Title page 1

Contents 4

Foreword 10

Acknowledgments 11

Abbreviations and Acronyms 12

Executive Summary 14

PART I: Conceptual Framework 19

Chapter 1. Why Risk-informed Urban Planning? 20

1.1. Risk-informed Urban Planning for Livable and Resilient Cities 23

1.2. Enabling Environment 32

1.3. Risk-informed Urban Planning Measures 38

Chapter 2. Understanding Urban Risk for Risk-informed Urban Planning 45

2.1. The Interplay Between Urbanization and Risk 46

2.2. Urbanization: A Driver of Risks or a Driver of Resilience 48

2.3. Definition and Classification of Natural Hazards 54

2.4. Assessing Hazards, Exposure, and Vulnerability 57

2.5. Methods for Risk Assessment and Mapping 61

2.6. The Concept of Acceptable Levels of Risk for Urban Planning 67

PART II: Process and Instruments for Planning and Implementation 74

Chapter 3. Operational Framework: Embedding Hazard and Risk Information in Urban Plans 75

3.1. Phase 1. Context Assessment and Diagnosis 77

3.2. Phase 2. Plan Formulation 82

3.3. Phase 3. Implementation, Monitoring, and Evaluation 97

Chapter 4. Instruments, Enforcement, Monitoring, and Evaluation 100

4.1. Regulatory and Incentive Instruments 101

4.2. Financial and Land Management Tools 105

4.3. Capacity Building and Public Engagement 113

4.4. Enforcement, Monitoring, and Evaluation 117

PART III: Integration of Different Types of Hazards and Risks Into Urban Plans 120

Chapter 5. Hydrometeorological Hazards: Floods 121

5.1. Flash Floods 127

5.2. Pluvial Floods 130

5.3. Riverine Floods 135

5.4. Coastal Floods 141

Chapter 6. Geohazards 150

6.1. Shallow Geohazards: Mass Movements 151

6.2. Earthquakes 164

6.3. Volcanic Processes 178

Chapter 7. Climatological Hazards 191

7.1. Extreme Heat, Heat Waves, and Urban Heat Islands 192

7.2. Urban Droughts 197

7.3. Wildfires 202

Key Takeaways 210

References 212

Tables 8

Table 1.1. An Example of a Risk-informed Urban Planning Stakeholder Map 34

Table 1.2. Spatial Planning Scales 35

Table 1.3. Hazard Categories 39

Table 2.1. Qualitative and Quantitative Risk Assessment Methods 61

Table 2.2. Probabilistic Quantitative Methods 64

Table 2.3. Scales Commonly Used in Hazard and Risk Mapping and Example Applications 66

Table 4.1. Examples of Market-Based Financial Instruments 113

Table 4.2. Summary of Instruments 115

Table 4.3. Information Required to Monitor the Risk-informed Urban Plan 118

Table 4.4. Sample Data for a Specific Target 119

Table 5.1. Flood-risk Assessment Methods and Data Requirements by Scale and Level of Detail 125

Table 5.2. A Summary of the Characteristics and Impacts of Flash Floods 128

Table 5.3. A Summary of the Characteristics and Impacts of Pluvial Flooding 131

Table 5.4. A Summary of the Characteristics and Impacts of Riverine Flooding 136

Table 5.5. A Summary of the Characteristics and Impacts of Coastal Flooding 142

Table 5.6. Examples of "Restrict" Measures for Flood-risk-informed Urban Planning 144

Table 5.7. Examples of "Condition" Measures for Flood-risk-informed Urban Planning 146

Table 5.8. Examples of "Promote" Measures for Flood-risk-informed Urban Planning 148

Table 6.1. A Summary of the Characteristics and Impacts of Landslides 155

Table 6.2. A Summary of the Characteristics and Impacts of Fluid-Driven Mass Movements 158

Table 6.3. A Summary of the Characteristics and Impacts of Rockfalls 160

Table 6.4. A Summary of the Characteristics and Impacts of Earthquakes 166

Table 6.5. A Summary of the Characteristics and Impacts of Liquefaction 168

Table 6.6. A Summary of the Characteristics and Impacts of Tsunamis 170

Table 6.7. A Summary of the Characteristics and Impacts of Volcanoes 181

Table 6.8. Examples of "Restrict" Measures for Geohazard Risk-informed Urban Planning 184

Table 6.9. Examples of "Condition" Measures for Geohazard Risk-informed Urban Planning 186

Table 6.10. Examples of "Promote" Measures for Geohazard Risk-informed Urban Planning 189

Table 7.1. A Summary of the Characteristics and Impacts of Extreme Heat 193

Table 7.2. Characteristics and Impacts of Droughts 198

Table 7.3. A Summary of the Characteristics and Impacts of Wildfires 203

Table 7.4. Examples of "Restrict" Measures for Climatological Risk-informed Urban Planning 205

Table 7.5. Examples of "Condition" Measures for Climatological Risk-informed Urban Planning 207

Table 7.6. Examples of "Promote" Measures for Climatological Risk-informed Urban Planning 208

Figures 6

Figure ES.1. Risk-informed Urban Planning Approach 15

Figure ES.2. Risk-informed Urban Planning Goals for Achieving Livable and Resilient Cities 16

Figure 1.1. A Comparison of the Global Population Living in Urban Areas in 1960 and 2022 20

Figure 1.2. Cities' Exposure to Natural Hazards 21

Figure 1.3. Urbanization and Risk: Overview of Urban Areas by Region 22

Figure 1.4. Risk-informed urban planning primary concepts 24

Figure 1.5. Basic Components of Spatial Plans 24

Figure 1.6. Risk-informed Urban Planning Principles 25

Figure 1.7. Risk-informed Urban Planning: Interconnected Goals 29

Figure 1.8. Key Elements of an Enabling Environment for Risk-informed Urban Planning 32

Figure 1.9. An Example of a Governance Structure for Risk-informed Urban Planning 33

Figure 1.10. Factors of Disaster Risk 38

Figure 1.11. Hazard-Based Planning in Undeveloped Areas 41

Figure 1.12. Risk-based Planning in Developed Areas 42

Figure 1.13. Restrict, Condition, and Promote Measures for Risk-informed Urban Planning 42

Figure 2.1. Interplay between Urbanization and Risk 48

Figure 2.2. Safe versus Risky Growth: Relative Difference between Settlement Growth in Safe and High-Risk Areas, 1985-2015 49

Figure 2.3. Examples of Common Hazards and their Interactions 55

Figure 2.4. Common Indicators for Exposure Assessments 59

Figure 2.5. Relevant Vulnerability Dimensions 60

Figure 2.6. Example Matrix for Determining Minimum Level of Detail Required for Land-use or Subdivision Consent in New Zealand 66

Figure 2.7. Example of Potential Building Zone in a High-Hazard Area and Illustration of the Proposed Solutions 72

Figure 3.1. Operational Framework for Risk-informed Urban Planning 76

Figure 3.2. Step 0. Preliminary Analysis and Key Entry Points 77

Figure 3.3. Step 1. Screen Hazards, Risks, and Urban Dynamics 79

Figure 3.4. Step 2. Hazard and Risk Mapping 83

Figure 3.5. Step 3: City Visioning and Appraisal of Options 85

Figure 3.6. Step 4. Risk-informed Urban Planning Decisions - RCP framework 90

Figure 3.7. Step-by-Step Decision Process for the RCP Framework 93

Figure 3.8. Step 5. Risk-informed Urban Planning Instruments 96

Figure 3.9. Step 6. Implementation of Instruments According to Local Capacities 98

Figure 4.1. Integration of Instruments in the Spatial Planning Phases 100

Figure 4.2. Graduated Planning Controls Developed in Hawkesbury-Nepean Valley, Australia 102

Figure 4.3. Examples of Incentives for Compliance 105

Figure 4.4. Transfer of Development Rights 108

Figure 4.5. Example of Land Readjustment 109

Figure 4.6. Mandatory Land Transfer for Public Space and Urban Facilities 110

Figure 5.1. Coastal, Pluvial, and Fluvial Floods and Their Impact Characteristics 122

Figure 5.2. Flood Hazard and Risk Mapping Flow Chart for Different Assessment Levels and Intended Applications 124

Figure 5.3. Risk-informed Planning Measures Along the River Basin 126

Figure 5.4. Effects of Urbanization and Flood Control Measures on Flow Velocity 128

Figure 5.5. Illustration of Pluvial Flood and Urban Drainage System Collapse 131

Figure 5.6. Coastal Flood Risk Under Current and Future Climate Projections 142

Figure 6.1. Example Process for Mass Movement Hazard Zoning 153

Figure 6.2. Example Process for Mass Movement Hazard for Risk-informed Urban Planning 154

Figure 6.3. An Illustration of Common Proximal Volcanic Hazards 181

Boxes 8

Box 1.1. Risk-informed Urban Planning as a Driver for Economic Growth in Beira, Mozambique 27

Box 1.2. Nature-based Solutions for Risk-informed Urban Planning 30

Box 2.1. Informal Settlement Upgrading and Urban Resilience in Kigali, Rwanda 51

Box 2.2. Acceptable Levels of Risk in Practice: Context Matters 68

Box 3.1. Flood Hazard and Risk Modeling and Strategic Spatial Planning in Bujumbura, Burundi 87

Box 3.2. Urban Planning Conditioned by Acceptable Risk in Cali, Colombia 93

Box 4.1. Land Value Capture to Fund Flood Resilience in Barranquilla, Colombia 106

Box 4.2. Public and Private Finance to Scale Sustainable Construction in Colombia 111

Box 5.1. Sustainable Drainage Systems 133

Box 5.2. Flood Protection in the Odra River Basin, Poland 139

Box 6.1. Hong Kong's Multitiered Risk-based Approach to Slope Safety 162

Box 6.2. Integrating Seismic Risk Management into Urban Planning. Lessons from Japan 173

Box 7.1. Urban Cooling Solutions in Guangzhou, China 195

Box 7.2. Evidential Learning in Urban Drought Management 200

Photos 50

Photo 2.1. Houses in Kaibata, Indonesia Submerged by the Overflowing of Ciliwung River, 2007 50

Photo 2.2. Devastating Floods and Mudslides in Valencia Province, Spain, 2024 56

Photo 4.1. Construction of Earthquake-resistant Steel Structure in Tokyo 103

Photo 4.2. Women in a community meeting to discuss village reconstruction, Yogyakarta, Indonesia, 2011 114

Photo 5.1. Water Level at the Flooded Abbey Mill in Tewkesbury, England 123

Photo 5.2. The Aftermath of the flash flood, in Donggala, Indonesia, 2025 127

Photo 5.3. The Aftermath of Floods in Kinshasa, Democratic Republic of Congo, 2024 130

Photo 5.4. Aerial view of flooded houses with dirty water of Dnister river, Ukraine, 2020 136

Photo 5.5. Coastal Flood in New Jersey as an effect of Hurricane Sandy, 2012 141

Photo 6.1. Rainfall-Triggered Landslide in the Municipality of Alausi, Ecuador, 2023 155

Photo 6.2. Debris Flow in Soche Mountain, Blantyre City, Malawi, during Tropical Cyclone Freddy, 2023 157

Box Tables 52

Table B2.1.1. Inundation along Wetlands in Kigali (Estimated Current and Future Flood Damage) 52

Table B6.2.1. Seismic Resistance Rates in Yokohama City - Target versus Actual 176

Box Figures 28

Figure B1.1.1. Computed Result for Climate Change Scenario for 2050 With and Without Project Implementation 28

Figure B1.2.1. Examples of NBS Implementation in Cities 30

Figure B2.1.1. Internal Displacement by Conflict and Violence and Country's Vulnerability to Climate Change 51

Figure B2.1.2. NBS Application in the Nyabisindu Settlement Urban Upgrading Area, Kigali 53

Figure B3.1.1. Hazard and Risk Modeling and Strategic Plan for Flood Risk Management in Ruzizi Catchment 89

Figure B3.2.1. Fluvial and Pluvial Hazard Maps 94

Figure B3.2.2/Figure B3.2.1. Section of the Dike Before and After the Plan's Implementation 95

Figure B4.1.1. Main Waterways Flowing into the Magdalena River 106

Figure B4.1.2. Box Culvert Section and Public Works 107

Figure B5.1.1. Reduction of Flooding by Retaining and Gradually Releasing Surplus Water through Quality Control Mechanisms 133

Figure B5.1.2. Improvement of Runoff Water Quality through Environmentally Friendly Strategies 133

Figure B5.1.3. Natural Recharge of Aquifers and Groundwater 134

Figure B5.1.4. Increase of Environmentally Friendly Habitats to Protect Biodiversity and Improve the Quality of Life in Urban Areas 134

Figure B5.1.5. Renaturalization of Riverbanks and Coastal Areas to Preserve the Ecosystem Balance 134

Figure B5.1.6. Restoration of Urban Wetlands to Benefit from Their Natural Water Storage and Flood Regulation Functions 135

Figure B5.1.7. New Green Spaces Designed to Increase Resilience and Biodiversity in Highly Urbanized Areas 135

Figure B6.1.1. Impact of Landslide Risk Reduction Strategies in Hong Kong 163

Figure B6.2.1. Building Communities Resilient to Tsunami 174

Figure B6.2.2. Damage to Building Structures in the Great Hanshin-Awaji Earthquake by Period of Construction 176

Figure B7.1.1. Dimensions and Tools of Urban Cooling Strategies in Guangzhou 196

Figure B7.1.2. Building-Level Cooling Measures 197

Box Photos 29

Photo B1.1.1. Chiveve River Green Infrastructure Project 29

Photo B1.2.1. Kunshan Forest Park West Entry Project 31

Photo B2.2.1. Panoramic View of Manizales 69

Photo B2.2.2. Flood Defense Structure. Longitudinal view on Afsluitdijk, North Holland 70

Photo B3.1.1. Massive Flooding in Gatumba in 2020 88

Photo B4.2.1. Jardines Curazaos Social Housing Project in Apartadó, Colombia 112

Photo B5.2.1. Racibórz Dry Polder in the Odra River, 2025 140

Photo B7.1.1. Aerial View, Guangzhou, 2025 195

Photo B7.2.1. People filling their containers with drinking water from a municipal tanker in Kolkata, India, 2019 201