HYDROGEOLOGICAL HAZARD SUSCEPTIBILITY AND COMMUNITY RISK PERCEPTION IN RWANDA : a case... study of floods and landslides

This book employs qualitative and quantitative methods to assess and scrutinize the impacts of climatic, topographic, land use, hydrologic and geologic factors on the hydrogeological disasters particularly flood and landslide in Rwanda. The hydrogeological hazard susceptibility and its spatial distribution is also mapped by integrating geospatial techniques and mathematical modeling approach through remote sensing and Geographical Information System (GIS). On the other hand, questionnaires and interview are used to evaluate the community's perception on the risk of hazards. The results unveiled different zones most susceptible to the incidence of both hazards as well as their main contributing factors. Furthermore, the results revealed that the government is perceived as responsible for all mitigation measures instead of being a shared responsibility, a perception that may also contribute to the increase in susceptibility. Therefore, it is necessary to deliver the extent of disaster-related courses and trainings in both schools (from primary to tertiary level) and local community members, which helps improving the public's awareness, understanding and ability by providing a new perspective toward disaster prevention and reduction. The book provides a reference for interested readers to understand the natural and human geography of Rwanda, the distribution of hydrogeological disasters, and the policy-making of disaster prevention and reduction. Preface Acknowledgments Contents Abbreviations Part I: Hydrogeological Hazard Susceptibility Chapter 1: Introduction References Chapter 2: Basic Information on Hydrogeological Hazards (Flood and Landslide) 2.1 Key Concepts Definitions 2.1.1 Hazard 2.1.2 Risk 2.1.3 Flood 2.1.4 Landslide 2.1.5 Susceptibility 2.2 Types of Floods and Landslides 2.2.1 Major Types of Floods (a) Flash Flood (b) Riverine Flooding (c) Coastal Flood (d) Urban Floods 2.2.2 Major Types of Landslides (a) Rotational Slides (b) Translational Slides (c) Topple (d) Deep-Seated Landslide (e) Shallow Landslide 2.3 Causes of Floods and Landslides 2.3.1 Climate Change 2.3.2 Atmospheric Precipitation 2.3.3 The Topography of the Area 2.3.4 Urbanization and Land Use Change 2.4 Impacts of Floods and Landslides 2.4.1 Agriculture and Food Security 2.4.2 Human Settlement and Infrastructure 2.4.3 Water and Sanitation 2.4.4 Health and Nutrition 2.4.5 Education 2.4.6 Infrastructure 2.5 Hydrogeological Hazards Profile and Susceptibility Context in Rwanda 2.6 Historical Records References Chapter 3: Description of Rwanda 3.1 Location and Administrative Division 3.2 Demography 3.2.1 Relief and Topography 3.2.2 Climate 3.2.3 Hydrology 3.2.4 Economy References Chapter 4: Data Preparation for Hazards ́ Modeling and Mapping 4.1 Hazards Inventory System 4.2 Influencing Factors for Floods and Landslides Occurrence 4.2.1 Altitude 4.2.2 Slope Gradient 4.2.3 Aspect (Slope Orientation) 4.2.4 Curvature (Slope Curve) 4.2.5 Proximity to Rivers 4.2.6 Proximity to Roads 4.2.7 Topographic Wetness Index (TWI) 4.2.8 Stream Power Index (SPI) 4.2.9 Sediment Transport Index (STI) 4.2.10 Normalized Difference Vegetation Index (NDVI) 4.2.11 Land Use Land Cover (LULC) 4.2.12 Soil Texture 4.2.13 Rainfall 4.2.14 Lithology 4.3 Multicollinearity Analysis References Chapter 5: Susceptibility Modeling and Mapping 5.1 Flood Susceptibility Modeling and Mapping 5.1.1 Methods: The Multivariate Logistic Regression (LR) Model 5.1.2 Spatial Correlation Between Influencing Factors and Flood Occurrence 5.1.3 Flood Susceptibility Mapping (FSM) 5.2 Landslide Susceptibility Modeling and Mapping 5.2.1 Methods: The Bivariate Frequency Ratio (BFR) Model 5.2.2 Spatial Correlation Between Influencing Factors and Landslide Occurrence per Class 5.2.3 Prognostic Weights and Ranking of the Factors Based on their Influence Level 5.2.4 Susceptibility Mapping for Landslide 5.3 Models ́ Accuracy and Validation 5.4 Limitations and Uncertainties References Part II: Community Perception on Flood and Landslide Risk Chapter 6: Introduction References Chapter 7: Local Community Sampling and Questionnaire Chapter 8: Local Community Perception 8.1 Experience and Belief Toward the Risk and Mitigation 8.2 Capacity, Concern and Responsibility 8.3 Mitigation Initiatives and Mechanisms References Part III: General Conclusion and Recommendations Chapter 9: Conclusion Chapter 10: Recommendations 10.1 The Government (Ministry in Charge) 10.2 The Local Community 10.3 Future Research