Green Roads for Water Guidelines for Road Infrastructure in Support of Water Management and Climate Resilience Frank van Steenbergen, Fatima Arroyo-Arroyo, Kulwinder Rao, Taye Alemayehu Hulluka, Kifle Woldearegay, and Anastasia Deligianni INTERNATIONAL DEVELOPMENT IN FOCUS INTERNATIONAL INTERNATIONAL DEVELOPMENT IN FOCUS Green Roads for Water Guidelines for Road Infrastructure in Support of Water Management and Climate Resilience FRANK VAN STEENBERGEN, FATIMA ARROYO-ARROYO, KULWINDER RAO, TAYE ALEMAYEHU HULLUKA, KIFLE WOLDEAREGAY, AND ANASTASIA DELIGIANNI © 2021 International Bank for Reconstruction and Development / The World Bank 1818 H Street NW, Washington, DC 20433 Telephone: 202-473-1000; Internet: www.worldbank.org Some rights reserved 1 2 3 4 24 23 22 21 Books in this series are published to communicate the results of World Bank research, analysis, and operational experience with the least possible delay. The extent of language editing varies from book to book. 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Contents Acknowledgments xi About the Authors xiii Executive Summary xv Abbreviations xxi PART I SETTING THE STAGE FOR ROADS FOR WATER Introduction 3 References 6 CHAPTER 1 Understanding the Concept and the Potential of Roads for Water 7 Changing the paradigm: Concept and principles of roads for water 7 The three levels of promoting resilience: Protective, adaptive, and proactive 10 The benefits and costs of roads for water 11 Road safety considerations 17 References 19 PART II GEOGRAPHIES AND USES CHAPTER 2 Roads for Watershed Management 23 Key messages and key techniques 23 Objective 23 Opportunities 26 Recommended practices 27 Notes 36 References 37 CHAPTER 3 Rural Roads and Water Supply 39 Key messages and key techniques 39 Objective 39 Opportunities 40 Recommended practices 42 Note 54 References 54 iii iv | GREEN ROADS FOR WATER CHAPTER 4 Roads for Water Harvesting in Semiarid Areas 57 Key messages and key techniques 57 Objective 57 Opportunities 58 General principles 62 Road safety principles 64 Techniques for road-water harvesting 65 Note 77 References 77 CHAPTER 5 Roads for Water in Coastal Lowlands 79 Key messages and main techniques 79 Objective 79 Opportunities 80 Recommended best practices 82 Note 99 References 99 CHAPTER 6 Roads for Water in Mountain Areas 101 Key messages and main techniques 101 Objective 101 Changing the mountain environment 103 Improving the mountain road 106 Notes 120 References 121 CHAPTER 7 Roads in Floodplains 123 Key messages and main techniques 123 Objective 123 Opportunities 124 Recommended practices and preferred options 125 Alternative road option in floodplains: Submersible roads 131 References 132 PART III TECHNIQUES CHAPTER 8 Borrow Pits 135 Key messages and main application 135 Objective 135 Opportunities 136 Recommended practices 138 Note 146 Reference 146 CHAPTER 9 Road Drifts 147 Key messages and main applications 147 Objective 147 Opportunities 148 Recommended practice: River crossings as sand dams and bed stabilizers 149 Construction 155 Notes 156 References 156 CHAPTER 10 Water Harvesting and Drainage from Unpaved Roads 157 Key messages and main applications 157 Objective 157 Contents | v Opportunities 159 Recommended practices 160 References 168 CHAPTER 11 Roadside Farm Ponds 169 Key message and key application 169 Objective 169 Opportunities 169 Recommended practices 171 References 181 CHAPTER 12 Roadside Tree Planting 183 Key messages and key applications 183 Objective 183 Opportunities 185 Recommended practices 186 Site selection 187 Species selection 190 Site preparation 190 Design of roadside vegetative barriers 191 Combining water harvesting and tree planting 193 Conclusions 198 Note 200 References 200 CHAPTER 13 Protecting Roads from Water 201 Key messages and key technique 201 Objectives 201 Impact of water 202 Mitigation measures 203 Roads as dams 204 Recommended practices 204 PART IV MANAGEMENT CHAPTER 14 Making It Work: Governance for Green Roads for Water 207 Key messages 207 Objectives 207 Governance for roads for water 208 Improved working methods for roads for water 210 Getting the process going 212 Annex 14A. Sample supplemental terms of reference for road programs 214 Note 215 CHAPTER 15 Making It Work: Community Engagement 217 Key messages 217 Objective 217 Scope for community engagement 218 Community engagement methods 221 Examples of community engagement at scale 227 Conclusions 234 References 234 Appendix A Participatory Rural Appraisal 237 vi | GREEN ROADS FOR WATER Boxes 1.1 Principles of roads for water 8 1.2 Examples of benefits and costs of roads for water around the world 14 3.1 Taanka or water cistern in Rajasthan, India 46 3.2 One Million Cisterns program in Brazil 47 3.3 Cistern program in Hezhang County, China 48 3.4 Advantages and disadvantages of spring protection schemes 50 4.1 Road-water harvesting campaigns in Ethiopia: Mobilizing millions to increase resilience 60 5.1 Controlling rice cultivation with dual-purpose culverts in Liberia 88 5.2 Repairing embankments using Green Soil Bags 95 6.1 Green Roads cut and fill method explained 108 6.2 Warping dams 118 8.1 Converting a gravel pit into an infiltration structure in Italy 137 8.2 Slope of the converted borrow pit 140 8.3 Calculating the size of converted borrow pits: Supply and demand 142 9.1 Sand dams 149 10.1 Creating youth employment with sand harvesting 160 10.2 Connecting drainage cuts to farm trenches in Mozambique 162 11.1 Growing grapes with road water in Bolivia 170 11.2 Siting of a roadside farm pond 175 11.3 Controlling sedimentation and contamination 179 12.1 Advantages of roadside vegetation