Consultant Report Project Number: 45206-001 September 2020 Nepal: Water Resources Project Preparatory Facility FINAL REPORT 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 Final Report 21 January 2020 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-Reports/FinalFlood Report/Final Final Submission/210120 WRPPF_Final Report.docx Risk ManagementMott MacDonald Project, Nepal Final Report 21 January 2020 Mott MacDonald Limited. Registered in England and Wales no. 1243967. Registered office: Mott MacDonald House, 8-10 Sydenham Road, Croydon CR0 2EE, United Kingdom Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal Final Report Issue and Revision Record Revision Date Originator Checker Approver Description 0 15/11/19 Consultants L. Akindiji C. Hetmank 1st submission (Draft Final) Team C. Hetmank E. Klaassen A. Choudhury 1 15/01/20 L Akindiji A C Hetmank 2nd submission (Final) C Eller Choudhury 2 21/01/20 L Akindiji A C Hetmank Revised to include updated Choudhury economics figures Document reference: 383877 | REP | 0062 Information class: Standard This document is issued for the party which commissioned it and for specific purposes connected with the above- captioned project only. It should not be relied upon by any other party or used for any other purpose. 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Fo r t he av oida nce o f do ubt t his Re port do es no t in any way pu rpo rt to includ e a ny leg al, ins ura nce or fin ancial advic e or opini on. 383877 | REP | 0062 | 21 January 2020 Final Report Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal Final Report Contents Executive summary 3 1 Introduction 3 1.1 Rational 3 1.2 Impact and Outcome 5 1.3 Outputs 6 1.4 Purpose of this report 6 2 Methodology 7 2.1 Introduction 7 2.2 Innovative and nature-based solutions 7 2.3 Hydrological and hydrodynamic modelling 8 2.3.1 Hydrological modelling 8 2.3.2 Hydrodynamic modelling 10 2.3.3 Design strategy of hydraulic structures for flood mitigation 12 2.4 Flood Forecasting and Early Warning Systems (FFEWS) 15 2.4.1 Understanding FFEWS Needs and River Regime in Basins 15 2.4.2 Flood Forecasting Modelling Framework 15 2.4.3 Assessment of Hydro-Meteorological Data and Gauging Network 15 2.4.4 Flood Forecasting Model Development 16 2.5 Community Based Disaster Risk Management 16 2.5.1 CBDRM Components 17 2.5.2 Management and Implementation of CBDRM 17 2.6 Methodology for Financial and Economic Analysis 18 3 Summary of project results 19 3.1 Introduction 19 3.2 Mawa – Ratuwa Basin 20 3.2.1 Location 20 3.2.2 Civil works 21 3.2.3 FFEWS and CBDRM 24 3.2.4 Safeguards 32 3.3 Bakraha Basin 33 3.3.1 Location 33 3.3.2 Civil works 34 3.3.3 FFEWS and CBDRM 37 3.3.4 Safeguards 44 3.4 Lakhandei Basin 45 3.4.1 Location 45 3.4.2 Civil works 46 383877 | REP | 0062 | 21 January 2020 Final Report Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal Final Report 3.4.3 FFEWS and CBDRM 50 3.4.4 Safeguards 57 3.5 East Rapti Basin 58 3.5.1 Location 58 3.5.2 FFEWS and CBDRM 59 3.5.3 Safeguards 64 3.6 West Rapti Basin 65 3.6.1 Location 65 3.6.2 Civil works 67 3.6.3 FFEWS and CBDRM 69 3.6.4 Safeguards 75 3.7 Mohana – Khutiya Basin 76 3.7.1 Location 76 3.7.2 Civil works 77 3.7.3 FFEWS and CBDRM 79 3.7.4 Safeguards 86 4 Cost Benefit Analysis 88 4.1 Introduction 88 4.1.1 Approach to Estimation of Sub Project Benefits 88 4.2 CBA Mawa – Ratuwa Basin 89 4.2.1 Subproject Interventions 89 4.2.2 Beneficiaries 91 4.2.3 Mawa Ratuwa Benefits 92 4.2.4 Mawa Ratuwa Project Costs 92 4.2.5 Results of Economic Analysis 93 4.3 CBA Bakraha Basin 94 4.3.1 Subproject Interventions 94 4.3.2 Beneficiaries 94 4.3.3 Benefits 95 4.3.4 Costs 96 4.3.5 Results of the Economic Analysis 96 4.4 CBA Lakhandei Basin 97 4.4.1 Subproject Interventions 97 4.4.2 Benefits 98 4.4.3 Benefits Not Quantified 98 4.4.4 Costs 98 4.5 CBA East Rapti Basin 99 4.5.1 Subproject Interventions 99 4.5.2 Beneficiaries 99 4.5.3 Benefits 99 4.5.4 Costs 100 4.6 CBA West Rapti Basin 101 4.6.1 Sub Project Interventions 101 4.6.2 Beneficiaries 102 383877 | REP | 0062 | 21 January 2020 Final Report Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal Final Report 4.6.3 Benefits 102 4.6.4 Costs 103 4.6.5 Results of the Economic Analysis 103 4.7 CBA Mohana – Khutiya Basin 104 4.7.1 Sub Project Interventions 104 4.7.2 Beneficiaries 106 Source: Consultants’ flood modelling results 106 4.7.3 Benefits 106 4.7.4 Costs 107 4.7.5 Results of Economic Analysis 108 4.8 CBA whole project 109 4.8.1 Subproject Benefits 109 4.8.2 Project Costs 1 4.8.3 Results of Economic Analysis 1 4.8.4 Distribution Analysis and Poverty Assessment 2 5 Deliverables 2 6 Implementation arrangements 4 6.1 Implementation organisation 4 6.2 Responsibilities 5 6.3 Implementation plan 11 7 Design Monitoring Framework 1 Appendices 6 A. Location of Priority Structures 7 A.1 Mawa Ratuwa 7 A.2 Bakraha 18 A.3 Lakhandei 22 A.4 West Rapti 26 A.5 Mohana Khutiya 29 B. Cost Benefit Analysis Results 37 B.1 Mawa Ratuwa Cost Benefit Analysis Results 37 B.2 Bakraha Cost Benefit Analysis Results 38 B.3 West Rapti Cost Benefit Analysis Results 39 B.4 Mohana Khutiya Cost Benefit Analysis Results 40 B.5 Whole Project Cost Benefit Analysis Results 41 383877 | REP | 0062 | 21 January 2020 Final Report Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 1 Final Report List of abbreviations ADB - Asian Development Bank ADCP - Acoustic Doppler Current Profiler BCR - Benefit Cost Ratio CBA - Cost Benefit Analysis CBDRM - Community Based Disaster Risk Management CBS - Central Bureau of Statistics CNP - Chitwan National Park DEM - Digital Elevation Model DGPS - Differential Global Positioning System DHM - Department of Hydrology and Meteorology DWRI - Department of Water Resources and Irrigation DP - Displaced People DPR - Detailed Project Report DWIDM - Department of Water Induced Disaster Management EARF - Environmental Assessment & Review Framework EIRR - Economic Internal Rate of Return EPR - Environmental Protection Rule 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 GSM - Global System for Mobile communication HEC-HMS - Hydrologic Engineering Center - Hydrologic Modelling System HEC-RAS - Hydrologic Engineering Center - River Analysis System IEE - Initial Environmental Examination IP - Indigenous People LARIP - Land Acquisition, Resettlement and Indigenous People MEWRI - Ministry of Energy, Water Resources and Irrigation MoF - Ministry of Finance MoHA - Ministry of Home Affairs NPR - Nepalese Rupee NPV - Nett Present Value PAM - Project Administration Manual PEP - People Embankment Program PIU - Project Implementation Unit PMU - Project Management Unit PRTW - Proposed River Training Works Q - Discharge RCP - Representative Concentration Pathways RRP - Report and Recommendation of the President SCF - Standard conversion factor SERF - Shadow Exchange Rate Factor SWRF - Shadow Wage Rate Factor TA - Technical Assistance UK - United Kingdom USD - Unites States Dollar 383877 | REP | 0062 | 21 January 2020 Final Report Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 2 Final Report VAT - Value Added Tax WL - Water level WRPPF - Water Resources Project Preparatory Facility 383877 | REP | 0062 | 21 January 2020 Final Report Mott MacDonald | WRPPF: Preparation of Priority River Basins Flood Risk Management Project, Nepal 3 Final Report Executive summary Introduction Nepal’s low level of development and complex topography renders the country highly vulnerable to climate change impacts and it is prone to natural hazards.