NATURE-BASED SOLUTIONS FOR BUILDING RESILIENCE IN TOWNS AND CITIES Case Studies from the Greater Mekong Subregion ASIAN DEVELOPMENT BANK Creative Commons Creative Commons Attribution-NonCommercial-NoDerivs 3.0 IGO license (CC BY-NC-ND 3.0 IGO) © 2016 Asian Development Bank 6 ADB Avenue, Mandaluyong City, 1550 Metro Manila, Philippines Tel +63 2 632 4444; Fax +63 2 636 2444 www.adb.org Some rights reserved. Published in 2016. Printed in the Philippines. ISBN 978-92-9257-657-8 (Print), 978-92-9257-658-5 (e-ISBN) Publication Stock No. TIM168331 Cataloging-In-Publication Data Asian Development Bank. Nature-based solutions for building resilience in towns and cities: Case studies from the Greater Mekong Subregion. Mandaluyong City, Philippines: Asian Development Bank, 2016. 1. Climate change resilience. 2. Nature-based adaptations. 3. Greater Mekong Subregion. i. Asian Development Bank. 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Printed on recycled paper Contents Foreword xi Message from the Nordic Development Fund xiii Acknowledgments xv Climate Change Core Groups Involved in Preparing the Resource Kit xv Mekong Resource Kit Partner Organizations xvi Cambodia xvi Viet Nam xvi Lao People’s Democratic Republic xvii International Organizations xvii Introduction 1 I.1 Purpose of This Publication 1 I.2 Trends and Regional Context for the Project 1 I.3 The Greater Mekong Subregion Climate Resilience in Cities Project 3 I.3.1 Economic Corridor Towns 3 I.3.2 Town Climate Change Core Groups as the Engines for Innovation 3 I.3.3 Output 1: Knowledge-Sharing Workshops and Policy Dialogue 5 I.3.4 Output 2: Resource Kit 7 1 Nature-Based Solutions for Sustainable and Resilient Mekong Towns 9 1.1 Principles for Applying Green Infrastructure to Build Resilience in Mekong Towns 9 1.2 Ten Strategies for Green Infrastructure and Nature-Based Solutions to Town Development 12 1.3 Lessons Learned by the Climate Change Core Groups in Battambang, Dong Ha, and Kaysone Phomvihane 15 iv Contents 1.4 Conclusion 18 Bibliography 19 2 Green Infrastructure for Resilient Mekong Towns 21 2.1 Introduction 21 2.2 Infrastructure Matrix 21 2.3 Water and Flood Management 23 2.3.1 Constructed Wetlands 23 2.3.2 Drainage Corridors 23 2.3.3 Permeable Paving 24 2.3.4 Rainwater Harvesting 25 2.3.5 Stormwater Tree Pits 26 2.3.6 Urban River Terracing 27 2.4 Slope Stabilization 28 2.4.1 Brush Mattress 28 2.4.2 Live Cribwalls 29 2.4.3 Live Fascines 29 2.4.4 Live Fencing 30 2.4.5 Live Staking 31 2.4.6 Log Terracing 32 2.4.7 Palisades 33 2.4.8 Vegetated Gabions 33 2.4.9 Vegetated Geotextiles 34 2.4.10 Vegetated Revetments 36 2.4.11 Vegetated Riprap 36 2.4.12 Vetiver Grass 37 2.5 Pollution Management 38 2.5.1 Bioretention Ponds 38 2.5.2 Bioswales 38 2.5.3 Graywater Recycling 39 2.5.4 Rain Gardens 40 2.6 Energy, Heat, and Greenhouse Gas Management 41 2.6.1 Green Roofs and Walls 41 2.6.2 Solid Waste Management 41 2.6.3 Urban Tree Canopy 45 Contents v 2.7 Case Studies 46 2.7.1 Balephi, Nepal 46 2.7.2 Ho Chi Minh City, Viet Nam 49 2.7.3 Pasig River, Philippines 51 2.7.4 Putrajaya, Malaysia 53 2.7.5 Seoul, Republic of Korea 56 2.7.6 Sydney, Australia 59 2.7.7 Veracruz, Mexico 62 2.7.8 Case Study Sources 62 2.8 Additional Reading 63 3 Urban Planning for Building Resilient Mekong Towns 65 3.1 Building Resilience through Urban Planning 65 3.1.1 Why Urban Planning? 65 3.1.2 Problems with Current Mekong Urban Planning 66 3.1.3 Objectives of This Chapter 67 3.2 Urban Planning for Resilience: Five Guiding Principles 67 3.2.1 Guiding Principle 1: Protecting, Rehabilitating, and Mimicking Natural Systems 68 3.2.2 Guiding Principle 2: Water Conservation and Wise Management 72 3.2.3 Guiding Principle 3: Energy Conservation and Wise Management to Reduce Reliance on Fossil Fuels 76 3.2.4 Guiding Principle 4: Sustainable Design in Buildings and Sites 78 3.2.5 Guiding Principle 5: Transit-Oriented Design 82 3.3 Urban Planning for Climate Resilience: Essential Components and Support Systems 85 3.3.1 Building Resilience and Sustainability into the Town Development Vision 85 3.3.2 Building Resilience and Sustainability into the Town Strategy 88 3.3.3 Building Resilience and Sustainability into Local Area Plans 91 3.3.4 Building Resilience and Sustainability into Development Controls 94 3.3.5 Development Review Process 100 3.3.6 Impact Assessment as a Tool in Development Control 101 3.3.7 Indicators of Green Performance (Sustainability and Resilience) 103 3.4 Conclusions 106 3.5 Additional Reading 106 vi Contents 4 Vulnerability Assessment and Adaptation Planning Guide for Building Resilient Mekong Towns 109 4.1 Introduction 109 4.2 Vulnerability Assessment and Adaptation Steps 110 4.3 Impact and Vulnerability Assessment 111 Step 1: Determining the Scope and Target Infrastructure Assets 111 Step 2: Conducting the Baseline Assessment 113 Step 3: Assessing the Impacts of Climate Change on Your System 115 Step 4: Assessing the Capacity to Avoid or Recover from the Impacts 118 Step 5: Scoring and Ranking Vulnerability 119 4.4 Adaptation Planning 121 Step 6: Identifying Adaptation Options to Address Impacts 121 Step 7: Defining the Priority Adaptation Measures 124 Step 8: Preparing the Adaptation Plan and Supporting Measures 128 4.5 Adaptation Implementation and Feedback 129 Step 9: Designing and Constructing Adaptation Measures 129 Step 10: Monitoring, Maintenance, and Repair 130 Step 11: Adaptation Phasing, Adjustment, and Retrofitting 132 Step 12: Replicating and Upscaling 132 4.6 Optional Steps and Tools for Large-Scale Plans and Projects 133 4.7 Additional Reading 135 Case Study 1: Building Climate Change Resilience in Battambang, Cambodia 137 5.1 Overview 137 5.2 The Work of the Climate Change Core Group 137 5.3 Case Studies 138 5.3.1 River Embankments 139 5.3.2 Railway and Surrounding Wetland Settlements 139 5.4 Key Conclusions and Lessons Learned 140 5.5 Battambang Core Group Members 141 Contents vii Case Study 2: Building Climate Change Resilience in Kaysone Phomvihane 143 6.1 Overview 143 6.2 Case Study Site 1: Southern Floodgate and Canal 143 6.3 Case Study Site 2: Savanxay Market 144 6.4 Key Conclusions and Lessons Learned 144 Case Study 3: Building Climate Change Resilience in Dong Ha 147 7.1 Case Study Site 1: The Box Canal and Drainage Basin of Ward 5 147 7.2 Case Study Site 2: The Market-to-Port Zone 148 7.3 Lessons Learned 149 Appendixes 151 Appendix 1: Baseline Assessment Field Report Template 151 Appendix 2: Vulnerability Assessment Field Report Template 154 Appendix 3: Vulnerability Assessment Matrix 155 Appendix 4: Adaptation Planning Matrix 157 Appendix 5: Vulnerability Assessment Scoring Tools 158 Appendix 6: Vulnerability Assessment Report Contents Description 159 Appendix 7: Monitoring and Evaluation Framework 160 Appendix 8: Tools Supporting the Vulnerability Assessment and Adaptation Process 161 Appendix 9: Approach to Economic Analysis of Adaptation Options 165 A9.1 Introduction 165 A9.2 Methods 166 A9.3 Conclusions 169 Appendix 10: Glossary 170 viii Contents Tables 1 Total and Urban Populations in the Greater Mekong Subregion, 2010–2030 2 2.1 Green Infrastructure Techniques and Development Needs Matrix 22 2.2 Slope Stabilization Combination Matrix 28 2.3 Solid Waste Management Techniques 42 2.4 Overall Biodiversity, 2003 (Prerestoration) vs 2008 58 3.1 Why Urban Planning and Management is a Good Framework for Promoting Green Infrastructure 66 3.2 Content of the Policy Instrument Supporting the Land-Use Zone Map 95 3.3 Safeguards Dealing with Flooding and Environmental Considerations 97 3.4 Most Common