 yr) 4359 238.25 242.12 0.000355 1.11 4391.14 2764.27 0.23 132819.* PF 5(50 yr) 5300 238.25 242.46 0.000314 1.14 5372.41 2997.97 0.22 132819.* PF 6(100 yr) 6410 238.25 242.73 0.000316 1.22 6211.81 3179.53 0.23

132656 PF 1 (2yr) 2099 237.73 240.97 0.001047 1.28 1805.56 2011.79 0.36 132656 PF 2(5 yr) 2893 237.73 241.42 0.000639 1.22 2784.19 2284.80 0.30 132656 PF 3(10 yr) 3426 237.73 241.66 0.000541 1.22 3347.07 2388.74 0.28 132656 PF 4(25 yr) 4359 237.73 242.05 0.000440 1.24 4299.54 2583.75 0.26 132656 PF 5(50 yr) 5300 237.73 242.40 0.000380 1.27 5243.84 2817.93 0.25 132656 PF 6(100 yr) 6410 237.73 242.67 0.000382 1.35 6029.52 2983.66 0.25

132403 PF 1 (2yr) 2099 237.25 240.87 0.000314 0.95 2255.81 1337.57 0.21 132403 PF 2(5 yr) 2893 237.25 241.33 0.000285 1.04 3059.66 1892.68 0.21 132403 PF 3(10 yr) 3426 237.25 241.57 0.000281 1.09 3530.61 1960.42 0.21 132403 PF 4(25 yr) 4359 237.25 241.96 0.000273 1.18 4319.32 2117.24 0.21 132403 PF 5(50 yr) 5300 237.25 242.31 0.000266 1.25 5089.94 2250.54 0.21 132403 PF 6(100 yr) 6410 237.25 242.57 0.000291 1.37 5688.25 2331.77 0.23

131465 PF 1 (2yr) 2099 235.79 240.30 0.000948 1.60 1315.19 677.65 0.37 131465 PF 2(5 yr) 2893 235.79 240.77 0.000951 1.75 1652.75 798.53 0.37 131465 PF 3(10 yr) 3426 235.79 240.99 0.000995 1.88 1851.64 952.55 0.39 131465 PF 4(25 yr) 4359 235.79 241.36 0.000980 2.05 2209.89 984.92 0.39 131465 PF 5(50 yr) 5300 235.79 241.70 0.000969 2.20 2544.06 1014.18 0.40 131465 PF 6(100 yr) 6410 235.79 241.96 0.000924 2.25 3347.25 1475.18 0.39

130224 PF 1 (2yr) 2099 234.09 237.03 0.007673 3.85 545.88 361.09 1.00

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 155 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 130224 PF 2(5 yr) 2893 234.09 237.44 0.007296 4.12 702.14 403.20 1.00 130224 PF 3(10 yr) 3426 234.09 237.77 0.006170 4.04 872.65 543.62 0.93 130224 PF 4(25 yr) 4359 234.09 238.07 0.006103 4.40 1034.49 556.42 0.95 130224 PF 5(50 yr) 5300 234.09 238.35 0.005888 4.68 1196.43 568.49 0.95 130224 PF 6(100 yr) 6410 234.09 238.73 0.005163 4.82 1461.25 791.98 0.91

129806 PF 1 (2yr) 2099 233.80 237.01 0.000424 1.16 2121.87 1303.66 0.25 129806 PF 2(5 yr) 2893 233.80 237.39 0.000436 1.31 2640.73 1395.47 0.26 129806 PF 3(10 yr) 3426 233.80 237.62 0.000441 1.39 2966.85 1450.70 0.27 129806 PF 4(25 yr) 4359 233.80 237.98 0.000450 1.53 3501.84 1535.03 0.27 129806 PF 5(50 yr) 5300 233.80 238.30 0.000458 1.64 4007.25 1608.96 0.28 129806 PF 6(100 yr) 6410 233.80 238.63 0.000475 1.77 4541.37 1683.57 0.29

127967 PF 1 (2yr) 2099 232.67 235.71 0.000935 1.49 1428.65 994.81 0.36 127967 PF 2(5 yr) 2893 232.67 236.15 0.000812 1.61 1910.73 1124.10 0.35 127967 PF 3(10 yr) 3426 232.67 236.37 0.000816 1.72 2158.99 1167.42 0.35 127967 PF 4(25 yr) 4359 232.67 236.70 0.000834 1.87 2562.54 1314.61 0.36 127967 PF 5(50 yr) 5300 232.67 237.00 0.000849 2.02 3051.91 1698.86 0.37 127967 PF 6(100 yr) 6410 232.67 237.31 0.000834 2.14 3596.54 1756.08 0.38

127727 PF 1 (2yr) 2099 232.05 235.37 0.001245 1.91 1193.95 717.60 0.42 127727 PF 2(5 yr) 2893 232.05 235.80 0.001415 2.11 1516.39 857.98 0.46 127727 PF 3(10 yr) 3426 232.05 235.99 0.001473 2.28 1686.77 917.47 0.47 127727 PF 4(25 yr) 4359 232.05 236.29 0.001562 2.54 1970.25 1002.41 0.50 127727 PF 5(50 yr) 5300 232.05 236.54 0.001633 2.76 2230.15 1036.84 0.51 127727 PF 6(100 yr) 6410 232.05 236.81 0.001709 2.99 2513.82 1073.15 0.53

125768 PF 1 (2yr) 2099 230.17 232.33 0.002096 1.57 1339.01 1286.13 0.49 125768 PF 2(5 yr) 2893 230.17 232.56 0.002079 1.77 1633.18 1297.84 0.50 125768 PF 3(10 yr) 3426 230.17 232.70 0.002065 1.89 1815.27 1305.04 0.51 125768 PF 4(25 yr) 4359 230.17 232.93 0.002052 2.07 2108.90 1316.57 0.52 125768 PF 5(50 yr) 5300 230.17 233.13 0.002034 2.22 2386.51 1374.35 0.53 125768 PF 6(100 yr) 6410 230.17 233.36 0.002032 2.39 2702.14 1462.29 0.54

125245.* PF 1 (2yr) 2099 229.50 231.50 0.001344 1.30 1615.83 1474.50 0.40 125245.* PF 2(5 yr) 2893 229.50 231.77 0.001248 1.43 2017.36 1501.27 0.40 125245.* PF 3(10 yr) 3426 229.50 231.93 0.001222 1.52 2255.14 1514.93 0.40 125245.* PF 4(25 yr) 4359 229.50 232.18 0.001199 1.65 2634.65 1545.88 0.40 125245.* PF 5(50 yr) 5300 229.50 232.40 0.001184 1.78 2987.09 1632.11 0.41 125245.* PF 6(100 yr) 6410 229.50 232.62 0.001204 1.93 3354.65 1702.73 0.42

124723.* PF 1 (2yr) 2099 228.82 231.23 0.000342 0.81 2603.54 1746.73 0.21 124723.* PF 2(5 yr) 2893 228.82 231.48 0.000392 0.95 3058.23 1890.76 0.23 124723.* PF 3(10 yr) 3426 228.82 231.63 0.000414 1.03 3354.37 1993.86 0.24 124723.* PF 4(25 yr) 4359 228.82 231.87 0.000444 1.16 3854.01 2151.03 0.25 124723.* PF 5(50 yr) 5300 228.82 232.09 0.000467 1.27 4339.49 2277.54 0.26 124723.* PF 6(100 yr) 6410 228.82 232.30 0.000509 1.40 4828.52 2462.45 0.28

124201 PF 1 (2yr) 2099 228.15 231.15 0.000108 0.53 4144.27 2483.29 0.12 124201 PF 2(5 yr) 2893 228.15 231.38 0.000137 0.65 4750.99 2640.53 0.14 124201 PF 3(10 yr) 3426 228.15 231.53 0.000153 0.71 5138.96 2739.94 0.15

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 156 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 124201 PF 4(25 yr) 4359 228.15 231.76 0.000176 0.82 5782.18 2819.66 0.16 124201 PF 5(50 yr) 5300 228.15 231.97 0.000195 0.91 6383.99 2892.26 0.18 124201 PF 6(100 yr) 6410 228.15 232.16 0.000224 1.02 6948.43 2958.74 0.19

123840 PF 1 (2yr) 2099 228.10 230.71 0.010512 2.38 880.73 1511.83 1.00 123840 PF 2(5 yr) 2893 228.10 230.85 0.009755 2.65 1092.26 1513.05 1.00 123840 PF 3(10 yr) 3426 228.10 230.94 0.009429 2.80 1221.52 1513.79 1.00 123840 PF 4(25 yr) 4359 228.10 231.08 0.008941 3.04 1434.62 1515.02 1.00 123840 PF 5(50 yr) 5300 228.10 231.22 0.008550 3.22 1648.10 1545.78 0.99 123840 PF 6(100 yr) 6410 228.10 231.37 0.008707 3.30 1942.70 1777.34 1.01

122539 PF 1 (2yr) 2099 226.03 229.10 0.000265 0.83 2544.98 1440.51 0.19 122539 PF 2(5 yr) 2893 226.03 229.61 0.000221 0.83 3928.97 2551.95 0.18 122539 PF 3(10 yr) 3426 226.03 229.85 0.000209 0.87 4554.68 2667.51 0.18 122539 PF 4(25 yr) 4359 226.03 230.24 0.000192 0.92 5623.12 2854.00 0.18 122539 PF 5(50 yr) 5300 226.03 230.55 0.000188 0.98 6546.20 3002.73 0.18 122539 PF 6(100 yr) 6410 226.03 230.86 0.000192 1.05 7482.65 3146.44 0.18

120519 PF 1 (2yr) 2099 223.70 228.40 0.000417 1.21 1735.23 731.39 0.25 120519 PF 2(5 yr) 2893 223.70 228.92 0.000484 1.32 2207.85 1019.11 0.27 120519 PF 3(10 yr) 3426 223.70 229.16 0.000490 1.41 2471.73 1100.96 0.28 120519 PF 4(25 yr) 4359 223.70 229.56 0.000496 1.55 2970.32 1552.44 0.28 120519 PF 5(50 yr) 5300 223.70 229.88 0.000494 1.65 3899.34 3115.13 0.29 120519 PF 6(100 yr) 6410 223.70 230.20 0.000479 1.72 4884.66 3163.58 0.29

120272.* PF 1 (2yr) 2099 223.63 228.28 0.000535 1.24 1696.49 834.50 0.28 120272.* PF 2(5 yr) 2893 223.63 228.79 0.000548 1.34 2156.98 957.29 0.29 120272.* PF 3(10 yr) 3426 223.63 229.03 0.000576 1.43 2397.46 1003.33 0.30 120272.* PF 4(25 yr) 4359 223.63 229.43 0.000604 1.55 2810.14 1077.75 0.31 120272.* PF 5(50 yr) 5300 223.63 229.74 0.000610 1.65 3569.48 2967.67 0.31 120272.* PF 6(100 yr) 6410 223.63 230.07 0.000572 1.71 4532.86 3019.00 0.31

120026.* PF 1 (2yr) 2099 223.56 228.14 0.000574 1.25 1684.93 864.18 0.28 120026.* PF 2(5 yr) 2893 223.56 228.63 0.000769 1.32 2187.59 1277.59 0.32 120026.* PF 3(10 yr) 3426 223.56 228.88 0.000704 1.36 2517.36 1317.95 0.31 120026.* PF 4(25 yr) 4359 223.56 229.29 0.000607 1.42 3070.37 1395.12 0.30 120026.* PF 5(50 yr) 5300 223.56 229.61 0.000579 1.51 3607.63 1959.65 0.30 120026.* PF 6(100 yr) 6410 223.56 229.95 0.000529 1.56 4670.83 2876.56 0.29

119287.* PF 1 (2yr) 2099 223.36 227.72 0.000576 1.12 1866.28 1119.40 0.28 119287.* PF 2(5 yr) 2893 223.36 228.18 0.000507 1.21 2390.10 1166.02 0.27 119287.* PF 3(10 yr) 3426 223.36 228.47 0.000476 1.26 2727.34 1200.25 0.27 119287.* PF 4(25 yr) 4359 223.36 228.92 0.000442 1.33 3297.07 1387.64 0.26 119287.* PF 5(50 yr) 5300 223.36 229.25 0.000435 1.42 3860.60 1971.91 0.27 119287.* PF 6(100 yr) 6410 223.36 229.62 0.000408 1.49 4811.06 2583.39 0.26

118056 PF 1 (2yr) 2099 223.02 227.22 0.000316 1.03 2033.03 883.41 0.22 118056 PF 2(5 yr) 2893 223.02 227.67 0.000352 1.18 2452.69 1053.26 0.23 118056 PF 3(10 yr) 3426 223.02 227.95 0.000376 1.26 2777.14 1260.84 0.24 118056 PF 4(25 yr) 4359 223.02 228.37 0.000439 1.35 3407.54 1804.19 0.26 118056 PF 5(50 yr) 5300 223.02 228.76 0.000384 1.38 4474.46 2580.05 0.25

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 157 Feasibility Report: West Rapti Basin

117747.* PF 1 (2yr) 2099 222.75 227.07 0.000538 1.20 1750.54 905.75 0.28 117747.* PF 2(5 yr) 2893 222.75 227.52 0.000527 1.32 2279.23 1473.15 0.28 117747.* PF 3(10 yr) 3426 222.75 227.81 0.000480 1.36 2753.97 1833.51 0.27 117747.* PF 4(25 yr) 4359 222.75 228.24 0.000423 1.42 3620.33 2152.30 0.26 117747.* PF 5(50 yr) 5300 222.75 228.64 0.000372 1.45 4528.35 2349.82 0.25 117747.* PF 6(100 yr) 6410 222.75 229.08 0.000325 1.47 5602.90 2514.15 0.24

117438.* PF 1 (2yr) 2099 222.48 226.85 0.000835 1.29 1625.64 1047.24 0.33 117438.* PF 2(5 yr) 2893 222.48 227.34 0.000640 1.34 2247.45 1605.05 0.30 117438.* PF 3(10 yr) 3426 222.48 227.65 0.000529 1.34 2784.08 1788.94 0.28 117438.* PF 4(25 yr) 4359 222.48 228.11 0.000434 1.37 3633.33 1934.81 0.26 117438.* PF 5(50 yr) 5300 222.48 228.53 0.000373 1.40 4502.09 2135.40 0.25 117438.* PF 6(100 yr) 6410 222.48 228.98 0.000321 1.42 5483.19 2191.43 0.24

117129 PF 1 (2yr) 2099 222.22 226.54 0.001049 1.44 1462.31 1042.10 0.37 117129 PF 2(5 yr) 2893 222.22 227.13 0.000656 1.41 2200.45 1490.99 0.31 117129 PF 3(10 yr) 3426 222.22 227.49 0.000516 1.38 2751.46 1576.82 0.28 117129 PF 4(25 yr) 4359 222.22 227.97 0.000425 1.41 3575.56 1778.64 0.26 117129 PF 5(50 yr) 5300 222.22 228.41 0.000366 1.44 4367.14 1834.86 0.25 117129 PF 6(100 yr) 6410 222.22 228.87 0.000325 1.48 5236.87 1915.24 0.24

116874 PF 1 (2yr) 2099 222.12 226.55 0.000090 0.66 3651.32 1936.06 0.12 116874 PF 2(5 yr) 2893 222.12 227.14 0.000084 0.72 4887.98 2194.19 0.12 116874 PF 3(10 yr) 3426 222.12 227.49 0.000080 0.75 5689.26 2283.05 0.12 116874 PF 4(25 yr) 4359 222.12 227.98 0.000081 0.81 6824.46 2403.31 0.12 116874 PF 5(50 yr) 5300 222.12 228.42 0.000082 0.87 7900.27 2511.98 0.13 116874 PF 6(100 yr) 6410 222.12 228.88 0.000082 0.92 9097.56 2627.64 0.13

115068 PF 1 (2yr) 2099 221.92 225.87 0.001199 2.33 901.19 313.81 0.44 115068 PF 2(5 yr) 2893 221.92 226.35 0.001634 2.71 1068.67 374.66 0.51 115068 PF 3(10 yr) 3426 221.92 226.66 0.002243 2.85 1201.33 494.21 0.58 115068 PF 4(25 yr) 4359 221.92 227.08 0.002278 3.06 1458.53 745.59 0.60 115068 PF 5(50 yr) 5300 221.92 227.51 0.002023 3.13 1830.08 930.82 0.58 115068 PF 6(100 yr) 6410 221.92 228.04 0.001596 3.08 2465.32 1304.23 0.52

113718 PF 1 (2yr) 2099 220.70 225.39 0.000255 0.89 2407.45 1411.20 0.19 113718 PF 2(5 yr) 2893 220.70 225.94 0.000224 0.95 3311.19 1924.22 0.19 113718 PF 3(10 yr) 3426 220.70 226.29 0.000197 0.96 4070.34 2339.43 0.18 113718 PF 4(25 yr) 4359 220.70 226.85 0.000158 0.97 5451.09 2556.28 0.17 113718 PF 5(50 yr) 5300 220.70 227.38 0.000131 0.97 6848.46 2701.28 0.15 113718 PF 6(100 yr) 6410 220.70 227.96 0.000111 0.97 8459.02 2871.86 0.14

112544 PF 1 (2yr) 2099 220.66 225.18 0.000141 0.67 3305.70 1923.33 0.14 112544 PF 2(5 yr) 2893 220.66 225.78 0.000113 0.70 4554.84 2216.24 0.13 112544 PF 3(10 yr) 3426 220.66 226.14 0.000100 0.71 5390.17 2304.21 0.13 112544 PF 4(25 yr) 4359 220.66 226.73 0.000085 0.74 6784.25 2443.99 0.12 112544 PF 5(50 yr) 5300 220.66 227.28 0.000075 0.76 8159.88 2574.50 0.12 112544 PF 6(100 yr) 6410 220.66 227.87 0.000067 0.78 9725.50 2715.40 0.11

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 158 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 111259 PF 1 (2yr) 2099 220.30 224.67 0.000820 1.75 1202.06 486.39 0.35 111259 PF 2(5 yr) 2893 220.30 225.29 0.000761 1.91 1522.81 572.97 0.35 111259 PF 3(10 yr) 3426 220.30 225.68 0.000708 2.00 1757.73 662.89 0.35 111259 PF 4(25 yr) 4359 220.30 226.28 0.000646 2.13 2168.66 709.97 0.34 111259 PF 5(50 yr) 5300 220.30 226.82 0.000607 2.25 2603.30 907.00 0.34 111259 PF 6(100 yr) 6410 220.30 227.43 0.000547 2.32 3163.05 939.30 0.33

109410 PF 1 (2yr) 2099 219.12 224.19 0.000156 0.93 2481.25 1063.08 0.16 109410 PF 2(5 yr) 2893 219.12 224.86 0.000149 1.02 3263.44 1238.24 0.16 109410 PF 3(10 yr) 3426 219.12 225.29 0.000139 1.06 3934.94 1663.49 0.16 109410 PF 4(25 yr) 4359 219.12 225.96 0.000124 1.10 5074.75 1766.35 0.16 109410 PF 5(50 yr) 5300 219.12 226.55 0.000114 1.13 6161.83 1867.28 0.15 109410 PF 6(100 yr) 6410 219.12 227.20 0.000105 1.17 7403.49 1976.26 0.15

108799.* PF 1 (2yr) 2099 218.93 224.07 0.000188 1.06 2296.47 981.65 0.18 108799.* PF 2(5 yr) 2893 218.93 224.74 0.000185 1.18 3064.57 1462.13 0.18 108799.* PF 3(10 yr) 3426 218.93 225.18 0.000169 1.21 3739.04 1594.81 0.18 108799.* PF 4(25 yr) 4359 218.93 225.86 0.000147 1.23 4855.24 1695.09 0.17 108799.* PF 5(50 yr) 5300 218.93 226.47 0.000134 1.26 5920.17 1814.94 0.17 108799.* PF 6(100 yr) 6410 218.93 227.12 0.000122 1.29 7148.46 1944.02 0.16

108188.* PF 1 (2yr) 2099 218.74 223.94 0.000243 1.03 2161.21 1012.23 0.20 108188.* PF 2(5 yr) 2893 218.74 224.63 0.000208 1.10 2961.25 1352.72 0.19 108188.* PF 3(10 yr) 3426 218.74 225.08 0.000182 1.12 3603.64 1479.44 0.18 108188.* PF 4(25 yr) 4359 218.74 225.77 0.000154 1.14 4678.66 1610.77 0.17 108188.* PF 5(50 yr) 5300 218.74 226.39 0.000137 1.17 5702.58 1715.95 0.16 108188.* PF 6(100 yr) 6410 218.74 227.05 0.000123 1.21 6873.89 1829.69 0.16

107577.* PF 1 (2yr) 2099 218.55 223.78 0.000285 1.09 2055.54 1063.14 0.21 107577.* PF 2(5 yr) 2893 218.55 224.49 0.000230 1.15 2867.83 1269.32 0.20 107577.* PF 3(10 yr) 3426 218.55 224.96 0.000197 1.16 3497.90 1393.50 0.19 107577.* PF 4(25 yr) 4359 218.55 225.67 0.000164 1.18 4534.25 1510.07 0.18 107577.* PF 5(50 yr) 5300 218.55 226.30 0.000145 1.21 5513.03 1616.43 0.17 107577.* PF 6(100 yr) 6410 218.55 226.97 0.000131 1.25 6631.21 1726.88 0.16

106966.* PF 1 (2yr) 2099 218.36 223.58 0.000383 1.10 1958.48 1021.34 0.24 106966.* PF 2(5 yr) 2893 218.36 224.34 0.000256 1.10 2796.73 1201.57 0.20 106966.* PF 3(10 yr) 3426 218.36 224.84 0.000206 1.09 3428.14 1327.88 0.19 106966.* PF 4(25 yr) 4359 218.36 225.58 0.000164 1.11 4443.83 1427.79 0.17 106966.* PF 5(50 yr) 5300 218.36 226.21 0.000143 1.14 5380.65 1510.48 0.17 106966.* PF 6(100 yr) 6410 218.36 226.89 0.000128 1.17 6433.73 1598.09 0.16

106355 PF 1 (2yr) 2099 218.17 223.33 0.000359 1.23 1847.15 976.56 0.24 106355 PF 2(5 yr) 2893 218.17 224.17 0.000249 1.23 2726.70 1139.16 0.21 106355 PF 3(10 yr) 3426 218.17 224.70 0.000205 1.22 3363.89 1269.49 0.19 106355 PF 4(25 yr) 4359 218.17 225.46 0.000168 1.24 4368.32 1360.23 0.18 106355 PF 5(50 yr) 5300 218.17 226.11 0.000150 1.27 5274.83 1428.30 0.17 106355 PF 6(100 yr) 6410 218.17 226.80 0.000137 1.31 6279.32 1500.14 0.17

104906 PF 1 (2yr) 2099 217.11 222.45 0.000638 2.24 958.02 283.29 0.34 104906 PF 2(5 yr) 2893 217.11 223.37 0.000611 2.49 1261.89 374.43 0.35

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 159 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 104906 PF 3(10 yr) 3426 217.11 223.94 0.000588 2.62 1490.81 451.69 0.35 104906 PF 4(25 yr) 4359 217.11 224.71 0.000587 2.84 1911.04 629.68 0.35 104906 PF 5(50 yr) 5300 217.11 225.37 0.000570 2.98 2370.64 738.43 0.35 104906 PF 6(100 yr) 6410 217.11 226.08 0.000538 3.08 2920.91 803.80 0.35

104562 PF 1 (2yr) 2099 217.05 221.42 0.002848 4.02 523.09 154.52 0.69 104562 PF 2(5 yr) 2893 217.05 222.17 0.002862 4.53 641.67 160.89 0.71 104562 PF 3(10 yr) 3426 217.05 222.65 0.003056 4.77 724.00 188.58 0.74 104562 PF 4(25 yr) 4359 217.05 223.29 0.002953 5.16 922.09 311.59 0.75 104562 PF 5(50 yr) 5300 217.05 223.83 0.002895 5.48 1095.20 320.76 0.75 104562 PF 6(100 yr) 6410 217.05 224.38 0.002924 5.87 1271.88 345.05 0.77

103309 PF 1 (2yr) 2099 214.20 220.10 0.000799 2.31 907.53 235.00 0.38 103309 PF 2(5 yr) 2893 214.20 221.08 0.000721 2.53 1164.67 293.76 0.37 103309 PF 3(10 yr) 3426 214.20 221.52 0.000745 2.72 1302.66 340.53 0.38 103309 PF 4(25 yr) 4359 214.20 222.20 0.000777 3.02 1583.35 460.50 0.40 103309 PF 5(50 yr) 5300 214.20 222.76 0.000809 3.27 1858.72 520.89 0.41 103309 PF 6(100 yr) 6410 214.20 223.33 0.000840 3.53 2232.61 725.07 0.43

102609.* PF 1 (2yr) 2099 213.71 219.54 0.000794 2.29 915.96 239.54 0.37 102609.* PF 2(5 yr) 2893 213.71 220.55 0.000845 2.44 1188.31 307.48 0.39 102609.* PF 3(10 yr) 3426 213.71 220.98 0.000861 2.60 1331.21 360.67 0.40 102609.* PF 4(25 yr) 4359 213.71 221.66 0.000862 2.82 1620.79 473.81 0.41 102609.* PF 5(50 yr) 5300 213.71 222.22 0.000861 3.03 1903.44 541.10 0.41 102609.* PF 6(100 yr) 6410 213.71 222.79 0.000863 3.24 2286.76 741.06 0.42

101909.* PF 1 (2yr) 2099 213.23 218.99 0.000788 2.27 925.29 244.41 0.37 101909.* PF 2(5 yr) 2893 213.23 219.95 0.000870 2.43 1192.42 316.06 0.39 101909.* PF 3(10 yr) 3426 213.23 220.38 0.000872 2.58 1335.96 363.68 0.40 101909.* PF 4(25 yr) 4359 213.23 221.06 0.000867 2.80 1626.86 479.80 0.41 101909.* PF 5(50 yr) 5300 213.23 221.63 0.000858 3.00 1916.56 544.83 0.41 101909.* PF 6(100 yr) 6410 213.23 222.20 0.000859 3.21 2297.50 753.01 0.42

101209.* PF 1 (2yr) 2099 212.74 218.45 0.000786 2.24 935.46 250.74 0.37 101209.* PF 2(5 yr) 2893 212.74 219.32 0.000903 2.44 1188.57 320.69 0.40 101209.* PF 3(10 yr) 3426 212.74 219.76 0.000892 2.58 1335.43 363.79 0.40 101209.* PF 4(25 yr) 4359 212.74 220.46 0.000851 2.79 1634.18 485.84 0.40 101209.* PF 5(50 yr) 5300 212.74 221.04 0.000838 2.98 1932.76 551.96 0.41 101209.* PF 6(100 yr) 6410 212.74 221.61 0.000843 3.19 2310.58 765.06 0.42

100509.* PF 1 (2yr) 2099 212.26 217.89 0.000801 2.22 945.16 261.06 0.37 100509.* PF 2(5 yr) 2893 212.26 218.72 0.000811 2.46 1189.84 325.88 0.38 100509.* PF 3(10 yr) 3426 212.26 219.15 0.000826 2.64 1335.74 364.42 0.39 100509.* PF 4(25 yr) 4359 212.26 219.86 0.000826 2.86 1639.35 491.18 0.40 100509.* PF 5(50 yr) 5300 212.26 220.45 0.000817 3.05 1946.49 558.18 0.41 100509.* PF 6(100 yr) 6410 212.26 221.00 0.000836 3.28 2310.73 775.63 0.42

99809.9* PF 1 (2yr) 2099 211.77 217.33 0.000819 2.20 952.91 270.98 0.38 99809.9* PF 2(5 yr) 2893 211.77 218.17 0.000794 2.43 1207.67 334.04 0.38 99809.9* PF 3(10 yr) 3426 211.77 218.58 0.000814 2.60 1352.84 375.26 0.39 99809.9* PF 4(25 yr) 4359 211.77 219.26 0.000910 2.83 1645.86 496.44 0.42

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 160 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 99809.9* PF 5(50 yr) 5300 211.77 219.84 0.000972 2.98 1952.41 561.99 0.43 99809.9* PF 6(100 yr) 6410 211.77 220.41 0.000939 3.15 2322.89 769.33 0.43

99110.1* PF 1 (2yr) 2099 211.29 216.75 0.000833 2.19 958.73 278.80 0.38 99110.1* PF 2(5 yr) 2893 211.29 217.58 0.000906 2.38 1215.41 340.05 0.40 99110.1* PF 3(10 yr) 3426 211.29 218.00 0.000893 2.53 1364.09 382.63 0.40 99110.1* PF 4(25 yr) 4359 211.29 218.64 0.000887 2.75 1643.82 493.68 0.41 99110.1* PF 5(50 yr) 5300 211.29 219.20 0.000872 2.94 1939.18 562.16 0.41 99110.1* PF 6(100 yr) 6410 211.29 219.78 0.000862 3.14 2305.28 735.52 0.42

98410.3* PF 1 (2yr) 2099 210.80 216.17 0.000827 2.18 964.10 282.39 0.38 98410.3* PF 2(5 yr) 2893 210.80 216.98 0.000794 2.41 1217.68 344.92 0.38 98410.3* PF 3(10 yr) 3426 210.80 217.39 0.000804 2.58 1366.07 385.21 0.39 98410.3* PF 4(25 yr) 4359 210.80 218.02 0.000824 2.85 1638.36 484.42 0.40 98410.3* PF 5(50 yr) 5300 210.80 218.57 0.000837 3.07 1929.13 563.67 0.41 98410.3* PF 6(100 yr) 6410 210.80 219.14 0.000850 3.30 2281.37 700.41 0.42

97710.5* PF 1 (2yr) 2099 210.32 215.60 0.000820 2.16 970.91 286.38 0.37 97710.5* PF 2(5 yr) 2893 210.32 216.39 0.000916 2.37 1223.15 350.34 0.40 97710.5* PF 3(10 yr) 3426 210.32 216.82 0.000885 2.51 1378.83 393.51 0.40 97710.5* PF 4(25 yr) 4359 210.32 217.45 0.000867 2.74 1659.19 490.43 0.40 97710.5* PF 5(50 yr) 5300 210.32 218.00 0.000858 2.94 1956.16 572.49 0.41 97710.5* PF 6(100 yr) 6410 210.32 218.57 0.000856 3.14 2313.21 717.47 0.42

97010.7* PF 1 (2yr) 2099 209.83 215.03 0.000822 2.15 978.52 290.43 0.37 97010.7* PF 2(5 yr) 2893 209.83 215.78 0.000812 2.40 1220.94 354.03 0.38 97010.7* PF 3(10 yr) 3426 209.83 216.21 0.000810 2.56 1380.79 396.79 0.39 97010.7* PF 4(25 yr) 4359 209.83 216.84 0.000819 2.81 1662.75 492.89 0.40 97010.7* PF 5(50 yr) 5300 209.83 217.39 0.000830 3.03 1956.80 575.61 0.41 97010.7* PF 6(100 yr) 6410 209.83 217.96 0.000840 3.25 2314.06 705.95 0.42

96310.9* PF 1 (2yr) 2099 209.35 214.46 0.000815 2.13 986.52 294.54 0.37 96310.9* PF 2(5 yr) 2893 209.35 215.22 0.000795 2.37 1237.40 361.76 0.38 96310.9* PF 3(10 yr) 3426 209.35 215.66 0.000789 2.52 1403.05 411.29 0.38 96310.9* PF 4(25 yr) 4359 209.35 216.29 0.000798 2.77 1691.02 502.42 0.39 96310.9* PF 5(50 yr) 5300 209.35 216.83 0.000811 2.99 1985.48 584.22 0.40 96310.9* PF 6(100 yr) 6410 209.35 217.39 0.000822 3.20 2339.61 683.24 0.41

95611.0* PF 1 (2yr) 2099 208.86 213.89 0.000804 2.11 996.39 298.90 0.37 95611.0* PF 2(5 yr) 2893 208.86 214.68 0.000769 2.33 1260.00 370.94 0.37 95611.0* PF 3(10 yr) 3426 208.86 215.12 0.000782 2.48 1430.47 427.77 0.38 95611.0* PF 4(25 yr) 4359 208.86 215.74 0.000786 2.71 1727.21 513.91 0.39 95611.0* PF 5(50 yr) 5300 208.86 216.28 0.000798 2.92 2023.31 594.80 0.40 95611.0* PF 6(100 yr) 6410 208.86 216.83 0.000806 3.13 2381.50 693.30 0.41

94911.2* PF 1 (2yr) 2099 208.38 213.34 0.000786 2.08 1009.91 303.98 0.36 94911.2* PF 2(5 yr) 2893 208.38 214.17 0.000726 2.27 1293.78 382.79 0.36 94911.2* PF 3(10 yr) 3426 208.38 214.60 0.000719 2.42 1471.38 447.37 0.37 94911.2* PF 4(25 yr) 4359 208.38 215.23 0.000727 2.65 1777.31 528.30 0.38 94911.2* PF 5(50 yr) 5300 208.38 215.75 0.000749 2.88 2073.65 608.25 0.39 94911.2* PF 6(100 yr) 6410 208.38 216.30 0.000765 3.09 2434.65 705.97 0.40

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 161 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

94211.4* PF 1 (2yr) 2099 207.89 212.81 0.000758 2.04 1028.89 309.95 0.36 94211.4* PF 2(5 yr) 2893 207.89 213.65 0.000795 2.18 1327.03 394.90 0.37 94211.4* PF 3(10 yr) 3426 207.89 214.12 0.000738 2.28 1526.69 470.04 0.36 94211.4* PF 4(25 yr) 4359 207.89 214.75 0.000714 2.48 1852.33 547.35 0.37 94211.4* PF 5(50 yr) 5300 207.89 215.27 0.000724 2.68 2156.22 631.94 0.38 94211.4* PF 6(100 yr) 6410 207.89 215.82 0.000731 2.88 2528.03 762.75 0.38

93511.6* PF 1 (2yr) 2099 207.41 212.30 0.000716 1.99 1056.73 317.44 0.35 93511.6* PF 2(5 yr) 2893 207.41 213.11 0.000764 2.15 1352.18 405.39 0.36 93511.6* PF 3(10 yr) 3426 207.41 213.60 0.000764 2.22 1571.07 488.36 0.37 93511.6* PF 4(25 yr) 4359 207.41 214.28 0.000700 2.36 1929.86 566.11 0.36 93511.6* PF 5(50 yr) 5300 207.41 214.80 0.000697 2.54 2247.01 656.89 0.37 93511.6* PF 6(100 yr) 6410 207.41 215.35 0.000691 2.71 2640.53 801.22 0.37

92811.8* PF 1 (2yr) 2099 206.92 211.83 0.000655 1.91 1098.24 327.08 0.33 92811.8* PF 2(5 yr) 2893 206.92 212.63 0.000644 2.10 1401.82 434.19 0.34 92811.8* PF 3(10 yr) 3426 206.92 213.10 0.000673 2.19 1626.83 507.45 0.35 92811.8* PF 4(25 yr) 4359 206.92 213.81 0.000674 2.32 2012.41 589.30 0.35 92811.8* PF 5(50 yr) 5300 206.92 214.34 0.000670 2.48 2346.34 682.91 0.36 92811.8* PF 6(100 yr) 6410 206.92 214.90 0.000653 2.64 2770.30 838.96 0.36

92112.0* PF 1 (2yr) 2099 206.44 211.41 0.000586 1.81 1157.95 350.80 0.32 92112.0* PF 2(5 yr) 2893 206.44 212.22 0.000586 2.00 1488.75 478.35 0.32 92112.0* PF 3(10 yr) 3426 206.44 212.68 0.000602 2.09 1721.04 532.00 0.33 92112.0* PF 4(25 yr) 4359 206.44 213.39 0.000592 2.21 2127.73 621.28 0.33 92112.0* PF 5(50 yr) 5300 206.44 213.92 0.000585 2.36 2483.61 717.28 0.34 92112.0* PF 6(100 yr) 6410 206.44 214.50 0.000567 2.50 2950.07 901.94 0.34

91412.2* PF 1 (2yr) 2099 205.95 211.07 0.000455 1.69 1251.13 390.65 0.28 91412.2* PF 2(5 yr) 2893 205.95 211.88 0.000443 1.87 1622.85 517.79 0.29 91412.2* PF 3(10 yr) 3426 205.95 212.34 0.000434 1.98 1870.22 565.01 0.29 91412.2* PF 4(25 yr) 4359 205.95 213.05 0.000422 2.14 2307.18 670.98 0.29 91412.2* PF 5(50 yr) 5300 205.95 213.58 0.000442 2.33 2682.38 762.99 0.30 91412.2* PF 6(100 yr) 6410 205.95 214.16 0.000450 2.50 3198.19 994.82 0.31

90712.4* PF 1 (2yr) 2099 205.47 210.76 0.000463 1.53 1372.20 439.49 0.28 90712.4* PF 2(5 yr) 2893 205.47 211.60 0.000437 1.63 1799.84 556.84 0.28 90712.4* PF 3(10 yr) 3426 205.47 212.07 0.000423 1.69 2073.53 604.43 0.27 90712.4* PF 4(25 yr) 4359 205.47 212.82 0.000374 1.79 2573.83 738.43 0.27 90712.4* PF 5(50 yr) 5300 205.47 213.35 0.000376 1.93 2999.07 893.99 0.27 90712.4* PF 6(100 yr) 6410 205.47 213.94 0.000364 2.04 3593.22 1063.85 0.27

90012.6* PF 1 (2yr) 2099 204.99 210.49 0.000362 1.38 1530.59 510.68 0.25 90012.6* PF 2(5 yr) 2893 204.99 211.36 0.000332 1.47 2009.46 597.66 0.24 90012.6* PF 3(10 yr) 3426 204.99 211.84 0.000312 1.53 2313.36 668.44 0.24 90012.6* PF 4(25 yr) 4359 204.99 212.62 0.000279 1.62 2892.80 858.17 0.23 90012.6* PF 5(50 yr) 5300 204.99 213.14 0.000285 1.75 3386.84 1039.43 0.24 90012.6* PF 6(100 yr) 6410 204.99 213.75 0.000279 1.86 4047.47 1153.49 0.24

89312.8* PF 1 (2yr) 2099 204.50 210.30 0.000257 1.21 1749.03 558.58 0.21

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 162 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 89312.8* PF 2(5 yr) 2893 204.50 211.18 0.000239 1.31 2278.80 654.33 0.21 89312.8* PF 3(10 yr) 3426 204.50 211.67 0.000225 1.37 2628.12 749.74 0.21 89312.8* PF 4(25 yr) 4359 204.50 212.47 0.000203 1.45 3316.18 1010.11 0.20 89312.8* PF 5(50 yr) 5300 204.50 212.99 0.000211 1.57 3881.41 1139.82 0.21 89312.8* PF 6(100 yr) 6410 204.50 213.60 0.000209 1.67 4623.87 1287.89 0.21

88613 PF 1 (2yr) 3482 204.02 209.90 0.000475 2.00 1870.34 584.42 0.30 88613 PF 2(5 yr) 4822 204.02 210.74 0.000490 2.28 2397.48 685.55 0.31 88613 PF 3(10 yr) 5683 204.02 211.22 0.000495 2.42 2749.96 778.67 0.32 88613 PF 4(25 yr) 7279 204.02 211.99 0.000503 2.65 3441.25 1051.13 0.33 88613 PF 5(50 yr) 8522 204.02 212.50 0.000504 2.79 4014.87 1205.84 0.33 88613 PF 6(100 yr) 10187 204.02 213.10 0.000505 2.94 4780.98 1340.11 0.34

87874.0* PF 1 (2yr) 3482 203.54 209.54 0.000532 1.92 1868.57 571.74 0.31 87874.0* PF 2(5 yr) 4822 203.54 210.38 0.000518 2.15 2387.93 672.54 0.31 87874.0* PF 3(10 yr) 5683 203.54 210.87 0.000510 2.28 2737.63 771.36 0.32 87874.0* PF 4(25 yr) 7279 203.54 211.64 0.000502 2.48 3423.05 1036.73 0.32 87874.0* PF 5(50 yr) 8522 203.54 212.15 0.000498 2.60 3993.32 1192.26 0.32 87874.0* PF 6(100 yr) 10187 203.54 212.75 0.000493 2.75 4754.47 1326.42 0.33

87135.0* PF 1 (2yr) 3482 203.07 209.14 0.000539 1.93 1845.58 554.45 0.31 87135.0* PF 2(5 yr) 4822 203.07 210.00 0.000523 2.17 2357.99 653.53 0.32 87135.0* PF 3(10 yr) 5683 203.07 210.49 0.000515 2.30 2702.80 757.20 0.32 87135.0* PF 4(25 yr) 7279 203.07 211.26 0.000507 2.50 3376.89 1010.02 0.32 87135.0* PF 5(50 yr) 8522 203.07 211.78 0.000502 2.62 3940.43 1168.53 0.33 87135.0* PF 6(100 yr) 10187 203.07 212.38 0.000498 2.77 4693.17 1308.58 0.33

86396.0* PF 1 (2yr) 3482 202.59 208.73 0.000566 1.94 1817.90 539.06 0.32 86396.0* PF 2(5 yr) 4822 202.59 209.60 0.000538 2.17 2326.61 637.68 0.32 86396.0* PF 3(10 yr) 5683 202.59 210.10 0.000524 2.29 2668.34 741.52 0.32 86396.0* PF 4(25 yr) 7279 202.59 210.89 0.000512 2.49 3335.30 986.22 0.32 86396.0* PF 5(50 yr) 8522 202.59 211.41 0.000506 2.61 3893.91 1148.54 0.33 86396.0* PF 6(100 yr) 10187 202.59 212.01 0.000501 2.76 4639.63 1290.86 0.33

85657.0* PF 1 (2yr) 3482 202.12 208.30 0.000570 1.99 1780.32 527.83 0.32 85657.0* PF 2(5 yr) 4822 202.12 209.19 0.000545 2.22 2284.64 618.41 0.32 85657.0* PF 3(10 yr) 5683 202.12 209.70 0.000531 2.34 2621.53 718.47 0.32 85657.0* PF 4(25 yr) 7279 202.12 210.49 0.000522 2.54 3276.31 955.35 0.33 85657.0* PF 5(50 yr) 8522 202.12 211.01 0.000517 2.68 3825.30 1125.88 0.33 85657.0* PF 6(100 yr) 10187 202.12 211.62 0.000513 2.83 4559.31 1269.80 0.34

84918.0* PF 1 (2yr) 3482 201.65 207.85 0.000626 2.02 1732.59 514.46 0.33 84918.0* PF 2(5 yr) 4822 201.65 208.76 0.000599 2.23 2234.97 595.78 0.33 84918.0* PF 3(10 yr) 5683 201.65 209.28 0.000612 2.34 2562.85 686.83 0.34 84918.0* PF 4(25 yr) 7279 201.65 210.09 0.000570 2.51 3218.10 930.20 0.34 84918.0* PF 5(50 yr) 8522 201.65 210.62 0.000552 2.62 3765.77 1107.27 0.34 84918.0* PF 6(100 yr) 10187 201.65 211.24 0.000537 2.76 4497.15 1249.58 0.34

84179.0* PF 1 (2yr) 3482 201.17 207.39 0.000558 2.15 1678.04 493.13 0.32 84179.0* PF 2(5 yr) 4822 201.17 208.29 0.000566 2.42 2161.86 571.85 0.33 84179.0* PF 3(10 yr) 5683 201.17 208.79 0.000569 2.58 2462.24 645.90 0.34

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 163 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 84179.0* PF 4(25 yr) 7279 201.17 209.59 0.000572 2.82 3073.44 881.78 0.35 84179.0* PF 5(50 yr) 8522 201.17 210.13 0.000572 2.96 3589.46 1062.82 0.35 84179.0* PF 6(100 yr) 10187 201.17 210.74 0.000572 3.13 4290.06 1210.34 0.36

83440.0* PF 1 (2yr) 3482 200.70 206.96 0.000574 2.19 1643.90 468.59 0.33 83440.0* PF 2(5 yr) 4822 200.70 207.85 0.000589 2.48 2108.14 562.08 0.34 83440.0* PF 3(10 yr) 5683 200.70 208.34 0.000598 2.64 2394.55 618.10 0.35 83440.0* PF 4(25 yr) 7279 200.70 209.14 0.000606 2.89 2971.62 829.59 0.36 83440.0* PF 5(50 yr) 8522 200.70 209.66 0.000608 3.05 3457.90 1024.19 0.36 83440.0* PF 6(100 yr) 10187 200.70 210.27 0.000610 3.22 4130.35 1172.36 0.37

82701.0* PF 1 (2yr) 3482 200.23 206.52 0.000599 2.23 1603.80 440.25 0.33 82701.0* PF 2(5 yr) 4822 200.23 207.38 0.000626 2.54 2038.95 549.24 0.35 82701.0* PF 3(10 yr) 5683 200.23 207.86 0.000640 2.71 2310.83 595.52 0.36 82701.0* PF 4(25 yr) 7279 200.23 208.63 0.000660 2.99 2840.85 789.68 0.37 82701.0* PF 5(50 yr) 8522 200.23 209.15 0.000664 3.16 3290.93 953.87 0.38 82701.0* PF 6(100 yr) 10187 200.23 209.76 0.000668 3.35 3923.09 1118.62 0.39

81962.0* PF 1 (2yr) 3482 199.75 206.04 0.000641 2.29 1552.88 421.17 0.35 81962.0* PF 2(5 yr) 4822 199.75 206.87 0.000687 2.64 1946.07 530.80 0.37 81962.0* PF 3(10 yr) 5683 199.75 207.32 0.000709 2.83 2197.90 574.83 0.38 81962.0* PF 4(25 yr) 7279 199.75 208.05 0.000755 3.15 2660.06 752.47 0.40 81962.0* PF 5(50 yr) 8522 199.75 208.57 0.000759 3.33 3068.39 864.37 0.40 81962.0* PF 6(100 yr) 10187 199.75 209.15 0.000771 3.54 3635.07 1055.33 0.41

81223 PF 1 (2yr) 3482 199.28 205.52 0.000716 2.38 1483.07 398.82 0.36 81223 PF 2(5 yr) 4822 199.28 206.27 0.000799 2.79 1815.05 497.95 0.39 81223 PF 3(10 yr) 5683 199.28 206.69 0.000839 3.01 2034.33 544.93 0.41 81223 PF 4(25 yr) 7279 199.28 207.37 0.000902 3.35 2428.49 615.32 0.43 81223 PF 5(50 yr) 8522 199.28 207.82 0.000960 3.62 2743.39 767.41 0.45 81223 PF 6(100 yr) 10187 199.28 208.36 0.000992 3.88 3192.43 912.72 0.46

80609.1* PF 1 (2yr) 3482 198.83 205.07 0.000815 2.28 1541.60 477.22 0.38 80609.1* PF 2(5 yr) 4822 198.83 205.80 0.000843 2.60 1921.24 550.68 0.40 80609.1* PF 3(10 yr) 5683 198.83 206.22 0.000860 2.78 2155.57 590.79 0.41 80609.1* PF 4(25 yr) 7279 198.83 206.89 0.000888 3.07 2609.13 718.99 0.42 80609.1* PF 5(50 yr) 8522 198.83 207.33 0.000906 3.27 2941.99 781.83 0.43 80609.1* PF 6(100 yr) 10187 198.83 207.87 0.000920 3.49 3412.58 925.48 0.44

79995.2* PF 1 (2yr) 3482 198.38 204.55 0.000945 2.17 1605.93 521.43 0.39 79995.2* PF 2(5 yr) 4822 198.38 205.30 0.000918 2.39 2031.66 622.71 0.40 79995.2* PF 3(10 yr) 5683 198.38 205.73 0.000877 2.51 2312.01 666.89 0.40 79995.2* PF 4(25 yr) 7279 198.38 206.42 0.000863 2.71 2803.02 802.78 0.40 79995.2* PF 5(50 yr) 8522 198.38 206.88 0.000844 2.86 3190.42 883.53 0.40 79995.2* PF 6(100 yr) 10187 198.38 207.44 0.000822 3.02 3712.26 970.22 0.41

79381.4* PF 1 (2yr) 3482 197.92 203.97 0.000954 2.14 1625.39 541.18 0.39 79381.4* PF 2(5 yr) 4822 197.92 204.75 0.000903 2.32 2083.26 608.81 0.39 79381.4* PF 3(10 yr) 5683 197.92 205.23 0.000827 2.41 2376.62 631.72 0.39 79381.4* PF 4(25 yr) 7279 197.92 205.93 0.000784 2.61 2860.28 785.63 0.39 79381.4* PF 5(50 yr) 8522 197.92 206.40 0.000768 2.75 3253.32 884.85 0.39

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 164 Feasibility Report: West Rapti Basin

78767.5* PF 1 (2yr) 3482 197.47 203.39 0.000935 2.13 1632.10 538.41 0.39 78767.5* PF 2(5 yr) 4822 197.47 204.23 0.000801 2.30 2103.49 574.59 0.38 78767.5* PF 3(10 yr) 5683 197.47 204.75 0.000731 2.38 2407.58 596.27 0.37 78767.5* PF 4(25 yr) 7279 197.47 205.47 0.000729 2.59 2901.37 802.58 0.37 78767.5* PF 5(50 yr) 8522 197.47 205.95 0.000716 2.73 3312.41 886.75 0.38 78767.5* PF 6(100 yr) 10187 197.47 206.54 0.000699 2.90 3847.65 932.82 0.38

78153.7* PF 1 (2yr) 3482 197.02 202.81 0.000904 2.20 1588.13 499.32 0.39 78153.7* PF 2(5 yr) 4822 197.02 203.74 0.000768 2.35 2074.14 540.79 0.37 78153.7* PF 3(10 yr) 5683 197.02 204.28 0.000786 2.42 2385.77 638.49 0.38 78153.7* PF 4(25 yr) 7279 197.02 205.02 0.000732 2.60 2935.11 817.75 0.38 78153.7* PF 5(50 yr) 8522 197.02 205.52 0.000708 2.73 3357.70 865.52 0.37 78153.7* PF 6(100 yr) 10187 197.02 206.12 0.000687 2.89 3891.23 905.53 0.38

77539.8* PF 1 (2yr) 3482 196.57 202.22 0.000876 2.36 1484.24 416.31 0.39 77539.8* PF 2(5 yr) 4822 196.57 203.20 0.000842 2.53 1933.94 485.00 0.39 77539.8* PF 3(10 yr) 5683 196.57 203.73 0.000831 2.63 2216.73 671.29 0.39 77539.8* PF 4(25 yr) 7279 196.57 204.50 0.000778 2.82 2789.71 803.95 0.39 77539.8* PF 5(50 yr) 8522 196.57 205.01 0.000755 2.96 3209.51 833.41 0.39 77539.8* PF 6(100 yr) 10187 196.57 205.62 0.000736 3.12 3731.03 868.72 0.39

76926 PF 1 (2yr) 3482 196.12 201.63 0.000837 2.58 1358.49 324.44 0.39 76926 PF 2(5 yr) 4822 196.12 202.54 0.000913 2.94 1673.06 406.63 0.42 76926 PF 3(10 yr) 5683 196.12 203.04 0.000910 3.12 1928.81 638.93 0.43 76926 PF 4(25 yr) 7279 196.12 203.80 0.000906 3.40 2467.02 762.76 0.43 76926 PF 5(50 yr) 8522 196.12 204.32 0.000898 3.57 2866.19 788.35 0.44 76926 PF 6(100 yr) 10187 196.12 204.93 0.000892 3.77 3359.21 818.87 0.44

76392.5* PF 1 (2yr) 3482 195.57 201.17 0.000947 2.53 1378.95 356.13 0.41 76392.5* PF 2(5 yr) 4822 195.57 202.08 0.000898 2.82 1734.46 431.12 0.41 76392.5* PF 3(10 yr) 5683 195.57 202.59 0.000880 2.99 1970.32 509.52 0.42 76392.5* PF 4(25 yr) 7279 195.57 203.35 0.000889 3.29 2444.37 711.20 0.43 76392.5* PF 5(50 yr) 8522 195.57 203.86 0.000887 3.47 2830.34 778.64 0.43 76392.5* PF 6(100 yr) 10187 195.57 204.48 0.000880 3.66 3322.11 813.50 0.44

75859.1* PF 1 (2yr) 3482 195.01 200.66 0.000934 2.55 1389.14 380.80 0.41 75859.1* PF 2(5 yr) 4822 195.01 201.58 0.000978 2.82 1764.14 437.17 0.43 75859.1* PF 3(10 yr) 5683 195.01 202.10 0.001008 2.95 2000.31 475.03 0.44 75859.1* PF 4(25 yr) 7279 195.01 202.87 0.000973 3.20 2417.53 644.75 0.44 75859.1* PF 5(50 yr) 8522 195.01 203.39 0.000959 3.38 2774.13 736.26 0.44 75859.1* PF 6(100 yr) 10187 195.01 204.01 0.000940 3.58 3258.63 800.74 0.45

75325.7* PF 1 (2yr) 3482 194.46 200.16 0.001004 2.48 1401.61 387.93 0.42 75325.7* PF 2(5 yr) 4822 194.46 201.06 0.001027 2.72 1774.62 436.76 0.43 75325.7* PF 3(10 yr) 5683 194.46 201.57 0.001040 2.84 2004.28 467.04 0.44 75325.7* PF 4(25 yr) 7279 194.46 202.37 0.000992 3.04 2406.57 546.79 0.44 75325.7* PF 5(50 yr) 8522 194.46 202.90 0.000963 3.21 2720.87 662.45 0.44 75325.7* PF 6(100 yr) 10187 194.46 203.54 0.000935 3.40 3178.39 777.09 0.44

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 165 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 74792.2* PF 1 (2yr) 3482 193.91 199.62 0.001016 2.49 1399.12 389.80 0.42 74792.2* PF 2(5 yr) 4822 193.91 200.51 0.001028 2.73 1766.91 432.48 0.43 74792.2* PF 3(10 yr) 5683 193.91 201.01 0.001037 2.86 1989.23 457.60 0.44 74792.2* PF 4(25 yr) 7279 193.91 201.83 0.001037 3.06 2381.54 513.07 0.45 74792.2* PF 5(50 yr) 8522 193.91 202.37 0.001011 3.21 2676.04 563.72 0.45 74792.2* PF 6(100 yr) 10187 193.91 203.02 0.000974 3.40 3079.86 691.81 0.45

74258.8* PF 1 (2yr) 3482 193.36 199.07 0.001026 2.50 1391.46 387.36 0.42 74258.8* PF 2(5 yr) 4822 193.36 199.96 0.001016 2.75 1756.55 428.76 0.43 74258.8* PF 3(10 yr) 5683 193.36 200.46 0.000993 2.88 1976.49 450.88 0.43 74258.8* PF 4(25 yr) 7279 193.36 201.27 0.000988 3.12 2354.18 489.46 0.44 74258.8* PF 5(50 yr) 8522 193.36 201.82 0.000958 3.29 2637.40 532.38 0.44 74258.8* PF 6(100 yr) 10187 193.36 202.47 0.000945 3.51 3000.61 582.82 0.44

73725.4* PF 1 (2yr) 3482 192.80 198.51 0.001031 2.52 1382.17 382.43 0.42 73725.4* PF 2(5 yr) 4822 192.80 199.40 0.001049 2.77 1740.34 422.88 0.44 73725.4* PF 3(10 yr) 5683 192.80 199.91 0.001048 2.90 1961.64 445.37 0.44 73725.4* PF 4(25 yr) 7279 192.80 200.74 0.001001 3.12 2342.27 478.36 0.44 73725.4* PF 5(50 yr) 8522 192.80 201.31 0.000972 3.27 2625.43 512.96 0.44 73725.4* PF 6(100 yr) 10187 192.80 201.97 0.000951 3.49 2979.52 556.81 0.45

73192 PF 1 (2yr) 3482 192.25 197.97 0.000982 2.54 1377.16 379.35 0.42 73192 PF 2(5 yr) 4822 192.25 198.85 0.000965 2.83 1725.40 415.63 0.43 73192 PF 3(10 yr) 5683 192.25 199.35 0.000958 2.99 1939.50 436.44 0.43 73192 PF 4(25 yr) 7279 192.25 200.17 0.000958 3.26 2312.04 470.39 0.44 73192 PF 5(50 yr) 8522 192.25 200.75 0.000951 3.44 2589.21 495.83 0.44 73192 PF 6(100 yr) 10187 192.25 201.40 0.000953 3.68 2926.42 533.82 0.45

72501.4* PF 1 (2yr) 3482 191.50 197.29 0.001023 2.51 1385.69 382.45 0.42 72501.4* PF 2(5 yr) 4822 191.50 198.17 0.001032 2.77 1739.92 417.44 0.43 72501.4* PF 3(10 yr) 5683 191.50 198.68 0.001032 2.90 1958.64 438.78 0.44 72501.4* PF 4(25 yr) 7279 191.50 199.51 0.001036 3.11 2337.43 472.17 0.45 72501.4* PF 5(50 yr) 8522 191.50 200.11 0.001019 3.25 2624.77 500.32 0.45 72501.4* PF 6(100 yr) 10187 191.50 200.77 0.001013 3.44 2972.24 539.83 0.45

71810.8* PF 1 (2yr) 3482 190.75 196.58 0.001024 2.51 1387.71 384.23 0.42 71810.8* PF 2(5 yr) 4822 190.75 197.46 0.001032 2.77 1740.41 417.90 0.43 71810.8* PF 3(10 yr) 5683 190.75 197.97 0.001034 2.90 1958.93 439.39 0.44 71810.8* PF 4(25 yr) 7279 190.75 198.80 0.001037 3.12 2336.54 472.01 0.45 71810.8* PF 5(50 yr) 8522 190.75 199.40 0.001041 3.24 2626.99 501.07 0.45 71810.8* PF 6(100 yr) 10187 190.75 200.07 0.001026 3.42 2980.72 541.87 0.46

71120.2* PF 1 (2yr) 3482 190.01 195.87 0.001024 2.51 1389.85 385.87 0.42 71120.2* PF 2(5 yr) 4822 190.01 196.75 0.001033 2.77 1740.97 418.25 0.43 71120.2* PF 3(10 yr) 5683 190.01 197.25 0.001036 2.90 1959.11 440.19 0.44 71120.2* PF 4(25 yr) 7279 190.01 198.08 0.001038 3.12 2335.49 471.92 0.45 71120.2* PF 5(50 yr) 8522 190.01 198.67 0.001047 3.25 2622.92 501.21 0.45 71120.2* PF 6(100 yr) 10187 190.01 199.38 0.000990 3.42 2993.07 544.58 0.45

70429.7* PF 1 (2yr) 3482 189.26 195.17 0.001024 2.50 1392.45 387.60 0.42 70429.7* PF 2(5 yr) 4822 189.26 196.03 0.001032 2.77 1742.07 418.81 0.43

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 166 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 70429.7* PF 3(10 yr) 5683 189.26 196.54 0.001034 2.90 1959.79 439.88 0.44 70429.7* PF 4(25 yr) 7279 189.26 197.36 0.001041 3.12 2334.12 472.04 0.45 70429.7* PF 5(50 yr) 8522 189.26 197.94 0.001055 3.26 2616.32 500.97 0.46 70429.7* PF 6(100 yr) 10187 189.26 198.67 0.001076 3.40 2998.14 546.63 0.46

69739.1* PF 1 (2yr) 3482 188.51 194.46 0.001027 2.50 1393.69 389.20 0.42 69739.1* PF 2(5 yr) 4822 188.51 195.32 0.001036 2.77 1741.76 419.70 0.43 69739.1* PF 3(10 yr) 5683 188.51 195.83 0.001034 2.90 1959.38 439.85 0.44 69739.1* PF 4(25 yr) 7279 188.51 196.64 0.001047 3.12 2329.57 472.07 0.45 69739.1* PF 5(50 yr) 8522 188.51 197.21 0.001043 3.27 2609.11 501.03 0.45 69739.1* PF 6(100 yr) 10187 188.51 197.93 0.001038 3.43 2984.82 546.90 0.46

69048.5* PF 1 (2yr) 3482 187.76 193.75 0.001024 2.49 1396.68 390.48 0.42 69048.5* PF 2(5 yr) 4822 187.76 194.61 0.001032 2.77 1743.33 419.41 0.43 69048.5* PF 3(10 yr) 5683 187.76 195.11 0.001032 2.90 1960.86 439.80 0.44 69048.5* PF 4(25 yr) 7279 187.76 195.92 0.001021 3.13 2330.71 472.43 0.44 69048.5* PF 5(50 yr) 8522 187.76 196.50 0.001011 3.27 2612.32 502.43 0.45 69048.5* PF 6(100 yr) 10187 187.76 197.22 0.001020 3.44 2986.87 548.93 0.46

68357.9* PF 1 (2yr) 3482 187.01 193.04 0.001023 2.49 1398.82 391.79 0.42 68357.9* PF 2(5 yr) 4822 187.01 193.89 0.001031 2.76 1744.01 419.47 0.43 68357.9* PF 3(10 yr) 5683 187.01 194.40 0.001033 2.90 1961.30 440.26 0.44 68357.9* PF 4(25 yr) 7279 187.01 195.22 0.001015 3.12 2336.98 473.64 0.44 68357.9* PF 5(50 yr) 8522 187.01 195.81 0.001003 3.26 2624.20 505.40 0.45 68357.9* PF 6(100 yr) 10187 187.01 196.51 0.001017 3.43 2996.23 552.22 0.45

67667.3* PF 1 (2yr) 3482 186.27 192.34 0.001028 2.49 1399.91 393.72 0.42 67667.3* PF 2(5 yr) 4822 186.27 193.18 0.001031 2.76 1743.98 419.40 0.43 67667.3* PF 3(10 yr) 5683 186.27 193.69 0.001036 2.90 1960.35 440.63 0.44 67667.3* PF 4(25 yr) 7279 186.27 194.51 0.001041 3.11 2339.13 474.76 0.45 67667.3* PF 5(50 yr) 8522 186.27 195.10 0.001059 3.24 2627.84 507.61 0.46 67667.3* PF 6(100 yr) 10187 186.27 195.79 0.001088 3.40 2996.59 569.81 0.47

66976.8* PF 1 (2yr) 3482 185.52 191.63 0.001032 2.49 1399.19 394.54 0.42 66976.8* PF 2(5 yr) 4822 185.52 192.47 0.001036 2.77 1742.47 420.18 0.43 66976.8* PF 3(10 yr) 5683 185.52 192.97 0.001042 2.90 1956.95 440.76 0.44 66976.8* PF 4(25 yr) 7279 185.52 193.79 0.001053 3.12 2332.78 475.41 0.45 66976.8* PF 5(50 yr) 8522 185.52 194.36 0.001080 3.26 2611.96 507.41 0.46 66976.8* PF 6(100 yr) 10187 185.52 195.03 0.001102 3.44 2976.52 592.94 0.47

66286.2* PF 1 (2yr) 3482 184.77 190.91 0.001044 2.50 1394.54 394.74 0.42 66286.2* PF 2(5 yr) 4822 184.77 191.75 0.001050 2.78 1736.21 420.40 0.44 66286.2* PF 3(10 yr) 5683 184.77 192.24 0.001059 2.92 1947.81 440.83 0.44 66286.2* PF 4(25 yr) 7279 184.77 193.05 0.001076 3.14 2318.15 475.60 0.45 66286.2* PF 5(50 yr) 8522 184.77 193.59 0.001101 3.30 2586.40 517.43 0.46 66286.2* PF 6(100 yr) 10187 184.77 194.24 0.001129 3.49 2951.27 615.68 0.47

65595.6* PF 1 (2yr) 3482 184.02 190.18 0.001058 2.50 1390.84 395.99 0.43 65595.6* PF 2(5 yr) 4822 184.02 191.02 0.001059 2.78 1732.36 420.85 0.44 65595.6* PF 3(10 yr) 5683 184.02 191.50 0.001074 2.93 1939.40 440.66 0.45 65595.6* PF 4(25 yr) 7279 184.02 192.28 0.001103 3.16 2300.03 475.18 0.46

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 167 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 65595.6* PF 5(50 yr) 8522 184.02 192.81 0.001112 3.33 2566.44 537.95 0.47 65595.6* PF 6(100 yr) 10187 184.02 193.45 0.001112 3.53 2939.55 652.79 0.47

64905.0* PF 1 (2yr) 3482 183.28 189.44 0.001070 2.52 1380.78 391.97 0.43 64905.0* PF 2(5 yr) 4822 183.28 190.27 0.001090 2.81 1717.23 420.81 0.44 64905.0* PF 3(10 yr) 5683 183.28 190.73 0.001112 2.96 1916.97 439.58 0.45 64905.0* PF 4(25 yr) 7279 183.28 191.49 0.001139 3.21 2266.53 489.37 0.47 64905.0* PF 5(50 yr) 8522 183.28 192.02 0.001143 3.39 2539.45 558.71 0.47 64905.0* PF 6(100 yr) 10187 183.28 192.65 0.001144 3.58 2931.30 659.49 0.48

64214.5* PF 1 (2yr) 3482 182.53 188.71 0.001036 2.53 1378.03 394.34 0.42 64214.5* PF 2(5 yr) 4822 182.53 189.53 0.001001 2.85 1713.09 421.36 0.43 64214.5* PF 3(10 yr) 5683 182.53 189.98 0.001008 3.05 1903.18 439.18 0.44 64214.5* PF 4(25 yr) 7279 182.53 190.68 0.001041 3.39 2234.30 507.23 0.46 64214.5* PF 5(50 yr) 8522 182.53 191.17 0.001066 3.62 2499.30 585.79 0.47 64214.5* PF 6(100 yr) 10187 182.53 191.77 0.001084 3.89 2872.78 651.67 0.48

63523.9* PF 1 (2yr) 3482 181.78 187.97 0.001102 2.54 1370.10 392.94 0.43 63523.9* PF 2(5 yr) 4822 181.78 188.82 0.001101 2.81 1717.36 423.80 0.45 63523.9* PF 3(10 yr) 5683 181.78 189.26 0.001111 2.98 1907.83 450.37 0.45 63523.9* PF 4(25 yr) 7279 181.78 189.97 0.001101 3.28 2259.00 547.76 0.46 63523.9* PF 5(50 yr) 8522 181.78 190.46 0.001098 3.48 2545.21 605.01 0.47 63523.9* PF 6(100 yr) 10187 181.78 191.06 0.001090 3.71 2927.58 660.91 0.48

62833.3* PF 1 (2yr) 3482 181.03 187.22 0.001056 2.57 1358.02 384.86 0.43 62833.3* PF 2(5 yr) 4822 181.03 188.04 0.001094 2.89 1691.66 423.01 0.45 62833.3* PF 3(10 yr) 5683 181.03 188.46 0.001098 3.08 1882.14 469.47 0.46 62833.3* PF 4(25 yr) 7279 181.03 189.17 0.001110 3.40 2248.84 573.86 0.47 62833.3* PF 5(50 yr) 8522 181.03 189.65 0.001115 3.61 2536.14 604.96 0.48 62833.3* PF 6(100 yr) 10187 181.03 190.25 0.001122 3.87 2914.59 665.64 0.49

62142.7* PF 1 (2yr) 3482 180.29 186.49 0.001061 2.57 1356.82 381.20 0.43 62142.7* PF 2(5 yr) 4822 180.29 187.27 0.001094 2.91 1680.87 447.09 0.45 62142.7* PF 3(10 yr) 5683 180.29 187.69 0.001102 3.11 1879.49 498.78 0.46 62142.7* PF 4(25 yr) 7279 180.29 188.39 0.001114 3.43 2261.54 576.20 0.47 62142.7* PF 5(50 yr) 8522 180.29 188.88 0.001120 3.64 2548.93 609.85 0.48 62142.7* PF 6(100 yr) 10187 180.29 189.47 0.001130 3.89 2925.09 669.28 0.49

61452.2* PF 1 (2yr) 3482 179.54 185.73 0.001114 2.58 1348.55 380.79 0.44 61452.2* PF 2(5 yr) 4822 179.54 186.50 0.001120 2.92 1675.49 472.83 0.45 61452.2* PF 3(10 yr) 5683 179.54 186.92 0.001123 3.12 1889.22 535.02 0.46 61452.2* PF 4(25 yr) 7279 179.54 187.62 0.001123 3.42 2278.07 582.53 0.47 61452.2* PF 5(50 yr) 8522 179.54 188.10 0.001126 3.63 2568.05 618.60 0.48 61452.2* PF 6(100 yr) 10187 179.54 188.69 0.001135 3.88 2946.62 680.15 0.49

60761.6* PF 1 (2yr) 3482 178.79 184.95 0.001117 2.62 1331.91 389.12 0.44 60761.6* PF 2(5 yr) 4822 178.79 185.71 0.001122 2.98 1669.37 515.58 0.46 60761.6* PF 3(10 yr) 5683 178.79 186.13 0.001125 3.17 1890.92 537.95 0.46 60761.6* PF 4(25 yr) 7279 178.79 186.82 0.001133 3.48 2280.66 589.48 0.48 60761.6* PF 5(50 yr) 8522 178.79 187.30 0.001143 3.70 2570.91 628.94 0.48 60761.6* PF 6(100 yr) 10187 178.79 187.88 0.001152 3.95 2950.89 678.02 0.49

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 168 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

60071.0* PF 1 (2yr) 3482 178.04 184.16 0.001144 2.66 1317.18 406.87 0.45 60071.0* PF 2(5 yr) 4822 178.04 184.92 0.001138 3.01 1674.48 520.72 0.46 60071.0* PF 3(10 yr) 5683 178.04 185.34 0.001139 3.20 1898.55 546.90 0.47 60071.0* PF 4(25 yr) 7279 178.04 186.03 0.001150 3.52 2291.31 601.59 0.48 60071.0* PF 5(50 yr) 8522 178.04 186.50 0.001158 3.73 2584.85 636.42 0.49 60071.0* PF 6(100 yr) 10187 178.04 187.09 0.001155 3.96 2964.27 662.49 0.49

59380.4* PF 1 (2yr) 3482 177.30 183.36 0.001132 2.71 1308.45 438.67 0.45 59380.4* PF 2(5 yr) 4822 177.30 184.13 0.001130 3.07 1679.97 524.34 0.46 59380.4* PF 3(10 yr) 5683 177.30 184.54 0.001144 3.27 1902.27 556.66 0.47 59380.4* PF 4(25 yr) 7279 177.30 185.21 0.001167 3.59 2294.82 609.21 0.48 59380.4* PF 5(50 yr) 8522 177.30 185.68 0.001168 3.80 2587.72 622.44 0.49 59380.4* PF 6(100 yr) 10187 177.30 186.27 0.001168 4.04 2958.32 643.52 0.50

58689.9* PF 1 (2yr) 3482 176.55 182.55 0.001181 2.75 1310.45 454.16 0.45 58689.9* PF 2(5 yr) 4822 176.55 183.33 0.001174 3.07 1692.86 525.94 0.47 58689.9* PF 3(10 yr) 5683 176.55 183.73 0.001188 3.28 1915.31 573.15 0.48 58689.9* PF 4(25 yr) 7279 176.55 184.41 0.001189 3.58 2309.04 594.94 0.49 58689.9* PF 5(50 yr) 8522 176.55 184.88 0.001184 3.77 2596.71 608.42 0.49 58689.9* PF 6(100 yr) 10187 176.55 185.47 0.001177 4.00 2960.74 627.19 0.50

56618.1* PF 1 (2yr) 3482 174.30 180.05 0.001232 2.78 1331.80 480.80 0.46 56618.1* PF 2(5 yr) 4822 174.30 180.80 0.001277 3.10 1695.23 502.04 0.48 56618.1* PF 3(10 yr) 5683 174.30 181.23 0.001242 3.26 1915.61 520.93 0.48 56618.1* PF 4(25 yr) 7279 174.30 181.93 0.001211 3.54 2293.79 549.05 0.49 56618.1* PF 5(50 yr) 8522 174.30 182.43 0.001195 3.73 2568.68 560.31 0.49 56618.1* PF 6(100 yr) 10187 174.30 183.04 0.001178 3.96 2918.85 577.26 0.50

55927.6* PF 1 (2yr) 3482 173.56 179.20 0.001236 2.80 1344.80 467.59 0.46 55927.6* PF 2(5 yr) 4822 173.56 179.92 0.001240 3.15 1683.49 471.81 0.48 55927.6* PF 3(10 yr) 5683 173.56 180.35 0.001259 3.32 1890.23 496.66 0.49 55927.6* PF 4(25 yr) 7279 173.56 181.08 0.001221 3.60 2262.47 532.21 0.49 55927.6* PF 5(50 yr) 8522 173.56 181.58 0.001207 3.79 2532.88 542.69 0.50 55927.6* PF 6(100 yr) 10187 173.56 182.20 0.001194 4.03 2875.63 560.41 0.50

55237.0* PF 1 (2yr) 3482 172.81 178.35 0.001235 2.81 1355.07 454.21 0.46 55237.0* PF 2(5 yr) 4822 172.81 179.05 0.001264 3.18 1675.40 458.09 0.48 55237.0* PF 3(10 yr) 5683 172.81 179.46 0.001272 3.38 1863.75 460.04 0.49 55237.0* PF 4(25 yr) 7279 172.81 180.20 0.001265 3.65 2222.01 500.66 0.50 55237.0* PF 5(50 yr) 8522 172.81 180.71 0.001250 3.85 2484.31 524.16 0.50 55237.0* PF 6(100 yr) 10187 172.81 181.34 0.001237 4.10 2817.68 542.70 0.51

54546.4* PF 1 (2yr) 3482 172.06 177.52 0.001280 2.54 1371.95 440.71 0.46 54546.4* PF 2(5 yr) 4822 172.06 178.23 0.001249 2.86 1685.59 444.38 0.47 54546.4* PF 3(10 yr) 5683 172.06 178.65 0.001228 3.04 1871.50 445.90 0.47 54546.4* PF 4(25 yr) 7279 172.06 179.39 0.001221 3.30 2212.02 480.13 0.48 54546.4* PF 5(50 yr) 8522 172.06 179.93 0.001169 3.46 2478.72 508.00 0.48 54546.4* PF 6(100 yr) 10187 172.06 180.58 0.001133 3.68 2813.59 527.87 0.48

53855.8* PF 1 (2yr) 3482 171.31 176.63 0.001264 2.56 1360.11 427.11 0.46

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 169 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 53855.8* PF 2(5 yr) 4822 171.31 177.37 0.001225 2.88 1674.25 430.13 0.47 53855.8* PF 3(10 yr) 5683 171.31 177.80 0.001203 3.05 1861.16 431.69 0.47 53855.8* PF 4(25 yr) 7279 171.31 178.55 0.001178 3.33 2186.60 438.23 0.48 53855.8* PF 5(50 yr) 8522 171.31 179.12 0.001137 3.49 2454.92 488.53 0.48 53855.8* PF 6(100 yr) 10187 171.31 179.79 0.001106 3.71 2790.19 512.15 0.48

53165.3* PF 1 (2yr) 3482 170.57 175.77 0.001222 2.57 1355.66 413.31 0.45 53165.3* PF 2(5 yr) 4822 170.57 176.54 0.001166 2.88 1674.62 416.04 0.46 53165.3* PF 3(10 yr) 5683 170.57 176.99 0.001141 3.05 1862.24 417.64 0.46 53165.3* PF 4(25 yr) 7279 170.57 177.76 0.001108 3.34 2184.84 420.37 0.47 53165.3* PF 5(50 yr) 8522 170.57 178.33 0.001124 3.51 2434.81 459.70 0.47 53165.3* PF 6(100 yr) 10187 170.57 179.03 0.001082 3.73 2771.20 496.96 0.47

52474.7* PF 1 (2yr) 3482 169.82 174.96 0.001126 2.54 1369.74 399.35 0.44 52474.7* PF 2(5 yr) 4822 169.82 175.78 0.001069 2.85 1695.22 402.19 0.44 52474.7* PF 3(10 yr) 5683 169.82 176.24 0.001052 3.02 1882.36 403.81 0.45 52474.7* PF 4(25 yr) 7279 169.82 177.03 0.001033 3.31 2201.31 406.57 0.45 52474.7* PF 5(50 yr) 8522 169.82 177.59 0.001026 3.52 2432.75 437.42 0.46 52474.7* PF 6(100 yr) 10187 169.82 178.30 0.001006 3.75 2762.49 482.74 0.46

51784.1* PF 1 (2yr) 3482 169.07 174.27 0.000947 2.45 1422.11 385.80 0.41 51784.1* PF 2(5 yr) 4822 169.07 175.11 0.000923 2.76 1747.06 388.69 0.41 51784.1* PF 3(10 yr) 5683 169.07 175.58 0.000926 2.95 1928.88 390.30 0.42 51784.1* PF 4(25 yr) 7279 169.07 176.36 0.000936 3.26 2236.87 393.02 0.43 51784.1* PF 5(50 yr) 8522 169.07 176.92 0.000944 3.48 2457.06 394.94 0.44 51784.1* PF 6(100 yr) 10187 169.07 177.63 0.000943 3.73 2775.44 470.75 0.45

51093.5* PF 1 (2yr) 3482 168.32 173.73 0.000726 2.28 1524.05 373.81 0.36 51093.5* PF 2(5 yr) 4822 168.32 174.55 0.000791 2.63 1835.62 390.52 0.39 51093.5* PF 3(10 yr) 5683 168.32 175.01 0.000807 2.82 2016.59 396.05 0.40 51093.5* PF 4(25 yr) 7279 168.32 175.79 0.000825 3.12 2384.92 519.61 0.41 51093.5* PF 5(50 yr) 8522 168.32 176.36 0.000822 3.31 2690.20 545.01 0.41 51093.5* PF 6(100 yr) 10187 168.32 177.10 0.000830 3.48 3140.29 630.40 0.42

50576.5 Bridge

50403 PF 1 (2yr) 3482 167.58 170.85 0.006148 4.45 782.95 351.90 0.95 50403 PF 2(5 yr) 4822 167.58 171.41 0.005657 4.93 978.34 353.76 0.95 50403 PF 3(10 yr) 5683 167.58 171.71 0.005554 5.23 1087.10 354.80 0.95 50403 PF 4(25 yr) 7279 167.58 172.23 0.005481 5.74 1269.00 356.52 0.97 50403 PF 5(50 yr) 8522 167.58 172.58 0.005522 6.11 1393.92 357.69 0.99 50403 PF 6(100 yr) 10187 167.58 173.04 0.005450 6.53 1560.76 359.26 1.00

50215 PF 1 (2yr) 3482 166.58 170.72 0.001668 2.87 1214.43 396.74 0.52 50215 PF 2(5 yr) 4822 166.58 171.34 0.001750 3.30 1460.49 400.16 0.55 50215 PF 3(10 yr) 5683 166.58 171.68 0.001810 3.55 1598.80 402.08 0.57 50215 PF 4(25 yr) 7279 166.58 172.27 0.001899 3.97 1834.68 405.32 0.60 50215 PF 5(50 yr) 8522 166.58 172.68 0.001965 4.26 2000.84 407.58 0.61 50215 PF 6(100 yr) 10187 166.58 173.17 0.002063 4.63 2200.88 410.30 0.64

48583 PF 1 (2yr) 3482 164.38 168.07 0.001687 2.44 1429.54 602.08 0.50

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 170 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 48583 PF 2(5 yr) 4822 164.38 168.59 0.001773 2.75 1751.05 637.01 0.53 48583 PF 3(10 yr) 5683 164.38 168.87 0.001818 2.94 1932.03 648.61 0.54 48583 PF 4(25 yr) 7279 164.38 169.30 0.001964 3.29 2213.81 666.27 0.58 48583 PF 5(50 yr) 8522 164.38 169.60 0.002071 3.53 2412.34 678.44 0.60 48583 PF 6(100 yr) 10187 164.38 169.92 0.002213 3.86 2683.96 976.51 0.63

47002 PF 1 (2yr) 3482 161.51 165.75 0.001340 2.32 1704.01 985.42 0.46 47002 PF 2(5 yr) 4822 161.51 166.23 0.001344 2.60 2199.70 1072.23 0.47 47002 PF 3(10 yr) 5683 161.51 166.50 0.001352 2.75 2490.60 1117.24 0.48 47002 PF 4(25 yr) 7279 161.51 166.95 0.001309 2.94 3196.06 1533.85 0.48 47002 PF 5(50 yr) 8522 161.51 167.27 0.001269 3.06 3705.40 1628.59 0.48 47002 PF 6(100 yr) 10187 161.51 167.68 0.001205 3.17 4388.66 1725.02 0.48

46382 PF 1 (2yr) 3482 161.14 163.55 0.007775 3.80 916.61 623.62 1.00 46382 PF 2(5 yr) 4822 161.14 163.90 0.007459 4.24 1138.34 637.52 1.01 46382 PF 3(10 yr) 5683 161.14 164.13 0.007027 4.42 1286.49 646.97 1.00 46382 PF 4(25 yr) 7279 161.14 164.50 0.006692 4.75 1531.28 665.00 1.00 46382 PF 5(50 yr) 8522 161.14 164.78 0.006498 4.97 1714.53 681.18 1.00 46382 PF 6(100 yr) 10187 161.14 165.10 0.006403 5.26 1938.26 700.42 1.01

44672 PF 1 (2yr) 3482 157.31 160.27 0.000934 1.36 2551.43 1645.75 0.35 44672 PF 2(5 yr) 4822 157.31 160.66 0.000861 1.51 3186.22 1671.32 0.35 44672 PF 3(10 yr) 5683 157.31 160.88 0.000830 1.60 3560.96 1686.18 0.35 44672 PF 4(25 yr) 7279 157.31 161.27 0.000785 1.73 4217.30 1711.88 0.35 44672 PF 5(50 yr) 8522 157.31 161.54 0.000760 1.83 4695.23 1731.21 0.35 44672 PF 6(100 yr) 10187 157.31 161.89 0.000719 1.92 5475.65 1943.56 0.35

43734 PF 1 (2yr) 3482 155.61 159.70 0.000464 1.09 3211.86 1818.74 0.25 43734 PF 2(5 yr) 4822 155.61 160.11 0.000454 1.23 3974.00 1863.52 0.26 43734 PF 3(10 yr) 5683 155.61 160.35 0.000454 1.31 4412.90 1879.78 0.26 43734 PF 4(25 yr) 7279 155.61 160.76 0.000447 1.44 5188.26 1911.78 0.27 43734 PF 5(50 yr) 8522 155.61 161.05 0.000446 1.53 5745.89 1949.21 0.27 43734 PF 6(100 yr) 10187 155.61 161.41 0.000444 1.63 6449.33 1976.49 0.28

41794 PF 1 (2yr) 3482 155.20 158.88 0.000392 1.03 3470.19 1923.93 0.24 41794 PF 2(5 yr) 4822 155.20 159.31 0.000383 1.16 4305.78 1988.58 0.24 41794 PF 3(10 yr) 5683 155.20 159.56 0.000380 1.24 4801.27 2025.93 0.24 41794 PF 4(25 yr) 7279 155.20 159.97 0.000376 1.35 5656.59 2088.85 0.25 41794 PF 5(50 yr) 8522 155.20 160.27 0.000375 1.44 6275.89 2133.25 0.25 41794 PF 6(100 yr) 10187 155.20 160.63 0.000376 1.54 7056.06 2187.90 0.26

40074 PF 1 (2yr) 3482 153.10 157.57 0.001309 2.22 1947.12 1455.33 0.45 40074 PF 2(5 yr) 4822 153.10 158.10 0.001106 2.32 2785.24 1713.38 0.43 40074 PF 3(10 yr) 5683 153.10 158.38 0.001036 2.38 3283.79 1833.46 0.42 40074 PF 4(25 yr) 7279 153.10 158.84 0.000949 2.49 4180.75 2044.64 0.41 40074 PF 5(50 yr) 8522 153.10 159.16 0.000904 2.56 4854.78 2189.97 0.40 40074 PF 6(100 yr) 10187 153.10 159.55 0.000857 2.65 5738.13 2366.96 0.40

37538 PF 1 (2yr) 3482 150.64 155.76 0.000484 1.59 2386.03 1094.97 0.28 37538 PF 2(5 yr) 4822 150.64 156.29 0.000521 1.83 3062.79 1406.17 0.30 37538 PF 3(10 yr) 5683 150.64 156.57 0.000542 1.96 3469.46 1486.51 0.31

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 171 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 37538 PF 4(25 yr) 7279 150.64 157.01 0.000585 2.18 4143.44 1610.87 0.33 37538 PF 5(50 yr) 8522 150.64 157.32 0.000608 2.32 4652.82 1698.82 0.34 37538 PF 6(100 yr) 10187 150.64 157.69 0.000632 2.49 5310.73 1806.10 0.35

35903 PF 1 (2yr) 3482 150.16 154.31 0.001549 2.32 1647.54 978.20 0.48 35903 PF 2(5 yr) 4822 150.16 154.90 0.001296 2.46 2353.35 1419.96 0.46 35903 PF 3(10 yr) 5683 150.16 155.21 0.001207 2.54 2830.94 1654.01 0.45 35903 PF 4(25 yr) 7279 150.16 155.71 0.001052 2.61 3703.56 1783.69 0.43 35903 PF 5(50 yr) 8522 150.16 156.06 0.000984 2.68 4343.35 1907.29 0.42 35903 PF 6(100 yr) 10187 150.16 156.50 0.000904 2.75 5209.45 2068.67 0.41

34889 PF 1 (2yr) 3482 149.27 153.57 0.000513 1.65 2223.97 874.37 0.29 34889 PF 2(5 yr) 4822 149.27 154.19 0.000525 1.87 2795.03 946.26 0.30 34889 PF 3(10 yr) 5683 149.27 154.48 0.000562 2.03 3071.49 975.11 0.32 34889 PF 4(25 yr) 7279 149.27 154.96 0.000617 2.28 3553.86 1021.55 0.34 34889 PF 5(50 yr) 8522 149.27 155.29 0.000661 2.47 3887.82 1052.17 0.36 34889 PF 6(100 yr) 10187 149.27 155.67 0.000716 2.70 4301.52 1088.36 0.38

34467 PF 1 (2yr) 3482 148.83 153.12 0.001147 2.29 1694.75 843.87 0.43 34467 PF 2(5 yr) 4822 148.83 153.75 0.001062 2.49 2263.88 969.17 0.43 34467 PF 3(10 yr) 5683 148.83 154.05 0.001014 2.57 2787.32 1305.68 0.42 PRTW.07 34467 PF 4(25 yr) 7279 148.83 154.54 0.000987 2.75 3451.06 1390.27 0.43 34467 PF 5(50 yr) 8522 148.83 154.87 0.000984 2.88 3911.16 1432.05 0.43 34467 PF 6(100 yr) 10187 148.83 155.26 0.000986 3.05 4483.12 1482.35 0.44

34097 PF 1 (2yr) 3482 147.50 151.45 0.007023 4.42 786.99 394.45 1.00 34097 PF 2(5 yr) 4822 147.50 151.98 0.006615 4.81 1003.03 426.79 1.00 34097 PF 3(10 yr) 5683 147.50 152.40 0.005412 4.76 1249.99 700.37 0.92 34097 PF 4(25 yr) 7279 147.50 152.96 0.004401 4.87 1692.14 867.59 0.86 34097 PF 5(50 yr) 8522 147.50 153.32 0.003972 4.96 2044.44 1059.74 0.83 34097 PF 6(100 yr) 10187 147.50 153.69 0.003819 5.18 2439.71 1117.65 0.83

32686 PF 1 (2yr) 3482 145.26 150.41 0.000384 1.32 3073.81 1479.31 0.25 32686 PF 2(5 yr) 4822 145.26 150.87 0.000417 1.52 3811.75 1721.53 0.27 32686 PF 3(10 yr) 5683 145.26 151.13 0.000432 1.63 4271.66 1810.12 0.27 32686 PF 4(25 yr) 7279 145.26 151.57 0.000450 1.79 5076.16 1907.19 0.28 32686 PF 5(50 yr) 8522 145.26 151.87 0.000459 1.90 5672.09 1968.96 0.29 32686 PF 6(100 yr) 10187 145.26 152.25 0.000468 2.03 6434.98 2044.94 0.30

30075 PF 1 (2yr) 3482 144.58 149.10 0.000721 1.63 2877.51 1900.59 0.33 30075 PF 2(5 yr) 4822 144.58 149.56 0.000666 1.76 3777.34 1995.86 0.33 30075 PF 3(10 yr) 5683 144.58 149.83 0.000639 1.83 4318.63 2051.05 0.33 30075 PF 4(25 yr) 7279 144.58 150.28 0.000604 1.94 5263.37 2143.96 0.32 30075 PF 5(50 yr) 8522 144.58 150.60 0.000582 2.01 5965.54 2210.49 0.32 30075 PF 6(100 yr) 10187 144.58 151.00 0.000564 2.11 6848.41 2291.40 0.32

27652 PF 1 (2yr) 3482 141.57 146.79 0.001178 2.03 1808.78 844.50 0.42 27652 PF 2(5 yr) 4822 141.57 147.27 0.001241 2.31 2220.83 901.34 0.44 27652 PF 3(10 yr) 5683 141.57 147.53 0.001275 2.46 2465.80 933.49 0.46 27652 PF 4(25 yr) 7279 141.57 147.98 0.001328 2.71 2892.08 986.95 0.47 27652 PF 5(50 yr) 8522 141.57 148.29 0.001361 2.88 3204.81 1026.40 0.49

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 172 Feasibility Report: West Rapti Basin

27200.6* PF 1 (2yr) 3482 141.41 146.27 0.001210 1.96 1853.78 917.39 0.42 27200.6* PF 2(5 yr) 4822 141.41 146.72 0.001259 2.22 2281.07 972.07 0.44 27200.6* PF 3(10 yr) 5683 141.41 146.98 0.001286 2.37 2534.11 1003.05 0.45 27200.6* PF 4(25 yr) 7279 141.41 147.41 0.001310 2.60 2979.27 1050.03 0.47 27200.6* PF 5(50 yr) 8522 141.41 147.72 0.001324 2.76 3302.58 1080.52 0.48 27200.6* PF 6(100 yr) 10187 141.41 148.09 0.001322 2.95 3714.31 1122.99 0.48

26749.3* PF 1 (2yr) 3482 141.25 145.73 0.001235 1.89 1903.78 1002.74 0.42 26749.3* PF 2(5 yr) 4822 141.25 146.17 0.001257 2.14 2359.76 1067.31 0.44 26749.3* PF 3(10 yr) 5683 141.25 146.43 0.001252 2.27 2637.05 1099.08 0.44 26749.3* PF 4(25 yr) 7279 141.25 146.87 0.001231 2.46 3133.67 1152.08 0.45 26749.3* PF 5(50 yr) 8522 141.25 147.18 0.001212 2.60 3500.03 1186.29 0.45 26749.3* PF 6(100 yr) 10187 141.25 147.58 0.001178 2.76 3974.01 1233.20 0.46

26298.0* PF 1 (2yr) 3482 141.09 145.19 0.001236 1.83 1968.95 1119.90 0.42 26298.0* PF 2(5 yr) 4822 141.09 145.65 0.001157 2.01 2517.56 1233.83 0.42 26298.0* PF 3(10 yr) 5683 141.09 145.93 0.001104 2.11 2868.56 1298.53 0.42 26298.0* PF 4(25 yr) 7279 141.09 146.41 0.001014 2.24 3522.92 1409.76 0.41 26298.0* PF 5(50 yr) 8522 141.09 146.76 0.000953 2.33 4020.55 1482.20 0.40 26298.0* PF 6(100 yr) 10187 141.09 147.19 0.000887 2.43 4682.33 1602.01 0.40

25846.6* PF 1 (2yr) 3482 140.93 144.68 0.001111 1.71 2085.44 1173.43 0.40 25846.6* PF 2(5 yr) 4822 140.93 145.22 0.000923 1.82 2738.38 1239.40 0.37 25846.6* PF 3(10 yr) 5683 140.93 145.53 0.000855 1.89 3127.99 1276.41 0.37 25846.6* PF 4(25 yr) 7279 140.93 146.06 0.000763 2.00 3820.18 1333.76 0.36 25846.6* PF 5(50 yr) 8522 140.93 146.43 0.000718 2.09 4319.13 1369.31 0.35 25846.6* PF 6(100 yr) 10187 140.93 146.88 0.000677 2.20 4964.90 1488.72 0.35

25395.3* PF 1 (2yr) 3482 140.77 144.28 0.000791 1.49 2380.88 1277.45 0.34 25395.3* PF 2(5 yr) 4822 140.77 144.92 0.000601 1.55 3224.35 1366.28 0.31 25395.3* PF 3(10 yr) 5683 140.77 145.26 0.000553 1.61 3694.21 1411.54 0.30 25395.3* PF 4(25 yr) 7279 140.77 145.83 0.000492 1.71 4513.78 1475.89 0.29 25395.3* PF 5(50 yr) 8522 140.77 146.21 0.000468 1.78 5130.27 1775.67 0.29 25395.3* PF 6(100 yr) 10187 140.77 146.69 0.000440 1.87 6071.09 2051.46 0.29

24944 PF 1 (2yr) 3482 140.61 144.05 0.000441 1.22 2907.37 1357.50 0.26 24944 PF 2(5 yr) 4822 140.61 144.75 0.000346 1.28 3885.68 1444.55 0.24 24944 PF 3(10 yr) 5683 140.61 145.10 0.000327 1.34 4401.10 1482.44 0.24 24944 PF 4(25 yr) 7279 140.61 145.68 0.000307 1.44 5286.08 1545.33 0.23 24944 PF 5(50 yr) 8522 140.61 146.08 0.000288 1.49 6322.36 2031.29 0.23 24944 PF 6(100 yr) 10187 140.61 146.57 0.000276 1.57 7338.66 2137.77 0.23

23188 PF 1 (2yr) 3482 139.01 143.87 0.000058 0.64 5947.76 1849.67 0.10 23188 PF 2(5 yr) 4822 139.01 144.57 0.000062 0.73 7305.81 2039.55 0.11 23188 PF 3(10 yr) 5683 139.01 144.92 0.000067 0.80 8035.21 2148.90 0.11 23188 PF 4(25 yr) 7279 139.01 145.50 0.000073 0.90 9332.99 2326.34 0.12 23188 PF 5(50 yr) 8522 139.01 145.90 0.000077 0.97 10284.05 2448.21 0.13 23188 PF 6(100 yr) 10187 139.01 146.38 0.000082 1.05 11503.17 2596.09 0.13

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 173 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 21140 PF 1 (2yr) 4306 138.11 143.39 0.000605 1.92 2630.92 1211.91 0.32 21140 PF 2(5 yr) 5971 138.11 144.06 0.000580 2.10 3529.83 1411.57 0.33 21140 PF 3(10 yr) 7027 138.11 144.38 0.000593 2.23 3981.90 1449.14 0.33 21140 PF 4(25 yr) 8991 138.11 144.91 0.000610 2.44 4768.18 1536.02 0.34 21140 PF 5(50 yr) 10532 138.11 145.27 0.000629 2.59 5336.24 1630.13 0.35 21140 PF 6(100 yr) 12613 138.11 145.70 0.000650 2.77 6069.66 1744.14 0.36

20425 Bridge

20348 PF 1 (2yr) 4306 136.98 140.65 0.001918 3.26 1600.05 880.41 0.57 20348 PF 2(5 yr) 5971 136.98 141.26 0.001723 3.44 2444.67 1478.86 0.55 20348 PF 3(10 yr) 7027 136.98 141.60 0.001613 3.51 2975.18 1691.56 0.54 20348 PF 4(25 yr) 8991 136.98 142.16 0.001417 3.58 4031.55 2050.32 0.52 20348 PF 5(50 yr) 10532 136.98 142.56 0.001296 3.60 4883.83 2299.45 0.50 20348 PF 6(100 yr) 12613 136.98 143.04 0.001158 3.61 6059.64 2588.30 0.48

19845 PF 1 (2yr) 4306 136.03 140.39 0.000598 1.86 2571.17 1269.12 0.32 19845 PF 2(5 yr) 5971 136.03 141.00 0.000607 2.09 3450.30 1592.32 0.33 19845 PF 3(10 yr) 7027 136.03 141.33 0.000608 2.20 4006.33 1760.03 0.34 19845 PF 4(25 yr) 8991 136.03 141.89 0.000601 2.37 5076.36 2079.42 0.34 19845 PF 5(50 yr) 10532 136.03 142.28 0.000590 2.47 5927.48 2298.86 0.34 19845 PF 6(100 yr) 12613 136.03 142.76 0.000574 2.58 7087.69 2567.96 0.34

19296 PF 1 (2yr) 4306 135.18 140.04 0.000599 2.10 2779.53 1412.76 0.33 19296 PF 2(5 yr) 5971 135.18 140.66 0.000602 2.32 3775.82 1714.65 0.34 19296 PF 3(10 yr) 7027 135.18 141.01 0.000593 2.41 4386.12 1814.34 0.34 19296 PF 4(25 yr) 8991 135.18 141.58 0.000575 2.54 5479.29 1978.72 0.34 19296 PF 5(50 yr) 10532 135.18 141.98 0.000566 2.64 6288.50 2091.01 0.34 19296 PF 6(100 yr) 12613 135.18 142.47 0.000557 2.76 7335.77 2227.96 0.34

PRTW.08 18840 PF 1 (2yr) 4306 135.10 139.80 0.000559 1.90 3036.75 1664.91 0.31 18840 PF 2(5 yr) 5971 135.10 140.45 0.000514 2.03 4164.50 1818.42 0.31 18840 PF 3(10 yr) 7027 135.10 140.80 0.000496 2.10 4824.55 1902.53 0.31 18840 PF 4(25 yr) 8991 135.10 141.39 0.000474 2.22 5983.73 2041.87 0.31 18840 PF 5(50 yr) 10532 135.10 141.79 0.000465 2.31 6824.17 2137.23 0.31 18840 PF 6(100 yr) 12613 135.10 142.28 0.000459 2.42 7896.47 2253.04 0.31

18406 PF 1 (2yr) 4306 135.06 139.75 0.000184 1.13 5261.83 2034.93 0.18 18406 PF 2(5 yr) 5971 135.06 140.40 0.000185 1.26 6613.09 2123.01 0.19 18406 PF 3(10 yr) 7027 135.06 140.76 0.000188 1.33 7375.22 2171.11 0.19 18406 PF 4(25 yr) 8991 135.06 141.34 0.000193 1.45 8673.94 2250.71 0.20 18406 PF 5(50 yr) 10532 135.06 141.74 0.000199 1.55 9587.86 2305.08 0.20 18406 PF 6(100 yr) 12613 135.06 142.23 0.000207 1.66 10726.07 2371.05 0.21

17785 PF 1 (2yr) 4306 134.42 139.68 0.000104 0.88 6414.27 2357.76 0.14 17785 PF 2(5 yr) 5971 134.42 140.33 0.000111 1.00 7999.55 2531.50 0.15 17785 PF 3(10 yr) 7027 134.42 140.69 0.000115 1.06 8912.26 2626.33 0.15 17785 PF 4(25 yr) 8991 134.42 141.27 0.000121 1.17 10497.16 2783.32 0.16 17785 PF 5(50 yr) 10532 134.42 141.67 0.000126 1.25 11631.56 2890.46 0.16 17785 PF 6(100 yr) 12613 134.42 142.16 0.000132 1.35 13065.77 3020.48 0.17

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 174 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 17069 PF 1 (2yr) 4306 133.91 139.63 0.000070 0.77 7303.64 2420.17 0.11 17069 PF 2(5 yr) 5971 133.91 140.27 0.000078 0.89 8905.69 2556.71 0.12 17069 PF 3(10 yr) 7027 133.91 140.62 0.000083 0.96 9816.65 2631.20 0.13 17069 PF 4(25 yr) 8991 133.91 141.21 0.000091 1.07 11382.83 2754.55 0.14 17069 PF 5(50 yr) 10532 133.91 141.60 0.000097 1.15 12491.46 2838.62 0.14 17069 PF 6(100 yr) 12613 133.91 142.08 0.000104 1.25 13881.13 2940.62 0.15

16550 PF 1 (2yr) 4306 133.78 139.60 0.000057 0.73 7844.29 2300.92 0.10 16550 PF 2(5 yr) 5971 133.78 140.24 0.000067 0.86 9351.30 2415.50 0.12 16550 PF 3(10 yr) 7027 133.78 140.59 0.000073 0.93 10203.85 2477.97 0.12 16550 PF 4(25 yr) 8991 133.78 141.17 0.000082 1.05 11663.76 2581.44 0.13 16550 PF 5(50 yr) 10532 133.78 141.56 0.000089 1.14 12692.11 2651.90 0.14 16550 PF 6(100 yr) 12613 133.78 142.03 0.000098 1.24 13976.30 2737.34 0.15

16053 PF 1 (2yr) 4306 133.51 139.55 0.000127 0.96 6877.93 2721.61 0.15 16053 PF 2(5 yr) 5971 133.51 140.19 0.000129 1.07 8674.05 2918.90 0.16 16053 PF 3(10 yr) 7027 133.51 140.54 0.000131 1.13 9706.66 3026.51 0.16 16053 PF 4(25 yr) 8991 133.51 141.11 0.000134 1.23 11501.42 3204.95 0.16 16053 PF 5(50 yr) 10532 133.51 141.50 0.000138 1.30 12782.34 3326.45 0.17 16053 PF 6(100 yr) 12613 133.51 141.98 0.000143 1.39 14397.56 3473.62 0.17

15483 PF 1 (2yr) 4306 133.30 139.47 0.000148 1.02 6064.99 2296.18 0.16 15483 PF 2(5 yr) 5971 133.30 140.10 0.000153 1.14 7560.25 2433.65 0.17 15483 PF 3(10 yr) 7027 133.30 140.44 0.000157 1.21 8410.29 2508.45 0.17 15483 PF 4(25 yr) 8991 133.30 141.01 0.000163 1.33 9875.78 2632.42 0.18 15483 PF 5(50 yr) 10532 133.30 141.40 0.000170 1.42 10910.96 2716.58 0.19 15483 PF 6(100 yr) 12613 133.30 141.87 0.000178 1.53 12206.31 2818.36 0.19

14747 PF 1 (2yr) 4306 133.27 139.28 0.000306 1.38 4771.51 2540.71 0.23 14747 PF 2(5 yr) 5971 133.27 139.93 0.000263 1.43 6476.30 2718.13 0.22 14747 PF 3(10 yr) 7027 133.27 140.28 0.000250 1.47 7440.47 2813.52 0.22 14747 PF 4(25 yr) 8991 133.27 140.85 0.000236 1.54 9105.44 2971.05 0.22 14747 PF 5(50 yr) 10532 133.27 141.24 0.000232 1.60 10279.16 3077.25 0.22 14747 PF 6(100 yr) 12613 133.27 141.71 0.000230 1.69 11749.73 3205.36 0.22

14000 PF 1 (2yr) 4306 133.01 139.27 0.000034 0.52 10808.92 3125.82 0.08 14000 PF 2(5 yr) 5971 133.01 139.91 0.000041 0.62 12885.93 3366.19 0.09 14000 PF 3(10 yr) 7027 133.01 140.25 0.000045 0.68 14069.58 3492.20 0.09 14000 PF 4(25 yr) 8991 133.01 140.82 0.000051 0.77 16119.38 3679.86 0.10 14000 PF 5(50 yr) 10532 133.01 141.21 0.000055 0.84 17560.50 3801.25 0.11 14000 PF 6(100 yr) 12613 133.01 141.67 0.000060 0.92 19362.40 3952.21 0.11

13016 PF 1 (2yr) 4306 132.90 138.97 0.000750 2.19 2730.46 1446.42 0.36 13016 PF 2(5 yr) 5971 132.90 139.57 0.000728 2.39 3690.19 1710.51 0.37 13016 PF 3(10 yr) 7027 132.90 139.90 0.000711 2.48 4275.35 1809.51 0.37 13016 PF 4(25 yr) 8991 132.90 140.44 0.000712 2.67 5319.88 2093.49 0.37 13016 PF 5(50 yr) 10532 132.90 140.81 0.000699 2.77 6131.69 2250.53 0.37 13016 PF 6(100 yr) 12613 132.90 141.27 0.000672 2.86 7182.56 2367.49 0.37

12081 PF 1 (2yr) 4306 132.60 138.64 0.000270 1.55 4014.38 1678.95 0.23 12081 PF 2(5 yr) 5971 132.60 139.23 0.000301 1.77 5039.30 1822.32 0.24

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 175 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 12081 PF 3(10 yr) 7027 132.60 139.55 0.000316 1.88 5634.62 1900.64 0.25 12081 PF 4(25 yr) 8991 132.60 140.07 0.000341 2.07 6656.99 2014.76 0.27 12081 PF 5(50 yr) 10532 132.60 140.43 0.000355 2.20 7393.19 2066.03 0.27 12081 PF 6(100 yr) 12613 132.60 140.87 0.000372 2.35 8318.52 2128.73 0.28

11157 PF 1 (2yr) 4306 132.40 138.33 0.000403 1.51 3363.77 1588.54 0.26 11157 PF 2(5 yr) 5971 132.40 138.89 0.000420 1.71 4278.18 1678.12 0.27 11157 PF 3(10 yr) 7027 132.40 139.20 0.000431 1.82 4797.55 1726.93 0.28 11157 PF 4(25 yr) 8991 132.40 139.69 0.000453 2.00 5670.24 1805.98 0.29 11157 PF 5(50 yr) 10532 132.40 140.03 0.000469 2.13 6294.97 1860.50 0.30 11157 PF 6(100 yr) 12613 132.40 140.45 0.000490 2.30 7083.22 1927.10 0.31

10061 PF 1 (2yr) 4306 132.21 137.84 0.000484 1.88 3578.83 1620.54 0.30 10061 PF 2(5 yr) 5971 132.21 138.37 0.000522 2.12 4474.46 1745.93 0.31 10061 PF 3(10 yr) 7027 132.21 138.66 0.000544 2.25 4986.73 1813.76 0.32 10061 PF 4(25 yr) 8991 132.21 139.12 0.000586 2.48 5847.10 1922.30 0.34 10061 PF 5(50 yr) 10532 132.21 139.43 0.000617 2.65 6466.47 1996.78 0.35 10061 PF 6(100 yr) 12613 132.21 139.82 0.000652 2.84 7258.64 2088.18 0.37

9077 PF 1 (2yr) 4306 132.21 137.09 0.000886 2.31 2592.88 1577.17 0.39 9077 PF 2(5 yr) 5971 132.21 137.54 0.000976 2.63 3356.12 1809.92 0.42 9077 PF 3(10 yr) 7027 132.21 137.79 0.001005 2.78 3832.81 1934.97 0.43 9077 PF 4(25 yr) 8991 132.21 138.22 0.001025 2.99 4692.51 2094.21 0.44 9077 PF 5(50 yr) 10532 132.21 138.52 0.001025 3.12 5329.71 2160.64 0.45 9077 PF 6(100 yr) 12613 132.21 138.89 0.001022 3.26 6149.07 2243.17 0.45

8282 PF 1 (2yr) 4306 131.87 136.33 0.001122 2.08 2793.22 1892.59 0.42 8282 PF 2(5 yr) 5971 131.87 136.81 0.000998 2.20 3721.10 1964.11 0.40 8282 PF 3(10 yr) 7027 131.87 137.08 0.000949 2.28 4259.22 2004.42 0.40 8282 PF 4(25 yr) 8991 131.87 137.52 0.000905 2.42 5157.98 2069.99 0.40 8282 PF 5(50 yr) 10532 131.87 137.82 0.000891 2.53 5795.44 2115.27 0.40 8282 PF 6(100 yr) 12613 131.87 138.20 0.000880 2.66 6600.05 2170.71 0.40

7734 PF 1 (2yr) 4306 131.12 135.32 0.001951 2.77 1759.61 1094.76 0.55 7734 PF 2(5 yr) 5971 131.12 135.72 0.002130 3.19 2235.19 1255.30 0.59 7734 PF 3(10 yr) 7027 131.12 135.93 0.002236 3.42 2513.92 1340.47 0.61 7734 PF 4(25 yr) 8991 131.12 136.29 0.002391 3.79 3007.26 1462.62 0.64 7734 PF 5(50 yr) 10532 131.12 136.53 0.002484 4.04 3367.18 1517.35 0.66 7734 PF 6(100 yr) 12613 131.12 136.82 0.002611 4.35 3814.00 1582.66 0.69

7233 PF 1 (2yr) 4306 130.80 134.70 0.001129 2.23 2675.66 1885.89 0.42 7233 PF 2(5 yr) 5971 130.80 135.13 0.001131 2.45 3546.95 2146.36 0.44 7233 PF 3(10 yr) 7027 130.80 135.36 0.001146 2.58 4043.77 2268.53 0.44 7233 PF 4(25 yr) 8991 130.80 135.72 0.001185 2.81 4903.32 2492.76 0.46 7233 PF 5(50 yr) 10532 130.80 135.96 0.001220 2.97 5537.04 2666.43 0.47 PRTW.09 7233 PF 6(100 yr) 12613 130.80 136.27 0.001249 3.15 6382.85 2881.97 0.48

6882 PF 1 (2yr) 4306 130.18 134.02 0.002129 2.64 1823.04 1598.02 0.56 6882 PF 2(5 yr) 5971 130.18 134.49 0.001871 2.81 2704.92 2147.51 0.54 6882 PF 3(10 yr) 7027 130.18 134.74 0.001744 2.88 3281.03 2386.15 0.53 6882 PF 4(25 yr) 8991 130.18 135.16 0.001552 2.96 4361.02 2757.26 0.51

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 176 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Frou- Structure period Station charge level level level channel Area Width de [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 6882 PF 5(50 yr) 10532 130.18 135.46 0.001429 3.00 5191.38 2928.16 0.50 6882 PF 6(100 yr) 12613 130.18 135.81 0.001316 3.06 6259.95 3133.62 0.49

6324 PF 1 (2yr) 4306 129.27 133.71 0.000481 1.27 3405.70 1601.74 0.27 6324 PF 2(5 yr) 5971 129.27 134.19 0.000490 1.44 4256.36 1950.03 0.28 6324 PF 3(10 yr) 7027 129.27 134.45 0.000499 1.54 4769.20 2113.01 0.29 6324 PF 4(25 yr) 8991 129.27 134.86 0.000516 1.71 5686.48 2372.66 0.30 6324 PF 5(50 yr) 10532 129.27 135.14 0.000529 1.83 6377.89 2541.82 0.30 6324 PF 6(100 yr) 12613 129.27 135.48 0.000546 1.97 7276.93 2746.24 0.31

5153 PF 1 (2yr) 4306 128.13 132.78 0.001239 1.74 2469.27 1362.54 0.41 5153 PF 2(5 yr) 5971 128.13 133.30 0.001083 1.85 3304.80 1789.81 0.40 5153 PF 3(10 yr) 7027 128.13 133.55 0.001053 1.93 3763.04 1870.34 0.40 5153 PF 4(25 yr) 8991 128.13 133.94 0.001043 2.09 4525.99 1997.24 0.41 5153 PF 5(50 yr) 10532 128.13 134.19 0.001062 2.22 5032.34 2081.55 0.41 5153 PF 6(100 yr) 12613 128.13 134.50 0.001066 2.38 5696.10 2193.59 0.42

4302 PF 1 (2yr) 4306 127.32 131.95 0.000828 1.51 2871.76 1548.79 0.34 4302 PF 2(5 yr) 5971 127.32 132.59 0.000727 1.51 4068.15 2281.03 0.33 4302 PF 3(10 yr) 7027 127.32 132.88 0.000685 1.55 4795.92 2627.23 0.32 4302 PF 4(25 yr) 8991 127.32 133.30 0.000665 1.63 5951.65 2863.08 0.32 4302 PF 5(50 yr) 10532 127.32 133.57 0.000646 1.72 6722.51 2977.59 0.32 4302 PF 6(100 yr) 12613 127.32 133.91 0.000617 1.81 7761.52 3124.10 0.32

3229 PF 1 (2yr) 4306 126.01 129.94 0.003009 3.31 1299.98 533.09 0.68 3229 PF 2(5 yr) 5971 126.01 130.87 0.002273 3.21 1914.05 1092.54 0.61 3229 PF 3(10 yr) 7027 126.01 131.18 0.002230 3.34 2296.89 1519.56 0.61 3229 PF 4(25 yr) 8991 126.01 131.72 0.001872 3.41 3295.53 2025.20 0.57 3229 PF 5(50 yr) 10532 126.01 132.11 0.001632 3.41 4112.61 2201.29 0.54 3229 PF 6(100 yr) 12613 126.01 132.58 0.001400 3.40 5204.94 2416.75 0.51

1812 PF 1 (2yr) 4306 124.12 129.64 0.000176 1.07 4021.69 1066.49 0.18 1812 PF 2(5 yr) 5971 124.12 130.65 0.000153 1.09 6378.54 3024.69 0.17 1812 PF 3(10 yr) 7027 124.12 130.97 0.000157 1.16 7388.06 3222.19 0.17 1812 PF 4(25 yr) 8991 124.12 131.51 0.000160 1.26 9213.05 3563.73 0.18 1812 PF 5(50 yr) 10532 124.12 131.89 0.000161 1.32 10603.39 3803.72 0.18 1812 PF 6(100 yr) 12613 124.12 132.35 0.000161 1.40 12445.62 4093.64 0.18

0 PF 1 (2yr) 4306 123.19 128.74 0.001090 2.36 1822.53 579.20 0.43 0 PF 2(5 yr) 5971 123.19 129.85 0.001092 2.22 2740.13 1116.39 0.42 0 PF 3(10 yr) 7027 123.19 130.13 0.001091 2.36 3068.70 1186.59 0.43 0 PF 4(25 yr) 8991 123.19 130.61 0.001090 2.59 3660.24 1290.11 0.44 0 PF 5(50 yr) 10532 123.19 130.95 0.001090 2.75 4106.33 1356.26 0.44 0 PF 6(100 yr) 12613 123.19 131.36 0.001090 2.94 4688.57 1438.03 0.45

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 177 Feasibility Report: West Rapti Basin

B.3 Modelling Results – Run 3

Table 31: Hydraulic modelling results – Run 3 Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 160985 2yr 2099 300.13 304.31 0.004581 3.45 609.22 322.67 0.80 160985 5yr 2893 300.13 304.92 0.003934 3.52 822.72 379.06 0.76 160985 10yr 3426 300.13 305.26 0.003438 3.60 954.69 392.18 0.73 160985 25yr 4359 300.13 305.83 0.002828 3.71 1185.23 415.71 0.68 160985 50yr 5300 300.13 306.37 0.002387 3.81 1417.88 436.06 0.64 160985 100yr 6410 300.13 307.01 0.001997 3.88 1702.54 459.73 0.60

160118 2yr 2099 298.76 303.32 0.000719 1.99 1105.25 466.53 0.35 160118 5yr 2893 298.76 304.03 0.000674 2.19 1452.64 506.30 0.35 160118 10yr 3426 298.76 304.44 0.000653 2.30 1668.51 525.08 0.35 160118 25yr 4359 298.76 305.13 0.000614 2.46 2039.29 553.38 0.35 160118 50yr 5300 298.76 305.78 0.000579 2.58 2404.04 579.89 0.34 160118 100yr 6410 298.76 306.48 0.000559 2.74 2842.61 666.35 0.34

159301 2yr 2099 297.22 301.31 0.004818 4.24 495.18 199.31 0.86 159301 5yr 2893 297.22 301.97 0.004614 4.57 633.49 220.53 0.86 159301 10yr 3426 297.22 302.34 0.004353 4.78 716.15 222.90 0.85 159301 25yr 4359 297.22 302.91 0.004090 5.17 844.41 234.40 0.85 159301 50yr 5300 297.22 303.39 0.004031 5.56 966.63 270.03 0.86 159301 100yr 6410 297.22 303.89 0.004038 5.99 1109.82 306.51 0.88

159088 2yr 2099 297.21 301.21 0.001309 2.69 784.51 255.09 0.47 159088 5yr 2893 297.21 301.91 0.001305 3.04 980.31 301.11 0.48 159088 10yr 3426 297.21 302.32 0.001301 3.24 1109.50 323.79 0.49 159088 25yr 4359 297.21 302.98 0.001292 3.54 1331.18 363.83 0.50 159088 50yr 5300 297.21 303.56 0.001282 3.79 1564.04 422.75 0.51 159088 100yr 6410 297.21 304.17 0.001267 4.03 1833.11 454.37 0.51

158876 Bridge

158639 2yr 2099 295.84 300.27 0.000907 2.19 960.52 299.55 0.39 158639 5yr 2893 295.84 300.64 0.001190 2.69 1096.00 343.20 0.45 158639 10yr 3426 295.84 300.92 0.001298 2.95 1190.07 345.91 0.48 158639 25yr 4359 295.84 301.33 0.001477 3.36 1334.43 350.03 0.52 158639 50yr 5300 295.84 301.71 0.001636 3.74 1465.49 353.73 0.56 158639 100yr 6410 295.84 302.10 0.001801 4.15 1609.55 370.77 0.59

158463 2yr 2099 295.29 299.89 0.002518 2.67 786.91 390.33 0.60 158463 5yr 2893 295.29 300.07 0.003642 3.39 854.52 390.89 0.73 158463 10yr 3426 295.29 300.33 0.003492 3.57 958.53 391.33 0.73 158463 25yr 4359 295.29 300.69 0.003578 3.96 1100.51 391.91 0.75 158463 50yr 5300 295.29 301.01 0.003696 4.32 1226.48 392.43 0.78 158463 100yr 6410 295.29 301.36 0.003814 4.70 1363.15 393.00 0.81

157563 2yr 2099 292.67 295.69 0.007207 4.27 491.20 264.48 1.00 157563 5yr 2893 292.67 295.99 0.005208 3.92 926.13 619.16 0.87 157563 10yr 3426 292.67 296.13 0.005715 4.24 1011.77 627.24 0.92

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 178 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 157563 25yr 4359 292.67 296.41 0.005885 4.59 1188.28 643.58 0.94 157563 50yr 5300 292.67 296.66 0.005989 4.87 1354.54 658.60 0.97 157563 100yr 6410 292.67 296.94 0.006090 5.17 1537.40 674.74 0.99

156720 2yr 2099 289.52 291.43 0.003075 2.14 981.12 787.66 0.61 156720 5yr 2893 289.52 291.68 0.003250 2.45 1179.77 804.64 0.65 156720 10yr 3426 289.52 291.83 0.003324 2.63 1303.77 815.06 0.66 156720 25yr 4359 289.52 292.09 0.003372 2.88 1512.63 832.32 0.68 156720 50yr 5300 289.52 292.34 0.003366 3.07 1724.60 860.49 0.69 156720 100yr 6410 289.52 292.61 0.003329 3.27 1961.39 885.00 0.70

155824 2yr 2099 287.01 288.77 0.002854 2.10 997.56 776.41 0.59 155824 5yr 2893 287.01 289.09 0.002630 2.33 1242.08 780.67 0.59 155824 10yr 3426 287.01 289.28 0.002535 2.46 1391.75 783.26 0.59 155824 25yr 4359 287.01 289.58 0.002447 2.68 1628.82 787.35 0.59 155824 50yr 5300 287.01 289.86 0.002392 2.87 1847.40 791.10 0.60 155824 100yr 6410 287.01 290.15 0.002374 3.08 2079.81 795.07 0.61

154466 2yr 2099 283.89 286.72 0.000996 1.48 1421.68 854.74 0.37 154466 5yr 2893 283.89 287.10 0.001006 1.65 1749.34 893.97 0.38 154466 10yr 3426 283.89 287.33 0.001007 1.75 1956.74 918.59 0.38 154466 25yr 4359 283.89 287.72 0.000977 1.88 2322.46 960.46 0.39 154466 50yr 5300 283.89 288.02 0.000984 2.03 2620.14 1012.18 0.39 154466 100yr 6410 283.89 288.34 0.000984 2.18 2959.10 1074.83 0.40

153554 2yr 2099 281.62 284.61 0.005711 2.74 764.89 672.11 0.82 153554 5yr 2893 281.62 284.83 0.006111 3.17 911.87 678.03 0.87 153554 10yr 3426 281.62 284.95 0.006402 3.44 995.98 679.23 0.91 153554 25yr 4359 281.62 285.10 0.007544 3.98 1096.06 679.95 1.00 153554 50yr 5300 281.62 285.32 0.007236 4.24 1248.81 681.05 1.00 153554 100yr 6410 281.62 285.57 0.006933 4.52 1419.07 682.47 1.00

153004 2yr 2099 279.14 280.60 0.009080 3.06 684.93 722.59 1.01 153004 5yr 2893 279.14 280.84 0.008396 3.39 854.26 731.53 1.00 153004 10yr 3426 279.14 280.98 0.008021 3.56 961.19 736.60 1.00 153004 25yr 4359 279.14 281.29 0.006543 3.67 1187.28 747.02 0.93 153004 50yr 5300 279.14 281.58 0.005530 3.75 1411.83 757.23 0.88 153004 100yr 6410 279.14 281.66 0.007141 4.37 1467.58 759.74 1.00

151861 2yr 2099 275.31 278.54 0.000797 1.47 1424.98 727.14 0.34 151861 5yr 2893 275.31 278.96 0.000796 1.67 1733.96 733.18 0.35 151861 10yr 3426 275.31 279.22 0.000792 1.78 1925.65 736.90 0.35 151861 25yr 4359 275.31 279.64 0.000791 1.95 2233.28 742.84 0.36 151861 50yr 5300 275.31 280.02 0.000791 2.10 2518.56 748.30 0.37 151861 100yr 6410 275.31 280.27 0.000541 1.79 4011.65 1214.08 0.31

150753 2yr 2099 273.95 277.07 0.001977 2.18 961.91 538.25 0.52 150753 5yr 2893 273.95 277.43 0.002058 2.50 1157.84 544.83 0.55 150753 10yr 3426 273.95 277.65 0.002109 2.69 1274.78 547.77 0.56 150753 25yr 4359 273.95 277.99 0.002190 2.98 1460.88 551.80 0.59 150753 50yr 5300 273.95 278.29 0.002264 3.25 1630.64 555.45 0.61

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 179 Feasibility Report: West Rapti Basin

149802 2yr 2099 272.02 274.53 0.003604 2.45 858.25 634.58 0.67 149802 5yr 2893 272.02 274.82 0.003575 2.76 1046.74 640.26 0.69 149802 10yr 3426 272.02 275.00 0.003558 2.95 1162.79 643.72 0.70 149802 25yr 4359 272.02 275.30 0.003527 3.22 1351.82 649.33 0.71 149802 50yr 5300 272.02 275.57 0.003494 3.47 1529.32 654.56 0.72 149802 100yr 6410 272.02 275.82 0.003679 3.79 1692.85 659.33 0.75

149495 2yr 2099 270.30 273.80 0.002018 1.95 1079.00 728.13 0.51 149495 5yr 2893 270.30 274.14 0.001928 2.18 1327.15 729.37 0.52 149495 10yr 3426 270.30 274.33 0.001950 2.34 1464.63 730.05 0.53 149495 25yr 4359 270.30 274.65 0.001914 2.56 1702.92 731.60 0.54 149495 50yr 5300 270.30 274.96 0.001884 2.75 1925.22 733.95 0.54 149495 100yr 6410 270.30 275.01 0.002570 3.26 1966.21 734.38 0.64

149173.* 2yr 2099 269.87 273.18 0.001847 1.95 1077.52 679.09 0.49 149173.* 5yr 2893 269.87 273.55 0.001761 2.18 1326.58 680.77 0.50 149173.* 10yr 3426 269.87 273.65 0.002070 2.45 1399.16 681.27 0.55 149173.* 25yr 4359 269.87 273.97 0.002075 2.69 1618.70 684.59 0.56 149173.* 50yr 5300 269.87 274.28 0.002066 2.90 1826.06 690.41 0.57 149173.* 100yr 6410 269.87 274.48 0.001717 2.78 2674.84 1173.41 0.52

148852.* 2yr 2099 269.44 272.62 0.001654 1.94 1081.75 631.18 0.47 148852.* 5yr 2893 269.44 273.00 0.001617 2.19 1323.89 637.42 0.48 148852.* 10yr 3426 269.44 273.25 0.001170 2.00 1998.04 1119.97 0.42 148852.* 25yr 4359 269.44 273.64 0.001034 2.08 2508.70 1245.19 0.40 148852.* 50yr 5300 269.44 274.00 0.000952 2.17 2962.27 1292.79 0.40 148852.* 100yr 6410 269.44 274.05 0.001307 2.57 3029.34 1299.69 0.46

148530.* 2yr 2099 269.01 272.13 0.001428 1.88 1127.93 649.79 0.44 148530.* 5yr 2893 269.01 272.52 0.001420 2.13 1387.45 673.80 0.46 148530.* 10yr 3426 269.01 272.75 0.001425 2.27 1543.74 685.28 0.47 148530.* 25yr 4359 269.01 273.13 0.001422 2.49 1803.23 703.92 0.48 148530.* 50yr 5300 269.01 273.46 0.001442 2.70 2037.45 721.97 0.49 148530.* 100yr 6410 269.01 273.77 0.000879 2.25 3532.29 1342.99 0.39

148209 2yr 2099 268.58 271.10 0.004968 2.84 739.16 556.12 0.79 148209 5yr 2893 268.58 271.31 0.006046 3.38 856.27 575.18 0.88 148209 10yr 3426 268.58 271.46 0.006346 3.63 942.88 588.88 0.92 148209 25yr 4359 268.58 271.66 0.006943 4.10 1063.26 601.52 0.98 148209 50yr 5300 268.58 271.89 0.006877 4.42 1203.71 615.53 0.99 148209 100yr 6410 268.58 272.16 0.006626 4.70 1372.54 631.95 0.99

PRTW.01 147709 2yr 2099 267.11 268.85 0.004418 2.36 894.29 865.61 0.72 147709 5yr 2893 267.11 269.16 0.003685 2.51 1177.02 944.94 0.68 147709 10yr 3426 267.11 269.30 0.003677 2.68 1313.89 946.15 0.69 147709 25yr 4359 267.11 269.55 0.003549 2.91 1549.24 948.23 0.70 147709 50yr 5300 267.11 269.77 0.003483 3.11 1762.80 950.12 0.70 147709 100yr 6410 267.11 270.02 0.003431 3.33 1994.91 952.16 0.71

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 180 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 147309 2yr 2099 266.13 268.19 0.001101 1.46 1433.51 941.27 0.38 147309 5yr 2893 266.13 268.53 0.001141 1.63 1772.69 1016.38 0.39 147309 10yr 3426 266.13 268.70 0.001143 1.73 2052.17 1227.55 0.40 147309 25yr 4359 266.13 268.95 0.001201 1.93 2368.82 1272.89 0.42 147309 50yr 5300 266.13 269.20 0.001205 2.08 2690.67 1289.01 0.43 147309 100yr 6410 266.13 269.48 0.001199 2.23 3078.49 1488.68 0.43

146660 2yr 2099 264.10 266.21 0.008581 3.09 683.96 712.96 0.99 146660 5yr 2893 264.10 266.45 0.008125 3.44 854.58 744.50 0.99 146660 10yr 3426 264.10 266.60 0.007682 3.60 971.17 765.31 0.98 146660 25yr 4359 264.10 266.86 0.006627 3.75 1241.57 923.49 0.94 146660 50yr 5300 264.10 267.06 0.006450 4.00 1427.50 928.70 0.94 146660 100yr 6410 264.10 267.28 0.006310 4.26 1629.38 934.32 0.95

146105 2yr 2099 262.15 264.49 0.001333 1.67 1259.81 784.79 0.42 146105 5yr 2893 262.15 264.80 0.001372 1.89 1620.88 1135.53 0.44 146105 10yr 3426 262.15 264.98 0.001392 2.02 1828.54 1199.39 0.45 146105 25yr 4359 262.15 265.26 0.001424 2.22 2186.02 1337.27 0.46 146105 50yr 5300 262.15 265.51 0.001449 2.40 2524.08 1408.80 0.47 146105 100yr 6410 262.15 265.77 0.001460 2.57 2912.27 1486.69 0.48

145481 2yr 2099 260.58 263.16 0.003481 1.98 1058.72 1045.96 0.63 145481 5yr 2893 260.58 263.36 0.003943 2.27 1273.05 1127.09 0.68 145481 10yr 3426 260.58 263.46 0.004246 2.46 1392.17 1160.93 0.72 145481 25yr 4359 260.58 263.60 0.004796 2.81 1553.22 1184.14 0.77 145481 50yr 5300 260.58 263.73 0.005192 3.11 1710.00 1206.32 0.82 145481 100yr 6410 260.58 263.87 0.005644 3.44 1876.02 1229.36 0.87

145087 2yr 2099 259.80 261.70 0.004103 1.88 1119.04 1359.11 0.66 145087 5yr 2893 259.80 261.92 0.003538 2.01 1445.96 1504.44 0.64 145087 10yr 3426 259.80 262.06 0.003228 2.09 1660.79 1586.16 0.62 145087 25yr 4359 259.80 262.30 0.002791 2.20 2044.73 1689.73 0.59 145087 50yr 5300 259.80 262.51 0.002530 2.30 2411.48 1771.57 0.58 145087 100yr 6410 259.80 262.75 0.002285 2.39 2839.60 1840.67 0.56

144542 2yr 2099 258.16 260.57 0.001330 1.49 1411.50 1053.58 0.41 PRTW.02 144542 5yr 2893 258.16 260.85 0.001346 1.70 1717.99 1127.21 0.42 144542 10yr 3426 258.16 261.01 0.001359 1.82 1909.10 1161.26 0.43 144542 25yr 4359 258.16 261.22 0.001518 2.07 2155.32 1203.70 0.47 144542 50yr 5300 258.16 261.42 0.001614 2.27 2404.74 1252.69 0.49 144542 100yr 6410 258.16 261.65 0.001682 2.48 2705.71 1366.04 0.51

144083 2yr 2099 257.14 258.91 0.009345 2.97 706.09 796.86 1.01 144083 5yr 2893 257.14 259.13 0.008853 3.24 893.85 852.68 1.01 144083 10yr 3426 257.14 259.27 0.008655 3.39 1010.98 884.99 1.01 144083 25yr 4359 257.14 259.60 0.006099 3.33 1318.15 985.00 0.88 144083 50yr 5300 257.14 259.88 0.004901 3.37 1609.42 1065.25 0.82 144083 100yr 6410 257.14 260.18 0.004177 3.45 1938.57 1172.89 0.77

143617 2yr 2099 255.52 258.60 0.000302 1.15 1828.70 1090.22 0.28 143617 5yr 2893 255.52 258.93 0.000337 1.31 2212.23 1176.26 0.30

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 181 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 143617 10yr 3426 255.52 259.14 0.000355 1.40 2454.84 1228.31 0.32 143617 25yr 4359 255.52 259.46 0.000378 1.52 2862.70 1316.00 0.33 143617 50yr 5300 255.52 259.74 0.000397 1.63 3247.46 1390.49 0.34 143617 100yr 6410 255.52 260.04 0.000413 1.74 3677.26 1466.85 0.35

142933 2yr 2099 254.01 257.88 0.004330 2.21 949.06 935.24 0.70 142933 5yr 2893 254.01 258.19 0.003503 2.33 1239.65 961.48 0.66 142933 10yr 3426 254.01 258.37 0.003232 2.42 1415.44 978.40 0.64 142933 25yr 4359 254.01 258.65 0.003014 2.58 1691.01 1009.41 0.64 142933 50yr 5300 254.01 258.89 0.002916 2.73 1941.38 1037.12 0.64 142933 100yr 6410 254.01 259.15 0.002828 2.90 2211.78 1056.00 0.64

142513 2yr 2099 253.96 257.31 0.000844 1.32 1590.29 998.99 0.33 142513 5yr 2893 253.96 257.64 0.000889 1.50 1925.58 1038.71 0.35 142513 10yr 3426 253.96 257.80 0.000973 1.64 2095.11 1077.37 0.37 142513 25yr 4359 253.96 258.07 0.001040 1.83 2393.02 1124.82 0.39 142513 50yr 5300 253.96 258.31 0.001098 2.01 2659.87 1150.58 0.41 142513 100yr 6410 253.96 258.55 0.001168 2.21 2944.36 1192.15 0.43

141711 2yr 2099 253.45 255.33 0.008431 3.05 697.45 815.19 0.98 141711 5yr 2893 253.45 255.58 0.007609 3.28 932.96 1087.76 0.96 141711 10yr 3426 253.45 255.78 0.006171 3.24 1184.04 1370.57 0.88 141711 25yr 4359 253.45 256.00 0.005650 3.42 1504.80 1555.71 0.86 141711 50yr 5300 253.45 256.19 0.005401 3.60 1807.40 1712.12 0.86 141711 100yr 6410 253.45 256.39 0.005143 3.77 2164.24 1879.91 0.85

141107 2yr 2099 251.56 254.46 0.000466 1.04 2319.02 1693.92 0.25 141107 5yr 2893 251.56 254.90 0.000382 1.09 3081.95 1790.06 0.24 141107 10yr 3426 251.56 255.14 0.000360 1.14 3526.15 1843.73 0.23 141107 25yr 4359 251.56 255.43 0.000384 1.27 4062.53 1906.53 0.25 141107 50yr 5300 251.56 255.73 0.000380 1.36 4656.96 1973.79 0.25 141107 100yr 6410 251.56 256.06 0.000378 1.45 5313.58 2045.52 0.25

140216 2yr 2099 250.70 253.85 0.000791 1.52 1384.54 733.00 0.34 140216 5yr 2893 250.70 254.35 0.000725 1.68 1794.08 912.23 0.34 140216 10yr 3426 250.70 254.58 0.000745 1.80 2017.48 973.06 0.34 140216 25yr 4359 250.70 254.88 0.000694 1.86 2904.86 1631.33 0.34 140216 50yr 5300 250.70 255.18 0.000703 1.99 3413.09 1806.41 0.35 PRTW.03 140216 100yr 6410 250.70 255.51 0.000688 2.10 4021.40 1874.67 0.35

139579 2yr 2099 249.22 251.80 0.007137 4.30 487.70 257.79 1.00 139579 5yr 2893 249.22 252.63 0.007787 3.76 770.26 533.42 1.00 139579 10yr 3426 249.22 252.86 0.007761 3.78 908.64 652.85 1.00 139579 25yr 4359 249.22 253.14 0.006937 4.01 1107.76 760.20 0.97 139579 50yr 5300 249.22 253.40 0.006287 4.19 1320.29 839.97 0.95 139579 100yr 6410 249.22 253.67 0.005975 4.43 1551.71 950.17 0.94

138812 2yr 2099 248.01 250.70 0.000882 1.18 1790.18 1456.16 0.33 138812 5yr 2893 248.01 251.00 0.000821 1.31 2250.79 1554.29 0.33 138812 10yr 3426 248.01 251.19 0.000786 1.38 2551.92 1615.22 0.33 138812 25yr 4359 248.01 251.50 0.000741 1.49 3060.85 1713.28 0.33

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 182 Feasibility Report: West Rapti Basin

138099 2yr 2099 247.20 248.69 0.008516 3.38 621.87 540.99 1.01 138099 5yr 2893 247.20 248.98 0.008038 3.71 780.58 565.19 1.01 138099 10yr 3426 247.20 249.15 0.007792 3.89 881.11 580.00 1.01 138099 25yr 4359 247.20 249.44 0.007229 4.14 1059.00 666.87 0.99 138099 50yr 5300 247.20 249.73 0.006401 4.30 1272.08 808.18 0.96 138099 100yr 6410 247.20 250.04 0.005712 4.45 1541.22 949.65 0.93

137644 2yr 2099 244.45 247.00 0.001249 1.68 1271.71 819.77 0.41 137644 5yr 2893 244.45 247.32 0.001298 1.92 1548.91 867.25 0.43 137644 10yr 3426 244.45 247.51 0.001339 2.07 1715.41 894.55 0.44 137644 25yr 4359 244.45 247.81 0.001414 2.31 1983.83 964.52 0.47 137644 50yr 5300 244.45 248.05 0.001519 2.55 2238.45 1141.68 0.49 137644 100yr 6410 244.45 248.31 0.001575 2.76 2695.96 1691.50 0.51

137467.* 2yr 2099 244.15 246.78 0.001224 1.63 1305.98 866.02 0.41 137467.* 5yr 2893 244.15 247.10 0.001267 1.87 1594.03 921.47 0.42 137467.* 10yr 3426 244.15 247.29 0.001312 2.02 1764.88 953.28 0.44 137467.* 25yr 4359 244.15 247.56 0.001411 2.27 2045.67 1133.17 0.46 137467.* 50yr 5300 244.15 247.80 0.001472 2.47 2426.90 1608.48 0.48 137467.* 100yr 6410 244.15 248.06 0.001504 2.65 2866.61 1822.24 0.49

137290.* 2yr 2099 243.85 246.56 0.001316 1.58 1333.30 914.41 0.41 137290.* 5yr 2893 243.85 246.89 0.001296 1.78 1642.03 985.35 0.42 137290.* 10yr 3426 243.85 247.07 0.001322 1.91 1821.57 1053.32 0.43 137290.* 25yr 4359 243.85 247.34 0.001360 2.12 2195.10 1478.35 0.45 137290.* 50yr 5300 243.85 247.58 0.001384 2.28 2568.47 1623.86 0.46 137290.* 100yr 6410 243.85 247.84 0.001397 2.45 3005.92 1790.35 0.47

137113.* 2yr 2099 243.55 246.33 0.001374 1.57 1340.41 964.08 0.42 137113.* 5yr 2893 243.55 246.67 0.001276 1.74 1688.28 1172.35 0.42 137113.* 10yr 3426 243.55 246.84 0.001282 1.86 1922.68 1384.77 0.43 137113.* 25yr 4359 243.55 247.12 0.001288 2.04 2325.38 1540.33 0.44 137113.* 50yr 5300 243.55 247.36 0.001300 2.19 2713.57 1684.47 0.45 137113.* 100yr 6410 243.55 247.62 0.001302 2.35 3167.53 1834.31 0.45

136936 2yr 2099 243.25 246.06 0.001634 1.60 1310.61 1011.20 0.45 136936 5yr 2893 243.25 246.42 0.001602 1.68 1735.21 1329.34 0.45 136936 10yr 3426 243.25 246.62 0.001474 1.74 2003.74 1420.91 0.44 136936 25yr 4359 243.25 246.91 0.001324 1.85 2446.53 1566.58 0.43 136936 50yr 5300 243.25 247.16 0.001264 1.96 2854.84 1689.81 0.43 136936 100yr 6410 243.25 247.43 0.001216 2.08 3321.41 1809.43 0.43

136745 2yr 2099 243.26 244.99 0.008571 3.29 638.63 580.94 1.00 136745 5yr 2893 243.26 245.26 0.007942 3.63 796.69 589.38 1.00 136745 10yr 3426 243.26 245.46 0.007861 3.73 918.73 648.09 1.00 136745 25yr 4359 243.26 245.75 0.007681 3.87 1126.12 738.18 1.00 136745 50yr 5300 243.26 246.03 0.006765 3.96 1368.12 1033.61 0.96 136745 100yr 6410 243.26 246.29 0.006080 4.11 1642.48 1083.30 0.93

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 183 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

136487 2yr 2099 242.34 245.09 0.000279 0.93 2825.40 1650.00 0.20 136487 5yr 2893 242.34 245.42 0.000309 1.08 3356.50 1650.00 0.22 136487 10yr 3426 242.34 245.60 0.000328 1.17 3666.78 1650.00 0.23 136487 25yr 4359 242.34 245.90 0.000358 1.30 4149.50 1650.00 0.24 136487 50yr 5300 242.34 246.16 0.000386 1.43 4578.75 1650.00 0.25 136487 100yr 6410 242.34 246.43 0.000417 1.57 5030.74 1650.00 0.27

136227 2yr 2099 241.97 244.61 0.000717 1.31 1982.72 1740.39 0.31 136227 5yr 2893 241.97 244.89 0.000745 1.47 2484.69 1816.79 0.33 136227 10yr 3426 241.97 245.05 0.000766 1.57 2782.51 1858.77 0.34 136227 25yr 4359 241.97 245.31 0.000801 1.72 3257.51 1919.17 0.35 136227 50yr 5300 241.97 245.53 0.000835 1.86 3688.47 1970.18 0.36 136227 100yr 6410 241.97 245.76 0.000875 2.01 4149.28 2022.78 0.38

135825 Bridge

135708 2yr 2099 241.22 244.13 0.001256 1.50 1557.15 1767.85 0.40 135708 5yr 2893 241.22 244.40 0.001227 1.66 2046.94 1919.59 0.41 135708 10yr 3426 241.22 244.55 0.001235 1.77 2336.60 2004.88 0.41 135708 25yr 4359 241.22 244.78 0.001249 1.92 2812.76 2137.70 0.43 135708 50yr 5300 241.22 244.98 0.001271 2.06 3253.50 2253.68 0.44 135708 100yr 6410 241.22 245.19 0.001300 2.21 3738.31 2374.71 0.45

135187.* 2yr 2099 240.71 243.47 0.001290 1.46 1464.24 1419.46 0.40 135187.* 5yr 2893 240.71 243.72 0.001365 1.68 1861.03 1979.64 0.42 135187.* 10yr 3426 240.71 243.85 0.001403 1.79 2138.66 2116.19 0.44 135187.* 25yr 4359 240.71 244.06 0.001470 1.98 2583.93 2293.72 0.46 135187.* 50yr 5300 240.71 244.24 0.001515 2.13 3011.97 2452.29 0.47 135187.* 100yr 6410 240.71 244.43 0.001540 2.28 3510.11 2624.80 0.48

134926.* 2yr 2099 240.57 243.23 0.000861 1.22 1726.39 1377.56 0.33 134926.* 5yr 2893 240.57 243.44 0.000991 1.44 2129.27 2168.33 0.36 134926.* 10yr 3426 240.57 243.56 0.001069 1.57 2392.48 2324.96 0.38 134926.* 25yr 4359 240.57 243.74 0.001185 1.76 2823.26 2499.26 0.41 134926.* 50yr 5300 240.57 243.91 0.001262 1.92 3250.20 2660.75 0.43 134926.* 100yr 6410 240.57 244.10 0.001291 2.06 3781.14 2848.85 0.44

133880 2yr 2099 240.02 242.14 0.001325 1.06 2022.47 2618.24 0.37 133880 5yr 2893 240.02 242.35 0.001170 1.16 2570.46 2692.04 0.37 133880 10yr 3426 240.02 242.49 0.001060 1.20 2951.03 2742.12 0.36 133880 25yr 4359 240.02 242.74 0.000879 1.24 3650.77 2831.90 0.33 133880 50yr 5300 240.02 243.00 0.000733 1.27 4388.12 2923.53 0.31 133880 100yr 6410 240.02 243.25 0.000659 1.32 5145.68 3024.00 0.30

133790.* 2yr 2099 239.87 242.04 0.001120 1.02 2091.50 2513.82 0.35 133790.* 5yr 2893 239.87 242.26 0.001000 1.12 2650.53 2591.58 0.34 133790.* 10yr 3426 239.87 242.40 0.000908 1.16 3041.45 2646.10 0.33 133790.* 25yr 4359 239.87 242.67 0.000758 1.21 3758.03 2742.71 0.31 133790.* 50yr 5300 239.87 242.94 0.000640 1.24 4505.47 2839.03 0.30 133790.* 100yr 6410 239.87 243.20 0.000590 1.29 5268.85 3021.14 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 184 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

133701.* 2yr 2099 239.72 241.92 0.001270 1.10 1944.43 2306.32 0.37 133701.* 5yr 2893 239.72 242.15 0.001102 1.19 2485.74 2377.79 0.36 133701.* 10yr 3426 239.72 242.31 0.000985 1.23 2867.73 2432.03 0.35 133701.* 25yr 4359 239.72 242.59 0.000810 1.28 3565.80 2537.40 0.33 133701.* 50yr 5300 239.72 242.87 0.000679 1.30 4287.75 2637.21 0.31 133701.* 100yr 6410 239.72 243.13 0.000624 1.37 4995.73 2731.56 0.30

133611.* 2yr 2099 239.56 241.77 0.001660 1.24 1721.78 2092.56 0.42 133611.* 5yr 2893 239.56 242.03 0.001322 1.31 2261.58 2153.95 0.39 133611.* 10yr 3426 239.56 242.20 0.001141 1.34 2639.27 2212.53 0.38 133611.* 25yr 4359 239.56 242.50 0.000907 1.37 3320.89 2327.11 0.35 133611.* 50yr 5300 239.56 242.80 0.000751 1.40 4016.64 2432.21 0.32 133611.* 100yr 6410 239.56 243.06 0.000694 1.47 4680.36 2528.41 0.32 PRTW.06 133254 2yr 2099 238.95 241.37 0.000862 1.06 1985.87 1798.75 0.32 133254 5yr 2893 238.95 241.73 0.000641 1.10 2675.88 1966.99 0.29 133254 10yr 3426 238.95 241.94 0.000571 1.13 3100.40 2038.99 0.28 133254 25yr 4359 238.95 242.29 0.000488 1.19 3832.59 2177.03 0.26 133254 50yr 5300 238.95 242.61 0.000433 1.23 4556.75 2295.67 0.26 133254 100yr 6410 238.95 242.89 0.000431 1.32 5200.75 2396.24 0.26

132929 2yr 2099 238.60 241.19 0.000421 0.89 2346.06 1566.66 0.23 132929 5yr 2893 238.60 241.58 0.000380 0.97 3046.66 1962.80 0.23 132929 10yr 3426 238.60 241.81 0.000357 1.01 3497.46 2055.75 0.23 132929 25yr 4359 238.60 242.17 0.000326 1.08 4272.62 2206.44 0.22 132929 50yr 5300 238.60 242.50 0.000304 1.14 5034.48 2345.13 0.22 132929 100yr 6410 238.60 242.78 0.000317 1.24 5687.92 2457.85 0.23

132874.* 2yr 2099 238.43 241.17 0.000451 0.89 2368.88 1690.38 0.24 132874.* 5yr 2893 238.43 241.56 0.000383 0.95 3068.62 1861.23 0.23 132874.* 10yr 3426 238.43 241.79 0.000357 0.99 3499.02 1968.58 0.23 132874.* 25yr 4359 238.43 242.15 0.000323 1.06 4264.50 2223.83 0.22 132874.* 50yr 5300 238.43 242.49 0.000299 1.11 5043.86 2377.86 0.22 132874.* 100yr 6410 238.43 242.76 0.000309 1.21 5777.84 3241.03 0.22

132819.* 2yr 2099 238.25 241.13 0.000552 0.97 2176.91 1633.42 0.26 132819.* 5yr 2893 238.25 241.53 0.000443 1.03 2866.08 1851.40 0.25 132819.* 10yr 3426 238.25 241.76 0.000411 1.07 3308.99 2039.55 0.24 PRTW.05 132819.* 25yr 4359 238.25 242.13 0.000366 1.13 4107.98 2254.09 0.24 132819.* 50yr 5300 238.25 242.46 0.000334 1.18 4886.58 2346.04 0.23 132819.* 100yr 6410 238.25 242.74 0.000349 1.28 5620.16 3203.42 0.24

132656 2yr 2099 237.73 240.97 0.001044 1.29 1783.39 1900.92 0.36 132656 5yr 2893 237.73 241.42 0.000648 1.24 2702.62 2092.79 0.30 132656 10yr 3426 237.73 241.67 0.000555 1.25 3213.85 2136.95 0.28 132656 25yr 4359 237.73 242.05 0.000461 1.28 4047.57 2207.07 0.26 132656 50yr 5300 237.73 242.40 0.000408 1.32 4825.17 2270.53 0.25 132656 100yr 6410 237.73 242.67 0.000419 1.42 5439.89 2319.46 0.26

132403 2yr 2099 237.25 240.87 0.000315 0.95 2241.78 1280.33 0.21

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 185 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 132403 5yr 2893 237.25 241.33 0.000289 1.04 2988.99 1841.00 0.21 132403 10yr 3426 237.25 241.58 0.000286 1.10 3452.37 1940.25 0.21 132403 25yr 4359 237.25 241.97 0.000279 1.19 4236.22 2113.67 0.22 132403 50yr 5300 237.25 242.32 0.000271 1.26 5006.35 2251.53 0.22 132403 100yr 6410 237.25 242.58 0.000297 1.39 5604.17 2332.52 0.23

131465 2yr 2099 235.79 240.30 0.000948 1.60 1315.19 677.65 0.37 131465 5yr 2893 235.79 240.77 0.000951 1.75 1652.75 798.53 0.37 131465 10yr 3426 235.79 240.99 0.000995 1.88 1851.64 952.55 0.39 131465 25yr 4359 235.79 241.36 0.000980 2.05 2209.89 984.92 0.39 131465 50yr 5300 235.79 241.70 0.000969 2.20 2544.06 1014.18 0.40 131465 100yr 6410 235.79 241.96 0.000924 2.25 3347.25 1475.18 0.39

130224 2yr 2099 234.09 237.03 0.007673 3.85 545.88 361.09 1.00 130224 5yr 2893 234.09 237.44 0.007296 4.12 702.14 403.20 1.00 130224 10yr 3426 234.09 237.77 0.006170 4.04 872.65 543.62 0.93 130224 25yr 4359 234.09 238.07 0.006103 4.40 1034.49 556.42 0.95 130224 50yr 5300 234.09 238.35 0.005888 4.68 1196.43 568.49 0.95 130224 100yr 6410 234.09 238.73 0.005163 4.82 1461.25 791.98 0.91

129806 2yr 2099 233.80 237.01 0.000424 1.16 2121.87 1303.66 0.25 129806 5yr 2893 233.80 237.39 0.000436 1.31 2640.73 1395.47 0.26 129806 10yr 3426 233.80 237.62 0.000441 1.39 2966.85 1450.70 0.27 129806 25yr 4359 233.80 237.98 0.000450 1.53 3501.84 1535.03 0.27 129806 50yr 5300 233.80 238.30 0.000458 1.64 4007.25 1608.96 0.28 129806 100yr 6410 233.80 238.63 0.000475 1.77 4541.37 1683.57 0.29

127967 2yr 2099 232.67 235.71 0.000935 1.49 1428.65 994.81 0.36 127967 5yr 2893 232.67 236.15 0.000812 1.61 1910.73 1124.10 0.35 127967 10yr 3426 232.67 236.37 0.000816 1.72 2158.99 1167.42 0.35 127967 25yr 4359 232.67 236.70 0.000834 1.87 2562.54 1314.61 0.36 127967 50yr 5300 232.67 237.00 0.000849 2.02 3051.91 1698.86 0.37 127967 100yr 6410 232.67 237.31 0.000834 2.14 3596.54 1756.08 0.38

127727 2yr 2099 232.05 235.37 0.001245 1.91 1193.95 717.60 0.42 127727 5yr 2893 232.05 235.80 0.001415 2.11 1516.39 857.98 0.46 127727 10yr 3426 232.05 235.99 0.001473 2.28 1686.77 917.47 0.47 127727 25yr 4359 232.05 236.29 0.001562 2.54 1970.25 1002.41 0.50 127727 50yr 5300 232.05 236.54 0.001633 2.76 2230.15 1036.84 0.51 127727 100yr 6410 232.05 236.81 0.001709 2.99 2513.82 1073.15 0.53

125768 2yr 2099 230.17 232.33 0.002096 1.57 1339.01 1286.13 0.49 125768 5yr 2893 230.17 232.56 0.002079 1.77 1633.18 1297.84 0.50 125768 10yr 3426 230.17 232.70 0.002065 1.89 1815.27 1305.04 0.51 125768 25yr 4359 230.17 232.93 0.002052 2.07 2108.90 1316.57 0.52 125768 50yr 5300 230.17 233.13 0.002034 2.22 2386.51 1374.35 0.53 125768 100yr 6410 230.17 233.36 0.002032 2.39 2702.14 1462.29 0.54

125245.* 2yr 2099 229.50 231.50 0.001344 1.30 1615.83 1474.50 0.40 125245.* 5yr 2893 229.50 231.77 0.001248 1.43 2017.36 1501.27 0.40 125245.* 10yr 3426 229.50 231.93 0.001222 1.52 2255.14 1514.93 0.40

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 186 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 125245.* 25yr 4359 229.50 232.18 0.001199 1.65 2634.65 1545.88 0.40 125245.* 50yr 5300 229.50 232.40 0.001184 1.78 2987.09 1632.11 0.41 125245.* 100yr 6410 229.50 232.62 0.001204 1.93 3354.65 1702.73 0.42

124723.* 2yr 2099 228.82 231.23 0.000342 0.81 2603.54 1746.73 0.21 124723.* 5yr 2893 228.82 231.48 0.000392 0.95 3058.23 1890.76 0.23 124723.* 10yr 3426 228.82 231.63 0.000414 1.03 3354.37 1993.86 0.24 124723.* 25yr 4359 228.82 231.87 0.000444 1.16 3854.01 2151.03 0.25 124723.* 50yr 5300 228.82 232.09 0.000467 1.27 4339.49 2277.54 0.26 124723.* 100yr 6410 228.82 232.30 0.000509 1.40 4828.52 2462.45 0.28

124201 2yr 2099 228.15 231.15 0.000108 0.53 4144.27 2483.29 0.12 124201 5yr 2893 228.15 231.38 0.000137 0.65 4750.99 2640.53 0.14 124201 10yr 3426 228.15 231.53 0.000153 0.71 5138.96 2739.94 0.15 124201 25yr 4359 228.15 231.76 0.000176 0.82 5782.18 2819.66 0.16 124201 50yr 5300 228.15 231.97 0.000195 0.91 6383.99 2892.26 0.18 124201 100yr 6410 228.15 232.16 0.000224 1.02 6948.43 2958.74 0.19

123840 2yr 2099 228.10 230.71 0.010512 2.38 880.73 1511.83 1.00 123840 5yr 2893 228.10 230.85 0.009755 2.65 1092.26 1513.05 1.00 123840 10yr 3426 228.10 230.94 0.009429 2.80 1221.52 1513.79 1.00 123840 25yr 4359 228.10 231.08 0.008941 3.04 1434.62 1515.02 1.00 123840 50yr 5300 228.10 231.22 0.008550 3.22 1648.10 1545.78 0.99 123840 100yr 6410 228.10 231.37 0.008707 3.30 1942.70 1777.34 1.01

122539 2yr 2099 226.03 229.10 0.000265 0.83 2544.98 1440.51 0.19 122539 5yr 2893 226.03 229.61 0.000221 0.83 3928.97 2551.95 0.18 122539 10yr 3426 226.03 229.85 0.000209 0.87 4554.73 2667.52 0.18 122539 25yr 4359 226.03 230.24 0.000192 0.92 5623.18 2854.01 0.18 122539 50yr 5300 226.03 230.55 0.000188 0.98 6546.20 3002.73 0.18 122539 100yr 6410 226.03 230.86 0.000192 1.05 7482.59 3146.43 0.18

120519 2yr 2099 223.70 228.40 0.000417 1.21 1735.23 731.39 0.25 120519 5yr 2893 223.70 228.92 0.000484 1.32 2207.87 1019.11 0.27 120519 10yr 3426 223.70 229.16 0.000490 1.41 2471.77 1100.98 0.28 120519 25yr 4359 223.70 229.56 0.000496 1.55 2970.37 1552.86 0.28 120519 50yr 5300 223.70 229.88 0.000494 1.65 3899.34 3115.13 0.29 120519 100yr 6410 223.70 230.20 0.000479 1.72 4884.42 3163.57 0.29

120272.* 2yr 2099 223.63 228.28 0.000535 1.24 1696.49 834.50 0.28 120272.* 5yr 2893 223.63 228.79 0.000548 1.34 2157.02 957.30 0.29 120272.* 10yr 3426 223.63 229.03 0.000576 1.43 2397.51 1003.34 0.30 120272.* 25yr 4359 223.63 229.43 0.000604 1.55 2810.18 1077.76 0.31 120272.* 50yr 5300 223.63 229.74 0.000610 1.65 3569.48 2967.67 0.31 120272.* 100yr 6410 223.63 230.07 0.000573 1.71 4532.63 3018.98 0.31

120026.* 2yr 2099 223.56 228.14 0.000574 1.25 1684.93 864.18 0.28 120026.* 5yr 2893 223.56 228.63 0.000769 1.32 2187.64 1277.64 0.32 120026.* 10yr 3426 223.56 228.88 0.000704 1.36 2517.43 1317.96 0.31 120026.* 25yr 4359 223.56 229.29 0.000607 1.42 3070.45 1395.14 0.30 120026.* 50yr 5300 223.56 229.61 0.000579 1.51 3607.63 1959.65 0.30

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 187 Feasibility Report: West Rapti Basin

119287.* 2yr 2099 223.36 227.72 0.000576 1.12 1866.28 1119.40 0.28 119287.* 5yr 2893 223.36 228.18 0.000506 1.21 2390.16 1166.03 0.27 119287.* 10yr 3426 223.36 228.47 0.000475 1.26 2727.45 1200.26 0.27 119287.* 25yr 4359 223.36 228.92 0.000442 1.33 3297.20 1387.71 0.26 119287.* 50yr 5300 223.36 229.25 0.000435 1.42 3860.60 1971.91 0.27 119287.* 100yr 6410 223.36 229.62 0.000408 1.49 4810.73 2583.35 0.26

118056 2yr 2099 223.02 227.22 0.000316 1.03 2033.03 883.41 0.22 118056 5yr 2893 223.02 227.67 0.000352 1.18 2452.79 1053.33 0.23 118056 10yr 3426 223.02 227.95 0.000375 1.26 2777.38 1260.97 0.24 118056 25yr 4359 223.02 228.38 0.000439 1.35 3407.84 1804.38 0.26 118056 50yr 5300 223.02 228.76 0.000384 1.38 4474.30 2578.93 0.25 118056 100yr 6410 223.02 229.19 0.000331 1.40 5604.29 2749.41 0.24

117747.* 2yr 2099 222.75 227.07 0.000538 1.20 1750.54 905.75 0.28 117747.* 5yr 2893 222.75 227.52 0.000527 1.32 2279.42 1473.33 0.28 117747.* 10yr 3426 222.75 227.81 0.000480 1.36 2754.38 1833.72 0.27 117747.* 25yr 4359 222.75 228.24 0.000423 1.42 3620.73 2152.42 0.26 117747.* 50yr 5300 222.75 228.64 0.000372 1.45 4528.34 2352.13 0.25 117747.* 100yr 6410 222.75 229.08 0.000326 1.47 5606.39 2532.61 0.24

117438.* 2yr 2099 222.48 226.85 0.000835 1.29 1625.64 1047.24 0.33 117438.* 5yr 2893 222.48 227.34 0.000640 1.34 2247.75 1605.17 0.30 117438.* 10yr 3426 222.48 227.65 0.000529 1.34 2784.61 1789.03 0.28 117438.* 25yr 4359 222.48 228.11 0.000434 1.37 3633.77 1934.87 0.26 117438.* 50yr 5300 222.48 228.53 0.000373 1.40 4501.98 2137.30 0.25 117438.* 100yr 6410 222.48 228.98 0.000322 1.42 5484.92 2204.95 0.24

117129 2yr 2099 222.22 226.54 0.001049 1.44 1462.31 1042.10 0.37 117129 5yr 2893 222.22 227.13 0.000656 1.40 2200.86 1491.09 0.31 117129 10yr 3426 222.22 227.49 0.000515 1.38 2752.08 1576.90 0.28 117129 25yr 4359 222.22 227.97 0.000424 1.41 3576.05 1778.68 0.26 117129 50yr 5300 222.22 228.41 0.000366 1.44 4366.96 1836.06 0.25 117129 100yr 6410 222.22 228.87 0.000326 1.48 5237.51 1924.68 0.24

116874 2yr 2099 222.12 226.55 0.000090 0.66 3652.05 1937.90 0.12 116874 5yr 2893 222.12 227.14 0.000084 0.72 4893.62 2213.68 0.12 116874 10yr 3426 222.12 227.49 0.000080 0.75 5705.15 2319.48 0.12 116874 25yr 4359 222.12 227.98 0.000081 0.81 6863.42 2462.62 0.12 116874 50yr 5300 222.12 228.42 0.000081 0.87 7968.90 2591.88 0.13 116874 100yr 6410 222.12 228.88 0.000082 0.92 9207.02 2729.39 0.13

115068 2yr 2099 221.92 225.87 0.001199 2.33 901.19 313.81 0.44 115068 5yr 2893 221.92 226.35 0.001634 2.71 1068.69 374.67 0.51 115068 10yr 3426 221.92 226.66 0.002243 2.85 1201.39 494.25 0.58 115068 25yr 4359 221.92 227.08 0.002277 3.06 1458.74 745.76 0.60 115068 50yr 5300 221.92 227.51 0.002022 3.13 1830.32 930.90 0.58 115068 100yr 6410 221.92 228.04 0.001596 3.08 2465.20 1304.19 0.52

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 188 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 113718 2yr 2099 220.70 225.39 0.000255 0.89 2407.45 1411.20 0.19 113718 5yr 2893 220.70 225.94 0.000224 0.94 3311.44 1924.32 0.19 113718 10yr 3426 220.70 226.29 0.000197 0.96 4071.08 2339.58 0.18 113718 25yr 4359 220.70 226.85 0.000158 0.97 5452.28 2556.43 0.17 113718 50yr 5300 220.70 227.38 0.000131 0.97 6849.47 2701.38 0.15 113718 100yr 6410 220.70 227.96 0.000111 0.97 8458.75 2871.83 0.14

112544 2yr 2099 220.66 225.18 0.000141 0.67 3305.70 1923.33 0.14 112544 5yr 2893 220.66 225.78 0.000113 0.70 4555.21 2216.28 0.13 112544 10yr 3426 220.66 226.15 0.000099 0.71 5391.07 2304.31 0.13 112544 25yr 4359 220.66 226.73 0.000085 0.74 6785.52 2444.12 0.12 112544 50yr 5300 220.66 227.28 0.000075 0.76 8160.94 2574.59 0.12 112544 100yr 6410 220.66 227.87 0.000067 0.78 9725.25 2715.38 0.11

111259 2yr 2099 220.30 224.67 0.000820 1.75 1202.06 486.39 0.35 111259 5yr 2893 220.30 225.29 0.000761 1.91 1522.96 573.00 0.35 111259 10yr 3426 220.30 225.68 0.000708 2.00 1758.14 662.94 0.35 111259 25yr 4359 220.30 226.28 0.000646 2.13 2169.21 710.02 0.34 111259 50yr 5300 220.30 226.82 0.000606 2.25 2603.80 907.15 0.34 111259 100yr 6410 220.30 227.43 0.000547 2.32 3162.93 939.29 0.33

109410 2yr 2099 219.12 224.19 0.000156 0.93 2481.25 1063.08 0.16 109410 5yr 2893 219.12 224.86 0.000149 1.02 3264.02 1243.71 0.16 109410 10yr 3426 219.12 225.29 0.000140 1.06 3940.25 1680.05 0.16 109410 25yr 4359 219.12 225.96 0.000125 1.10 5097.22 1801.44 0.16 109410 50yr 5300 219.12 226.55 0.000114 1.13 6211.86 1922.91 0.15 109410 100yr 6410 219.12 227.20 0.000105 1.16 7496.88 2054.06 0.15

108799.* 2yr 2099 218.93 224.07 0.000188 1.06 2296.47 981.65 0.18 108799.* 5yr 2893 218.93 224.74 0.000185 1.18 3064.57 1462.13 0.18 108799.* 10yr 3426 218.93 225.18 0.000169 1.21 3739.05 1595.31 0.18 108799.* 25yr 4359 218.93 225.86 0.000148 1.23 4857.82 1702.05 0.17 108799.* 50yr 5300 218.93 226.47 0.000134 1.26 5928.99 1827.70 0.17 108799.* 100yr 6410 218.93 227.12 0.000122 1.30 7167.67 1962.99 0.16

108188.* 2yr 2099 218.74 223.94 0.000243 1.03 2161.21 1012.23 0.20 108188.* 5yr 2893 218.74 224.63 0.000208 1.10 2961.25 1352.72 0.19 108188.* 10yr 3426 218.74 225.08 0.000182 1.12 3603.64 1479.44 0.18 108188.* 25yr 4359 218.74 225.77 0.000154 1.14 4678.77 1612.08 0.17 108188.* 50yr 5300 218.74 226.39 0.000137 1.17 5705.90 1724.98 0.16 108188.* 100yr 6410 218.74 227.05 0.000123 1.21 6885.98 1847.11 0.16

107577.* 2yr 2099 218.55 223.78 0.000285 1.09 2055.54 1063.14 0.21 107577.* 5yr 2893 218.55 224.49 0.000230 1.15 2867.83 1269.32 0.20 107577.* 10yr 3426 218.55 224.96 0.000197 1.16 3497.90 1393.50 0.19 107577.* 25yr 4359 218.55 225.67 0.000164 1.18 4534.25 1510.07 0.18 107577.* 50yr 5300 218.55 226.30 0.000145 1.21 5513.60 1618.61 0.17 107577.* 100yr 6410 218.55 226.97 0.000131 1.25 6634.26 1732.10 0.16

106966.* 2yr 2099 218.36 223.58 0.000383 1.10 1958.48 1021.34 0.24 106966.* 5yr 2893 218.36 224.34 0.000256 1.10 2796.73 1201.57 0.20

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 189 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 106966.* 10yr 3426 218.36 224.84 0.000206 1.09 3428.14 1327.88 0.19 106966.* 25yr 4359 218.36 225.58 0.000164 1.11 4443.83 1427.79 0.17 106966.* 50yr 5300 218.36 226.21 0.000143 1.14 5381.01 1512.15 0.17 106966.* 100yr 6410 218.36 226.89 0.000128 1.17 6436.11 1602.41 0.16

106355 2yr 2099 218.17 223.33 0.000359 1.23 1847.15 976.56 0.24 106355 5yr 2893 218.17 224.17 0.000249 1.23 2726.70 1139.16 0.21 106355 10yr 3426 218.17 224.70 0.000205 1.22 3363.89 1269.49 0.19 106355 25yr 4359 218.17 225.46 0.000168 1.24 4368.32 1360.23 0.18 106355 50yr 5300 218.17 226.11 0.000150 1.27 5274.83 1428.30 0.17 106355 100yr 6410 218.17 226.80 0.000137 1.31 6279.32 1500.14 0.17

104906 2yr 2099 217.11 222.45 0.000638 2.24 958.02 283.29 0.34 104906 5yr 2893 217.11 223.37 0.000611 2.49 1261.89 374.43 0.35 104906 10yr 3426 217.11 223.94 0.000588 2.62 1490.81 451.69 0.35 104906 25yr 4359 217.11 224.71 0.000587 2.84 1911.04 629.68 0.35 104906 50yr 5300 217.11 225.37 0.000570 2.98 2370.64 738.43 0.35 104906 100yr 6410 217.11 226.08 0.000538 3.08 2920.91 803.80 0.35

104562 2yr 2099 217.05 221.42 0.002848 4.02 523.09 154.52 0.69 104562 5yr 2893 217.05 222.17 0.002862 4.53 641.67 160.89 0.71 104562 10yr 3426 217.05 222.65 0.003056 4.77 724.00 188.58 0.74 104562 25yr 4359 217.05 223.29 0.002953 5.16 922.09 311.59 0.75 104562 50yr 5300 217.05 223.83 0.002895 5.48 1095.20 320.76 0.75 104562 100yr 6410 217.05 224.38 0.002924 5.87 1271.88 345.05 0.77

103309 2yr 2099 214.20 220.10 0.000799 2.31 907.53 235.00 0.38 103309 5yr 2893 214.20 221.08 0.000721 2.53 1164.67 293.76 0.37 103309 10yr 3426 214.20 221.52 0.000745 2.72 1302.66 340.53 0.38 103309 25yr 4359 214.20 222.20 0.000777 3.02 1583.35 460.50 0.40 103309 50yr 5300 214.20 222.76 0.000809 3.27 1858.72 520.89 0.41 103309 100yr 6410 214.20 223.33 0.000840 3.53 2232.61 725.07 0.43

102609.* 2yr 2099 213.71 219.54 0.000794 2.29 915.96 239.54 0.37 102609.* 5yr 2893 213.71 220.55 0.000845 2.44 1188.31 307.48 0.39 102609.* 10yr 3426 213.71 220.98 0.000861 2.60 1331.21 360.67 0.40 102609.* 25yr 4359 213.71 221.66 0.000862 2.82 1620.79 473.81 0.41 102609.* 50yr 5300 213.71 222.22 0.000861 3.03 1903.44 541.10 0.41 102609.* 100yr 6410 213.71 222.79 0.000863 3.24 2286.76 741.06 0.42

101909.* 2yr 2099 213.23 218.99 0.000788 2.27 925.29 244.41 0.37 101909.* 5yr 2893 213.23 219.95 0.000870 2.43 1192.42 316.06 0.39 101909.* 10yr 3426 213.23 220.38 0.000872 2.58 1335.96 363.68 0.40 101909.* 25yr 4359 213.23 221.06 0.000867 2.80 1626.86 479.80 0.41 101909.* 50yr 5300 213.23 221.63 0.000858 3.00 1916.56 544.83 0.41 101909.* 100yr 6410 213.23 222.20 0.000859 3.21 2297.50 753.01 0.42

101209.* 2yr 2099 212.74 218.45 0.000786 2.24 935.46 250.74 0.37 101209.* 5yr 2893 212.74 219.32 0.000903 2.44 1188.57 320.69 0.40 101209.* 10yr 3426 212.74 219.76 0.000892 2.58 1335.43 363.79 0.40 101209.* 25yr 4359 212.74 220.46 0.000851 2.79 1634.18 485.84 0.40

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 190 Feasibility Report: West Rapti Basin

100509.* 2yr 2099 212.26 217.89 0.000801 2.22 945.16 261.06 0.37 100509.* 5yr 2893 212.26 218.72 0.000811 2.46 1189.84 325.88 0.38 100509.* 10yr 3426 212.26 219.15 0.000826 2.64 1335.74 364.42 0.39 100509.* 25yr 4359 212.26 219.86 0.000826 2.86 1639.35 491.18 0.40 100509.* 50yr 5300 212.26 220.45 0.000817 3.05 1946.49 558.18 0.41 100509.* 100yr 6410 212.26 221.00 0.000836 3.28 2310.73 775.63 0.42

99809.9* 2yr 2099 211.77 217.33 0.000819 2.20 952.91 270.98 0.38 99809.9* 5yr 2893 211.77 218.17 0.000794 2.43 1207.67 334.04 0.38 99809.9* 10yr 3426 211.77 218.58 0.000814 2.60 1352.84 375.26 0.39 99809.9* 25yr 4359 211.77 219.26 0.000910 2.83 1645.86 496.44 0.42 99809.9* 50yr 5300 211.77 219.84 0.000972 2.98 1952.41 561.99 0.43 99809.9* 100yr 6410 211.77 220.41 0.000939 3.15 2322.89 769.33 0.43

99110.1* 2yr 2099 211.29 216.75 0.000833 2.19 958.73 278.80 0.38 99110.1* 5yr 2893 211.29 217.58 0.000906 2.38 1215.41 340.05 0.40 99110.1* 10yr 3426 211.29 218.00 0.000893 2.53 1364.09 382.63 0.40 99110.1* 25yr 4359 211.29 218.64 0.000887 2.75 1643.82 493.68 0.41 99110.1* 50yr 5300 211.29 219.20 0.000872 2.94 1939.18 562.16 0.41 99110.1* 100yr 6410 211.29 219.78 0.000862 3.14 2305.28 735.52 0.42

98410.3* 2yr 2099 210.80 216.17 0.000827 2.18 964.10 282.39 0.38 98410.3* 5yr 2893 210.80 216.98 0.000794 2.41 1217.68 344.92 0.38 98410.3* 10yr 3426 210.80 217.39 0.000804 2.58 1366.07 385.21 0.39 98410.3* 25yr 4359 210.80 218.02 0.000824 2.85 1638.36 484.42 0.40 98410.3* 50yr 5300 210.80 218.57 0.000837 3.07 1929.13 563.67 0.41 98410.3* 100yr 6410 210.80 219.14 0.000850 3.30 2281.37 700.41 0.42

97710.5* 2yr 2099 210.32 215.60 0.000820 2.16 970.91 286.38 0.37 97710.5* 5yr 2893 210.32 216.39 0.000916 2.37 1223.15 350.34 0.40 97710.5* 10yr 3426 210.32 216.82 0.000885 2.51 1378.83 393.51 0.40 97710.5* 25yr 4359 210.32 217.45 0.000867 2.74 1659.19 490.43 0.40 97710.5* 50yr 5300 210.32 218.00 0.000858 2.94 1956.16 572.49 0.41 97710.5* 100yr 6410 210.32 218.57 0.000856 3.14 2313.21 717.47 0.42

97010.7* 2yr 2099 209.83 215.03 0.000822 2.15 978.52 290.43 0.37 97010.7* 5yr 2893 209.83 215.78 0.000812 2.40 1220.94 354.03 0.38 97010.7* 10yr 3426 209.83 216.21 0.000810 2.56 1380.79 396.79 0.39 97010.7* 25yr 4359 209.83 216.84 0.000819 2.81 1662.75 492.89 0.40 97010.7* 50yr 5300 209.83 217.39 0.000830 3.03 1956.80 575.61 0.41 97010.7* 100yr 6410 209.83 217.96 0.000840 3.25 2314.06 705.95 0.42

96310.9* 2yr 2099 209.35 214.46 0.000815 2.13 986.52 294.54 0.37 96310.9* 5yr 2893 209.35 215.22 0.000795 2.37 1237.40 361.76 0.38 96310.9* 10yr 3426 209.35 215.66 0.000789 2.52 1403.05 411.29 0.38 96310.9* 25yr 4359 209.35 216.29 0.000798 2.77 1691.02 502.42 0.39 96310.9* 50yr 5300 209.35 216.83 0.000811 2.99 1985.48 584.22 0.40 96310.9* 100yr 6410 209.35 217.39 0.000822 3.20 2339.61 683.24 0.41

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 191 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

95611.0* 2yr 2099 208.86 213.89 0.000804 2.11 996.39 298.90 0.37 95611.0* 5yr 2893 208.86 214.68 0.000769 2.33 1260.00 370.94 0.37 95611.0* 10yr 3426 208.86 215.12 0.000782 2.48 1430.47 427.77 0.38 95611.0* 25yr 4359 208.86 215.74 0.000786 2.71 1727.21 513.91 0.39 95611.0* 50yr 5300 208.86 216.28 0.000798 2.92 2023.31 594.80 0.40 95611.0* 100yr 6410 208.86 216.83 0.000806 3.13 2381.50 693.30 0.41

94911.2* 2yr 2099 208.38 213.34 0.000786 2.08 1009.91 303.98 0.36 94911.2* 5yr 2893 208.38 214.17 0.000726 2.27 1293.78 382.79 0.36 94911.2* 10yr 3426 208.38 214.60 0.000719 2.42 1471.38 447.37 0.37 94911.2* 25yr 4359 208.38 215.23 0.000727 2.65 1777.31 528.30 0.38 94911.2* 50yr 5300 208.38 215.75 0.000749 2.88 2073.65 608.25 0.39 94911.2* 100yr 6410 208.38 216.30 0.000765 3.09 2434.65 705.97 0.40

94211.4* 2yr 2099 207.89 212.81 0.000758 2.04 1028.89 309.95 0.36 94211.4* 5yr 2893 207.89 213.65 0.000795 2.18 1327.03 394.90 0.37 94211.4* 10yr 3426 207.89 214.12 0.000738 2.28 1526.69 470.04 0.36 94211.4* 25yr 4359 207.89 214.75 0.000714 2.48 1852.33 547.35 0.37 94211.4* 50yr 5300 207.89 215.27 0.000724 2.68 2156.22 631.94 0.38 94211.4* 100yr 6410 207.89 215.82 0.000731 2.88 2528.03 762.75 0.38

93511.6* 2yr 2099 207.41 212.30 0.000716 1.99 1056.73 317.44 0.35 93511.6* 5yr 2893 207.41 213.11 0.000764 2.15 1352.18 405.39 0.36 93511.6* 10yr 3426 207.41 213.60 0.000764 2.22 1571.07 488.36 0.37 93511.6* 25yr 4359 207.41 214.28 0.000700 2.36 1929.86 566.11 0.36 93511.6* 50yr 5300 207.41 214.80 0.000697 2.54 2247.01 656.89 0.37 93511.6* 100yr 6410 207.41 215.35 0.000691 2.71 2640.53 801.22 0.37

92811.8* 2yr 2099 206.92 211.83 0.000655 1.91 1098.24 327.08 0.33 92811.8* 5yr 2893 206.92 212.63 0.000644 2.10 1401.82 434.19 0.34 92811.8* 10yr 3426 206.92 213.10 0.000673 2.19 1626.83 507.45 0.35 92811.8* 25yr 4359 206.92 213.81 0.000674 2.32 2012.41 589.30 0.35 92811.8* 50yr 5300 206.92 214.34 0.000670 2.48 2346.34 682.91 0.36 92811.8* 100yr 6410 206.92 214.90 0.000653 2.64 2770.30 838.96 0.36

92112.0* 2yr 2099 206.44 211.41 0.000586 1.81 1157.95 350.80 0.32 92112.0* 5yr 2893 206.44 212.22 0.000586 2.00 1488.75 478.35 0.32 92112.0* 10yr 3426 206.44 212.68 0.000602 2.09 1721.04 532.00 0.33 92112.0* 25yr 4359 206.44 213.39 0.000592 2.21 2127.73 621.28 0.33 92112.0* 50yr 5300 206.44 213.92 0.000585 2.36 2483.61 717.28 0.34 92112.0* 100yr 6410 206.44 214.50 0.000567 2.50 2950.07 901.94 0.34

91412.2* 2yr 2099 205.95 211.07 0.000455 1.69 1251.13 390.65 0.28 91412.2* 5yr 2893 205.95 211.88 0.000443 1.87 1622.85 517.79 0.29 91412.2* 10yr 3426 205.95 212.34 0.000434 1.98 1870.22 565.01 0.29 91412.2* 25yr 4359 205.95 213.05 0.000422 2.14 2307.18 670.98 0.29 91412.2* 50yr 5300 205.95 213.58 0.000442 2.33 2682.38 762.99 0.30 91412.2* 100yr 6410 205.95 214.16 0.000450 2.50 3198.19 994.82 0.31

90712.4* 2yr 2099 205.47 210.76 0.000463 1.53 1372.20 439.49 0.28

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 192 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 90712.4* 5yr 2893 205.47 211.60 0.000437 1.63 1799.84 556.84 0.28 90712.4* 10yr 3426 205.47 212.07 0.000423 1.69 2073.53 604.43 0.27 90712.4* 25yr 4359 205.47 212.82 0.000374 1.79 2573.83 738.43 0.27 90712.4* 50yr 5300 205.47 213.35 0.000376 1.93 2999.07 893.99 0.27 90712.4* 100yr 6410 205.47 213.94 0.000364 2.04 3593.22 1063.85 0.27

90012.6* 2yr 2099 204.99 210.49 0.000362 1.38 1530.59 510.68 0.25 90012.6* 5yr 2893 204.99 211.36 0.000332 1.47 2009.46 597.66 0.24 90012.6* 10yr 3426 204.99 211.84 0.000312 1.53 2313.36 668.44 0.24 90012.6* 25yr 4359 204.99 212.62 0.000279 1.62 2892.80 858.17 0.23 90012.6* 50yr 5300 204.99 213.14 0.000285 1.75 3386.84 1039.43 0.24 90012.6* 100yr 6410 204.99 213.75 0.000279 1.86 4047.47 1153.49 0.24

89312.8* 2yr 2099 204.50 210.30 0.000257 1.21 1749.03 558.58 0.21 89312.8* 5yr 2893 204.50 211.18 0.000239 1.31 2278.80 654.33 0.21 89312.8* 10yr 3426 204.50 211.67 0.000225 1.37 2628.12 749.74 0.21 89312.8* 25yr 4359 204.50 212.47 0.000203 1.45 3316.18 1010.11 0.20 89312.8* 50yr 5300 204.50 212.99 0.000211 1.57 3881.41 1139.82 0.21 89312.8* 100yr 6410 204.50 213.60 0.000209 1.67 4623.89 1287.89 0.21

88613 2yr 3482 204.02 209.90 0.000475 2.00 1870.34 584.42 0.30 88613 5yr 4822 204.02 210.74 0.000490 2.28 2397.48 685.55 0.31 88613 10yr 5683 204.02 211.22 0.000495 2.42 2749.96 778.67 0.32 88613 25yr 7279 204.02 211.99 0.000503 2.65 3441.25 1051.13 0.33 88613 50yr 8522 204.02 212.50 0.000504 2.79 4014.87 1205.84 0.33 88613 100yr 10187 204.02 213.10 0.000505 2.94 4781.01 1340.11 0.34

87874.0* 2yr 3482 203.54 209.54 0.000532 1.92 1868.57 571.74 0.31 87874.0* 5yr 4822 203.54 210.38 0.000518 2.15 2387.93 672.54 0.31 87874.0* 10yr 5683 203.54 210.87 0.000510 2.28 2737.63 771.36 0.32 87874.0* 25yr 7279 203.54 211.64 0.000502 2.48 3423.05 1036.73 0.32 87874.0* 50yr 8522 203.54 212.15 0.000498 2.60 3993.32 1192.26 0.32 87874.0* 100yr 10187 203.54 212.75 0.000493 2.75 4754.50 1326.42 0.33

87135.0* 2yr 3482 203.07 209.14 0.000539 1.93 1845.58 554.45 0.31 87135.0* 5yr 4822 203.07 210.00 0.000523 2.17 2357.99 653.53 0.32 87135.0* 10yr 5683 203.07 210.49 0.000515 2.30 2702.80 757.20 0.32 87135.0* 25yr 7279 203.07 211.26 0.000507 2.50 3376.89 1010.02 0.32 87135.0* 50yr 8522 203.07 211.78 0.000502 2.62 3940.43 1168.53 0.33 87135.0* 100yr 10187 203.07 212.38 0.000498 2.77 4693.19 1308.58 0.33

86396.0* 2yr 3482 202.59 208.73 0.000566 1.94 1817.90 539.06 0.32 86396.0* 5yr 4822 202.59 209.60 0.000538 2.17 2326.61 637.68 0.32 86396.0* 10yr 5683 202.59 210.10 0.000524 2.29 2668.34 741.52 0.32 86396.0* 25yr 7279 202.59 210.89 0.000512 2.49 3335.30 986.22 0.32 86396.0* 50yr 8522 202.59 211.41 0.000506 2.61 3893.91 1148.54 0.33 86396.0* 100yr 10187 202.59 212.01 0.000501 2.76 4639.65 1290.86 0.33

85657.0* 2yr 3482 202.12 208.30 0.000570 1.99 1780.32 527.83 0.32 85657.0* 5yr 4822 202.12 209.19 0.000545 2.22 2284.64 618.41 0.32 85657.0* 10yr 5683 202.12 209.70 0.000531 2.34 2621.53 718.47 0.32

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 193 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 85657.0* 25yr 7279 202.12 210.49 0.000522 2.54 3276.31 955.35 0.33 85657.0* 50yr 8522 202.12 211.01 0.000517 2.68 3825.30 1125.88 0.33 85657.0* 100yr 10187 202.12 211.62 0.000513 2.83 4559.33 1269.80 0.34

84918.0* 2yr 3482 201.65 207.85 0.000626 2.02 1732.59 514.46 0.33 84918.0* 5yr 4822 201.65 208.76 0.000599 2.23 2234.97 595.78 0.33 84918.0* 10yr 5683 201.65 209.28 0.000612 2.34 2562.85 686.83 0.34 84918.0* 25yr 7279 201.65 210.09 0.000570 2.51 3218.10 930.20 0.34 84918.0* 50yr 8522 201.65 210.62 0.000552 2.62 3765.77 1107.27 0.34 84918.0* 100yr 10187 201.65 211.24 0.000537 2.76 4497.17 1249.58 0.34

84179.0* 2yr 3482 201.17 207.39 0.000558 2.15 1678.04 493.13 0.32 84179.0* 5yr 4822 201.17 208.29 0.000566 2.42 2161.86 571.85 0.33 84179.0* 10yr 5683 201.17 208.79 0.000569 2.58 2462.24 645.90 0.34 84179.0* 25yr 7279 201.17 209.59 0.000572 2.82 3073.44 881.78 0.35 84179.0* 50yr 8522 201.17 210.13 0.000572 2.96 3589.46 1062.82 0.35 84179.0* 100yr 10187 201.17 210.74 0.000572 3.13 4290.06 1210.34 0.36

83440.0* 2yr 3482 200.70 206.96 0.000574 2.19 1643.90 468.59 0.33 83440.0* 5yr 4822 200.70 207.85 0.000589 2.48 2108.14 562.08 0.34 83440.0* 10yr 5683 200.70 208.34 0.000598 2.64 2394.55 618.10 0.35 83440.0* 25yr 7279 200.70 209.14 0.000606 2.89 2971.62 829.59 0.36 83440.0* 50yr 8522 200.70 209.66 0.000608 3.05 3457.90 1024.19 0.36 83440.0* 100yr 10187 200.70 210.27 0.000610 3.22 4130.35 1172.36 0.37

82701.0* 2yr 3482 200.23 206.52 0.000599 2.23 1603.80 440.25 0.33 82701.0* 5yr 4822 200.23 207.38 0.000626 2.54 2038.95 549.24 0.35 82701.0* 10yr 5683 200.23 207.86 0.000640 2.71 2310.83 595.52 0.36 82701.0* 25yr 7279 200.23 208.63 0.000660 2.99 2840.85 789.68 0.37 82701.0* 50yr 8522 200.23 209.15 0.000664 3.16 3290.93 953.87 0.38 82701.0* 100yr 10187 200.23 209.76 0.000668 3.35 3923.09 1118.62 0.39

81962.0* 2yr 3482 199.75 206.04 0.000641 2.29 1552.88 421.17 0.35 81962.0* 5yr 4822 199.75 206.87 0.000687 2.64 1946.07 530.80 0.37 81962.0* 10yr 5683 199.75 207.32 0.000709 2.83 2197.90 574.83 0.38 81962.0* 25yr 7279 199.75 208.05 0.000755 3.15 2660.06 752.47 0.40 81962.0* 50yr 8522 199.75 208.57 0.000759 3.33 3068.39 864.37 0.40 81962.0* 100yr 10187 199.75 209.15 0.000771 3.54 3635.07 1055.33 0.41

81223 2yr 3482 199.28 205.52 0.000716 2.38 1483.07 398.82 0.36 81223 5yr 4822 199.28 206.27 0.000799 2.79 1815.05 497.95 0.39 81223 10yr 5683 199.28 206.69 0.000839 3.01 2034.33 544.93 0.41 81223 25yr 7279 199.28 207.37 0.000902 3.35 2428.49 615.32 0.43 81223 50yr 8522 199.28 207.82 0.000960 3.62 2743.39 767.41 0.45 81223 100yr 10187 199.28 208.36 0.000992 3.88 3192.43 912.72 0.46

80609.1* 2yr 3482 198.83 205.07 0.000815 2.28 1541.60 477.22 0.38 80609.1* 5yr 4822 198.83 205.80 0.000843 2.60 1921.24 550.68 0.40 80609.1* 10yr 5683 198.83 206.22 0.000860 2.78 2155.57 590.79 0.41 80609.1* 25yr 7279 198.83 206.89 0.000888 3.07 2609.13 718.99 0.42 80609.1* 50yr 8522 198.83 207.33 0.000906 3.27 2941.99 781.83 0.43

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 194 Feasibility Report: West Rapti Basin

79995.2* 2yr 3482 198.38 204.55 0.000945 2.17 1605.93 521.43 0.39 79995.2* 5yr 4822 198.38 205.30 0.000918 2.39 2031.66 622.71 0.40 79995.2* 10yr 5683 198.38 205.73 0.000877 2.51 2312.01 666.89 0.40 79995.2* 25yr 7279 198.38 206.42 0.000863 2.71 2803.02 802.78 0.40 79995.2* 50yr 8522 198.38 206.88 0.000844 2.86 3190.42 883.53 0.40 79995.2* 100yr 10187 198.38 207.44 0.000822 3.02 3712.26 970.22 0.41

79381.4* 2yr 3482 197.92 203.97 0.000954 2.14 1625.39 541.18 0.39 79381.4* 5yr 4822 197.92 204.75 0.000903 2.32 2083.26 608.81 0.39 79381.4* 10yr 5683 197.92 205.23 0.000827 2.41 2376.62 631.72 0.39 79381.4* 25yr 7279 197.92 205.93 0.000784 2.61 2860.28 785.63 0.39 79381.4* 50yr 8522 197.92 206.40 0.000768 2.75 3253.32 884.85 0.39 79381.4* 100yr 10187 197.92 206.98 0.000748 2.91 3786.36 954.94 0.39

78767.5* 2yr 3482 197.47 203.39 0.000935 2.13 1632.10 538.41 0.39 78767.5* 5yr 4822 197.47 204.23 0.000801 2.30 2103.49 574.59 0.38 78767.5* 10yr 5683 197.47 204.75 0.000731 2.38 2407.58 596.27 0.37 78767.5* 25yr 7279 197.47 205.47 0.000729 2.59 2901.37 802.58 0.37 78767.5* 50yr 8522 197.47 205.95 0.000716 2.73 3312.41 886.75 0.38 78767.5* 100yr 10187 197.47 206.54 0.000699 2.90 3847.65 932.82 0.38

78153.7* 2yr 3482 197.02 202.81 0.000904 2.20 1588.13 499.32 0.39 78153.7* 5yr 4822 197.02 203.74 0.000768 2.35 2074.14 540.79 0.37 78153.7* 10yr 5683 197.02 204.28 0.000786 2.42 2385.77 638.49 0.38 78153.7* 25yr 7279 197.02 205.02 0.000732 2.60 2935.11 817.75 0.38 78153.7* 50yr 8522 197.02 205.52 0.000708 2.73 3357.70 865.52 0.37 78153.7* 100yr 10187 197.02 206.12 0.000687 2.89 3891.23 905.53 0.38

77539.8* 2yr 3482 196.57 202.22 0.000876 2.36 1484.24 416.31 0.39 77539.8* 5yr 4822 196.57 203.20 0.000842 2.53 1933.94 485.00 0.39 77539.8* 10yr 5683 196.57 203.73 0.000831 2.63 2216.73 671.29 0.39 77539.8* 25yr 7279 196.57 204.50 0.000778 2.82 2789.71 803.95 0.39 77539.8* 50yr 8522 196.57 205.01 0.000755 2.96 3209.51 833.41 0.39 77539.8* 100yr 10187 196.57 205.62 0.000736 3.12 3731.03 868.72 0.39

76926 2yr 3482 196.12 201.63 0.000837 2.58 1358.49 324.44 0.39 76926 5yr 4822 196.12 202.54 0.000913 2.94 1673.06 406.63 0.42 76926 10yr 5683 196.12 203.04 0.000910 3.12 1928.81 638.93 0.43 76926 25yr 7279 196.12 203.80 0.000906 3.40 2467.02 762.76 0.43 76926 50yr 8522 196.12 204.32 0.000898 3.57 2866.19 788.35 0.44 76926 100yr 10187 196.12 204.93 0.000892 3.77 3359.21 818.87 0.44

76392.5* 2yr 3482 195.57 201.17 0.000947 2.53 1378.95 356.13 0.41 76392.5* 5yr 4822 195.57 202.08 0.000898 2.82 1734.46 431.12 0.41 76392.5* 10yr 5683 195.57 202.59 0.000880 2.99 1970.32 509.52 0.42 76392.5* 25yr 7279 195.57 203.35 0.000889 3.29 2444.37 711.20 0.43 76392.5* 50yr 8522 195.57 203.86 0.000887 3.47 2830.34 778.64 0.43 76392.5* 100yr 10187 195.57 204.48 0.000880 3.66 3322.11 813.50 0.44

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 195 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 75859.1* 2yr 3482 195.01 200.66 0.000934 2.55 1389.14 380.80 0.41 75859.1* 5yr 4822 195.01 201.58 0.000978 2.82 1764.14 437.17 0.43 75859.1* 10yr 5683 195.01 202.10 0.001008 2.95 2000.31 475.03 0.44 75859.1* 25yr 7279 195.01 202.87 0.000973 3.20 2417.53 644.75 0.44 75859.1* 50yr 8522 195.01 203.39 0.000959 3.38 2774.13 736.26 0.44 75859.1* 100yr 10187 195.01 204.01 0.000940 3.58 3258.63 800.74 0.45

75325.7* 2yr 3482 194.46 200.16 0.001004 2.48 1401.61 387.93 0.42 75325.7* 5yr 4822 194.46 201.06 0.001027 2.72 1774.62 436.76 0.43 75325.7* 10yr 5683 194.46 201.57 0.001040 2.84 2004.28 467.04 0.44 75325.7* 25yr 7279 194.46 202.37 0.000992 3.04 2406.57 546.79 0.44 75325.7* 50yr 8522 194.46 202.90 0.000963 3.21 2720.87 662.45 0.44 75325.7* 100yr 10187 194.46 203.54 0.000935 3.40 3178.39 777.09 0.44

74792.2* 2yr 3482 193.91 199.62 0.001016 2.49 1399.12 389.80 0.42 74792.2* 5yr 4822 193.91 200.51 0.001028 2.73 1766.91 432.48 0.43 74792.2* 10yr 5683 193.91 201.01 0.001037 2.86 1989.23 457.60 0.44 74792.2* 25yr 7279 193.91 201.83 0.001037 3.06 2381.54 513.07 0.45 74792.2* 50yr 8522 193.91 202.37 0.001011 3.21 2676.04 563.72 0.45 74792.2* 100yr 10187 193.91 203.02 0.000974 3.40 3079.86 691.81 0.45

74258.8* 2yr 3482 193.36 199.07 0.001026 2.50 1391.46 387.36 0.42 74258.8* 5yr 4822 193.36 199.96 0.001016 2.75 1756.55 428.76 0.43 74258.8* 10yr 5683 193.36 200.46 0.000993 2.88 1976.49 450.88 0.43 74258.8* 25yr 7279 193.36 201.27 0.000988 3.12 2354.18 489.46 0.44 74258.8* 50yr 8522 193.36 201.82 0.000958 3.29 2637.40 532.38 0.44 74258.8* 100yr 10187 193.36 202.47 0.000945 3.51 3000.61 582.82 0.44

73725.4* 2yr 3482 192.80 198.51 0.001031 2.52 1382.17 382.43 0.42 73725.4* 5yr 4822 192.80 199.40 0.001049 2.77 1740.34 422.88 0.44 73725.4* 10yr 5683 192.80 199.91 0.001048 2.90 1961.64 445.37 0.44 73725.4* 25yr 7279 192.80 200.74 0.001001 3.12 2342.27 478.36 0.44 73725.4* 50yr 8522 192.80 201.31 0.000972 3.27 2625.43 512.96 0.44 73725.4* 100yr 10187 192.80 201.97 0.000951 3.49 2979.52 556.81 0.45

73192 2yr 3482 192.25 197.97 0.000982 2.54 1377.16 379.35 0.42 73192 5yr 4822 192.25 198.85 0.000965 2.83 1725.40 415.63 0.43 73192 10yr 5683 192.25 199.35 0.000958 2.99 1939.50 436.44 0.43 73192 25yr 7279 192.25 200.17 0.000958 3.26 2312.04 470.39 0.44 73192 50yr 8522 192.25 200.75 0.000951 3.44 2589.21 495.83 0.44 73192 100yr 10187 192.25 201.40 0.000953 3.68 2926.42 533.82 0.45

72501.4* 2yr 3482 191.50 197.29 0.001023 2.51 1385.69 382.45 0.42 72501.4* 5yr 4822 191.50 198.17 0.001032 2.77 1739.92 417.44 0.43 72501.4* 10yr 5683 191.50 198.68 0.001032 2.90 1958.64 438.78 0.44 72501.4* 25yr 7279 191.50 199.51 0.001036 3.11 2337.43 472.17 0.45 72501.4* 50yr 8522 191.50 200.11 0.001019 3.25 2624.77 500.32 0.45 72501.4* 100yr 10187 191.50 200.77 0.001013 3.44 2972.24 539.83 0.45

71810.8* 2yr 3482 190.75 196.58 0.001024 2.51 1387.71 384.23 0.42 71810.8* 5yr 4822 190.75 197.46 0.001032 2.77 1740.41 417.90 0.43

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 196 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 71810.8* 10yr 5683 190.75 197.97 0.001034 2.90 1958.93 439.39 0.44 71810.8* 25yr 7279 190.75 198.80 0.001037 3.12 2336.54 472.01 0.45 71810.8* 50yr 8522 190.75 199.40 0.001041 3.24 2626.99 501.07 0.45 71810.8* 100yr 10187 190.75 200.07 0.001026 3.42 2980.72 541.87 0.46

71120.2* 2yr 3482 190.01 195.87 0.001024 2.51 1389.85 385.87 0.42 71120.2* 5yr 4822 190.01 196.75 0.001033 2.77 1740.97 418.25 0.43 71120.2* 10yr 5683 190.01 197.25 0.001036 2.90 1959.11 440.19 0.44 71120.2* 25yr 7279 190.01 198.08 0.001038 3.12 2335.49 471.92 0.45 71120.2* 50yr 8522 190.01 198.67 0.001047 3.25 2622.92 501.21 0.45 71120.2* 100yr 10187 190.01 199.38 0.000990 3.42 2993.07 544.58 0.45

70429.7* 2yr 3482 189.26 195.17 0.001024 2.50 1392.45 387.60 0.42 70429.7* 5yr 4822 189.26 196.03 0.001032 2.77 1742.07 418.81 0.43 70429.7* 10yr 5683 189.26 196.54 0.001034 2.90 1959.79 439.88 0.44 70429.7* 25yr 7279 189.26 197.36 0.001041 3.12 2334.12 472.04 0.45 70429.7* 50yr 8522 189.26 197.94 0.001055 3.26 2616.32 500.97 0.46 70429.7* 100yr 10187 189.26 198.67 0.001076 3.40 2998.14 546.63 0.46

69739.1* 2yr 3482 188.51 194.46 0.001027 2.50 1393.69 389.20 0.42 69739.1* 5yr 4822 188.51 195.32 0.001036 2.77 1741.76 419.70 0.43 69739.1* 10yr 5683 188.51 195.83 0.001034 2.90 1959.38 439.85 0.44 69739.1* 25yr 7279 188.51 196.64 0.001047 3.12 2329.57 472.07 0.45 69739.1* 50yr 8522 188.51 197.21 0.001043 3.27 2609.11 501.03 0.45 69739.1* 100yr 10187 188.51 197.93 0.001038 3.43 2984.82 546.90 0.46

69048.5* 2yr 3482 187.76 193.75 0.001024 2.49 1396.68 390.48 0.42 69048.5* 5yr 4822 187.76 194.61 0.001032 2.77 1743.33 419.41 0.43 69048.5* 10yr 5683 187.76 195.11 0.001032 2.90 1960.86 439.80 0.44 69048.5* 25yr 7279 187.76 195.92 0.001021 3.13 2330.71 472.43 0.44 69048.5* 50yr 8522 187.76 196.50 0.001011 3.27 2612.32 502.43 0.45 69048.5* 100yr 10187 187.76 197.22 0.001020 3.44 2986.87 548.93 0.46

68357.9* 2yr 3482 187.01 193.04 0.001023 2.49 1398.82 391.79 0.42 68357.9* 5yr 4822 187.01 193.89 0.001031 2.76 1744.01 419.47 0.43 68357.9* 10yr 5683 187.01 194.40 0.001033 2.90 1961.30 440.26 0.44 68357.9* 25yr 7279 187.01 195.22 0.001015 3.12 2336.98 473.64 0.44 68357.9* 50yr 8522 187.01 195.81 0.001003 3.26 2624.20 505.40 0.45 68357.9* 100yr 10187 187.01 196.51 0.001017 3.43 2996.23 552.22 0.45

67667.3* 2yr 3482 186.27 192.34 0.001028 2.49 1399.91 393.72 0.42 67667.3* 5yr 4822 186.27 193.18 0.001031 2.76 1743.98 419.40 0.43 67667.3* 10yr 5683 186.27 193.69 0.001036 2.90 1960.35 440.63 0.44 67667.3* 25yr 7279 186.27 194.51 0.001041 3.11 2339.13 474.76 0.45 67667.3* 50yr 8522 186.27 195.10 0.001059 3.24 2627.84 507.61 0.46 67667.3* 100yr 10187 186.27 195.79 0.001088 3.40 2996.59 569.81 0.47

66976.8* 2yr 3482 185.52 191.63 0.001032 2.49 1399.19 394.54 0.42 66976.8* 5yr 4822 185.52 192.47 0.001036 2.77 1742.47 420.18 0.43 66976.8* 10yr 5683 185.52 192.97 0.001042 2.90 1956.95 440.76 0.44 66976.8* 25yr 7279 185.52 193.79 0.001053 3.12 2332.78 475.41 0.45

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 197 Feasibility Report: West Rapti Basin

66286.2* 2yr 3482 184.77 190.91 0.001044 2.50 1394.54 394.74 0.42 66286.2* 5yr 4822 184.77 191.75 0.001050 2.78 1736.21 420.40 0.44 66286.2* 10yr 5683 184.77 192.24 0.001059 2.92 1947.81 440.83 0.44 66286.2* 25yr 7279 184.77 193.05 0.001076 3.14 2318.15 475.60 0.45 66286.2* 50yr 8522 184.77 193.59 0.001101 3.30 2586.40 517.43 0.46 66286.2* 100yr 10187 184.77 194.24 0.001129 3.49 2951.27 615.68 0.47

65595.6* 2yr 3482 184.02 190.18 0.001058 2.50 1390.84 395.99 0.43 65595.6* 5yr 4822 184.02 191.02 0.001059 2.78 1732.36 420.85 0.44 65595.6* 10yr 5683 184.02 191.50 0.001074 2.93 1939.40 440.66 0.45 65595.6* 25yr 7279 184.02 192.28 0.001103 3.16 2300.03 475.18 0.46 65595.6* 50yr 8522 184.02 192.81 0.001112 3.33 2566.44 537.95 0.47 65595.6* 100yr 10187 184.02 193.45 0.001112 3.53 2939.55 652.79 0.47

64905.0* 2yr 3482 183.28 189.44 0.001070 2.52 1380.78 391.97 0.43 64905.0* 5yr 4822 183.28 190.27 0.001090 2.81 1717.23 420.81 0.44 64905.0* 10yr 5683 183.28 190.73 0.001112 2.96 1916.97 439.58 0.45 64905.0* 25yr 7279 183.28 191.49 0.001139 3.21 2266.53 489.37 0.47 64905.0* 50yr 8522 183.28 192.02 0.001143 3.39 2539.45 558.71 0.47 64905.0* 100yr 10187 183.28 192.65 0.001144 3.58 2931.30 659.49 0.48

64214.5* 2yr 3482 182.53 188.71 0.001036 2.53 1378.03 394.34 0.42 64214.5* 5yr 4822 182.53 189.53 0.001001 2.85 1713.09 421.36 0.43 64214.5* 10yr 5683 182.53 189.98 0.001008 3.05 1903.18 439.18 0.44 64214.5* 25yr 7279 182.53 190.68 0.001041 3.39 2234.30 507.23 0.46 64214.5* 50yr 8522 182.53 191.17 0.001066 3.62 2499.30 585.79 0.47 64214.5* 100yr 10187 182.53 191.77 0.001084 3.89 2872.78 651.67 0.48

63523.9* 2yr 3482 181.78 187.97 0.001102 2.54 1370.10 392.94 0.43 63523.9* 5yr 4822 181.78 188.82 0.001101 2.81 1717.36 423.80 0.45 63523.9* 10yr 5683 181.78 189.26 0.001111 2.98 1907.83 450.37 0.45 63523.9* 25yr 7279 181.78 189.97 0.001101 3.28 2259.00 547.76 0.46 63523.9* 50yr 8522 181.78 190.46 0.001098 3.48 2545.21 605.01 0.47 63523.9* 100yr 10187 181.78 191.06 0.001090 3.71 2927.58 660.91 0.48

62833.3* 2yr 3482 181.03 187.22 0.001056 2.57 1358.02 384.86 0.43 62833.3* 5yr 4822 181.03 188.04 0.001094 2.89 1691.66 423.01 0.45 62833.3* 10yr 5683 181.03 188.46 0.001098 3.08 1882.14 469.47 0.46 62833.3* 25yr 7279 181.03 189.17 0.001110 3.40 2248.84 573.86 0.47 62833.3* 50yr 8522 181.03 189.65 0.001115 3.61 2536.14 604.96 0.48 62833.3* 100yr 10187 181.03 190.25 0.001122 3.87 2914.59 665.64 0.49

62142.7* 2yr 3482 180.29 186.49 0.001061 2.57 1356.82 381.20 0.43 62142.7* 5yr 4822 180.29 187.27 0.001094 2.91 1680.87 447.09 0.45 62142.7* 10yr 5683 180.29 187.69 0.001102 3.11 1879.49 498.78 0.46 62142.7* 25yr 7279 180.29 188.39 0.001114 3.43 2261.54 576.20 0.47 62142.7* 50yr 8522 180.29 188.88 0.001120 3.64 2548.93 609.85 0.48 62142.7* 100yr 10187 180.29 189.47 0.001130 3.89 2925.09 669.28 0.49

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 198 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

61452.2* 2yr 3482 179.54 185.73 0.001114 2.58 1348.55 380.79 0.44 61452.2* 5yr 4822 179.54 186.50 0.001120 2.92 1675.49 472.83 0.45 61452.2* 10yr 5683 179.54 186.92 0.001123 3.12 1889.22 535.02 0.46 61452.2* 25yr 7279 179.54 187.62 0.001123 3.42 2278.07 582.53 0.47 61452.2* 50yr 8522 179.54 188.10 0.001126 3.63 2568.05 618.60 0.48 61452.2* 100yr 10187 179.54 188.69 0.001135 3.88 2946.62 680.15 0.49

60761.6* 2yr 3482 178.79 184.95 0.001117 2.62 1331.91 389.12 0.44 60761.6* 5yr 4822 178.79 185.71 0.001122 2.98 1669.37 515.58 0.46 60761.6* 10yr 5683 178.79 186.13 0.001125 3.17 1890.92 537.95 0.46 60761.6* 25yr 7279 178.79 186.82 0.001133 3.48 2280.66 589.48 0.48 60761.6* 50yr 8522 178.79 187.30 0.001143 3.70 2570.91 628.94 0.48 60761.6* 100yr 10187 178.79 187.88 0.001152 3.95 2950.89 678.02 0.49

60071.0* 2yr 3482 178.04 184.16 0.001144 2.66 1317.18 406.87 0.45 60071.0* 5yr 4822 178.04 184.92 0.001138 3.01 1674.48 520.72 0.46 60071.0* 10yr 5683 178.04 185.34 0.001139 3.20 1898.55 546.90 0.47 60071.0* 25yr 7279 178.04 186.03 0.001150 3.52 2291.31 601.59 0.48 60071.0* 50yr 8522 178.04 186.50 0.001158 3.73 2584.85 636.42 0.49 60071.0* 100yr 10187 178.04 187.09 0.001155 3.96 2964.27 662.49 0.49

59380.4* 2yr 3482 177.30 183.36 0.001132 2.71 1308.45 438.67 0.45 59380.4* 5yr 4822 177.30 184.13 0.001130 3.07 1679.97 524.34 0.46 59380.4* 10yr 5683 177.30 184.54 0.001144 3.27 1902.27 556.66 0.47 59380.4* 25yr 7279 177.30 185.21 0.001167 3.59 2294.82 609.21 0.48 59380.4* 50yr 8522 177.30 185.68 0.001168 3.80 2587.72 622.44 0.49 59380.4* 100yr 10187 177.30 186.27 0.001168 4.04 2958.32 643.52 0.50

58689.9* 2yr 3482 176.55 182.55 0.001181 2.75 1310.45 454.16 0.45 58689.9* 5yr 4822 176.55 183.33 0.001174 3.07 1692.86 525.94 0.47 58689.9* 10yr 5683 176.55 183.73 0.001188 3.28 1915.31 573.15 0.48 58689.9* 25yr 7279 176.55 184.41 0.001189 3.58 2309.04 594.94 0.49 58689.9* 50yr 8522 176.55 184.88 0.001184 3.77 2596.71 608.42 0.49 58689.9* 100yr 10187 176.55 185.47 0.001177 4.00 2960.74 627.19 0.50

56618.1* 2yr 3482 174.30 180.05 0.001232 2.78 1331.80 480.80 0.46 56618.1* 5yr 4822 174.30 180.80 0.001277 3.10 1695.23 502.04 0.48 56618.1* 10yr 5683 174.30 181.23 0.001242 3.26 1915.61 520.93 0.48 56618.1* 25yr 7279 174.30 181.93 0.001211 3.54 2293.78 549.05 0.49 56618.1* 50yr 8522 174.30 182.43 0.001195 3.73 2568.68 560.31 0.49 56618.1* 100yr 10187 174.30 183.04 0.001178 3.96 2918.85 577.26 0.50

55927.6* 2yr 3482 173.56 179.20 0.001236 2.80 1344.80 467.59 0.46 55927.6* 5yr 4822 173.56 179.92 0.001240 3.15 1683.49 471.81 0.48 55927.6* 10yr 5683 173.56 180.35 0.001259 3.32 1890.23 496.66 0.49 55927.6* 25yr 7279 173.56 181.08 0.001221 3.60 2262.46 532.21 0.49 55927.6* 50yr 8522 173.56 181.58 0.001207 3.79 2532.88 542.69 0.50 55927.6* 100yr 10187 173.56 182.20 0.001194 4.03 2875.63 560.41 0.50

55237.0* 2yr 3482 172.81 178.35 0.001235 2.81 1355.07 454.21 0.46

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 199 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 55237.0* 5yr 4822 172.81 179.05 0.001264 3.18 1675.40 458.09 0.48 55237.0* 10yr 5683 172.81 179.46 0.001272 3.38 1863.75 460.04 0.49 55237.0* 25yr 7279 172.81 180.20 0.001265 3.65 2222.00 500.66 0.50 55237.0* 50yr 8522 172.81 180.71 0.001250 3.85 2484.31 524.16 0.50 55237.0* 100yr 10187 172.81 181.34 0.001237 4.10 2817.68 542.70 0.51

54546.4* 2yr 3482 172.06 177.52 0.001280 2.54 1371.95 440.71 0.46 54546.4* 5yr 4822 172.06 178.23 0.001249 2.86 1685.59 444.38 0.47 54546.4* 10yr 5683 172.06 178.65 0.001228 3.04 1871.50 445.90 0.47 54546.4* 25yr 7279 172.06 179.39 0.001221 3.30 2212.01 480.13 0.48 54546.4* 50yr 8522 172.06 179.93 0.001169 3.46 2478.72 508.00 0.48 54546.4* 100yr 10187 172.06 180.58 0.001133 3.68 2813.59 527.87 0.48

53855.8* 2yr 3482 171.31 176.63 0.001264 2.56 1360.11 427.11 0.46 53855.8* 5yr 4822 171.31 177.37 0.001225 2.88 1674.25 430.13 0.47 53855.8* 10yr 5683 171.31 177.80 0.001203 3.05 1861.16 431.69 0.47 53855.8* 25yr 7279 171.31 178.55 0.001178 3.33 2186.59 438.23 0.48 53855.8* 50yr 8522 171.31 179.12 0.001137 3.49 2454.92 488.53 0.48 53855.8* 100yr 10187 171.31 179.79 0.001106 3.71 2790.19 512.15 0.48

53165.3* 2yr 3482 170.57 175.77 0.001222 2.57 1355.66 413.31 0.45 53165.3* 5yr 4822 170.57 176.54 0.001166 2.88 1674.62 416.04 0.46 53165.3* 10yr 5683 170.57 176.99 0.001141 3.05 1862.24 417.64 0.46 53165.3* 25yr 7279 170.57 177.76 0.001108 3.34 2184.84 420.37 0.47 53165.3* 50yr 8522 170.57 178.33 0.001124 3.51 2434.81 459.70 0.47 53165.3* 100yr 10187 170.57 179.03 0.001082 3.73 2771.20 496.96 0.47

52474.7* 2yr 3482 169.82 174.96 0.001126 2.54 1369.74 399.35 0.44 52474.7* 5yr 4822 169.82 175.78 0.001069 2.85 1695.22 402.19 0.44 52474.7* 10yr 5683 169.82 176.24 0.001052 3.02 1882.36 403.81 0.45 52474.7* 25yr 7279 169.82 177.03 0.001033 3.31 2201.30 406.57 0.45 52474.7* 50yr 8522 169.82 177.59 0.001026 3.52 2432.75 437.42 0.46 52474.7* 100yr 10187 169.82 178.30 0.001006 3.75 2762.49 482.74 0.46

51784.1* 2yr 3482 169.07 174.27 0.000947 2.45 1422.09 385.80 0.41 51784.1* 5yr 4822 169.07 175.11 0.000923 2.76 1747.06 388.69 0.41 51784.1* 10yr 5683 169.07 175.58 0.000926 2.95 1928.88 390.30 0.42 51784.1* 25yr 7279 169.07 176.36 0.000936 3.26 2236.87 393.02 0.43 51784.1* 50yr 8522 169.07 176.92 0.000944 3.48 2457.06 394.94 0.44 51784.1* 100yr 10187 169.07 177.63 0.000943 3.73 2775.44 470.75 0.45

51093.5* 2yr 3482 168.32 173.73 0.000726 2.28 1524.03 373.81 0.36 51093.5* 5yr 4822 168.32 174.55 0.000791 2.63 1835.62 390.52 0.39 51093.5* 10yr 5683 168.32 175.01 0.000807 2.82 2016.59 396.05 0.40 51093.5* 25yr 7279 168.32 175.79 0.000825 3.12 2384.91 519.61 0.41 51093.5* 50yr 8522 168.32 176.36 0.000822 3.31 2690.20 545.01 0.41 51093.5* 100yr 10187 168.32 177.10 0.000830 3.48 3140.29 630.40 0.42

50576.5 Bridge

50403 2yr 3482 167.58 170.86 0.006119 4.44 784.08 351.91 0.95

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 200 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 50403 5yr 4822 167.58 171.41 0.005658 4.93 978.28 353.76 0.95 50403 10yr 5683 167.58 171.71 0.005554 5.23 1087.11 354.80 0.95 50403 25yr 7279 167.58 172.23 0.005479 5.74 1269.18 356.52 0.97 50403 50yr 8522 167.58 172.58 0.005519 6.11 1394.17 357.69 0.99 50403 100yr 10187 167.58 173.04 0.005450 6.53 1560.76 359.26 1.00

50215 2yr 3482 166.58 170.73 0.001659 2.86 1216.34 396.76 0.52 50215 5yr 4822 166.58 171.34 0.001751 3.30 1460.40 400.16 0.55 50215 10yr 5683 166.58 171.68 0.001810 3.55 1598.81 402.08 0.57 50215 25yr 7279 166.58 172.27 0.001898 3.97 1834.90 405.32 0.60 50215 50yr 8522 166.58 172.68 0.001964 4.26 2001.13 407.59 0.61 50215 100yr 10187 166.58 173.17 0.002064 4.63 2200.53 410.29 0.64

48583 2yr 3482 164.38 168.07 0.001693 2.44 1427.48 601.66 0.51 48583 5yr 4822 164.38 168.59 0.001772 2.75 1751.55 637.04 0.53 48583 10yr 5683 164.38 168.87 0.001818 2.94 1931.97 648.61 0.54 48583 25yr 7279 164.38 169.30 0.001968 3.29 2212.36 666.18 0.58 48583 50yr 8522 164.38 169.59 0.002076 3.54 2410.44 678.33 0.60 48583 100yr 10187 164.38 169.92 0.002210 3.86 2685.41 976.80 0.63

47002 2yr 3482 161.51 165.76 0.001326 2.31 1711.01 987.39 0.45 47002 5yr 4822 161.51 166.23 0.001347 2.60 2198.83 1074.44 0.47 47002 10yr 5683 161.51 166.50 0.001351 2.75 2492.81 1121.04 0.48 47002 25yr 7279 161.51 166.96 0.001302 2.94 3207.15 1541.31 0.48 47002 50yr 8522 161.51 167.28 0.001261 3.05 3720.83 1638.76 0.48 47002 100yr 10187 161.51 167.68 0.001212 3.18 4388.85 1738.30 0.48

46382 2yr 3482 161.14 163.53 0.008023 3.84 907.78 623.21 1.01 46382 5yr 4822 161.14 163.90 0.007415 4.23 1140.46 637.65 1.01 46382 10yr 5683 161.14 164.13 0.007039 4.42 1285.81 646.93 1.00 46382 25yr 7279 161.14 164.49 0.006797 4.78 1523.51 664.31 1.01 46382 50yr 8522 161.14 164.76 0.006617 5.00 1704.39 680.29 1.01 46382 100yr 10187 161.14 165.12 0.006287 5.22 1950.08 701.42 1.00

44672 2yr 3482 157.31 160.27 0.000934 1.36 2551.46 1645.75 0.35 44672 5yr 4822 157.31 160.66 0.000860 1.51 3186.63 1671.34 0.35 44672 10yr 5683 157.31 160.88 0.000830 1.60 3561.68 1686.20 0.35 44672 25yr 7279 157.31 161.27 0.000785 1.73 4217.84 1711.90 0.35 44672 50yr 8522 157.31 161.54 0.000760 1.83 4695.49 1731.22 0.35 44672 100yr 10187 157.31 161.89 0.000718 1.92 5475.90 1943.58 0.35

43734 2yr 3482 155.61 159.70 0.000464 1.09 3211.93 1818.75 0.25 43734 5yr 4822 155.61 160.11 0.000453 1.23 3975.21 1863.58 0.26 43734 10yr 5683 155.61 160.35 0.000453 1.31 4414.86 1879.82 0.26 43734 25yr 7279 155.61 160.76 0.000447 1.44 5189.54 1911.82 0.27 43734 50yr 8522 155.61 161.05 0.000446 1.53 5746.51 1949.24 0.27 43734 100yr 10187 155.61 161.41 0.000444 1.63 6449.70 1976.50 0.28

41794 2yr 3482 155.20 158.88 0.000392 1.03 3469.40 1923.87 0.24 41794 5yr 4822 155.20 159.31 0.000382 1.16 4309.88 1988.89 0.24 41794 10yr 5683 155.20 159.56 0.000378 1.23 4807.15 2026.37 0.24

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 201 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 41794 25yr 7279 155.20 159.97 0.000375 1.35 5660.60 2089.14 0.25 41794 50yr 8522 155.20 160.27 0.000375 1.44 6277.63 2133.37 0.25 41794 100yr 10187 155.20 160.63 0.000376 1.54 7056.95 2187.96 0.26

40074 2yr 3482 153.10 157.61 0.001233 2.18 2000.29 1478.76 0.44 40074 5yr 4822 153.10 158.13 0.001059 2.28 2836.30 1722.20 0.42 40074 10yr 5683 153.10 158.40 0.001005 2.36 3326.76 1844.13 0.41 40074 25yr 7279 153.10 158.85 0.000938 2.48 4201.35 2049.23 0.41 40074 50yr 8522 153.10 159.16 0.000900 2.56 4862.60 2191.60 0.40 40074 100yr 10187 153.10 159.55 0.000856 2.65 5741.61 2367.63 0.40

37538 2yr 3482 150.64 155.59 0.000585 1.68 2213.78 968.06 0.31 37538 5yr 4822 150.64 156.09 0.000646 1.96 2790.80 1325.22 0.33 37538 10yr 5683 150.64 156.37 0.000664 2.09 3179.38 1429.67 0.34 37538 25yr 7279 150.64 156.84 0.000682 2.29 3881.92 1563.79 0.35 37538 50yr 8522 150.64 157.18 0.000688 2.42 4416.94 1658.67 0.36 37538 100yr 10187 150.64 157.58 0.000691 2.57 5118.37 1775.40 0.37

35903 2yr 3482 150.16 154.38 0.000934 1.94 2187.05 1383.75 0.38 35903 5yr 4822 150.16 154.99 0.000766 2.02 3101.54 1620.88 0.36 35903 10yr 5683 150.16 155.32 0.000707 2.07 3646.58 1716.93 0.35 35903 25yr 7279 150.16 155.86 0.000637 2.16 4626.41 1895.89 0.34 35903 50yr 8522 150.16 156.23 0.000601 2.22 5362.25 2021.98 0.33 35903 100yr 10187 150.16 156.69 0.000568 2.30 6319.79 2181.24 0.33

34889 2yr 3482 149.27 153.57 0.000709 1.88 1880.88 682.31 0.34 34889 5yr 4822 149.27 154.18 0.000746 2.15 2328.19 779.59 0.36 34889 10yr 5683 149.27 154.48 0.000798 2.33 2567.02 839.38 0.38 34889 25yr 7279 149.27 154.97 0.000875 2.62 3004.23 942.93 0.40 34889 50yr 8522 149.27 155.31 0.000922 2.80 3333.14 990.20 0.42 34889 100yr 10187 149.27 155.71 0.000981 3.04 3743.06 1042.96 0.43

34467 2yr 3482 148.83 153.15 0.001051 2.20 1814.84 891.32 0.41 34467 5yr 4822 148.83 153.80 0.000959 2.36 2429.96 1003.97 0.41 34467 10yr 5683 148.83 154.08 0.000980 2.51 2721.97 1037.68 0.42 PRTW.07 34467 25yr 7279 148.83 154.57 0.000994 2.74 3234.61 1066.01 0.43 34467 50yr 8522 148.83 154.90 0.001010 2.91 3589.48 1075.81 0.43 34467 100yr 10187 148.83 155.28 0.001058 3.14 4002.87 1099.19 0.45

34097 2yr 3482 147.50 151.48 0.007021 4.46 780.19 385.86 1.00 34097 5yr 4822 147.50 152.00 0.006846 4.87 990.91 425.29 1.01 34097 10yr 5683 147.50 152.48 0.005148 4.68 1291.16 776.91 0.90 34097 25yr 7279 147.50 152.97 0.004514 4.89 1692.47 854.23 0.87 34097 50yr 8522 147.50 153.32 0.004174 5.03 2010.35 1037.48 0.85 34097 100yr 10187 147.50 153.70 0.003911 5.21 2424.38 1109.89 0.84

32686 2yr 3482 145.26 150.41 0.000384 1.32 3073.81 1479.31 0.25 32686 5yr 4822 145.26 150.87 0.000417 1.52 3811.75 1721.53 0.27 32686 10yr 5683 145.26 151.13 0.000432 1.63 4271.65 1810.12 0.27 32686 25yr 7279 145.26 151.57 0.000450 1.79 5076.18 1907.19 0.28 32686 50yr 8522 145.26 151.87 0.000459 1.90 5672.05 1968.96 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 202 Feasibility Report: West Rapti Basin

30075 2yr 3482 144.58 149.10 0.000721 1.63 2877.51 1900.59 0.33 30075 5yr 4822 144.58 149.56 0.000666 1.76 3777.32 1995.86 0.33 30075 10yr 5683 144.58 149.83 0.000639 1.83 4318.61 2051.05 0.33 30075 25yr 7279 144.58 150.28 0.000604 1.94 5263.47 2143.97 0.32 30075 50yr 8522 144.58 150.60 0.000582 2.01 5965.42 2210.48 0.32 30075 100yr 10187 144.58 151.00 0.000564 2.11 6848.41 2291.40 0.32

27652 2yr 3482 141.57 146.79 0.001178 2.03 1808.78 844.50 0.42 27652 5yr 4822 141.57 147.27 0.001241 2.31 2220.84 901.34 0.44 27652 10yr 5683 141.57 147.53 0.001275 2.46 2465.86 933.50 0.46 27652 25yr 7279 141.57 147.98 0.001328 2.71 2892.04 986.95 0.47 27652 50yr 8522 141.57 148.29 0.001361 2.88 3204.89 1026.43 0.49 27652 100yr 10187 141.57 148.66 0.001377 3.10 3613.47 1169.68 0.50

27200.6* 2yr 3482 141.41 146.27 0.001210 1.96 1853.78 917.39 0.42 27200.6* 5yr 4822 141.41 146.72 0.001259 2.22 2281.07 972.07 0.44 27200.6* 10yr 5683 141.41 146.98 0.001286 2.37 2534.25 1003.07 0.45 27200.6* 25yr 7279 141.41 147.41 0.001311 2.60 2979.17 1050.02 0.47 27200.6* 50yr 8522 141.41 147.72 0.001324 2.76 3302.73 1080.53 0.48 27200.6* 100yr 10187 141.41 148.09 0.001321 2.95 3714.42 1123.01 0.48

26749.3* 2yr 3482 141.25 145.73 0.001235 1.89 1903.79 1002.74 0.42 26749.3* 5yr 4822 141.25 146.17 0.001257 2.14 2359.75 1067.31 0.44 26749.3* 10yr 5683 141.25 146.43 0.001252 2.27 2637.41 1099.12 0.44 26749.3* 25yr 7279 141.25 146.87 0.001231 2.46 3133.45 1152.05 0.45 26749.3* 50yr 8522 141.25 147.19 0.001211 2.60 3500.37 1186.32 0.45 26749.3* 100yr 10187 141.25 147.58 0.001178 2.76 3974.21 1233.25 0.46

26298.0* 2yr 3482 141.09 145.19 0.001236 1.83 1969.01 1119.91 0.42 26298.0* 5yr 4822 141.09 145.65 0.001157 2.01 2517.51 1233.82 0.42 26298.0* 10yr 5683 141.09 145.93 0.001103 2.11 2869.52 1298.70 0.42 26298.0* 25yr 7279 141.09 146.41 0.001014 2.24 3522.37 1409.67 0.41 26298.0* 50yr 8522 141.09 146.76 0.000952 2.33 4021.32 1482.31 0.40 26298.0* 100yr 10187 141.09 147.19 0.000887 2.43 4682.73 1602.08 0.40

25846.6* 2yr 3482 140.93 144.68 0.001111 1.71 2085.67 1173.46 0.40 25846.6* 5yr 4822 140.93 145.22 0.000923 1.82 2738.24 1239.39 0.37 25846.6* 10yr 5683 140.93 145.53 0.000854 1.89 3129.70 1276.57 0.37 25846.6* 25yr 7279 140.93 146.06 0.000763 2.00 3819.32 1333.70 0.36 25846.6* 50yr 8522 140.93 146.43 0.000717 2.09 4320.16 1369.38 0.35 25846.6* 100yr 10187 140.93 146.88 0.000676 2.20 4965.40 1488.80 0.35

25395.3* 2yr 3482 140.77 144.28 0.000790 1.49 2381.46 1277.52 0.34 25395.3* 5yr 4822 140.77 144.92 0.000601 1.55 3224.14 1366.26 0.31 25395.3* 10yr 5683 140.77 145.26 0.000552 1.61 3696.98 1411.77 0.30 25395.3* 25yr 7279 140.77 145.82 0.000493 1.71 4512.53 1475.79 0.29 25395.3* 50yr 8522 140.77 146.21 0.000468 1.78 5131.97 1776.48 0.29 25395.3* 100yr 10187 140.77 146.69 0.000440 1.87 6071.91 2051.54 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 203 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 24944 2yr 3482 140.61 144.05 0.000441 1.22 2908.30 1357.58 0.26 24944 5yr 4822 140.61 144.75 0.000346 1.28 3885.38 1444.52 0.24 24944 10yr 5683 140.61 145.10 0.000327 1.34 4404.65 1482.70 0.23 24944 25yr 7279 140.61 145.68 0.000307 1.44 5284.56 1545.23 0.23 24944 50yr 8522 140.61 146.09 0.000288 1.49 6324.58 2031.53 0.23 24944 100yr 10187 140.61 146.57 0.000276 1.57 7339.62 2137.87 0.23

23188 2yr 3482 139.01 143.87 0.000058 0.64 5949.31 1849.76 0.10 23188 5yr 4822 139.01 144.57 0.000062 0.73 7305.32 2039.48 0.11 23188 10yr 5683 139.01 144.92 0.000066 0.80 8041.25 2149.76 0.11 23188 25yr 7279 139.01 145.50 0.000073 0.90 9330.31 2325.98 0.12 23188 50yr 8522 139.01 145.90 0.000077 0.97 10287.10 2448.60 0.13 23188 100yr 10187 139.01 146.38 0.000082 1.05 11504.50 2596.25 0.13

21140 2yr 4306 138.11 143.39 0.000606 1.92 2629.55 1211.43 0.32 21140 5yr 5971 138.11 144.06 0.000581 2.10 3529.29 1411.53 0.33 21140 10yr 7027 138.11 144.39 0.000591 2.23 3988.27 1449.65 0.33 21140 25yr 8991 138.11 144.91 0.000611 2.44 4765.43 1535.55 0.35 21140 50yr 10532 138.11 145.27 0.000628 2.59 5339.38 1630.63 0.35 21140 100yr 12613 138.11 145.70 0.000650 2.77 6071.09 1744.35 0.36

20425 Bridge

20348 2yr 4306 136.98 140.69 0.001948 3.31 1497.00 756.72 0.57 20348 5yr 5971 136.98 141.30 0.001925 3.66 2091.83 1191.86 0.59 20348 10yr 7027 136.98 141.64 0.001851 3.79 2547.20 1432.05 0.58 20348 25yr 8991 136.98 142.23 0.001591 3.83 3480.82 1721.09 0.55 20348 50yr 10532 136.98 142.64 0.001448 3.85 4236.95 1980.95 0.53 20348 100yr 12613 136.98 143.14 0.001284 3.85 5286.29 2215.11 0.51

19845 2yr 4306 136.03 140.43 0.000619 1.89 2417.01 1069.66 0.33 19845 5yr 5971 136.03 141.06 0.000635 2.14 3182.42 1357.56 0.34 19845 10yr 7027 136.03 141.41 0.000638 2.27 3676.40 1487.55 0.34 19845 25yr 8991 136.03 141.98 0.000633 2.45 4613.08 1833.06 0.35 19845 50yr 10532 136.03 142.39 0.000621 2.56 5421.57 2136.95 0.35 19845 100yr 12613 136.03 142.89 0.000594 2.65 6518.06 2291.33 0.35

PRTW.08 19296 2yr 4306 135.18 140.12 0.000550 2.04 2892.05 1446.94 0.32 19296 5yr 5971 135.18 140.77 0.000537 2.22 3931.87 1661.44 0.32 19296 10yr 7027 135.18 141.13 0.000524 2.30 4540.55 1718.78 0.32 19296 25yr 8991 135.18 141.73 0.000507 2.43 5598.57 1814.13 0.32 19296 50yr 10532 135.18 142.14 0.000500 2.53 6362.17 1879.95 0.32 19296 100yr 12613 135.18 142.64 0.000495 2.65 7329.91 1960.20 0.33

18840 2yr 4306 135.10 139.91 0.000489 1.81 3196.58 1623.25 0.29 18840 5yr 5971 135.10 140.58 0.000448 1.93 4317.88 1716.81 0.29 18840 10yr 7027 135.10 140.95 0.000434 2.00 4957.21 1767.95 0.29 18840 25yr 8991 135.10 141.56 0.000418 2.13 6055.89 1852.53 0.29 18840 50yr 10532 135.10 141.97 0.000414 2.22 6839.16 1910.54 0.29 18840 100yr 12613 135.10 142.48 0.000412 2.34 7822.60 1980.97 0.29

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 204 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 18406 2yr 4306 135.06 139.85 0.000185 1.15 4792.32 1573.80 0.18 18406 5yr 5971 135.06 140.52 0.000197 1.32 5861.13 1635.83 0.19 18406 10yr 7027 135.06 140.88 0.000205 1.41 6461.88 1669.68 0.20 18406 25yr 8991 135.06 141.48 0.000218 1.57 7482.39 1725.67 0.21 18406 50yr 10532 135.06 141.89 0.000228 1.68 8200.64 1764.01 0.22 18406 100yr 12613 135.06 142.39 0.000242 1.83 9093.01 1810.51 0.23

17785 2yr 4306 134.42 139.78 0.000108 0.91 5852.32 1908.18 0.14 17785 5yr 5971 134.42 140.44 0.000118 1.05 7154.86 2023.52 0.15 17785 10yr 7027 134.42 140.81 0.000124 1.12 7897.78 2086.46 0.16 17785 25yr 8991 134.42 141.40 0.000134 1.25 9177.60 2190.63 0.17 17785 50yr 10532 134.42 141.81 0.000141 1.35 10089.62 2261.94 0.17 17785 100yr 12613 134.42 142.31 0.000151 1.46 11235.64 2348.48 0.18

17069 2yr 4306 133.91 139.72 0.000077 0.82 6696.49 2048.12 0.12 17069 5yr 5971 133.91 140.38 0.000088 0.95 8073.99 2148.55 0.13 17069 10yr 7027 133.91 140.74 0.000094 1.03 8853.09 2203.33 0.14 17069 25yr 8991 133.91 141.33 0.000104 1.15 10186.42 2294.04 0.15 17069 50yr 10532 133.91 141.74 0.000112 1.25 11129.17 2356.08 0.15 17069 100yr 12613 133.91 142.23 0.000121 1.36 12306.71 2431.34 0.16

16550 2yr 4306 133.86 139.69 0.000068 0.80 7024.98 1898.53 0.11 16550 5yr 5971 133.86 140.34 0.000081 0.94 8284.10 1974.49 0.13 16550 10yr 7027 133.86 140.69 0.000089 1.03 8991.15 2015.88 0.13 16550 25yr 8991 133.86 141.28 0.000101 1.17 10194.16 2084.42 0.15 16550 50yr 10532 133.86 141.68 0.000111 1.27 11038.95 2131.24 0.15 16550 100yr 12613 133.86 142.17 0.000122 1.39 12088.32 2188.00 0.16

16053 2yr 4306 133.51 139.62 0.000181 1.15 5623.09 2047.17 0.18 16053 5yr 5971 133.51 140.26 0.000189 1.29 6987.41 2195.33 0.19 16053 10yr 7027 133.51 140.61 0.000195 1.38 7771.34 2276.10 0.19 16053 25yr 8991 133.51 141.20 0.000204 1.51 9133.88 2410.06 0.20 16053 50yr 10532 133.51 141.59 0.000211 1.60 10109.17 2501.54 0.21 16053 100yr 12613 133.51 142.07 0.000221 1.72 11341.46 2612.56 0.21

15483 2yr 4306 133.32 139.51 0.000186 1.13 5347.08 1880.96 0.18 15483 5yr 5971 133.32 140.15 0.000196 1.28 6572.60 1971.19 0.19 15483 10yr 7027 133.32 140.50 0.000203 1.36 7262.63 2020.22 0.20 15483 25yr 8991 133.32 141.07 0.000215 1.51 8443.51 2101.48 0.21 15483 50yr 10532 133.32 141.46 0.000225 1.61 9273.52 2156.76 0.21 15483 100yr 12613 133.32 141.93 0.000238 1.75 10307.59 2223.71 0.22

14747 2yr 4306 133.27 139.29 0.000348 1.48 4195.54 2014.43 0.25 14747 5yr 5971 133.27 139.94 0.000314 1.57 5516.42 2071.57 0.24 14747 10yr 7027 133.27 140.29 0.000306 1.63 6239.72 2102.20 0.24 14747 25yr 8991 133.27 140.86 0.000300 1.74 7456.52 2152.75 0.24 14747 50yr 10532 133.27 141.24 0.000302 1.83 8293.04 2186.82 0.25 14747 100yr 12613 133.27 141.71 0.000309 1.95 9319.58 2234.14 0.25

14000 2yr 4306 133.01 139.28 0.000040 0.56 10236.96 3088.05 0.09 14000 5yr 5971 133.01 139.92 0.000047 0.66 12302.55 3364.77 0.10

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 205 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-] 14000 10yr 7027 133.01 140.26 0.000051 0.72 13486.14 3495.81 0.10 14000 25yr 8991 133.01 140.83 0.000056 0.81 15536.38 3682.90 0.11 14000 50yr 10532 133.01 141.22 0.000061 0.88 16978.78 3804.29 0.11 14000 100yr 12613 133.01 141.68 0.000066 0.96 18782.24 3955.38 0.12

13016 2yr 4306 132.90 138.97 0.000750 2.19 2730.81 1446.53 0.36 13016 5yr 5971 132.90 139.57 0.000728 2.39 3691.16 1710.75 0.37 13016 10yr 7027 132.90 139.91 0.000710 2.48 4276.83 1809.73 0.37 13016 25yr 8991 132.90 140.44 0.000711 2.67 5323.02 2094.37 0.37 13016 50yr 10532 132.90 140.82 0.000697 2.77 6137.15 2251.22 0.37 13016 100yr 12613 132.90 141.27 0.000670 2.86 7190.78 2368.31 0.37

12081 2yr 4306 132.60 138.65 0.000270 1.55 4014.99 1679.03 0.23 12081 5yr 5971 132.60 139.23 0.000300 1.77 5040.80 1822.52 0.24 12081 10yr 7027 132.60 139.55 0.000316 1.88 5636.81 1900.92 0.25 12081 25yr 8991 132.60 140.07 0.000340 2.07 6661.26 2015.06 0.27 12081 50yr 10532 132.60 140.44 0.000354 2.20 7400.19 2066.52 0.27 12081 100yr 12613 132.60 140.88 0.000371 2.35 8328.62 2129.41 0.28

11157 2yr 4306 132.40 138.33 0.000403 1.51 3364.62 1588.63 0.26 11157 5yr 5971 132.40 138.89 0.000420 1.70 4280.18 1678.31 0.27 11157 10yr 7027 132.40 139.20 0.000430 1.81 4800.38 1727.19 0.28 11157 25yr 8991 132.40 139.69 0.000451 2.00 5675.60 1806.45 0.29 11157 50yr 10532 132.40 140.04 0.000467 2.13 6303.81 1861.26 0.30 11157 100yr 12613 132.40 140.46 0.000487 2.29 7095.97 1928.16 0.31

10061 2yr 4306 132.21 137.84 0.000483 1.88 3580.51 1620.89 0.30 10061 5yr 5971 132.21 138.37 0.000521 2.12 4478.39 1748.48 0.31 10061 10yr 7027 132.21 138.66 0.000543 2.25 4992.88 1817.55 0.32 10061 25yr 8991 132.21 139.12 0.000584 2.48 5859.99 1928.38 0.34 10061 50yr 10532 132.21 139.44 0.000613 2.64 6487.94 2004.82 0.35 10061 100yr 12613 132.21 139.83 0.000646 2.83 7290.65 2098.48 0.37

9077 2yr 4306 132.21 137.09 0.000883 2.31 2598.32 1578.95 0.39 9077 5yr 5971 132.21 137.55 0.000968 2.62 3368.04 1813.32 0.42 9077 10yr 7027 132.21 137.80 0.000994 2.77 3851.39 1939.00 0.43 9077 25yr 8991 132.21 138.23 0.001006 2.97 4726.88 2097.78 0.44 9077 50yr 10532 132.21 138.54 0.001000 3.09 5383.17 2167.84 0.44 9077 100yr 12613 132.21 138.92 0.000991 3.23 6224.57 2254.48 0.44

8282 2yr 4306 131.87 136.35 0.001071 2.05 2843.37 1896.72 0.41 8282 5yr 5971 131.87 136.83 0.000958 2.17 3777.45 1969.61 0.40 8282 10yr 7027 131.87 137.11 0.000909 2.24 4327.41 2011.28 0.39 8282 25yr 8991 131.87 137.56 0.000860 2.37 5254.22 2079.62 0.39 8282 50yr 10532 131.87 137.88 0.000837 2.47 5926.25 2127.81 0.39 8282 100yr 12613 131.87 138.27 0.000821 2.60 6764.13 2183.28 0.39

7734 2yr 4306 131.12 135.36 0.002103 2.62 1729.84 989.00 0.56 7734 5yr 5971 131.12 135.81 0.002104 2.96 2210.25 1151.19 0.58 7734 10yr 7027 131.12 136.06 0.002114 3.15 2506.73 1249.18 0.59 7734 25yr 8991 131.12 136.47 0.002118 3.44 3053.04 1412.18 0.60

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 206 Feasibility Report: West Rapti Basin

7233 2yr 4306 130.80 134.69 0.001138 2.26 2452.77 1411.95 0.43 7233 5yr 5971 130.80 135.18 0.001129 2.50 3173.30 1538.52 0.44 7233 10yr 7027 130.80 135.45 0.001128 2.63 3588.70 1585.89 0.44 7233 25yr 8991 130.80 135.88 0.001146 2.86 4285.39 1661.00 0.45 7233 50yr 10532 130.80 136.17 0.001169 3.03 4780.49 1712.38 0.46 7233 100yr 12613 130.80 136.52 0.001233 3.27 5394.39 1834.31 0.48

6882 2yr 4306 130.18 134.09 0.001748 2.57 1891.08 1370.71 0.52 6882 5yr 5971 130.18 134.61 0.001570 2.76 2655.63 1582.56 0.51 6882 10yr 7027 130.18 134.89 0.001508 2.87 3117.16 1720.59 0.50 PRTW.09 6882 25yr 8991 130.18 135.35 0.001420 3.03 3948.36 1912.15 0.50 6882 50yr 10532 130.18 135.66 0.001381 3.15 4559.17 2032.27 0.50 6882 100yr 12613 130.18 136.03 0.001349 3.30 5343.49 2174.40 0.50

6324 2yr 4306 129.27 133.70 0.000610 1.55 2786.42 1124.46 0.31 6324 5yr 5971 129.27 134.23 0.000620 1.77 3470.33 1426.01 0.32 6324 10yr 7027 129.27 134.51 0.000639 1.90 3876.41 1538.75 0.33 6324 25yr 8991 129.27 134.95 0.000676 2.12 4594.78 1716.49 0.35 6324 50yr 10532 129.27 135.24 0.000708 2.27 5114.10 1826.83 0.36 6324 100yr 12613 129.27 135.59 0.000750 2.47 5775.68 1958.42 0.37

5153 2yr 4306 128.13 132.71 0.001072 1.85 2358.13 1228.53 0.40 5153 5yr 5971 128.13 133.26 0.001030 2.00 3173.39 1699.48 0.40 5153 10yr 7027 128.13 133.53 0.001039 2.09 3633.98 1810.97 0.41 5153 25yr 8991 128.13 133.93 0.001072 2.27 4402.76 1966.93 0.42 5153 50yr 10532 128.13 134.19 0.001111 2.41 4911.44 2064.20 0.43 5153 100yr 12613 128.13 134.50 0.001128 2.58 5572.69 2185.08 0.44

4302 2yr 4306 127.32 131.95 0.000828 1.51 2871.76 1548.79 0.34 4302 5yr 5971 127.32 132.59 0.000727 1.51 4068.15 2281.03 0.33 4302 10yr 7027 127.32 132.88 0.000685 1.55 4795.95 2627.24 0.32 4302 25yr 8991 127.32 133.30 0.000665 1.63 5951.65 2863.08 0.32 4302 50yr 10532 127.32 133.57 0.000646 1.72 6722.40 2977.58 0.32 4302 100yr 12613 127.32 133.91 0.000617 1.81 7760.73 3124.00 0.32

3229 2yr 4306 126.01 129.94 0.003009 3.31 1299.97 533.08 0.68 3229 5yr 5971 126.01 130.87 0.002273 3.21 1914.05 1092.54 0.61 3229 10yr 7027 126.01 131.18 0.002231 3.34 2296.88 1519.90 0.61 3229 25yr 8991 126.01 131.72 0.001872 3.41 3296.25 2026.35 0.57 3229 50yr 10532 126.01 132.11 0.001631 3.40 4113.82 2202.33 0.54 3229 100yr 12613 126.01 132.58 0.001400 3.40 5206.98 2417.69 0.51

1812 2yr 4306 124.12 129.64 0.000176 1.07 4021.69 1066.49 0.18 1812 5yr 5971 124.12 130.65 0.000153 1.09 6378.54 3024.69 0.17 1812 10yr 7027 124.12 130.97 0.000157 1.16 7388.03 3222.19 0.17 1812 25yr 8991 124.12 131.51 0.000160 1.26 9214.03 3567.29 0.18 1812 50yr 10532 124.12 131.89 0.000161 1.33 10606.24 3809.87 0.18 1812 100yr 12613 124.12 132.35 0.000161 1.40 12451.72 4109.42 0.18

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 207 Feasibility Report: West Rapti Basin

Slope Return River Dis- Bed Water bottom Velocity Flow Top Structure period Station charge level level level channel Area Width Froude [years] [m3/s] [m] [m] [m/m] [m/s] [m2] [m] [-]

0 2yr 4306 123.19 128.74 0.001090 2.36 1822.53 579.20 0.43 0 5yr 5971 123.19 129.85 0.001092 2.22 2740.13 1116.39 0.42 0 10yr 7027 123.19 130.13 0.001091 2.36 3068.70 1186.59 0.43 0 25yr 8991 123.19 130.61 0.001090 2.59 3660.24 1290.11 0.44 0 50yr 10532 123.19 130.95 0.001090 2.75 4106.33 1356.26 0.44 0 100yr 12613 123.19 131.36 0.001090 2.94 4688.57 1438.03 0.45

B.4 Velocity distribution over cross-section for all runs – 50 year return period

Table 32: Velocity distribution over cross-section for all runs – 50 year return period River Run 1 - Velocities Run 2 - Velocities Run 3 - Velocities Station Left Channel Right Left Channel Right Left Channel Right [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] 160985 0.65 3.79 1.00 0.69 3.81 1.03 0.69 3.81 1.03 160118 0.87 2.56 1.08 0.88 2.58 1.11 0.88 2.58 1.11 159301 0.68 5.49 0.87 0.75 5.56 0.92 0.75 5.56 0.92 159088 0.64 3.75 1.16 0.69 3.79 1.20 0.69 3.79 1.20 158639 1.25 3.68 0.89 1.29 3.74 0.92 1.29 3.74 0.92 158463 4.26 4.32 4.32 0.00 157563 4.82 2.62 4.87 2.67 4.87 2.67 156720 3.04 3.07 3.07 155824 2.83 2.87 2.87 154466 0.15 2.00 0.18 2.03 0.18 2.03 153554 4.18 4.24 4.24 153004 3.74 3.75 3.75 151861 2.08 2.10 2.10 150753 3.20 3.25 3.25 149802 3.42 3.47 3.47 149495 0.33 2.72 0.36 2.76 0.36 2.75 149173.* 2.89 0.11 2.93 0.17 2.90 0.19 148852.* 0.74 2.19 1.07 0.76 2.21 1.08 0.75 2.17 1.07 148530.* 1.03 2.74 1.05 2.78 1.03 2.70 0.03 148209 0.54 4.36 0.59 4.41 0.73 4.42 147709 1.03 3.04 1.07 3.07 1.38 3.11 147309 0.69 2.05 0.39 0.70 2.08 0.41 0.85 2.08 0.42 146660 0.66 3.96 1.56 0.70 4.00 1.61 0.94 4.00 1.61 146105 0.21 2.35 0.72 0.25 2.38 0.74 2.40 0.79 145481 0.38 3.01 0.75 0.41 3.06 0.78 0.63 3.11 0.49 145087 2.28 0.70 2.30 0.72 2.30 0.70 144542 2.24 0.58 2.27 0.60 2.27 0.60 144083 0.54 3.30 0.41 0.58 3.31 0.47 0.72 3.37 0.76 143617 1.33 1.35 1.63 142933 2.60 2.63 2.73

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 208 Feasibility Report: West Rapti Basin

River Run 1 - Velocities Run 2 - Velocities Run 3 - Velocities Station Left Channel Right Left Channel Right Left Channel Right [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] 142513 0.17 1.97 0.36 0.19 2.00 0.38 0.36 2.01 0.41 141711 0.93 3.42 1.15 0.96 3.46 1.18 3.60 1.17 141107 0.65 1.22 0.43 0.65 1.23 0.43 0.84 1.36 0.48 140216 0.54 1.96 0.74 0.55 1.99 0.75 0.55 1.99 0.75 139579 0.91 4.17 0.96 4.19 0.96 4.19 138812 0.45 1.50 0.48 0.46 1.51 0.49 1.59 0.52 138099 0.34 4.27 0.75 0.42 4.30 0.81 0.42 4.30 0.81 137644 0.62 2.51 0.65 0.64 2.55 0.64 0.64 2.55 0.64 137467.* 0.61 2.43 0.50 0.62 2.47 0.53 0.62 2.47 0.53 137290.* 0.58 2.25 0.51 0.59 2.28 0.53 0.59 2.28 0.53 137113.* 0.56 2.16 0.59 0.58 2.19 0.61 0.58 2.19 0.61 136936 0.38 1.94 0.57 0.40 1.96 0.58 0.40 1.96 0.58 136745 0.42 3.95 0.52 3.96 0.52 3.96 136487 0.49 0.90 0.52 0.50 0.91 0.52 0.85 1.43 0.93 136227 0.89 1.84 0.82 0.91 1.86 0.84 0.91 1.86 0.84 135708 0.84 2.03 0.71 0.86 2.06 0.72 0.86 2.06 0.72 135187.* 0.69 2.10 0.55 0.71 2.13 0.57 0.71 2.13 0.57 134926.* 0.55 1.88 0.50 0.57 1.91 0.51 0.57 1.92 0.51 133880 1.31 0.56 1.31 0.56 1.27 0.54 133790.* 1.28 0.52 1.28 0.53 1.24 0.51 133701.* 0.02 1.25 0.50 0.06 1.26 0.50 1.30 0.53 133611.* 0.19 1.23 0.48 0.22 1.23 0.48 1.40 0.56 133254 0.43 1.20 0.40 0.44 1.21 0.41 1.23 0.41 132929 0.21 1.01 0.33 0.22 1.02 0.34 1.14 0.37 132874.* 0.28 1.08 0.33 0.29 1.08 0.34 0.30 1.11 0.44 132819.* 0.37 1.13 0.35 0.38 1.14 0.36 0.39 1.18 132656 0.62 1.26 0.39 0.62 1.27 0.40 0.65 1.32 132403 0.45 1.24 0.36 0.46 1.25 0.37 0.45 1.26 0.33 131465 0.62 2.17 0.65 2.20 0.65 2.20 130224 1.58 4.64 1.63 4.68 1.63 4.68 129806 0.90 1.63 0.55 0.91 1.64 0.56 0.91 1.64 0.56 127967 0.32 1.98 0.80 0.36 2.02 0.68 0.36 2.02 0.68 127727 1.18 2.72 0.52 1.21 2.76 0.54 1.21 2.76 0.54 125768 0.10 2.19 0.15 2.22 0.15 2.22 125245.* 0.20 1.76 0.12 0.22 1.78 0.15 0.22 1.78 0.15 124723.* 0.29 1.25 0.28 0.30 1.27 0.30 0.30 1.27 0.30 124201 0.25 0.89 0.42 0.26 0.91 0.43 0.26 0.91 0.43 123840 3.20 3.22 3.22 122539 0.35 0.96 0.40 0.35 0.98 0.41 0.35 0.98 0.41 120519 1.64 0.26 1.65 0.29 1.65 0.29 120272.* 1.64 0.19 1.65 0.23 1.65 0.23 120026.* 1.49 0.16 1.51 0.19 1.51 0.19 119287.* 0.10 1.41 0.17 0.13 1.42 0.19 0.13 1.42 0.19 118056 0.33 1.37 0.34 0.35 1.38 0.36 0.35 1.38 0.36

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 209 Feasibility Report: West Rapti Basin

River Run 1 - Velocities Run 2 - Velocities Run 3 - Velocities Station Left Channel Right Left Channel Right Left Channel Right [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] 117747.* 0.41 1.44 0.47 0.43 1.45 0.48 0.43 1.45 0.48 117438.* 0.50 1.39 0.44 0.52 1.40 0.46 0.51 1.40 0.46 117129 0.58 1.43 0.53 0.59 1.44 0.54 0.59 1.44 0.54 116874 0.36 0.86 0.34 0.37 0.87 0.35 0.36 0.87 0.35 115068 0.62 3.13 0.67 3.13 0.67 3.13 113718 0.38 0.97 0.32 0.38 0.97 0.33 0.38 0.97 0.33 112544 0.34 0.75 0.21 0.34 0.76 0.22 0.34 0.76 0.22 111259 0.50 2.23 0.80 0.52 2.25 0.81 0.52 2.25 0.81 109410 0.49 1.13 0.35 0.50 1.13 0.35 0.48 1.13 0.35 108799.* 0.55 1.26 0.41 0.56 1.26 0.42 0.55 1.26 0.42 108188.* 0.48 1.17 0.42 0.49 1.17 0.43 0.48 1.17 0.43 107577.* 0.48 1.21 0.48 0.48 1.21 0.49 0.48 1.21 0.49 106966.* 0.48 1.13 0.41 0.48 1.14 0.42 0.48 1.14 0.42 106355 0.57 1.27 0.48 0.58 1.27 0.49 0.58 1.27 0.49 104906 0.76 2.96 0.81 0.78 2.98 0.83 0.78 2.98 0.83 104562 1.40 5.42 1.72 1.47 5.48 1.75 1.47 5.48 1.75 103309 0.58 3.23 0.79 0.60 3.27 0.82 0.60 3.27 0.82 102609.* 0.38 2.99 0.72 0.39 3.03 0.75 0.39 3.03 0.75 101909.* 0.39 2.97 0.70 0.41 3.00 0.74 0.41 3.00 0.74 101209.* 0.44 2.95 0.69 0.46 2.98 0.72 0.46 2.98 0.72 100509.* 0.41 3.01 0.77 0.43 3.05 0.81 0.43 3.05 0.81 99809.9* 2.95 0.83 0.03 2.98 0.87 0.03 2.98 0.87 99110.1* 0.44 2.91 0.65 0.47 2.94 0.69 0.47 2.94 0.69 98410.3* 0.55 3.04 0.73 0.57 3.07 0.76 0.57 3.07 0.76 97710.5* 0.58 2.90 0.63 0.60 2.94 0.66 0.60 2.94 0.66 97010.7* 0.48 2.99 0.74 0.51 3.03 0.77 0.51 3.03 0.77 96310.9* 0.50 2.95 0.74 0.53 2.99 0.77 0.53 2.99 0.77 95611.0* 0.48 2.89 0.74 0.51 2.92 0.77 0.51 2.92 0.77 94911.2* 0.53 2.84 0.73 0.55 2.88 0.76 0.55 2.88 0.76 94211.4* 0.56 2.64 0.62 0.56 2.68 0.65 0.56 2.68 0.65 93511.6* 0.40 2.51 0.64 0.41 2.54 0.66 0.41 2.54 0.66 92811.8* 0.19 2.46 0.75 0.23 2.48 0.77 0.23 2.48 0.77 92112.0* 0.23 2.35 0.74 0.27 2.36 0.75 0.27 2.36 0.75 91412.2* 0.52 2.31 0.69 0.53 2.33 0.70 0.53 2.33 0.70 90712.4* 0.25 1.92 0.55 0.28 1.93 0.57 0.28 1.93 0.57 90012.6* 0.26 1.75 0.54 0.28 1.75 0.55 0.28 1.75 0.55 89312.8* 0.29 1.57 0.51 0.31 1.57 0.52 0.31 1.57 0.52 88613 0.60 2.75 0.94 0.62 2.79 0.97 0.62 2.79 0.97 87874.0* 0.52 2.57 0.84 0.54 2.60 0.86 0.54 2.60 0.86 87135.0* 0.50 2.59 0.82 0.53 2.62 0.84 0.53 2.62 0.84 86396.0* 0.48 2.58 0.78 0.51 2.61 0.80 0.51 2.61 0.80 85657.0* 0.45 2.64 0.80 0.49 2.68 0.83 0.49 2.68 0.83 84918.0* 0.36 2.59 0.78 0.41 2.62 0.81 0.41 2.62 0.81 84179.0* 0.38 2.93 0.90 0.42 2.96 0.93 0.42 2.96 0.93

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 210 Feasibility Report: West Rapti Basin

River Run 1 - Velocities Run 2 - Velocities Run 3 - Velocities Station Left Channel Right Left Channel Right Left Channel Right [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] 83440.0* 0.35 3.00 0.89 0.37 3.05 0.92 0.37 3.05 0.92 82701.0* 0.30 3.11 0.88 0.33 3.16 0.92 0.33 3.16 0.92 81962.0* 0.26 3.27 0.87 0.26 3.33 0.91 0.26 3.33 0.91 81223 3.56 0.83 0.08 3.62 0.88 0.08 3.62 0.88 80609.1* 0.15 3.22 0.90 0.21 3.27 0.94 0.21 3.27 0.94 79995.2* 0.40 2.82 0.81 0.44 2.86 0.84 0.44 2.86 0.84 79381.4* 0.40 2.71 0.69 0.44 2.75 0.72 0.44 2.75 0.72 78767.5* 0.43 2.70 0.76 0.49 2.73 0.79 0.49 2.73 0.79 78153.7* 0.56 2.70 0.88 0.61 2.73 0.91 0.61 2.73 0.91 77539.8* 0.69 2.92 1.02 0.74 2.96 1.04 0.74 2.96 1.04 76926 0.85 3.52 1.18 0.91 3.57 1.20 0.91 3.57 1.20 76392.5* 0.75 3.42 0.87 0.81 3.47 0.90 0.81 3.47 0.90 75859.1* 0.51 3.33 1.31 0.56 3.38 1.33 0.56 3.38 1.33 75325.7* 0.39 3.16 0.46 0.42 3.21 0.51 0.42 3.21 0.51 74792.2* 0.39 3.17 0.02 0.44 3.21 0.14 0.44 3.21 0.14 74258.8* 0.27 3.24 0.78 0.33 3.29 0.81 0.33 3.29 0.81 73725.4* 0.17 3.23 0.57 0.25 3.27 0.61 0.25 3.27 0.61 73192 0.06 3.39 1.08 0.17 3.44 1.12 0.17 3.44 1.12 72501.4* 3.22 0.19 3.25 0.27 3.25 0.27 71810.8* 3.21 3.24 3.24 71120.2* 3.22 3.25 3.25 70429.7* 3.22 3.26 3.26 69739.1* 3.23 0.17 3.27 0.25 3.27 0.25 69048.5* 3.24 0.43 3.27 0.49 3.27 0.49 68357.9* 3.22 0.44 3.26 0.49 3.26 0.49 67667.3* 3.21 3.24 3.24 66976.8* 3.23 3.26 3.26 66286.2* 3.26 3.30 0.15 3.30 0.15 65595.6* 3.29 0.24 3.33 0.31 3.33 0.31 64905.0* 3.34 0.37 3.39 0.42 3.39 0.42 64214.5* 1.04 3.56 0.67 1.05 3.62 0.68 1.05 3.62 0.68 63523.9* 0.62 3.43 0.58 0.63 3.48 0.65 0.63 3.48 0.65 62833.3* 1.16 3.55 0.73 1.18 3.61 0.78 1.18 3.61 0.78 62142.7* 1.13 3.58 0.85 1.16 3.64 0.90 1.16 3.64 0.90 61452.2* 0.96 3.57 0.96 0.99 3.63 1.00 0.99 3.63 1.00 60761.6* 1.05 3.64 1.04 1.08 3.70 1.08 1.08 3.70 1.08 60071.0* 1.00 3.68 1.12 1.03 3.73 1.18 1.03 3.73 1.18 59380.4* 1.08 3.74 1.27 1.11 3.80 1.33 1.11 3.80 1.33 58689.9* 0.89 3.72 1.43 0.92 3.77 1.48 0.92 3.77 1.48 56618.1* 0.79 3.67 1.75 0.83 3.73 1.80 0.83 3.73 1.80 55927.6* 0.73 3.74 1.88 0.78 3.79 1.92 0.78 3.79 1.92 55237.0* 0.59 3.80 2.02 0.65 3.85 2.07 0.65 3.85 2.07 54546.4* 0.41 3.41 0.73 0.49 3.46 0.77 0.49 3.46 0.77 53855.8* 0.33 3.44 0.40 3.49 0.40 3.49

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 211 Feasibility Report: West Rapti Basin

River Run 1 - Velocities Run 2 - Velocities Run 3 - Velocities Station Left Channel Right Left Channel Right Left Channel Right [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] 53165.3* 0.13 3.46 0.93 0.25 3.51 0.96 0.25 3.51 0.96 52474.7* 3.46 0.99 0.13 3.52 1.02 0.13 3.52 1.02 51784.1* 3.42 1.06 3.48 1.09 3.48 1.09 51093.5* 3.26 0.62 3.31 0.70 3.31 0.70 50403 6.01 6.11 6.11 50215 4.18 4.26 4.26 48583 3.46 3.53 3.54 47002 0.75 3.03 1.27 0.80 3.06 1.29 0.80 3.05 1.29 46382 4.91 4.97 5.00 44672 1.80 0.48 0.06 1.83 0.50 0.06 1.83 0.50 43734 1.50 0.56 1.53 0.56 1.53 0.56 41794 1.41 0.60 1.44 0.61 1.44 0.61 40074 1.12 2.54 0.90 1.14 2.56 0.91 1.14 2.56 0.91 37538 0.83 2.28 0.71 0.85 2.32 0.73 0.87 2.42 0.75 35903 1.03 2.65 0.96 1.00 2.68 0.99 0.80 2.22 0.97 34889 0.91 2.41 0.93 2.47 0.84 2.80 34467 1.16 2.84 0.95 1.20 2.88 0.98 1.34 2.91 34097 1.40 5.00 1.25 1.47 4.96 0.69 1.54 5.03 0.63 32686 0.51 1.87 0.90 0.53 1.90 0.92 0.53 1.90 0.92 30075 0.89 1.99 1.12 0.90 2.01 1.13 0.90 2.01 1.13 27652 2.84 1.34 0.02 2.88 1.36 0.02 2.88 1.36 27200.6* 2.72 1.29 0.08 2.76 1.31 0.08 2.76 1.31 26749.3* 0.05 2.58 1.14 0.14 2.60 1.16 0.14 2.60 1.16 26298.0* 0.16 2.33 0.89 0.22 2.33 0.89 0.22 2.33 0.89 25846.6* 0.25 2.10 0.88 0.29 2.09 0.88 0.29 2.09 0.88 25395.3* 0.34 1.79 0.72 0.15 1.78 0.72 0.15 1.78 0.72 24944 0.37 1.50 0.57 0.40 1.49 0.57 0.40 1.49 0.57 23188 0.47 0.96 0.29 0.47 0.97 0.30 0.47 0.97 0.30 21140 1.08 2.51 0.64 1.13 2.59 0.65 1.13 2.59 0.65 20348 1.32 3.59 1.00 1.35 3.60 1.03 1.59 3.85 0.88 19845 0.83 2.42 0.72 0.85 2.47 0.75 1.05 2.56 0.59 19296 0.94 2.59 1.01 0.98 2.64 1.05 1.12 2.53 1.01 18840 0.93 2.26 0.93 0.96 2.31 0.96 1.10 2.22 0.94 18406 0.78 1.50 0.78 0.82 1.55 0.80 1.04 1.68 0.88 17785 0.57 1.21 0.57 0.59 1.25 0.59 0.81 1.35 0.64 17069 0.48 1.11 0.54 0.50 1.15 0.56 1.25 0.62 16550 0.46 1.09 0.59 0.48 1.14 0.61 1.27 0.69 16053 0.59 1.26 0.67 0.61 1.30 0.69 1.60 0.86 15483 0.59 1.38 0.77 0.61 1.42 0.79 1.61 0.92 14747 0.63 1.57 0.80 0.65 1.60 0.83 0.89 1.83 0.94 14000 0.33 0.80 0.51 0.35 0.84 0.53 0.37 0.88 0.53 13016 1.07 2.73 1.02 1.11 2.77 1.05 1.11 2.77 1.05 12081 0.90 2.14 0.88 0.94 2.20 0.92 0.94 2.20 0.92 11157 0.87 2.07 0.87 0.91 2.13 0.91 0.91 2.13 0.90

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 212 Feasibility Report: West Rapti Basin

River Run 1 - Velocities Run 2 - Velocities Run 3 - Velocities Station Left Channel Right Left Channel Right Left Channel Right [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] [m/s] 10061 1.10 2.56 1.24 1.14 2.65 1.29 1.14 2.64 1.28 9077 1.18 3.04 1.10 1.23 3.12 1.15 1.23 3.09 1.15 8282 1.24 2.44 1.16 1.30 2.53 1.21 1.27 2.47 1.19 7734 1.34 3.97 1.08 1.54 4.04 1.37 1.29 3.63 1.08 7233 1.02 2.65 1.18 1.16 2.97 1.19 1.46 3.03 1.38 6882 0.91 2.95 1.06 0.97 3.00 1.10 3.15 1.16 6324 0.37 1.73 0.47 0.40 1.83 0.53 2.27 0.61 5153 2.34 0.83 0.12 2.22 0.76 0.12 2.41 0.88 4302 0.10 1.68 0.60 0.16 1.72 0.63 0.16 1.72 0.63 3229 1.05 3.41 0.76 1.11 3.41 0.85 1.11 3.40 0.85 1812 0.37 1.29 0.41 0.39 1.32 0.43 0.39 1.33 0.43 0 0.67 2.67 0.80 0.74 2.75 0.84 0.74 2.75 0.84

B.5 Comparison modelling results 1 per 50 years return period

Table 33: Comparison modelling results, return period 1 per 50 years Change: Run 2 - Run 1 Change: Run 3 - Run 2 Change: Run 3 - Run 1 River Water Top Water Top Water Top Station level Velocity width level Velocity width level Velocity width [cm] [m/s] [m] [cm] [m/s] [m] [cm] [m/s] [m] 160985 10.0 0.02 3.7 0.00 0.00 0.00 10.0 0.02 3.72 160118 12.0 0.02 4.8 0.00 0.00 -0.13 12.0 0.02 4.65 159301 8.0 0.07 6.2 0.00 0.00 0.00 8.0 0.07 6.23 159088 11.0 0.04 5.4 0.00 0.00 0.00 11.0 0.04 5.35 158639 7.0 0.06 0.7 0.00 0.00 0.00 7.0 0.06 0.66 158463 5.0 0.06 0.1 0.00 0.00 0.00 5.0 0.06 0.09 157563 4.0 0.05 2.6 0.00 0.00 0.00 4.0 0.05 2.58 156720 5.0 0.03 6.9 0.00 0.00 0.00 5.0 0.03 6.92 155824 5.0 0.04 0.6 0.00 0.00 0.00 5.0 0.04 0.65 154466 6.0 0.03 10.7 0.00 0.00 0.00 6.0 0.03 10.70 153554 3.0 0.06 0.2 0.00 0.00 0.00 3.0 0.06 0.17 153004 5.0 0.01 1.9 0.00 0.00 0.00 5.0 0.01 1.87 151861 7.0 0.02 1.0 0.00 0.00 0.00 7.0 0.02 0.99 150753 5.0 0.05 0.7 0.00 0.00 -0.01 5.0 0.05 0.65 149802 5.0 0.05 0.9 0.00 0.00 0.03 5.0 0.05 0.97 149495 5.0 0.04 0.4 1.00 -0.01 0.04 6.0 0.03 0.46 149173.* 5.0 0.04 1.5 3.00 -0.03 0.62 8.0 0.01 2.09 148852.* 6.0 0.02 8.7 4.00 -0.04 0.72 10.0 -0.02 9.40 148530.* 5.0 0.04 2.8 9.00 -0.08 5.80 14.0 -0.04 8.65 148209 4.0 0.05 2.5 12.00 0.01 -0.99 16.0 0.06 1.53 147709 4.0 0.03 3.5 2.00 0.04 -127.31 6.0 0.07 -123.79 147309 5.0 0.03 16.4 1.00 0.00 -93.04 6.0 0.03 -76.68 146660 4.0 0.04 2.2 0.00 0.00 -8.89 4.0 0.04 -6.69 146105 4.0 0.03 16.3 17.00 0.02 -78.86 21.0 0.05 -62.56 145481 3.0 0.05 3.2 18.00 0.05 18.40 21.0 0.10 21.58 145087 3.0 0.02 17.9 17.00 0.00 -55.85 20.0 0.02 -37.93 144542 4.0 0.03 21.5 17.00 0.00 7.40 21.0 0.03 28.94

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 213 Feasibility Report: West Rapti Basin

Change: Run 2 - Run 1 Change: Run 3 - Run 2 Change: Run 3 - Run 1 River Water Top Water Top Water Top Station level Velocity width level Velocity width level Velocity width [cm] [m/s] [m] [cm] [m/s] [m] [cm] [m/s] [m] 144083 5.0 0.01 12.5 11.00 0.06 112.09 16.0 0.07 124.56 143617 5.0 0.02 8.7 8.00 0.28 40.30 13.0 0.30 49.04 142933 4.0 0.03 2.0 8.00 0.10 -6.53 12.0 0.13 -4.53 142513 4.0 0.03 15.1 7.00 0.01 -51.34 11.0 0.04 -36.21 141711 2.0 0.04 28.2 0.00 0.14 -300.26 2.0 0.18 -272.06 141107 5.0 0.01 19.3 2.00 0.13 -696.56 7.0 0.14 -677.22 140216 5.0 0.03 34.4 0.00 0.00 -2.67 5.0 0.03 31.71 139579 5.0 0.02 13.0 0.00 0.00 0.00 5.0 0.02 12.95 138812 5.0 0.01 30.8 3.00 0.08 -562.14 8.0 0.09 -531.33 138099 5.0 0.03 23.5 0.00 0.00 -0.09 5.0 0.03 23.43 137644 4.0 0.04 40.5 0.00 0.00 -0.12 4.0 0.04 40.34 137467.* 4.0 0.04 31.4 0.00 0.00 -1.25 4.0 0.04 30.13 137290.* 4.0 0.03 27.8 0.00 0.00 -0.22 4.0 0.03 27.53 137113.* 4.0 0.03 25.6 0.00 0.00 -3.14 4.0 0.03 22.44 136936 4.0 0.02 21.0 0.00 0.00 3.31 4.0 0.02 24.31 136745 5.0 0.01 29.8 0.00 0.00 0.00 5.0 0.01 29.79 136487 4.0 0.01 17.9 18.00 0.52 -2354.52 22.0 0.53 -2336.58 136227 4.0 0.02 9.0 0.00 0.00 -0.01 4.0 0.02 8.98 135708 4.0 0.03 20.5 0.00 0.00 -0.03 4.0 0.03 20.47 135187.* 3.0 0.03 27.9 0.00 0.00 -3.14 3.0 0.03 24.81 134926.* 3.0 0.03 28.4 0.00 0.01 -8.27 3.0 0.04 20.11 133880 5.0 0.00 16.9 6.00 -0.04 20.13 11.0 -0.04 37.01 133790.* 5.0 0.00 17.8 7.00 -0.04 23.11 12.0 -0.04 40.96 133701.* 6.0 0.01 58.4 5.00 0.04 -152.70 11.0 0.05 -94.27 133611.* 5.0 0.00 22.0 4.00 0.17 -295.90 9.0 0.17 -273.89 133254 6.0 0.01 22.9 2.00 0.02 -129.25 8.0 0.03 -106.37 132929 6.0 0.01 64.6 0.00 0.12 -690.64 6.0 0.13 -626.00 132874.* 6.0 0.00 43.3 1.00 0.03 -665.15 7.0 0.03 -621.84 132819.* 6.0 0.01 40.5 0.00 0.04 -651.93 6.0 0.05 -611.39 132656 7.0 0.01 41.7 0.00 0.05 -547.40 7.0 0.06 -505.67 132403 6.0 0.01 19.1 1.00 0.01 0.99 7.0 0.02 20.07 131465 6.0 0.03 5.0 0.00 0.00 0.00 6.0 0.03 5.01 130224 5.0 0.04 2.4 0.00 0.00 0.00 5.0 0.04 2.35 129806 6.0 0.01 14.8 0.00 0.00 0.00 6.0 0.01 14.84 127967 6.0 0.04 164.8 0.00 0.00 0.00 6.0 0.04 164.81 127727 5.0 0.04 6.4 0.00 0.00 0.00 5.0 0.04 6.41 125768 3.0 0.03 20.6 0.00 0.00 0.00 3.0 0.03 20.57 125245.* 4.0 0.02 15.9 0.00 0.00 0.00 4.0 0.02 15.93 124723.* 4.0 0.02 17.8 0.00 0.00 0.00 4.0 0.02 17.83 124201 4.0 0.02 12.8 0.00 0.00 0.00 4.0 0.02 12.80 123840 3.0 0.02 11.2 0.00 0.00 0.00 3.0 0.02 11.23 122539 5.0 0.02 25.1 0.00 0.00 0.00 5.0 0.02 25.08 120519 5.0 0.01 8.5 0.00 0.00 0.00 5.0 0.01 8.48 120272.* 5.0 0.01 8.9 0.00 0.00 0.00 5.0 0.01 8.91 120026.* 5.0 0.02 37.6 0.00 0.00 0.00 5.0 0.02 37.59 119287.* 6.0 0.01 48.1 0.00 0.00 0.00 6.0 0.01 48.09 118056 7.0 0.01 28.4 0.00 0.00 -1.12 7.0 0.01 27.31 117747.* 7.0 0.01 26.6 0.00 0.00 2.31 7.0 0.01 28.87 117438.* 8.0 0.01 8.0 0.00 0.00 1.90 8.0 0.01 9.93 117129 8.0 0.01 7.5 0.00 0.00 1.20 8.0 0.01 8.73 116874 8.0 0.01 19.4 0.00 0.00 79.90 8.0 0.01 99.34

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 214 Feasibility Report: West Rapti Basin

Change: Run 2 - Run 1 Change: Run 3 - Run 2 Change: Run 3 - Run 1 River Water Top Water Top Water Top Station level Velocity width level Velocity width level Velocity width [cm] [m/s] [m] [cm] [m/s] [m] [cm] [m/s] [m] 115068 8.0 0.00 23.6 0.00 0.00 0.08 8.0 0.00 23.63 113718 9.0 0.00 25.0 0.00 0.00 0.10 9.0 0.00 25.12 112544 10.0 0.01 23.3 0.00 0.00 0.09 10.0 0.01 23.35 111259 10.0 0.02 26.3 0.00 0.00 0.15 10.0 0.02 26.49 109410 10.0 0.00 18.0 0.00 0.00 55.63 10.0 0.00 73.61 108799.* 11.0 0.00 21.3 0.00 0.00 12.76 11.0 0.00 34.07 108188.* 11.0 0.00 18.8 0.00 0.00 9.03 11.0 0.00 27.84 107577.* 11.0 0.00 18.3 0.00 0.00 2.18 11.0 0.00 20.49 106966.* 11.0 0.01 14.8 0.00 0.00 1.67 11.0 0.01 16.47 106355 11.0 0.00 12.0 0.00 0.00 0.00 11.0 0.00 11.96 104906 12.0 0.02 10.9 0.00 0.00 0.00 12.0 0.02 10.86 104562 9.0 0.06 1.7 0.00 0.00 0.00 9.0 0.06 1.66 103309 10.0 0.04 10.7 0.00 0.00 0.00 10.0 0.04 10.69 102609.* 10.0 0.04 17.4 0.00 0.00 0.00 10.0 0.04 17.35 101909.* 10.0 0.03 14.2 0.00 0.00 0.00 10.0 0.03 14.22 101209.* 10.0 0.03 14.0 0.00 0.00 0.00 10.0 0.03 14.01 100509.* 11.0 0.04 13.6 0.00 0.00 0.00 11.0 0.04 13.57 99809.9* 10.0 0.03 12.3 0.00 0.00 0.00 10.0 0.03 12.26 99110.1* 10.0 0.03 11.0 0.00 0.00 0.00 10.0 0.03 11.01 98410.3* 10.0 0.03 11.0 0.00 0.00 0.00 10.0 0.03 11.03 97710.5* 10.0 0.04 11.3 0.00 0.00 0.00 10.0 0.04 11.29 97010.7* 10.0 0.04 11.5 0.00 0.00 0.00 10.0 0.04 11.45 96310.9* 10.0 0.04 11.6 0.00 0.00 0.00 10.0 0.04 11.63 95611.0* 10.0 0.03 12.2 0.00 0.00 0.00 10.0 0.03 12.24 94911.2* 10.0 0.04 13.4 0.00 0.00 0.00 10.0 0.04 13.37 94211.4* 10.0 0.04 17.4 0.00 0.00 0.00 10.0 0.04 17.43 93511.6* 10.0 0.03 18.1 0.00 0.00 0.00 10.0 0.03 18.12 92811.8* 11.0 0.02 19.4 0.00 0.00 0.00 11.0 0.02 19.40 92112.0* 12.0 0.01 21.0 0.00 0.00 0.00 12.0 0.01 21.04 91412.2* 13.0 0.02 20.3 0.00 0.00 0.00 13.0 0.02 20.32 90712.4* 13.0 0.01 34.2 0.00 0.00 0.00 13.0 0.01 34.19 90012.6* 14.0 0.00 44.4 0.00 0.00 0.00 14.0 0.00 44.41 89312.8* 14.0 0.00 30.1 0.00 0.00 0.00 14.0 0.00 30.15 88613 14.0 0.04 53.0 0.00 0.00 0.00 14.0 0.04 52.99 87874.0* 13.0 0.03 51.1 0.00 0.00 0.00 13.0 0.03 51.07 87135.0* 14.0 0.03 43.6 0.00 0.00 0.00 14.0 0.03 43.60 86396.0* 14.0 0.03 38.5 0.00 0.00 0.00 14.0 0.03 38.45 85657.0* 14.0 0.04 35.7 0.00 0.00 0.00 14.0 0.04 35.73 84918.0* 14.0 0.03 35.3 0.00 0.00 0.00 14.0 0.03 35.26 84179.0* 15.0 0.03 41.1 0.00 0.00 0.00 15.0 0.03 41.09 83440.0* 14.0 0.05 56.7 0.00 0.00 0.00 14.0 0.05 56.72 82701.0* 14.0 0.05 46.0 0.00 0.00 0.00 14.0 0.05 46.03 81962.0* 14.0 0.06 45.8 0.00 0.00 0.00 14.0 0.06 45.82 81223 12.0 0.06 16.5 0.00 0.00 0.00 12.0 0.06 16.46 80609.1* 12.0 0.05 21.4 0.00 0.00 0.00 12.0 0.05 21.39 79995.2* 13.0 0.04 23.0 0.00 0.00 0.00 13.0 0.04 23.04 79381.4* 13.0 0.04 28.9 0.00 0.00 0.00 13.0 0.04 28.92 78767.5* 13.0 0.03 11.5 0.00 0.00 0.00 13.0 0.03 11.49 78153.7* 13.0 0.03 9.1 0.00 0.00 0.00 13.0 0.03 9.07 77539.8* 14.0 0.04 8.0 0.00 0.00 0.00 14.0 0.04 7.97 76926 14.0 0.05 6.9 0.00 0.00 0.00 14.0 0.05 6.90

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 215 Feasibility Report: West Rapti Basin

Change: Run 2 - Run 1 Change: Run 3 - Run 2 Change: Run 3 - Run 1 River Water Top Water Top Water Top Station level Velocity width level Velocity width level Velocity width [cm] [m/s] [m] [cm] [m/s] [m] [cm] [m/s] [m] 76392.5* 14.0 0.05 7.9 0.00 0.00 0.00 14.0 0.05 7.88 75859.1* 14.0 0.05 24.8 0.00 0.00 0.00 14.0 0.05 24.81 75325.7* 14.0 0.05 37.2 0.00 0.00 0.00 14.0 0.05 37.17 74792.2* 14.0 0.04 13.3 0.00 0.00 0.00 14.0 0.04 13.30 74258.8* 15.0 0.05 11.7 0.00 0.00 0.00 15.0 0.05 11.68 73725.4* 16.0 0.04 10.4 0.00 0.00 0.00 16.0 0.04 10.36 73192 16.0 0.05 9.3 0.00 0.00 0.00 16.0 0.05 9.31 72501.4* 17.0 0.03 9.8 0.00 0.00 0.00 17.0 0.03 9.83 71810.8* 17.0 0.03 10.0 0.00 0.00 0.00 17.0 0.03 10.04 71120.2* 17.0 0.03 10.0 0.00 0.00 0.00 17.0 0.03 9.97 70429.7* 16.0 0.04 9.7 0.00 0.00 0.00 16.0 0.04 9.74 69739.1* 16.0 0.04 9.8 0.00 0.00 0.00 16.0 0.04 9.84 69048.5* 16.0 0.03 10.2 0.00 0.00 0.00 16.0 0.03 10.15 68357.9* 16.0 0.04 10.6 0.00 0.00 0.00 16.0 0.04 10.63 67667.3* 16.0 0.03 10.9 0.00 0.00 0.00 16.0 0.03 10.94 66976.8* 16.0 0.03 10.5 0.00 0.00 0.00 16.0 0.03 10.51 66286.2* 15.0 0.04 21.4 0.00 0.00 0.00 15.0 0.04 21.40 65595.6* 14.0 0.04 20.6 0.00 0.00 0.00 14.0 0.04 20.57 64905.0* 15.0 0.05 22.8 0.00 0.00 0.00 15.0 0.05 22.83 64214.5* 13.0 0.06 26.5 0.00 0.00 0.00 13.0 0.06 26.50 63523.9* 14.0 0.05 9.9 0.00 0.00 0.00 14.0 0.05 9.90 62833.3* 13.0 0.06 9.4 0.00 0.00 0.00 13.0 0.06 9.41 62142.7* 14.0 0.06 9.3 0.00 0.00 0.00 14.0 0.06 9.29 61452.2* 13.0 0.06 10.2 0.00 0.00 0.00 13.0 0.06 10.19 60761.6* 13.0 0.06 10.6 0.00 0.00 0.00 13.0 0.06 10.64 60071.0* 13.0 0.05 5.0 0.00 0.00 0.00 13.0 0.05 5.00 59380.4* 13.0 0.06 3.6 0.00 0.00 0.00 13.0 0.06 3.62 58689.9* 13.0 0.05 3.7 0.00 0.00 0.00 13.0 0.05 3.69 56618.1* 14.0 0.06 3.8 0.00 0.00 0.00 14.0 0.06 3.75 55927.6* 14.0 0.05 3.9 0.00 0.00 0.00 14.0 0.05 3.93 55237.0* 14.0 0.05 4.4 0.00 0.00 0.00 14.0 0.05 4.35 54546.4* 14.0 0.05 4.3 0.00 0.00 0.00 14.0 0.05 4.34 53855.8* 14.0 0.05 9.3 0.00 0.00 0.00 14.0 0.05 9.28 53165.3* 15.0 0.05 8.2 0.00 0.00 0.00 15.0 0.05 8.23 52474.7* 16.0 0.06 29.4 0.00 0.00 0.00 16.0 0.06 29.43 51784.1* 15.0 0.06 0.5 0.00 0.00 0.00 15.0 0.06 0.53 51093.5* 16.0 0.05 1.2 0.00 0.00 0.00 16.0 0.05 1.24 50403 10.0 0.10 0.3 0.00 0.00 0.00 10.0 0.10 0.32 50215 12.0 0.08 0.6 0.00 0.00 0.01 12.0 0.08 0.63 48583 8.0 0.07 3.3 -1.00 0.01 -0.11 7.0 0.08 3.16 47002 8.0 0.03 20.9 1.00 -0.01 10.17 9.0 0.02 31.03 46382 8.0 0.06 4.5 -2.00 0.03 -0.89 6.0 0.09 3.63 44672 7.0 0.03 6.0 0.00 0.00 0.01 7.0 0.03 5.97 43734 8.0 0.03 14.3 0.00 0.00 0.03 8.0 0.03 14.33 41794 8.0 0.03 12.2 0.00 0.00 0.12 8.0 0.03 12.31 40074 9.0 0.02 39.7 0.00 0.00 1.63 9.0 0.02 41.29 37538 9.0 0.04 24.3 -14.00 0.10 -40.15 -5.0 0.14 -15.89 35903 9.0 0.03 42.2 17.00 -0.46 114.69 26.0 -0.43 156.87 34889 8.0 0.06 7.7 2.00 0.33 -61.97 10.0 0.39 -54.25 34467 8.0 0.04 10.0 3.00 0.03 -356.24 11.0 0.07 -346.28 34097 13.0 -0.04 160.4 0.00 0.07 -22.26 13.0 0.03 138.10

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 216 Feasibility Report: West Rapti Basin

Change: Run 2 - Run 1 Change: Run 3 - Run 2 Change: Run 3 - Run 1 River Water Top Water Top Water Top Station level Velocity width level Velocity width level Velocity width [cm] [m/s] [m] [cm] [m/s] [m] [cm] [m/s] [m] 32686 8.0 0.03 16.8 0.00 0.00 0.00 8.0 0.03 16.76 30075 8.0 0.02 17.5 0.00 0.00 -0.01 8.0 0.02 17.49 27652 9.0 0.04 12.7 0.00 0.00 0.03 9.0 0.04 12.73 27200.6* 9.0 0.04 8.6 0.00 0.00 0.01 9.0 0.04 8.62 26749.3* 10.0 0.02 10.1 1.00 0.00 0.03 11.0 0.02 10.14 26298.0* 13.0 0.00 26.3 0.00 0.00 0.11 13.0 0.00 26.38 25846.6* 15.0 -0.01 14.3 0.00 0.00 0.07 15.0 -0.01 14.33 25395.3* 16.0 -0.01 275.2 0.00 0.00 0.81 16.0 -0.01 276.03 24944 17.0 -0.01 38.9 1.00 0.00 0.24 18.0 -0.01 39.10 23188 19.0 0.01 57.4 0.00 0.00 0.39 19.0 0.01 57.84 21140 18.0 0.08 45.8 0.00 0.00 0.50 18.0 0.08 46.29 20348 20.0 0.01 122.7 8.00 0.25 -318.50 28.0 0.26 -195.79 19845 19.0 0.05 108.1 11.00 0.09 -161.91 30.0 0.14 -53.86 19296 19.0 0.05 55.1 16.00 -0.11 -211.06 35.0 -0.06 -155.93 18840 19.0 0.05 46.7 18.00 -0.09 -226.69 37.0 -0.04 -179.98 18406 19.0 0.05 26.6 15.00 0.13 -541.07 34.0 0.18 -514.45 17785 19.0 0.04 52.4 14.00 0.10 -628.52 33.0 0.14 -576.10 17069 19.0 0.04 41.1 14.00 0.10 -482.54 33.0 0.14 -441.43 16550 19.0 0.05 34.4 12.00 0.13 -520.66 31.0 0.18 -486.22 16053 19.0 0.04 59.4 9.00 0.30 -824.91 28.0 0.34 -765.54 15483 19.0 0.04 41.1 6.00 0.19 -559.82 25.0 0.23 -518.75 14747 19.0 0.03 51.7 0.00 0.23 -890.43 19.0 0.26 -838.72 14000 19.0 0.04 59.1 1.00 0.04 3.04 20.0 0.08 62.14 13016 18.0 0.04 52.6 1.00 0.00 0.69 19.0 0.04 53.30 12081 18.0 0.06 25.2 1.00 0.00 0.49 19.0 0.06 25.66 11157 16.0 0.06 26.7 1.00 0.00 0.76 17.0 0.06 27.42 10061 15.0 0.09 36.1 1.00 -0.01 8.04 16.0 0.08 44.12 9077 14.0 0.08 30.5 2.00 -0.03 7.20 16.0 0.05 37.74 8282 12.0 0.09 18.1 6.00 -0.06 12.54 18.0 0.03 30.66 7734 22.0 0.07 170.4 23.00 -0.41 7.95 45.0 -0.34 178.32 7233 9.0 0.32 4.7 21.00 0.06 -954.05 30.0 0.38 -949.32 6882 12.0 0.05 69.8 20.00 0.15 -895.89 32.0 0.20 -826.08 6324 11.0 0.10 62.3 10.00 0.44 -714.99 21.0 0.54 -652.69 5153 13.0 -0.12 65.1 0.00 0.19 -17.35 13.0 0.07 47.74 4302 14.0 0.04 56.7 0.00 0.00 -0.01 14.0 0.04 56.65 3229 19.0 0.00 87.3 0.00 -0.01 1.04 19.0 -0.01 88.32 1812 19.0 0.03 119.1 0.00 0.01 6.15 19.0 0.04 125.29 0 17.0 0.08 33.0 0.00 0.00 0.00 17.0 0.08 33.02

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 217 Feasibility Report: West Rapti Basin

C. Design calculations

This appendix includes the preliminary design calculations of the hydraulic structures for West Rapti Basin.

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 226 Feasibility Report: West Rapti Basin

D. Civil works: BoQ and cost estimates

This appendix includes the BoQ and cost estimates of the hydraulic structures for West Rapti river. The following is included:

1. West Rapti (Banke District) a. Abstract of costs – Embankment with revetment b. Abstract of costs – Spurs c. Detail estimate – Embankment with revetment d. Detail estimate – Spurs e. Rate Analysis f. Labour calculation g. Cost for equipment (e.g. excavator) h. District rate of Banke FY 2075/76 2. West Rapti (Dang District) a. Abstract of costs – Embankment with revetment b. Abstract of costs – Spurs c. Detail estimate – Embankment with revetment d. Detail estimate – Spurs e. Rate Analysis f. Labour calculation g. Cost for equipment (e.g. excavator) h. District rate of Dang FY 2075/76

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 227 Feasibility Report: West Rapti Basin

E. Methodology for the Economic Analysis

E.1 Background to the Analysis Pre-feasibility studies for the priority basins were carried out in 2015/16. The methodology used in the economic analysis prepared for these studies was detailed and comprehensive, particularly with regard to the factors contributing to project benefits. Sub-project costs, however, appear to have been under- estimated, resulting in relatively high indicators of project outcomes. The present analysis uses the benefit estimation methodology and models prepared for the pre-feasibility studies but with updated data for the areas vulnerable to floods of different return periods and for the infrastructure within each flood envelope. Prices for infrastructure, agriculture and livestock are also updated to third quarter 2018 prices for each subproject area and inputs and outputs in the agricultural crop budgets – for estimating the value of flood damage to crops – have been modified to bring them into line with current conditions. At the same time, sub-project designs have been entirely revised and costs updated in accordance with the current district unit costs for the relevant districts.

While doing detailed techno-economic assessment during feasibility phase, it was found that the cost benefit analysis is influenced by the fact of (a) compared to pre-feasibility studies, significant shrinking of the benefit area was observed due to use of advanced flood models and (b) Increased investment costs due to post 2015 earthquake cost escalations in civil works. In order to address these challenges, the Consultants discussed and come up with the proposal of revisiting the methods used during pre- feasibility study

Feasibility phase CBA analysis uses the benefit estimation methodology and models prepared for the pre-feasibility studies but with updated data for the areas vulnerable to floods of different return periods and for the infrastructure within each flood envelope. During pre-feasibility studies, the benefit estimation was centred on avoidance of loss and damage by structural measures. The extent of benefits estimation of non-structural measures such as FFEWS and CBDRM in the entire flood envelope area was not prominently incorporated.

The methodology during feasibility study uses advanced and customized hydrodynamic model to model the hydraulic conditions in the basins. The results were converted into flood maps and used to design the structural measures. The flood envelope – benefit area derived from this model is specific to the sub project structural interventions. The method enables deriving evidence based flood envelopes of different return periods.

When analysed, these flood model results have generated two layers of flood envelope- first layer is of flood protected area due to the structural measures. This area is obtained from Flood model results by using formula that is Run 2 (existing situation including the impact of climate change) model results minus Run 3 (future situation including the impact of climate change and the proposed structural measures) model results. The formula is:

Protected Area = Run 2 – Run 3

The second layer is of entire flood envelope (including first layer of protected area with structural measures). The entire flood envelope will be benefiting by non-structural measures such as FFEWS and CBDRM. Therefore the benefit area of the FFEWS and CBDRM under the sub project is Flood Model Run 3 result area.

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 228 Feasibility Report: West Rapti Basin

E.2 Approach The analysis uses a general model for the calculation of incremental avoided losses and incurred benefits between the without-project and with-project situations for the six sub-project basins.

The protected area (Flood Model Results: Run 2 – Run 3) have significant benefit streams such as they have benefit of avoidance of losses and damages to the houses and infrastructure, agriculture, livestock, human mortality, coping mechanism to the fullest extent. Therefore the protected area benefit fully under each of the benefit stream.

FFEWS and CBDRM Benefit area: the benefits of avoidance of losses due to non-structural measures are to be combined with benefit streams of the structurl measures in the sub project. The non-structural measures help generate benefit of avoidance of losses of the inside house contents – furniture, movable items, valuables, vehicles. FFEWS and CBDRM enables people to save these losses. However, the amount of benefits amounts to 25% of total house / building cost. Similarly, FFEWS and CBFRM will benefit avoidance of losses of livestock and mortality, funeral of the deceased and some savings on coping mechanism. In case of Bakraha sub project no data from prefeasibility phase was available such as infrastructure, housing, agriculture, livestock, human mortality, and coping mechanism available. The model estimates expected direct losses (losses incurred directly as a result of the flood event) and indirect losses and benefits (losses and benefits incurred as a result of changes in market conditions, technology and investment) under the expected flood regimes. Losses and benefits are estimated under the headings of infrastructure, agriculture, human injury and mortality, livestock mortality and prevention and coping mechanisms (which is a grouping of miscellaneous items).

The incremental benefit of the flood management project is the difference between avoided losses in the without and with project situations, plus indirect benefits obtained as a result of the proposed project. Avoided losses are weighted by the probability of their future occurrence and benefits independent of flood events are scheduled with reference to the project flood management time frame. The project performance indicators of internal rate of return (IRR) and net present value (NPV) are then obtained in the normal way by offsetting project costs against the estimated stream of incremental benefits.

The expected number of casualties saved during the project, both life and injury, is also calculated but this is not expressed in monetary terms, except that provision is included for the cost of treatment of injuries and the estimated cost of funerals.

The data required by the model are the hydrological characteristics of floods of different probabilities (1 year in 2 (50% probability), 1 year in 5 (20%), 1 year in 10 (10%), 1 year in 25 (4%), 1 year in 50 (2%) and 1 year in 100 (1%)) and infrastructure and land use data within each of the “flood envelopes” impacted by these floods of defined probability, both without and with-project. The impact of floods with intermediate probabilities is interpolated.

The Flood Hazard Rating (FHR) is a product of the predicted depth, velocity and debris content of floods within flood envelopes. Duration is not included in the rating. This does not matter because flood duration is usually less than one day in the subproject areas. The FHR is a quantitative, continuous variable. The higher the rating, the greater the risks to human life, and also of flood damage to property. The damage impact as determined by the FHR is weighted in two ways. The first is required to estimate the flood impact on housing, so the percentage of houses located in areas of low, moderate, significant and extreme FHR areas is multiplied by the FHR of each class. The weighted FHR for agricultural areas follows a similar procedure, but weighting by the area in each FHR class. It is attempted to preserve the dimension of the FHR by giving the flowing values to each rank:

Low: FHR=<0.75; Moderate: FHR=1.25; Significant: FHR=2.0; Extreme: FHR=>3.0. The weighted values are then used in Lookup Tables to give an estimate of damage to houses (by four different types of house and public infrastructure and the yield reduction for rice. The Lookup Table for houses and infrastructure is shown in Table 34.

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The model can be run with the hydrological characteristics of both historical floods and expected future floods taking into account climate change. With climate change, the estimated flood envelope of a flood of defined probability is usually larger and the FHR is higher.

Financial and economic costs and prices are included in the model and project indicators may be calculated in either financial or economic terms.

The sources of benefits for the subprojects are direct benefits from

· avoided damage to infrastructure, including houses; · avoided losses in agriculture; · reductions in human mortality; · avoided losses of livestock; · miscellaneous prevention and coping mechanisms. Indirect benefits from changes in market conditions, technology and investment during the project life and are included under the above headings.

The procedures for estimating each of these benefit classes are outlined in the following sections.

E.3 Infrastructure and Housing Damage to housing and infrastructure is the single largest source of benefits for the sub-projects.

E.3.1 Estimate of Housing and Infrastructure Affected Annual damage to infrastructure from historical floods is well documented in Ministry of Home Affairs (MOHA) and Department of Water Induced Disaster Prevention (DWIDP) reports, but on its own the historical record is an inadequate guide to the infrastructure that would be affected by a flood event of exactly the same hydrological characteristics today, because of the increase in investment, particularly housing numbers, within the affected area over time. Therefore a method to disaggregate flood risk and flood vulnerability over time was developed during the pre-feasibility studies to make forecasts for future infrastructure losses (i.e. the proportion of houses damaged or destroyed during a flood event) on the basis of the present infrastructure stock.

The resulting pre-feasibility estimates for future infrastructure losses are used in this feasibility analysis, but the estimated number of houses in the flood affected areas are derived from 2011 census data while the estimated number in each protected area is based on a physical count from Google maps.

In the pre-feasibility study consultants obtained the number of houses by VDC and ward for 1991 from GIS imagery sources9 and compared it with the number of houses reported by VDC and ward in the Population and Housing Census 2011.

It was then assumed that the same proportion of 2012 house numbers would be located in flood-prone areas as observed in 1992. This is expected to be a conservative estimate, because with increasing housing density in the project area as a whole, the proportion of housing in areas at risk from flooding should increase rather than decline. The data suggest a disproportionate expansion of housing, most probably of the poorer members of society, into flood-risk areas. Continuing the trend of growth, an average rate of growth of housing over the life of the project might conceivably be 2.2% per annum or 165% over a 25-year period.

Using the 1992 and 2012 data, the area of the 1 year in 100 flood envelope was known by VDC and ward and the number of houses was estimated so the housing density at ward level in 2012 could be calculated. Then, taking the incremental area between the flood return period classes and applying the housing density applicable to each ward, the number of houses in each flood envelope could be

9 Source: Esri, Digital Globe Earthstar Geographics

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 230 Feasibility Report: West Rapti Basin calculated. It was apparent from that data that a high proportion of 2012 house numbers were estimated to be located in the 1 year in 2 envelope. (The revised modelling carried out for the feasibility studies places little housing in this flood envelope.)

The pre-feasibility team’s Hydrologists calculated the annual maximum flows for the sub-projects rivers and the likely return periods of the resulting floods, which were presumed to be the maximum flood for the year. The hydrological data was only available for varying periods between 1991-2010. Historical floods after this year could not be assigned a return period. However, for annual maximum historical floods the available records provide an indicative return period that could be assigned, and then matched to the infrastructure losses reported in the historical record.

Housing density was difficult to derive, and required matching the ward area reported as affected by the flood with the interpolated number of houses by ward in the year of the flood. Each flood affected several or even many wards, and so housing density in each ward provided a weight for the total reported affected area.

Where the assembled data permitted, a linear regression was carried out for each subproject area, with the number of houses damaged or destroyed as the independent variable and flood return period and housing population as the explanatory variables. The relationship is useful, when available, because it provides a basis for estimating the number of houses affected by a flood of any given magnitude up to 1:20 - providing the house population is known.

The number of houses damaged or destroyed from the 2012 housing stock in each subproject area could then be estimated using the derived coefficients and compared with the house population and affected housing in each flood envelope. Affected houses are located in those wards reported as affected by historical flood events, but only a proportion of affected houses are actually damaged or destroyed, as specified by the regression equations. The equations subsume variations in house quality and variation in the flood hazard index during a flood event. Clearly some houses in a flood-affected area will resist a flood while others are damaged or destroyed.

However, as flood return period increases, a greater proportion of the house population of the envelope is affected. The interpolation up the 1 year in 100 event is unsupported by observation but the model suggests that as a result of an historical 1 year in 100 event, a very high proportion (greater than 90%) of the housing stock would be destroyed.

The calculation of houses damaged or destroyed was prepared outside the model for the calculation of avoided losses and incurred benefits. These estimates for calculating houses damaged or destroyed are used in these feasibility assessments, but the house depend on the affected and protected areas which are different as a result of the new modelling.

It may also be observed that the historical growth of housing is an indicator of the rate of change of investment in the basin modelled area in the future. The cost benefit analysis takes account of this by assuming this investment will expand by about 25% over the life of the project. Over the last 20 years the housing stock appears to have expanded in ward areas at about 2% per annum, so the assumption is very conservative.

E.3.2 Estimate of Quality of Housing For the pre-feasibility studies, a rating of house quality in VDCs was made. The Population and Housing Census 2011 includes a count of housing at VDC level by type of foundation and type of wall material. Using this data, four house classes were identified. Foundation quality is rated as follows: Class 1: Cement bonded bricks and stone; Class 2: Mud bonded bricks and stone and RCC pillars; Class 3: Wooden pillars; Class 4: Other foundations and not stated. Wall quality is rated as follows:

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Class 1: Cement bonded bricks and stone; Class 2: Mud boned brick and stone; Class 3: Wood and/or planks; Class 4: Bamboo, unbaked brick, others and not stated. Class 1, 2, 3 and 4 were then summed and weighted by the total housing stock to get an aggregate housing quality classification for each VDC in the priority basins. This classification has been used for the feasibility studies.

The total area of each VDC was known and the proportion of each VDC in the flood affected area (using the historical 1 year in 100 return period) of each subproject basin was known from the modelling studies. Reason suggests that house quality should be poorer on flood plains than in non-flood affected areas: households with fewer resources will tend to be marginalized in higher risk areas, the investment in housing at risk from flooding will be lower and past flood damage will lower the value of the housing stock. At pre-feasibility, the data available was used for regression analysis to test this assumption: the higher the proportion of a VDC in the flood affected area then the higher the proportion of poor quality housing in the VDC. The proportion of poor quality housing (Classes 3 and 4) was regressed on the proportion of VDC area within the area affected by 1:100 year floods. The results below showed a positive correlation at 90% probability that the proportion of “poor quality” housing (Classes 3 and 4 combined) is greater in VDCs with a higher proportion of village area on land prone to flooding. The analysis also showed that in the VDCs of the subproject areas, at least 52% of housing will be of poor quality, even if little or none of the VDC falls in the flood-affected area. Furthermore, for every percentage increase in VDC area at risk from flooding, the proportion of poor quality houses increases by 0.29%.

These coefficients from the whole data set of all the VDCs associated with all subproject areas were then applied to the percentage of each VDC within the flood affected areas in order to obtain an estimate of the proportion of poor quality housing. Based on the VDC data from the Population and Housing Census, 61% of these would be classified as poor quality (Class 3 or 4). Adjusting the estimate of poor quality housing for the proportion of VDC within the flood plain increases proportion overall to 62%.

This may seem a small adjustment, but there are differences between the basins. Both East and West Rapti have significant upward adjustments to the numbers of poor quality houses but Mawa Ratuwa and Lakhandei have small reductions compared with the numbers observed by the Population and Housing Census. However, since these reductions are small compared with the strong upward adjustment required for East and West Rapti, the unadjusted housing quality classes were used when estimating housing damage from floods for these three areas.

The adjusted data was compiled into the four classes of housing already classified by taking into account both foundation and wall quality (see Table 34). These percentages of house quality were used in the model to represent the value of the current housing stock. The same percentages are used for the feasibility studies as it is unlikely they would have changed significantly in the intervening 3 years.

The building classes “public buildings” and “other buildings” which at pre-feasibility were originally considered important in the flood damage estimate are not included as there is no data on their distribution and their location in the flood plain is unlikely.

Table 34: Housing by House Quality Class Mawa East Rapti West Rapti Ratuwa Lakhandei Mohana Class 1 22% 6% 27% 25% 31% Class 2 22% 30% 11% 8% 11% Class 3 33% 35% 32% 33% 55% Class 4 24% 30% 29% 35% 3%

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E.3.3 Estimate of Flood Induced Loss of Value to Housing Houses in the four classes at were assigned a depreciated value as follows: Class 1: NPR 1,121,624; Class 2: NPR 720,658; Class 3: NPR 1,050,960; Class 4: NPR 612,359. These rates are based current (2018) average per unit area costs of construction on the Terai advised by building consultants and the average per house areas used in the pre-feasibility studies. An average house age of 12 years has been assumed and new construction costs have been depreciated at 2% per year declining value for this period. These values are averages for construction in the Terai region apply to all subproject areas.

In addition, it is necessary to identify the level of damage a house will sustain under floods of pre- defined characteristics. This is difficult and, without empirical data, contentious. In Section E.3.1 the number of houses damaged or destroyed under floods of defined return period and known housing stock has been specified by regression coefficients derived from observed data.

The level of damage and the proportion of damaged or destroyed houses actually damaged or destroyed also needed to be identified. The Project GIS for the 1992 housing stock was used to establish the number of houses within each FHR area. The FHR was used to generate an estimate the house damages (see Table 35).

Obviously no damage is assumed with a rating of 0: there is no velocity, no depth and no debris. It is assumed a Class 4 house will be destroyed when the rating equals 1.5, which signifies a flood of 0.4 m depth. 0.75 m/sec velocity and debris factor of 1. This is classified as a “significant” flood hazard.

Class 3 housing is more resilient and will survive a FHR up to 2.5, classified as “extreme”. Classes 1 and 2 are assumed to resist up to a FHR of 3. Without empirical data, the amount of damage sustained to the house at lesser FHRs is only conjecture, so the percentage of damage sustained to the depreciated value of the house is assumed to be in direct proportion to the FHR.

Table 35: Reduction of House Depreciated Value in Response to FHR Public FHR Class 4 Class 3 Class 2 Class 1 Infrastructure 0 0% 0% 0% 0% 0% 0.5 0% 0% 0% 0% 6% 0.6 10% 5% 4% 4% 13% 0.7 20% 10% 8% 8% 19% 0.8 30% 15% 12% 12% 25% 0.9 40% 20% 16% 16% 31% 1 50% 25% 20% 20% 38% 1.1 60% 30% 24% 24% 44% 1.2 70% 35% 28% 28% 50% 1.3 80% 40% 32% 32% 56% 1.4 90% 45% 36% 36% 63% 1.5 100% 50% 40% 40% 69% 1.6 100% 55% 44% 44% 75% 1.7 100% 60% 48% 48% 81% 1.8 100% 65% 52% 52% 88% 1.9 100% 70% 56% 56% 94% 2 100% 75% 60% 60% 100% 2.1 100% 80% 64% 64% 100% 2.2 100% 85% 68% 68% 100%

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Public FHR Class 4 Class 3 Class 2 Class 1 Infrastructure 2.3 100% 90% 72% 72% 100% 2.4 100% 95% 76% 76% 100% 2.5 100% 100% 80% 80% 100% 2.6 100% 100% 84% 84% 100% 2.7 100% 100% 88% 88% 100% 2.8 100% 100% 92% 92% 100% 2.9 100% 100% 96% 96% 100% 3 100% 100% 100% 100% 100% 3.1 100% 100% 100% 100% 100% 3.2 100% 100% 100% 100% 100% 3.3 100% 100% 100% 100% 100% 3.4 100% 100% 100% 100% 100% 3.5 100% 100% 100% 100% 100%

E.3.4 Cost of Damage to Building Occupants The impact on occupants must be added to the loss of value of buildings from flood damage. Four categories of direct loss are counted. Firstly, those households suffering a loss of value of less than 25% of the value of the house in which they live are assumed to stay in place during the flood event and do not incur any displacement costs.

Those living in housing which is more than 25% damaged during a flood event are assumed to leave the property and incur a disturbance cost per household that is estimated to be 5% of the depreciated value of the house in which they live.

Households suffering a loss in value of the house of more than 50% will be entitled to emergency assistance, a cost incurred by the local administration which is estimated to be NPR 2,080 per person. These households will repair their houses at their own expense in the future so will not be entitled to resettlement.

Households for which the house is 100% damaged by a flood event will re-settle elsewhere, or re-build their assets in the same place, either with or without Government support. If they settle elsewhere, the re-housing cost is estimated at NPR 350,000. Land acquisition is estimated to be NPR 1,200,000 per ha and an allowance of 0.1 ha has been budgeted. The rates indicated here are indicative. Actual compensation rates are set by the responsible local government authority for each subproject area. They are flood specific and will vary from district to district. It is also noted that these are transfer payments and are included in the financial analysis but excluded from the economic analysis.

E.3.5 Damage to Public Infrastructure Damage to public infrastructure will occur within the flood envelope, particularly for large magnitude floods. Physical quantities of roads, bridges, power lines and telephone lines are estimated on a unit per house basis: i.e. the quantity of public infrastructure damaged is based on the numbers of houses within the flood envelope. It is assumed there are:

· 0.5 metres of Pukka road per housing unit; · 12 meters of Kuchha road per housing unit; · 0.005 bridges adequate for motor vehicles per housing unit; · 2.5 meters of power line per housing unit; and · 1 meter of telephone line per housing unit. The value of public infrastructure damaged by a flood is the equivalent to the cost of repairing or replacing it after a flood event. Current construction costs are estimated to be:

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· Pukka roads: NPR 48,575,221 per km; · Kuchha roads: NPR 12,743,363 per km; · Bridges: NPR 33,119,469 each; · Power 11 kva NPR 706,549 per km; · Telephone lines: NPR 264,959 per km.

E.3.6 Estimate of Infrastructure Direct Losses Without and With the Project The without and with-project incremental direct loss is the difference between the sum of the cost of damage to buildings and infrastructure, displacement costs, emergency relief and resettlement costs without and with project. The values for these losses for each subproject are shown in the subproject sections below.

The incremental benefit from the project is expressed in the model as an annual probability of avoided direct loss (APL). The without and with project loss to events up to 1:100 is calculated by interpolating the values between 1:2, 1:5, 1:10, 1:25, 1:50 and 1:100 and multiplying by the probability of each event occurring. The sum of the loss induced by each event: 1:2, 1:5, 1:6, 1:7,…1:100 is the annual probability of loss that is constant for each year. The combination of adjustment of the expected loss by the probability of loss occurring in each year, and then discounting that APL in the cost benefit analysis means that avoided loss is smaller than might be expected.

Since the project design will provide protection only up to 1 in 50 year floods and the annual probabilities of loss applied in the feasibility analysis are the sum of the losses induced by each event up to 1:50.

E.3.7 Indirect Benefit from Increased Infrastructure Development Without and With project Increased security from flood events is likely to induce increased investment in existing infrastructure in the with-project situation with owners improving the housing stock and existing public infrastructure being up-graded. With-project, there may also be an increase in the affected population, resulting in the construction of new housing. This indirect benefit is not flood-dependent: with flood management it will take place over the whole project area. However, new investment is time dependent and it is assumed it takes place incrementally over the whole project life of 25 years.

It is also necessary to take into account the change in housing and infrastructure in the basin modelled area over time with-project. The losses and benefits described in the sections above are based on assumptions about present infrastructure. Even the direct benefit described in the preceding paragraph refers to incremental improvement of the existing infrastructure. Population growth on the Terai is currently about 2% per annum and it is reasonable to assume that socio-economic conditions will change over time both without and with-project. Population will increase, land use will intensify and investment per unit area will increase. That being so, it is reasonable to scale up the direct benefits to the project to take this indirect benefit of protecting as yet undeveloped assets in the future into account. It is therefore assumed that without and with-project direct losses would be 25% greater than present after 25 years in the future. Direct losses are simply recalculated using this factor and processed to calculate annual probability of loss as described above. Then, instead of using a constant value for APL for each year of project life, it can be interpolated between APL in the present and APL in the future.

E.4 Agriculture The model calculates the avoided direct loss of crops and the indirect benefit of the flood management project using the same without and with project flood envelopes as described above. Avoided direct loss is the value of the crop lost to flood and the indirect benefit is the increase in agricultural economic activity that comes as a result of with-project flood management.

Key data is the agricultural area within each flood envelope, which, at pre-feasibility was obtained from the Project GIS output. The data suggest that the area of agriculture in the flood envelopes is large and will be an important source of damage. However, the argument above suggests that the not all the envelope area will be affected. Floods with a frequent return period will affect a relatively small

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 235 Feasibility Report: West Rapti Basin proportion of the area defined, while floods that return infrequently will affect a much larger proportion. Consistency requires that the affected agricultural area should be adjusted for each flood return period, as was done to calculate infrastructure damage, but the statistical evidence in the historical flood record for doing so is lacking. However, to avoid inflating benefits the affected agricultural area of each subproject has been adjusted downwards in the same proportion as between the total and affected housing population.

After adjusting the total agricultural area to the affected agricultural area, the cropping pattern and cropping intensity in the affected area must be established. In all subproject areas, rice is the most important crop during the flood period of July to September. Rice is cultivated under the technologies:

· improved rice with irrigation; · improved rice rain fed; · traditional rice with irrigation; · traditional rice rain fed; Crop gross margins have been prepared for each of these in the without-project, without flood situation and the with-project, without flood situation. (Crop budgets are shown for each subproject area in the respective sections below.)

Cropping patterns for each subproject area have been modified based on the most recently available district statistics and prices.

In order to prepare gross margins for flood envelopes, the impact of floods on the baseline gross margins was assessed. The expected yield reduction under specified FHRs was defined, taking into account planting date and growth stage of the crop as indicated in Table 36. Floods during July will affect the crop at a recently planted stage and cause a considerable yield reduction. A flood from mid- August through to the end of September will cause comparatively little damage. The known dates of floods for each subproject area were used to weight the anticipated yield reduction by growth stage to derive basin specific yield losses.

Table 36: Expected Loss of Yield of Rice Depending on Flood Date Weighted expected yield loss as function of FHR and Flood Hazard historical flood Rating July 1 to 31 Aug 1 to Aug 15 Aug 15 to Sep 30 dates 0 0% 0% 0% 0% 0.5 60% 20% 10% 25% 0.6 60% 20% 10% 25% 0.7 60% 20% 10% 25% 0.8 60% 20% 10% 25% 0.9 70% 20% 10% 27% 1 70% 20% 10% 27% 1.1 70% 20% 10% 27% 1.2 70% 20% 10% 27% 1.3 70% 20% 10% 27% 1.4 70% 20% 10% 27% 1.5 70% 20% 10% 27% 1.6 70% 20% 10% 27% 1.7 70% 20% 10% 27% 1.8 100% 80% 40% 64% 1.9 100% 80% 40% 64% 2 100% 80% 40% 64%

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Weighted expected yield loss as function of FHR and Flood Hazard historical flood Rating July 1 to 31 Aug 1 to Aug 15 Aug 15 to Sep 30 dates 2.1 100% 80% 40% 64% 2.2 100% 80% 40% 64% 2.3 100% 80% 40% 64% 2.4 100% 80% 40% 64% 2.5 100% 80% 40% 64% 2.6 100% 100% 100% 100% 2.7 100% 100% 100% 100% 2.8 100% 100% 100% 100% 2.9 100% 100% 100% 100% 3 100% 100% 100% 100% 3.1 100% 100% 100% 100% 3.2 100% 100% 100% 100% 3.3 100% 100% 100% 100% 3.4 100% 100% 100% 100% 3.5 100% 100% 100% 100% The FHR for each flood envelope was defined, based on the proportion of the agricultural area affected by low, moderate, significant and extreme risk ratings. Then, the FHR of each flood envelope was used to specify the expected yield reduction, using the above as an Excel LOOKUP table. Having defined the yield reduction, the gross margins then were revised for the four crops under flood conditions of 1:2 1:5, 1:20, 1:50 and 1:100 depending on the area weighted FHR for each envelope.

The issue of loss of both crop value and loss of inputs is treated as follows. Yield cannot be negative, but if it is zero the crop will not be harvested, so variable costs will be incurred only up to the date of flood. This is simulated by a calculation of pre-flood variable costs that exclude the cost of harvesting. In the case of zero yield, gross margin will be negative to the value of the variable costs incurred up to the point of flooding.

Project interventions will protect the areas of agriculture up to a return period of 1:50 with climate change. The balance of the agricultural area in each basin will continue to be flood affected. The CBA model adds the value of production from both areas and subtracts the value of the production in the without project situation to calculate the net benefit with project.

The gross margins show that a small increase in the use of inputs is expected in the protected area with-project: farmers will intensify production if they are more confident that flood damage will be reduced by flood management. It is also assumed there will be some intensification of the cropping pattern, mainly with an increase in the area irrigated together with small increases in improved varieties. This intensification will be an indirect benefit of flood management.

According to agricultural census data, 75% of the cultivated area of the terai is irrigated, either by gravity irrigation from dams or pump irrigation from waterways or groundwater, and 95% of rice planted is of improved varieties. Allowing for some possible over-estimation in these figures - for example from irrigation systems not operating at full efficiency – the cropping pattern used in the analysis has been adjusted to reflect the current situation. It is also noted, that given a good monsoon season, irrigation may not make much difference to paddy yields in this season. Irrigation is much more critical for dry season crops.

With-project gross margins apply only to the protected area and within that area no flood damage is assumed. With-project, without-project gross margins continue to be applied on the whole unprotected area and within that, on the flood affected area, the without-project gross margins with floods are applied.

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The appropriate gross margin per ha and production per ha are then by multiplied by affected and unaffected agricultural area in each without and with-project flood envelope and in the with-project situation the production from the protected area is added. By subtracting gross margin for each flood return period in the without and with-project situation the incremental direct loss can be calculated. By subtracting gross margin without-project from gross margin with-project for each flood envelope the indirect benefit of increased cropping intensity with-project can also be estimated.

The losses under each flood event are then weighted by the probability of the event occurring, the sum of the damages being the annual probability of loss (APL). A small refinement can improve APL. Bearing in mind that APL is calculated on the basis of the present cropping pattern and technology, it can be inflated slightly as cropping intensity increases and technology improves over the life of the project.

The indirect benefit quantifies the difference in value of production between different (future without and future with-project) technologies. It is not dependent on flood probability and is applicable to the whole of the affected area.

E.5 Human Mortality and Injury The historical flood record includes reports of loss of life, missing persons and injuries. Loss of life and missing persons as a result of flooding is probably more consistently reported than destruction and damage to property. Reports of injury in the same record are rarer.

At pre-feasibility it was found difficult to demonstrate any relationship between flood return period and the number of deaths reported. This is probably because flood deaths frequently occur as a result of “risk-taking” behaviour. Risk-taking is an individual situation uncorrelated with loss of property, the total numbers of people affected by a flood and the return period of the flood.

The parameters mortality and morbidity are expressed as a percentage of a population – the population has to be known before a death or injury rate can be calculated. Thus, flood events associated with deaths but with no reported affected population are useless for analysis of mortality. But this can be turned into an advantage for analysis because this set of data includes risk-taking behaviour, for example misjudged attempts to ford rivers in spate.

A data set of 505 flood records for the period 1991-2015 that included an estimate of the affected population was available from the Basin Ranking Study previously carried out. A composite measure of magnitude was calculated, sufficient to classify floods as low, high, very high and extreme in damage impact, but no flood return periods were available. Ninety-five records included reports of death, missing persons or injury. Summing these reports by damage magnitude gave an estimate of mortality, mortality and missing persons, and mortalities, missing persons and morbidity, as shown in the table.

Table 37: Estimate of Mortality and Morbidity by Magnitude of Flood Damage Mortality, Magnitude Mortality missing of flood Affected Dead Missing Injured & and damage Events persons People People People Mortality missing Morbidity Low 373 222,110 43 9 26 0.019% 0.023% 0.035% High 91 233,618 55 14 6 0.024% 0.030% 0.032% Very high 32 425,852 170 9 50 0.040% 0.042% 0.054% Extreme 8 154,933 125 7 37 0.081% 0.085% 0.109%

These results are intuitively reasonable, with all three rates increasing with flood damage magnitude. The rates can be expressed as incidents per 10,000 people and plotted on a graph (see Figure 54). There are very few records of extreme events and it is not known if any of them represent a flood of 1:100 return period. Assuming extreme events of flood damage are related to 1:50 events, the graph can be interpolated for an estimate of the number of deaths, missing persons and injuries expected in

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 238 Feasibility Report: West Rapti Basin the range of return periods that are of interest to the CBA. But the approach is not rigorous because rates are only implicitly linked to flood return periods.

Having made an estimate of likely dead, missing and injured per 10,000 flood affected people it is easy enough to apply these rates to the flood affected population as defined in the sections above, taking care to disaggregate the rates and specify dead, missing and injured separately. Combined, the statistic is referred to as “casualties”.

Figure 54: Mortality and Morbidity Rates by Magnitude of Flood Damage The same data can be used to establish an annual probability of casualties without and with project using the annual probability of loss method described in above. The difference between the APL without and with project basically represents the number of casualties the project expects to avert per year of its existence. There is no need to express this in monetary terms; it can stand alone as a project indicator, along with NPV, IRR etc. The CBA, however, does include funeral costs for the deceased and medical costs for the injured.

Table 38: Annual Probability of Casualties Saved

Saved, attributable to Without project With project project

Lives saved 0.48 0.09 0.396 Injuries saved 0.04 0.01 0.029 Missing saved 0.15 0.06 0.125 Casualties 0.67 0.26 0.551 The Flood Forecasting and Early Warning Systems (FFEWS) now included in the project will provide flood warnings to the whole basin and not just to the flood protected area. The benefits of the system for the wider basin will be reflected in lives, missing and injuries saved as well as in reduced basin wide livestock mortality. It is assumed that those living outside the protected area will not have access to flood shelters provided under the project, but will receive sufficient warning to move both themselves and their livestock to higher ground ahead of the approaching flood. The appropriate annual probability of casualties for those living outside the protected area are the without project values in the table above. The FFEWS give the population warning to move to higher ground, but it cannot be assumed that it will be 100% effective in any or all cases. For this reason, the ‘without project’ annual probability of casualties saved have been discounted by 50% for this calculation.

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E.6 Livestock The same procedure described for quantifying the probability of mortality and morbidity was used to estimate the probability of the death of livestock during a flood event. The main issue was how to establish the “affected” livestock population so that a mortality rate to be calculated. This was complicated by the fact that the historical flood record specifies only “livestock” deaths. There is obviously a huge difference in value if each livestock unit represented one head of cattle rather than one head of poultry. Further, it is known that poultry suffer disproportionately compared to other livestock types from flood events.

The procedure used required estimating the livestock herd of each flood-affected household. This was assisted by an FAO study on livestock in Nepal10, though the estimates in the study were modified to be relevant to the subproject areas. The study notes that the statistics for the period show that 86% of households in the Terai were livestock owners and provides sufficient additional information to show that the mean household herd size is 2.2 Tropical Livestock Units (TLU) composed of 8% cattle (2 head), 8% sheep and goats (2 head), 8% pigs (2 head) and 77% chickens (20 head). Bearing in mind that one TLU must then equal 11.82 head of the household livestock herd, this is sufficient to calculate the affected population of animals by type, against which “livestock” deaths can be disaggregated and measured. The disadvantage of the method is that it does not take into account bias in livestock deaths.

Figure 55, based on MOHA/DWIDP data, shows that “livestock” mortality in flood events can be deduced as about 300 head per 10,000 for extreme events. The calculation for deriving this statistic required, for each reported flood:

· adjusting the affected households to derive the number of affected households owning livestock; · deriving the numbers of affected households owning cattle, sheep and goats, pigs and poultry; · disaggregating livestock deaths according to the composition of the household herd; · expressing reported mortality per 10,000 head by livestock type for reported floods of low, high, very high and extreme events as shown in Figure 55.

Figure 55: Livestock Mortality Rates by Magnitude of Flood Damage The affected livestock herd in both TLU and number of head (owned by the affected population expressed as households) could then be estimated and the expected fatalities for each flood envelope calculated by applying the mortality rates shown in Figure 54.

10 Poverty, Livestock and Household Typologies in Nepal, Maltsoglou and Taniguchi, PPLPI Working Paper 13, FAO 2004

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These fatalities can then be valued because the value of the household herd is estimated by applying current prices to each livestock type. This has the effect of giving more weight to the value of poultry, but bias in mortality between livestock types is still not accounted for.

The annual probability of loss for livestock is calculated in the usual way. It is rather low, but likely to be realistic when one considers that most livestock deaths from flood events are probably of chickens. No adjustment is made for anticipated indirect benefits as households are unlikely to improve or invest in more livestock as a result of improved flood management.

As mentioned in the previous section, basin-wide benefits for livestock will accrue for livestock from implementation of the FFEWS. The expected reduction in livestock losses is calculated in the same way as for casualties. The without project annual probability of losses are discounted by 50% to estimate the reduction in livestock losses in the wider, unprotected part of the basin.

E.7 Prevention and Coping Mechanisms Residents living in flood risk areas incur flood damage prevention costs before flood events. Prevention costs cover flood proofing of houses, bank stabilization by tree and grass planting and maintenance, and establishment and maintenance of live fencing to check floods. The measures taken may be individual or cooperative. In the without-project situation it is assumed that between five and ten person days per annum are spent per (affected) house in flood proofing and a further 50 days per hectare in “built up” areas (as specified on the land use map) carrying out bank stabilization and live fencing. There will be minor material costs but only labour has been costed.

Costs of coping after flood events are much more significant. These costs relate to house repair after flood damage. Although the value lost by flood damage has already been estimated as an infrastructure cost, an additional cost is incurred by the owner in making good that damage: the situation is analogous to the negative gross margin incurred as a result of losing both the crop and the inputs required to grow that crop up to the point of destruction. Only damaged houses are repaired, destroyed houses are replaced through re-settlement measures already included. Repairing damage is assumed to cost about 10% of depreciated house value for a house sustaining <25% damage and 25% of depreciated house value for a house sustaining >25% damage.

Repairing in-field infrastructure after a flood event is a significant cost to be added to the loss of crop production and operating costs. Paddy bunds must be re-made (40 person days per ha), water points for both irrigation and water supply repaired (10 days per ha), cattle sheds re-constructed (10 days per unit) and areas affected by sedimentation reclaimed (200 days per ha). By far the greatest cost is the repair of paddy bunds and land reclamation.

The cost of labour is used is the unskilled wage rate applicable in each subproject area.

Indirect coping costs are also incurred within post-flood food markets. It is well known that the price of staples rises in flood-affected areas as crop losses are substituted for by food purchases; demand for food rises and supply falls. The situation was analysed based on The Food Balance Sheet for Nepal, FAO 2011. Table 39 shows the average food consumed per person per year providing 2,530 kcals per capita per day. In 2018 prices this diet costs about NPR 196 per capita per day.

Table 39: Summarised Food Budget Per Capita Food Food Food Cost of supply supply % of food supply Rs/kg daily diet Item quantity (kg/capita/ supply (kcal/capita/ 2018 2015 (kg/capita/ yr) day) (NPR) day) Cereals 186.6 33% 1609 48 0.51 24 Roots 80.1 14% 150 100 0.22 22 Sugar 35.4 6% 28 75 0.10 8 Pulses 10.6 2% 92 100 0.03 3

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Food Food Food Cost of supply supply % of food supply Rs/kg daily diet Item quantity (kg/capita/ supply (kcal/capita/ 2018 2015 (kg/capita/ yr) day) (NPR) day) Nuts 2.0 0% 13 - 0.01 - Oilseeds 0.7 0% 5 100 0.002 0 Veg. oils 10.1 2% 243 200 0.03 6 Vegetables 112.2 20% 74 250 0.31 78 Fruit 53.8 10% 65 120 0.15 18 Stimulants 0.4 0% 1 - 0.00 - Spices 6.2 1% 57 400 0.02 8 Tea 1.8 0% 4 800 0.005 4 Meat 12.2 2% 44 325 0.03 10 Butter/ghee 1.4 0% 34 860 0.004 4 Eggs (kg) 1.1 0% 4 225 0.003 1 Milk (kg) 49.6 9% 103 70 0.14 10 564.2 2,526 196

This estimate can be used to calculate the amount of food stuff required per capita per year in crop equivalent, allowing for processing, feed, seed and waste. The figure of most interest is the annual requirement of 187 kg of cereal per person, which in practice means rice. Using standard milling percentage and allowance for wastage, this is equivalent to 315 kg of paddy. Increased market demand for paddy by the displaced will increase the price of paddy depending on the price elasticity of demand. For simplicity, it is assumed that the price elasticity is 1 – i.e. a 1% increase in demand will increase price by 1%. The actual price increase will depend on the return period of any flood event and the damage to crops.

E.8 Economic Assumptions

E.9 Numeraire and prices: The analysis uses the domestic price level numeraire, expressed in local currency. The financial prices used are those applying in the market in the third quarter of 2019. To convert financial prices and costs to economic prices and costs when using the domestic price level numeraire, the foreign component of the price of traded goods is adjusted by the shadow exchange rate factor (SERF), scarce labour is adjusted by the shadow wage rate factor (SWRF), taxes are removed from prices and domestic resources are multiplied by a factor of 1 (i.e. the financial prices of domestic resources are equal to the economic prices).

Taxes and duties: Nepal applies a value added tax of 13% on most goods but most agricultural inputs and outputs are not subject to VAT. Import duties also apply on many imported goods, most notably, in the context of the present project on most equipment.

Conversion factors and exchange rate: The standard conversion factor (SCF) for the project has been estimated, as shown in Table 40, using import and export data for the most recent fiscal years. The SCF of 0.92 used in the analysis is the average of the values estimated for the years 2015 to 2017 (SERF = 1.09). The exchange rate used throughout the analysis is USD1 = NPR 114.9.

Table 40: Estimate of Standard Conversion Factor (NPR ‘000) 2015 2016 2017 2018

Imports (M) 786,191,403 774,712,277 984,302,948 1,244,814,417 Exports (X) 85,194,754 70,254,165 73,036,244 97,109,521

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Taxes on imports (TM) 70,487,070 79,436,558 96,890,912 131,705,665

Taxes on exports (TX) 314,556 113,683 125,200 165,086 Standard Conversion Factor 0.925 0.914 0.916 0.911 Shadow Wage Rate Factor 1.08 1.09 1.09 1.10

Standard conversion factor = (M + X)/(M + TM + X - TX) Sources: Import, export and import taxes - www.customs.gov.np ; Export taxes, http://mof.gov.np/en/archive-documents/budget-speech

Conversion factors have been calculated for specific expenditure categories, taking into account estimated foreign, tax and unskilled labour components. The derivations of these are given in Table 41.

Table 41: Specific Conversion Factors unskilled domestic labour foreign tax SWRF SERF CF civil works 0.7 0.1 0.2 0.885 0.8 1.09 0.883 Equipment 0.25 0 0.75 0.847 0.8 1.09 0.904 supplies, materials 1 0 0 0.885 0.8 1.09 0.885 studies & surveys 1 0 0 0.885 0.8 1.09 0.885 training & workshops 1 0 0 0.885 0.8 1.09 0.885 consulting services 0.5 0 0.5 0.885 0.8 1.09 0.925 government. staff 1 0 0 0.000 0.8 1.09 1.000 O&M, house repair, etc 0.7 0.2 0.1 0.885 0.8 1.09 0.858 kacha roads &c 0.8 0.2 0 0.885 0.8 1.09 0.850

Labour: The hourly wage rate for labour varies among regions in the country and the rate used for each subproject is that which is current in each subproject area. For this analysis a SWRF of 0.8 has been adopted to adjust the price of unskilled labour to its economic value. This is the value used in the pre-feasibility studies and in other recent projects in Nepal. It’s impact on the outcome of the analysis is tested in the sensitivity analysis.

Opportunity cost of capital: The opportunity cost of capital used for the analysis is 9%.

E.10 Prices Prices used in this analysis are current third quarter 2018 prices. Key prices applicable for this subproject are included in the table below. In some cases, regional variations apply which will be noted in the relevant subproject sections below.

Table 42: Key Prices Prices (NPR) Conversion Item Unit Financial Economic Factor Infrastructure Class 1 house unit 840,430 722.770 0.86 Class 2 house unit 540,280 464,640 0.86 Class 3 house unit 787,900 677,600 0.86 Class 4 house unit 459,236 394,940 0.86 Pukka roads km 58,905,000 52,064,100 0.88

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Prices (NPR) Conversion Item Unit Financial Economic Factor Kacha roads km 16,065,000 13,648,140 0.85 Bridges m 1,606,500 1,413,720 0.88 Power lines km 856,800 756,710 0.88 Telephone lines km 321,300 283,770 0.88 Emergency relief person 2,080 0 0 Rehousing cost hh 350,000 0 0 Land ha 1,200,000 0 0 Mortality Funeral person 20,000 20,000 1.0 Injury (treatment) person 50,000 50,000 1.0 Agriculture 1) Rice ton 23,000 26,634 - Urea ton 17,000 47,380 - DAP ton 47,000 46,862 - Potash ton 50,000 39,880 - Labour day 450 360 0.8 Livestock Buffalo (cow) head 110,000 110,000 1.0 Buffalo (bull) head 90,000 90,000 1.0 Goat / sheep head 20,000 20,000 1.0 Pig head 30,000 30,000 1.0 Chicken head 1,000 1,000 1.0

Note: 1) Financial prices are local market prices (may vary among regions); economic prices calculated from World Bank Pinksheet average prices for 2nd quarter 2019

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F. CBA data West Rapti

F.1 Background to the Subproject Area The West Rapti river rises south of a prominent east-west ridgeline midway between the western Dhaulagiri Himalaya and the Mahabharat Range in north western part of Rolpa District. The river descends south from rugged high land of Rolpa district and crosses in to Pyuthan. After the confluence with Jhimruk and Madi, the river is called West Rapti River. It flows for a short distance towards southwest and makes a turn and flows due northwest parallel to the Churia (Siwalik) range till Shamsergunj in Banke District. Here it makes a turn and flows due southeast before joining the Chagra (Karnali) river in India.

The catchment area of the study basin is 6,500 km2 and the length of the mainstream channel is 257 km. The major towns along the study reach are Bhaluban, Sisanniya, Sonpur, Lamahi, Satbariya, Baijapur, Kanchanpur, Phattepur, Betahani and Holiya. The study reach covers Deukuri valley of Dang district the plains in Banke District. West Rapti is a perennial river and flooding in the river is characterized as being flashy in the narrow valley and prolonged in the wider plain areas in the downstream reaches. There has been history of over 50 flood events during 1993 to 2015 of which a significant proportion cause low to moderate damage. In recent years, the river has experienced high sediment loads often aggravated by landslides in the upper catchment. According to the current Bureau of Statistics land use data, the proportion of the area under agricultural cultivation is 28%.

The Terai region of Nepal is frequently affected by floods during the monsoon season due to heavy rain locally and in the hill and mountain regions. Flooding in these areas causes damage to farmland and crops and to housing and public infrastructure. It also kills livestock and can result in deaths and injury among the local populations. The risks associated with flooding are also increasing with growth in the population as well as in urban and public infrastructure.

F.2 Subproject Interventions The CBA of the subproject includes the following structures:

· Embankments totalling 12,530 metres; · Revetments totalling 13,580 metres; · A total of 36 spurs. In addition to the civil works, the FFEWS and CBDRM will be implemented and 10 flood shelters to provide safe locations for affected households outside the protected areas during flood events will also be constructed.

F.2.1 Alternatives Alternative solutions to address flooding have been considered and the selection and design of the preferred solution has been made in consultation with WRPPF. Designs are in accordance with government standards and costing of proposed interventions has been estimated using the current unit costs for each district. Throughout the selection and design process priority has been given, wherever possible, to the use of low cost solutions.

F.3 Beneficiaries The estimated population and number of houses in the area that will be protected by the project are shown in Table 43, based on the flood modelling results for the subproject. The population data is derived from the 2011 census data for Dang and Banke districts adjusted by 2% per annum for the intervening period. This is a slightly lower growth than the rate of just over 2.2% observed between the 2001 and 2011 censuses.

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Estimates for the population and houses (and other infrastructure) affected by flooding include 3 scenarios:

1) the present situation based on historical flood events – this is the base case; 2) the present situation taking into account the expected impact on flooded areas of climate change and the “affected area” and is the “without project” scenario; and 3) the future situation taking into account the expected impacts of climate change and the infrastructural interventions proposed for the subproject. This is the “with project” scenario.

Those in the affected area outside the protected area will also benefit from the FFEWS and anticipated reductions in loss of life, injuries and loss of livestock.

Table 43: Population and Houses (2018 estimates) Return period 1:2 1:5 1:10 1:25 1:50 1:100 Base case Population 11,490 16,657 21,520 26,583 30,081 34,584 Houses 1,915 2,776 3,587 4,430 5,013 5,764 Affected Area Population 13,396 19,852 23,729 29,218 33,465 38,679 Houses 2,233 3,309 3,955 4,870 5,578 6,447 Protected Area Population 3,166 4,238 5,271 6,077 6,276 5,669 Houses 528 706 879 1,013 1,046 945 Unprotected Area Population 10,229 15,614 18,458 23,141 27,189 33,010 Houses 1,705 2,602 3,076 3,857 4,532 5,502 Source: Consultants’ flood modelling results; the population in the unprotected areas will be those most benefitting from the FFEWS and CBDRM measures.

F.4 Benefits Benefits of the subproject depend on the flood affected and protected areas without and with project implementation. These are shown in Table 44. Areas are included for protection up to the 1:50 year flood level, in accordance with the design criteria.

Table 44: Flood Affected and Protected Areas (ha) Return periods 1:2 1:5 1:10 1:25 1:50 1:100 Base case (historical floods) 7,838 9,866 11,247 12,927 14,092 15,319 Affected area without project 8,650 10,869 11,904 13,539 14,821 15,824 Affected area with project 8,107 9,929 10,843 12,333 13,551 15,057 Protected area 543 940 1,061 1,206 1,270 767 Unprotected area 8,107 9,929 10,843 12,333 13,551 15,057 Source: Consultants’ flood modelling results

F.4.1 Housing and Infrastructure Avoided damage to housing and public infrastructure are the major sources of benefits for the subproject.

The extent of damage to houses and infrastructure depends on flood return period and location, as explained in Section F.3.1. The estimated proportions of houses damaged as estimated in the pre- feasibility study for West Rapti are given in the table and are unlikely to have changed in the intervening period. These proportions also determine the estimated damage to public infrastructure. Sources of data for the inventory of the infrastructure, buildings and houses are as follows:

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1. Name of Municipality: Geographic Information Infrastructure Division, Ministry of Land Management, Cooperatives and Poverty Alleviation (Area calculated from GIS); 2. Land Cover – Google Earth Image; 3. Roads - Open Street maps- freely available and downloadable; 4. Transmission Line – Data from Nepal Electricity Authority; 5. Bridges: Based on the survey carried out during the RTW survey of the structure by Sub Consultants; 6. Household counts: Based on the google earth image of the date (11/25/2016 and 1/12/2017); 7. Other infrastructure (Like Brick Factory): Visibility based on the google earth image.

Table 45: Estimated Percentage of Houses Damaged or Destroyed Return periods 1:2 1:5 1:10 1:25 1:50 % damaged or destroyed 0% 57.8% 16.0% 21.9% 39.3% Source: Package 3 pre-feasibility study

The classification of houses by quality into 4 classes is described in Section F.3.2, above, with Class 1 the highest class and Class 4 the lowest. The proportions of each class estimated for the West Rapti sub-project area are Class 1 (6%), Class 2 (30%), Class 3 (34%) and Class 4 (30%) – i.e. the majority of housing in this subproject area is of lower grade.

The total damage to housing and infrastructure for different flood levels are summarised in Table 47 and Table 48, including direct damage to houses and infrastructure as well as relief and resettlement costs, as appropriate. As explained in the methodology sections above, the loss of value to housing is estimated based on the depreciated value of average costs for each class of house and damage to public infrastructure is based on fixed lengths per damaged house and the current costs for construction of the various infrastructure categories. These costs are shown in Table 46 and have been updated to 2019 costs by applying the GDP inflator for 2018.

Table 46: Values Used for Houses and Infrastructure

NPR NPR Houses Non-Depreciated Depreciated Class 1 1,049,580 840,432 Class 2 674,730 540,277 Class 3 983,981 787,905 Class 4 573,521 459,236 Other Infrastructure Pucca roads km 58,905,000 Kacha roads km 16,065,000 Bridge (vehicular) m 1,606,500 Power lines km 856,800 Telephone lines km 321,300 Source: MPIT; costs updated to 2019 prices with GDP deflator

Table 47: Damage to Infrastructure, without project (financial prices) Flood with Return Period Item Unit 1:2 1:5 1:10 1:25 1:50 1:100 Damage to housing NPR m 900.0 1,154 553 971 2,070 3,520 Displacement costs NPR m 70.02 33.5 58.9 125.6 179.1 - Relief and resettlement NPR m 38 44 21 37 78 957 Damage to infrastructure NPR m 950 1,086 520 913 1,947 2,777 Total Direct Cost NPR m 1,958.2 2,317.1 1,152.4 2,046.4 4,274.3 7,254.8

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Table 48: Damage to Infrastructure, with project (financial prices) Flood with Return Period Item Unit 1:2 1:5 1:10 1:25 1:5- 1:100 Damage to housing NPR m 891.0 1,080.5 517.4 908.8 1,937.7 3,424.3 Displacement costs NPR m 60.7 69.3 33.2 58.3 124.3 177.3 Relief and resettlement NPR m 37.8 43.2 20.7 36.4 77.5 947.9 Damage to infrastructure NPR m 940.5 1,074.8 514.7 904.1 1,927.5 2,749.1 Total Direct Cost NPR m 1,929.9 2.267.8 2,086.0 1,907.6 4,067.0 7,298.5

The estimated avoided losses (in financial prices) from damage to buildings and infrastructure accruing to the subproject from each flood event are shown in Table 49 together with the estimated annual probabilities of loss calculated from the losses estimated for the specified return periods, the estimated probabilities of occurrence with climate change and with interpolation of values for intervening years.

Table 49: Housing and Infrastructure (NPR million) Annual Probability Flood envelopes of Loss Incre- APL 1:2 1:5 1:10 1:25 1:50 ment Direct loss of present infrastructure Without project 1,969.2 2.376.2 1,137.8 1,998.7 4,261.3 9,539.6 With project 1,949.5 2,290.2 1,096.7 1,926.4 4,107.1 9,330.64 209.0 Direct loss of future infrastructure Without project 2,461.5 2,970.2 1,422.3 2,498.4 5,326.7 11,924.6 With project 2,436.9 2,862.7 1,370.8 2,408.0 5,133.9 11,663.3 261.26 Independent of flood Indirect benefit 1) 10.2 15.1 18.0 22.17 25.4 events Note: 1) From increased investment and independent of flood events

Over the 25-year life of the project, the discounted direct benefits accruing from housing and infrastructure amount to NPR 2,190.4 million (in financial prices) are constitute 85.1% of subproject benefits. The indirect benefits due to incremental growth of infrastructure and economic activities amounting to financial value of NPR 81.80 million equal to 3.2% of total benefits. Flood protection activities in the sub project area will boost economic investments and in infrastructure.

F.4.2 Agriculture The benefits accruing from agriculture are based on crop budgets for paddy, which is by far the dominant crop in the monsoon season. Four crop budgets are used, for irrigated and rain fed rice and for improved and traditional rice varieties. According to Department of Agriculture data, 75% of rice production in the Terai is irrigated and 95% of the area is planted with improved varieties. In years when the monsoon is good, the difference between irrigated and rain fed production may not be significant. For West Rapti sub project key parameters are summarised in the table. In addition, the weighted average return to labour, in financial prices, is NPR 116 without the project and NPR 169 with the project.

Table 50: Key Characteristics of Rice Crop Budgets Improved Varieties Traditional Varieties Irrigated Rain fed Irrigated Rain fed Without project, no flood impact Crop budget distribution 50% 33% 6% 11% Yield (tons) 3.94 3.64 3.62 3.25 Gross margin per ha (NPR) 27,471 25,230 3,977 3,583

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With project, no flood impact Crop budget distribution 64% 25% 6% 5% Yield (tons) 4.14 3.72 3.65 3.30 Gross margin per ha (NPR) 29,565 26,968 26,355 23,806

Production areas, production and gross margins without and with the project are summarised in Table 51 and Table 52.

Table 51: Agriculture without project (financial prices) Flood with Return Period Unit 1:2 1:5 1:10 1:25 1:50 1:100 Total agricultural area ha 4,106 5,463 6,122 7,180 7,992 8,735 Agricultural area affected ha 36.04 62.50 219.29 511.40 6,493.87 7,702.65 Protected agricultural area ha ------Gross margin without flood NPR mln 105.98 141.00 158.02 185.32 206.28 225.46 Gross margin with flood NPR mln 105.98 136.15 141.01 145.66 (297.35) (371.92) Total direct loss with flood NPR mln - 4.85 17.01 39.66 503.63 597.37 Total indirect benefit with flood NPR mln ------Production without flood tons 15,398 20,486 22,958 26,925 29,970 32,757 Production with flood tons 15,398 20,251 22,136 25,007 5,619 3,872 Change in production tons -- 234 - 822 - 1,918 - 24,352 - 28,884

Table 52: Agriculture with project (financial prices) Flood with Return Period Unit 1:2 1:5 1:10 1:25 1:50 1:100 Total agricultural area ha 3,779 5,067 5,686 6,675 7,406 - Agricultural area affected ha 33 58 204 475 6,017 - Protected agricultural area ha 394 792 915 1,051 1,108 767 Gross margin without flood NPR mln 97.55 130.77 146.75 172.27 191.14 - Gross margin with flood NPR mln 106.84 137.54 143.37 149.77 (258.85) 248.38 Total direct loss with flood NPR mln - 4.50 15.79 36.87 466.67 - Total indirect benefit with flood NPR mln 0.86 1.04 1.15 1.33 1.54 22.92 Production without flood tons 16,271 21,647 24,260 28,451 31,669 34,613 Production with flood tons 16,271 21,417 23,453 26,567 7,826 34,613 Change in production tons 2,590 3,370 4,267 5,889 28,492 69,226

The benefits from agriculture for the specified flood return periods are given in Table 53 together with the annual probabilities of loss for the present and future cases. Total discounted benefits from agriculture over the project life amount to NPR 30.56 million (in financial prices), that is 1.22% of total benefit.

Table 53: Agricultural Losses and Annual Probabilities of Loss (financial prices) Annual Probability of Flood envelopes (NPR million) Loss 1:2 1:5 1:10 1:25 1:50 APL Increment Direct loss of present production Without project - 4.85 17.01 39.66 503.63 29.97 With project - 4.50 15.79 36.87 466.67 27.81 2.16 Direct loss of future production Without project - 6.06 21.26 49.58 629.54 37.46 With project - 5.62 19.74 46.09 583.33 34.76 2.71 Independent of flood Indirect benefit 1) 0.86 1.04 1.15 1.33 1.54 events Note: 1) From increased investment and independent of flood events

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F.4.3 Mortality and Injury The annual probability of loss for life, missing persons and injuries estimated for this subproject are shown in the table. These probabilities refer to the protected area. Reductions in losses will also accrue in the affected area due to the implementation of the FFEWS. The avoided losses in these areas are assumed to be at half the without project rate. Over the 25 year life of the project the total direct losses prevented are estimated to amount to 6.7 casualties prevented. In addition, indirect losses prevented due to the FFEWS and CBDRM amount to almost 15.

Table 54: Loss of life, missing persons and injuries Annual probability of loss

Saved due to Without project With project project

Loss of life 19.12 18.93 0.191 Injuries 7.19 7.11 0.072 Missing 2.83 2.80 0.028 Total Casualties 29.14 28.84 0.300

F.4.4 Livestock The methodology for estimating livestock losses is described in Section E.6. For West Rapti, the value of the composite livestock unit is NPR 340,000. Losses for the specified flood return periods up to 1:50 years are shown in the table together with the calculated annual probability of loss.

In addition, since livestock losses in the affected area will be reduced with implementation of the subproject FFEWS, the reduction of losses in this area is assumed to be at the rate of half of the without project APL.

Table 55: Livestock Losses (financial prices) Annual Probability of Flood envelopes (losses NPR million) Loss 1:2 1:5 1:10 1:25 1:50 Incremental Without project - 1.55 19.64 29.87 129.81 18.09 With project - 1.54 19.44 29.57 128.51 17.91 0.18

Over the project life, total discounted livestock losses avoided (in financial prices) are NPR 89.54 million and constitute 8.51% of total discounted benefits.

F.4.5 Prevention and Coping Costs Prevention and coping costs include all the repair and restoration costs of flood induced damage to buildings and paddy fields, restoration of areas affected by sedimentation and increases in food prices resulting from damage to crops and local supply. They are an important source of benefits for the subproject. A high proportion of the totals in each category are costs of labour to carry out the repair works. Estimates for the component costs for each return period, without and with the subproject, are shown in the following two tables.

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Table 56: Prevention and Coping Costs without project Flood with Return Period Unit 1:2 1:5 1:10 1:25 1:50 Costs of flood prevention NPR mln 3.50 5.19 6.21 7.64 8.75 Costs of flood coping Repair of housing NPR mln 253 290 139 244 519 Repair of paddy field structures NPR mln 0.24 0.41 1.44 3.36 42.67 Repair of water points NPR mln 3.42 5.07 6.06 7.47 8.55 Repair of cattle sheds NPR mln 3.33 3.81 1.82 3.20 6.83 Repair of miscelaneous NPR mln 3.33 3.81 1.82 3.20 6.83 Areas affected by sedimentation ha 789 1,369 4,803 11,201 142,226 Reclamation of sedimentation areas NPR mln 0.12 0.21 0.72 1.68 21.33 Increased food expenditure NPR mln 19.34 19.20 4.03 11.00 84.81 Total NPR mln 286.70 327.31 160.79 281.16 699.14

Table 57: Prevention and Coping Costs with project Flood with Return Period Unit 1:2 1:5 1:10 1:25 1:50 Costs of flood prevention NPR mln 3.47 5.14 6.14 7.57 8.67 Costs of flood coping Repair of housing NPR mln 251 287 137 241 514 Repair of paddy field structures NPR mln 0.38 1.34 3.12 39.54 - Repair of water points NPR mln 3.39 5.02 6.00 7.39 8.47 Repair of cattle sheds NPR mln 3.30 3.77 1.80 3.17 6.76 Repair of miscelaneous NPR mln 3.30 3.77 1.80 3.17 6.76 Areas affected by sedimentation NPR mln 726 1,270 4,460 10,412 131,787 Reclamation of sedimentation areas NPR mln 0.11 0.19 0.67 1.56 19.77 Increased food expenditure NPR mln 17.94 17.80 3.73 10.15 83.96 Total NPR mln 282.77 323.74 160.57 313.72 648.55

The annual value of these costs is initially NPR 15.08 million, increasing to an annual NPR 18.85 million by the end of the project life. The discounted value of prevention and coping costs in West Rapti over the project life is NPR 158.08 million (in financial prices), constituting 6.19% of total discounted benefits.

Table 58: Prevention and Coping Costs (financial prices)

Flood envelopes 2 5 10 25 50 Incremental 50% 20% 10% 4% 2% APL APL Without project cost of present prevention and NPR m 287.90 329.06 162.86 283.65 702.28 1,083.90 coping With project cost of present coping and NPR m 283.8 324.5 160.9 279.8 691.2 1,068.82 15.08 prevention Without project cost of present and future NPR m 359.87 411.33 203.57 354.57 877.85 1,354.88 prevention and coping With project cost of present and future coping NPR m 354.7 405.7 201.1 349.7 864.0 1,336.02 18.85 and prevention

F.4.6 Benefits Not Quantified Benefits that have not been quantified for the analysis include possible impacts on bank erosion along the rivers in the vicinity of or downstream from subproject interventions. There may also be other, unspecified impacts on the environment. Minor benefits may also accrue in the protected area from the prevention of flood contamination of wells and other water sources. There are also benefits that will accrue from the implementation of the FFEWS and CBDRM, in terms of life and property saved, that are only partially accounted for in the quantitative analysis.

F.5 Total Subproject Benefits Benefits of the subproject come from the avoided losses accruing with implementation of the flood protection measures. Direct benefits quantified for the analysis are avoided damage and destruction of buildings and public infrastructure, avoided damage to monsoon season crops, prevented human injury and mortality, avoided livestock deaths and the avoided costs of repairing buildings, bunds and other

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 251 Feasibility Report: West Rapti Basin field infrastructure and addressing the effects of sedimentation. Indirect benefits include the value of increases in private and public infrastructure and increases in agricultural productivity and production inside the flood protected area that are induced by the increased security from flood damage.

The incremental benefits of the subprojects are the difference between avoided losses in the without and with project situations, plus indirect benefits obtained as a result of the proposed project. Avoided losses are weighted by the probability of their future occurrence and benefits independent of flood events are scheduled with reference to the project flood management time frame. These benefits for the West Rapti subproject are summarised in the following table.

Table 59: Discounted Benefits (financial prices) NPV of Benefit Source of Incremental Benefits % Total Benefits Stream (NPR mln) Direct infrastructure avoided losses 2,450.4 85.6 Indirect infrastructure benefit 86.4 3.0 Direct agriculture avoided losses 30.45 1.06 Indirect agriculture benefit 9.55 0.33 Direct livestock avoided losses 1.76 0.06 FFEWS direct livestock avoided loss 87.78 3.06 Direct funeral and injury expenses avoided 0.06 0.00 FFEWS Direct funeral and medical avoided costs 3.14 0.11 Direct and indirect avoided prevention & coping costs 194.4 6.8 TOTAL BENEFITS 2,864.3 100

F.6 Costs Total subproject costs amount to NPR 2,228.4 million (USD 16.83 million). In economic prices, the cost is NPR 1,986.9 million (USD 15.00 milion).

Table 60: Costs by Expenditure Category (NPR ‘000) Expenditure Category 2020 2021 2022 2023 2024 2025 2026 Total Civil Works 0 36,407 410,769 440,362 464,286 441,065 0 1,792,889 Equipment 0 40,591 42,963 45,451 0 0 0 129,006 Supplies, materials and 548 7,817 8,438 9,059 9,411 9,986 8,734 53,992 operations Studies and Surveys 611 7,932 8,562 8,452 0 0 0 25,556 Training and Workshops 121 1,577 1,702 1,833 1,970 1,937 0 9,141 Consulting Services 1,585 20,296 21,629 23,024 24,484 24,387 6,323 121,727 Government Staff 1,082 8,465 16,893 18,192 19,548 19,744 12,168 96,092 Total (Financial Prices) 3,947 123,085 510,957 546,372 519,699 497,119 27,225 2,228,403

Total (Economic Prices) 3,681 111,414 455,000 486,535 462,232 442314 25746.1 1,986,922

F.7 Results of the Economic Analysis The West Rapti subproject has an economic internal rate of return (EIRR) of 29.1%, which is above the discount rate of 9% that is the hurdle for confirming economic viability. As may be seen from Table 19Table 23 the EIRR is resilient to changes in the levels of damage sustained by buildings and public infrastructure during flood events.

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Risks to the subproject may occur in implementation if, for any reason, structures are not completed to the required standard. Another source of risk would be climate change engenders more and larger floods than have so far been predicted.

Table 19: Result of the Economic Analysis NPV Switching % change EIRR (NPR mil.) Value Base case 29.1% 957.1 Investment costs +10% 21.9% 790.1 +57% +20% 17.8% 623.0 Benefits -10% 21.6% 694.4 -36.3% -20% 15.9% 431.6 Buildings affected in flood envelope +10% 48.5% 1,221.6 -36.5% -10% 21.3% 694.1 % buildings damaged/destroyed +10% 46.3% 1,204.2 -39.1% -10% 21.7% 711.1 Public infrastructure affected +10% 30.9% 1.000.8 - -10% 27.7% 917.3 Future growth in infrastructure +10% 29.3% 965.1 - -10% 29.0% 949.2 Agricultural area affected +10% 29.7% 960.7 - -10% 29.0% 953,5

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Economic analysis

West Rapti: ADJUSTED PROBABILITIES for FLOODS WITH CLIMATE CHANGE West Rapti CBA Project costs in Economic prices in NPR m Project benefits in Economic prices in NPR m Benefit stream Casualties Incremental Incremental Incremental FFEWS FFEWS Incremental direct direct Incremental direct agriculture Incremental Incremental Incremental direct Incremental direct and indirect Annual Total dead, infrastructure infrastructure agriculture indirect direct livestock direct livestock funeral and funeral and prevention and Total benefit missing and Investment NPR Maintenance Total costs, avoided loss, indirect benefit, avoided loss, benefit, NPR avoided loss, avoided loss, medical avoided medical avoided coping costs benefits, stream, NPR injured saved m NPR m NPR m NPR m NPR m NPR m m NPR m NPR m costs, NPR m costs, NPR m saved, NPR m NPR m m per annum Year 1 3.68 - 3.68 --3.68 Year 2 111.41 - 111.41 233.81 0 2.90 0 0.18 9.04 0.0065 0.323 18.58 264.84 153.43 - Year 3 455.00 0.96 455.96 236.25 1.17 2.93 0.17 0.18 9.04 0.0065 0.323 18.77 268.83 -187.13 0.29 Year 4 486.54 11.85 498.38 238.68 2.33 2.96 0.33 0.18 9.04 0.0065 0.323 18.97 272.83- 225.55 0.29 Year 5 462.23 23.51 485.74 241.12 3.50 2.99 0.50 0.18 9.04 0.0065 0.323 19.16 276.82- 208.92 0.29 Year 6 442.31 35.81 478.12 243.55 4.66 3.02 0.67 0.18 9.04 0.0065 0.323 19.35 280.81- 197.31 0.29 Year 7 25.75 47.49 73.24 245.99 5.83 3.05 0.83 0.18 9.04 0.0065 0.323 19.55 284.80 211.57 0.29 Year 8 47.49 47.49 248.43 6.99 3.09 1.00 0.18 9.04 0.0065 0.323 19.74 288.80 241.30 0.29 Year 9 47.49 47.49 250.86 8.16 3.12 1.17 0.18 9.04 0.0065 0.323 19.93 292.79 245.30 0.29 Year 10 47.49 47.49 253.30 9.32 3.15 1.33 0.18 9.04 0.0065 0.323 20.13 296.78 249.29 0.29 Year 11 47.49 47.49 255.73 10.49 3.18 1.50 0.18 9.04 0.0065 0.323 20.32 300.78 253.28 0.29 Year 12 47.49 47.49 258.17 11.65 3.21 1.67 0.18 9.04 0.0065 0.323 20.51 304.77 257.27 0.29 Year 13 47.49 47.49 260.60 12.82 3.24 1.67 0.18 9.04 0.0065 0.323 20.71 308.59 261.10 0.29 Year 14 47.49 47.49 263.04 13.98 3.27 1.67 0.18 9.04 0.0065 0.323 20.90 312.42 264.93 0.29 Year 15 47.49 47.49 265.47 15.15 3.31 1.67 0.18 9.04 0.0065 0.323 21.10 316.25 268.75 0.29 Year 16 47.49 47.49 267.91 16.31 3.34 1.67 0.18 9.04 0.0065 0.323 21.29 320.07 272.58 0.29 Year 17 47.49 47.49 270.34 17.48 3.37 1.67 0.18 9.04 0.0065 0.323 21.48 323.90 276.40 0.29 Year 18 47.49 47.49 272.78 18.64 3.40 1.67 0.18 9.04 0.0065 0.323 21.68 327.72 280.23 0.29 Year 19 47.49 47.49 275.22 19.81 3.43 1.67 0.18 9.04 0.0065 0.323 21.87 331.55 284.06 0.29 Year 20 47.49 47.49 277.65 20.98 3.46 1.67 0.18 9.04 0.0065 0.323 22.06 335.37 287.88 0.29 Year 21 47.49 47.49 280.09 22.14 3.50 1.67 0.18 9.04 0.0065 0.323 22.26 339.20 291.71 0.29 Year 22 47.49 47.49 282.52 23.31 3.53 1.67 0.18 9.04 0.0065 0.323 22.45 343.03 295.53 0.29 Year 23 47.49 47.49 284.96 24.47 3.56 1.67 0.18 9.04 0.0065 0.323 22.64 346.85 299.36 0.29 Year 24 47.49 47.49 287.39 25.64 3.59 1.67 0.18 9.04 0.0065 0.323 22.84 350.68 303.18 0.29 Year 25 47.49 47.49 292.26 26.80 3.62 1.67 0.18 9.04 0.0065 0.323 23.22 357.13 309.64 0.29 1,371.41 299.23 1,670.64 Discount rate 9% NPV benefiit 2,450.41 86.40 30.45 9.55 1.76 87.78 0.06 3.14 194.72 2,864.26 6.70 NPV 957.13 NPR m % NPV benefit 85.55% 3.02% 1.06% 0.33% 0.06% 3.06% 0.00% 0.11% 6.80% 100% over the life of IRR 29.13% 289.83 26.80 3.62 40.00 23.03 the project

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G. IEE

Will be submitted under separate cover.

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 257 Feasibility Report: West Rapti Basin

H. GESI Action Plan

Will be submitted under separate cover.

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I. Civil works: Preliminary designs

I.1 Priority areas

I.2 Drawings preliminary design Index

Title DWG No. Sheets Description - WR_OV 1 Overview WR_OV_01 1-3 Overview PRTW.01 WR.001 1 Typical cross section of embankment with revetment 2 Typical spur section WR_LP_001 1-4 Longitudinal Profile PRTW.02 WR_OV_02 1-3 Overview WR.002 1 Typical cross section of revetment 2 Typical cross section of embankment with revetment 3 Typical spur section WR_LP_002 1-4 Longitudinal Profile PRTW.03 WR_OV_03 1-5 Overview WR.003 1 Typical cross section of embankment with revetment 2 Typical spur section WR_LP_003 1-9 Longitudinal Profile PRTW.04 WR_OV_04 1 Overview WR.004 1 Typical cross section of embankment with revetment WR_LP_004 1 Longitudinal Profile PRTW.05 WR_OV_05 1 Overview WR.005 1 Typical cross section of embankment with revetment

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Title DWG No. Sheets Description 2 Typical spur section WR_LP_005 1 Longitudinal Profile PRTW.06 WR_OV_06 1 Overview WR.006 1 Typical cross section of embankment with revetment 2 Typical spur section WR_LP_006 1-2 Longitudinal Profile PRTW.07 WR_OV_07 1 Overview WR.007 1 Typical cross section of embankment with revetment 2 Typical spur section WR_LP_007 1-2 Longitudinal Profile PRTW.08 WR_OV_08 1-5 Overview WR.008 1 Typical cross section of embankment with revetment 2 Typical spur section WR_LP_008 1-8 Longitudinal Profile PRTW.09 WR_OV_09 1 Overview WR.009 1 Typical cross section of embankment with revetment 2 Typical spur section WR_LP_009 1-2 Longitudinal Profile

Drawings

The drawings, A3-size, are submitted under a seperte cover.

383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 260 Feasibility Report: West Rapti Basin

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383877 | REP | 0044 | 10 October 2019 Feasibility Report: West Rapti Basin