The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Issue | 27 September 2018 This report takes into account the particular instructions and requirements of our client. It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party. Job number 252746 Ove Arup & Partners International Ltd. 13 Fitzroy Street London W1T 4BQ United Kingdom www.arup.com Document Verification Job title Sierra Leone Multi-City Hazard Review and Risk Job number Assessment 252746 Document title Final Report (Volume 4 of 5): Bo City Hazard and File reference Risk Assessment Document ref Revision Date Filename 20180504_Final_Rep_Bo_City.docx Draft 1 04 May Description Incorporating feedback from Mission #4 and World Bank. 2018 Prepared by Checked by Approved by Name ALM, PR, JB, DB Anna Morley Matthew Free Signature Draft 2 19 Sept Filename 2018 Description Incorporating further comments from World Bank team. Prepared by Checked by Approved by ALM, GC, PR, JB, Name Anna Morley Matthew Free DB Signature Issue 27 Sep Filename 20180927-DOC-05A-V4of5_Bo.docx 2018 Description Prepared by Checked by Approved by Name ALM, GC, PR, JB Anna Morley Matthew Free Signature Issue Document Verification with Document | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Contents Page Summary of Report 6 1 Introduction 37 1.1 Project background 37 1.2 Outline of this report 38 1.3 Maps and data 39 1.4 Limitations to this report 39 2 Bo: City Profile and Context 42 2.1 Introduction 42 2.2 Geographic setting of Bo 42 2.3 Urbanization in Bo 44 2.4 Socio-economics in Bo 47 2.5 Governance in Bo 47 2.6 Resilience challenges in Bo 48 3 Exposure and Vulnerability in Bo 51 3.1 Introduction 51 3.2 Population 51 3.3 Buildings 51 3.4 Roads 52 3.5 Vulnerability 52 4 Flood Hazard and Risk in Bo 56 4.1 Introduction 56 4.2 Overview of qualitative assessment 56 4.3 Overview of quantitative flood hazard and risk assessment 58 5 Landslide Hazard and Risk in Bo 72 5.1 Introduction 72 5.2 Overview of qualitative assessment 72 6 Identification of Areas at Highest Risk 76 6.1 Introduction 76 6.2 Urban development in flood hazard zones 76 7 Opportunities for DRR/DRM in Bo 83 7.1 Introduction 83 7.2 Sendai Framework 83 7.3 General DRR Approaches for Bo 84 | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8 Hazard and Catchment Specific DRR/DRM Measures 100 8.1 Introduction 100 8.2 Flood Hazard Specific DRR/DRM Measures 100 8.3 Flood DRR/DRM recommendations by catchment for Bo 112 9 Recommendations 115 9.1 Recommendations for DRR/DRM Priorities 115 9.2 Recommendations from Stakeholders 116 9.3 Hazard and Risk Research and Development for Bo 117 9.4 Management of Rainfall Run-off in Communities 118 9.5 Call for Action 118 10 References 120 Tables Table 1 – High-hazard hotspots in Bo. Table 2 – Existing development within flood hazard zones Map Bo-0019 (Page 1) Table 3 – Quantitative flood risk to Bo Table 4 – Appropriate DRR/DRM measures for Bo Table 5 – Natural hazard and risk assessment scope in Freetown, Makeni and Bo Table 6 – Approximate urbanised area and built environment expansion rate in Bo. Table 7 – Modelled distribution of building typology in Bo Table 8 – Summary of flood risk for Bo Table 9 – Summary of the flood losses for different return periods for Bo Table 10 – Urban development within flood hazard zones. Table 11 – DRR/DRM for Bo within the context of the Sendai Framework. Table 12 – Flood hazard DRR/DRM options recommended for Bo. Table 13 – Capital and operational costs for Option 1 – Hazard and Risk Communication Table 14 – Risk reduction benefits from Option 1 – Hazard and Risk Communication Table 15 – Cost-Benefit Results for Option 1 – Hazard and Risk Communication Table 16 – Capital and operational costs for Option 2 – Re-sizing of culverts and clearing waste from existing channels Table 17 – Risk reduction benefits from Option 2 – Re-sized culverts and clearing waste from existing channels Table 18 – Cost-Benefit Results for Option 2 – Re-sized culverts and clearing waste from existing channels Table 19 – Summary of Cost-Benefit Results for Bo | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figures Figure 1 – Overview of the key stages in this project. Figure 2 – The relatively flat, low relief of Bo city and surrounding areas, southern province Sierra Leone. Grey lines and stippling indicates the extent of urban roads and the urban area, thicker brown lines are the ward boundaries, thick yellow lines the main highways and thick blue lines are main rivers. Figure 3 – Image of standing flood waters after moderate annual flooding in Bo in March 2017. Figure 4 – Overview of the exposure gridding process: A. Buildings digitised to approximate outline in OpenStreetMap and downloaded into GIS; B. Building location, value and typology are gridded to a 30m regularly spaced grid; and C. This grid is used to facilitate hazard and risk calculations. Light to dark on grid (B. and C.) indicates increasing building density. Field of view is approximately 700m across. Figure 5 – View of a typical residential house in Bo Figure 6 –Schematic illustration of a typical river catchment in Bo and proposed flood hazard DRR/DRM options for Bo. Illustrations of measures adapted from the Sustainable Urban Drainage Manual (Woods- Ballard et al., 2007). Figure 7 – Excerpt from MAP BO-0028, Page 1 showing the 100 year flood mapping and several of the DRR measures proposed for Bo city. Figure 8 – Murals educating communities about Ebola, an example of effective hazard and risk communication in Freetown. Figure 9 – Diagram extracted from the World Bank report “Learning from Mega disasters – Lessons from the Great East Japan Earthquake”. Figure 10 – Simplified geological map of Sierra Leone. Bo city is outlined in black. Source, Ministry of Water Resources/ASI (2015). Figure 11 – Satellite imagery of eastern Bo. The natural river floodplain is covered in green vegetation predominantly in well organised plots indicating farmed land in this image. It is surrounded by buildings and roads, which are pale yellow-orange. Imagery source: Google Earth Pro, 2017. Figure 12 – Satellite images in the southern part of Bo in (a) Year 2003 and (b) Year 2017 showing rapid built environment expansion. Google Earth Pro, 2017. Figure 13 – Example of quantitative flood hazard data viewed in a GIS (river and surface water flooding, 20 year return flood). Area shown is in East Ward - Batiema (see inset map for approximate location). Light blue indicates lower floodwater depth and dark blue indicates greater floodwater depth. Building polygons and road polylines are from the exposure dataset developed as part of this study and derived from OpenStreetMap. Field of view is approximately 1.5km across and oriented north. Figure 14 – Loss exceedance curve (flooding, no. people affected) for Bo (also showing Freetown and Makeni for comparison). Figure 15 – Loss exceedance curve (flooding, no. fatalities) for Bo (also showing Freetown and Makeni for comparison). | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 16 – Loss exceedance curve (flooding, direct loss to all buildings) for Bo (also showing Freetown and Makeni for comparison). Figure 17 – Excerpt of MAP BO-0006 showing the qualitative landslide hazard results. Localised areas of the city where there are hills have higher landslide susceptibility. Figure 18 – Example of qualitative landslide hazard data viewed in a GIS. Area shown is in North Ward - Reservation (see inset map for approximate location). Light pink indicates low qualitative landslide hazard and darker pink indicates high qualitative landslide hazard. Building polygons and road polylines are from the exposure dataset developed as part of this study and derived from OpenStreetMap. Field of view is approximately 1.5km across and oriented north. Figure 19 – Schematic illustration of a river catchment in Bo and proposed flood hazard DRR/DRM options for Bo. Illustrations of measures adapted from the Sustainable Urban Drainage Manual (Woods-Ballard et al., 2007). Figure 20 – The MoSSaiC community based drainage system to reduce flooding and landslide hazard and risk (World Bank Project Insights 78723 Issue #12). Figure 21 – Land readjustment can be an alternative to high-rise construction for densification of safer areas through spot zoning (diagram from https://unhabitat.org/books/remaking-the-urban-mosaic- participatory-and-inclusive-land-readjustment/ ) Appendices Appendix A Cost Benefit Analysis for Bo city Appendix B Natural Hazard and Risk Maps for Bo city | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Acknowledgements The Sierra Leone Multi-City Hazard Review and Risk Assessment would not have been possible without the dedication and support of different partners and stakeholders at national and local levels, who contributed both time and expertise. The assessment was prepared by the Project Team, which consisted of experts from Arup (as the lead organisation), the British Geological Survey (BGS), JBA flood risk consultancy, and the Integrated Geo-information and Environmental Management Services (INTEGEMS) consultancy. Arup wishes to extend great thanks to each member organisation and individual of the Project Team. The dedication, creativity, technical capacity and enthusiasm of the team members made the completion of this project to the best possible quality and practical use possible. The assessment was carried out in partnership with the World Bank, the Government of Sierra Leone, ministries, City and District Councils, and the community. The financial support for this assessment was provided by the Global Facility for Disaster Reduction and Recovery (GFDRR) and the European Union, in the framework of the Africa Caribbean Pacific–European Union Natural Disaster Risk Reduction (ACP–EU NDRR) Program, managed by GFDRR. Arup wishes to acknowledge the World Bank Task Team Leader for this project, Dr. Isabelle Celine Kane, for her commitment, vision, critical feedback, and leadership throughout this project. We would also like to thank a number of other key World Bank staff and consultants for their critical feedback, direction and support in completing this project, including: Deepali Tewari, Sokhna BA, Swati Sachdeva, Robert Reid, and Megha Mukim. We thank Mr. Parminder P. S. Brar, former Country Manager, World Bank Group, for his commitment to the project and in-country support. In addition we thank Gayle Martin, Country Manager and Sheikh Sesay, Operations Officer. Arup would like to extend its appreciation and acknowledge the numerous ministries and organizations for their assistance in granting access to information, providing support to the report and for their availability for discussions during the assessment. The Office of National Security (ONS) played a critical role in co- ordinating in-country meetings and workshops with members of the ministries and councils. We thank Mr. Ismail Sheriff Tarashid Tarawali, National Security Coordinator, Mr. John Vandy Rodgers and Mr Nabie Kamara, and many other senior officials from all participating ministries for their immense contribution to the process. In particular, we would also like to acknowledge Mr. Harold Tucker for his contribution to this project: for introducing us to the city and the problems it faces, connecting us with local passionate engineers who know intimately the problems faced by the city, and sharing his knowledge and his aspirations for a green and sustainable future of the city. During the course of this project, the Regent-Lumley flood and landslide disaster occurred on August 14th 2017 in Freetown. Subsequently, the Project Team spent two weeks in country collaborating with the World Bank and other government representatives and numerous experts from UN agencies and development | Issue | 27 September 2018 Page 1 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment partners to complete a Rapid Damage and Loss Assessment (DaLA). Arup would like to acknowledge and thank the extreme effort and quality contributions from all those involved in this mission, as acknowledged in the official World Bank DaLA Report published following the Disaster1. To all the contributors, the team expresses its deepest gratitude and appreciation, especially to the local communities and affected populations, who experience annual flooding during the wet season, and who experienced the devastating effects of the August 14th Disaster. This report would not have been possible without their trust and engagement. 1 http://documents.worldbank.org/curated/en/523671510297364577/Sierra-Leone-Rapid-damage- and-loss-assessment-of-August-14th-2017-landslides-and-floods-in-the-western-area | Issue | 27 September 2018 Page 2 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Abbreviations and Acronyms AAL Average annual loss ALARP As low as reasonably possible (or practicable) B/C Benefit cost ratio BCC Bo City Council BGS British Geological Survey CIDMEWS Climate Information, Disaster Management, and Early Warning System DaLA Damage and Loss Assessment DR Discount rate EU European Union EPA Environmental Protection Agency FCC Freetown City Council GDP Gross Domestic Product GFDRR Global Facility for Disaster Reduction and Recovery GVWC Guma Valley Water Company INTEGEMS Integrated Geo-information and Environmental Management Services IRR Internal rate of return JBA JBA Consulting is part of the JBA Group, an environmental, engineering and risk group. km Kilometres m a.s.l. Metres above sea level mm Millimetre No. Number MoWR Ministry of Water Resources NGO Nongovernmental organization NMA Nationals Minerals Agency NPAA National Protected Area Authority NPV Net present value ONS Office of National Security | Issue | 27 September 2018 Page 3 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment OSM OpenStreetMap SLL Sierra Leone Leone (currency) SLPP Sierra Leone Peoples Party SuDS Sustainable Urban Drainage UN United Nations UNDP United Nations Development Programme UNICEF United Nations International Children’s Emergency Fund UNOPS United Nations Office for Project Services USD United States Dollar VSL Value of statistical life WASH Water Supply, Sanitation, and Hygiene WFP World Food Programme WHO World Health Organization | Issue | 27 September 2018 Page 4 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 5 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Summary of Report This report provides a summary of the results from a natural hazard and risk assessment undertaken for the city of Bo in Sierra Leone. The key stages of the project are outlined in Figure 1. The report provides guidance to the Government of Sierra Leone and other key stakeholders to prioritise a range of disaster risk reduction (DRR) and disaster risk management (DRM) options that will save lives, reduce the potential for damage to critical buildings and infrastructure, and reduce the potential economic losses caused by flooding and other hazards. Figure 1 – Overview of the key stages in this project. Project Reports Five report volumes have been prepared for this project including: • Volume 1 – Methodology and Summary of Results for all cities. • Volume 2 – Freetown City Hazard and Risk Assessment Hazard • Volume 3 – Makeni City Hazard and Risk Assessment Hazard • Volume 4 – Bo City Hazard and Risk Assessment Hazard • Volume 5 – Map Volume, containing all maps for all cities in A3 page size format. Volumes 2, 3 and 4 should be read in combination with Volumes 1 and 5. | Issue | 27 September 2018 Page 6 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Project Data This project has produced a series of maps that show where the high-hazard and high-risk areas are in Bo. These maps (and tables) also provide quantitative numbers in terms of for example, the modelled depth of floodwaters, the number of fatalities, people affected, and damage to buildings in USD$ that can result from the different natural hazards. The maps have been reduced in size to fit on an A4 page to provide an example of the type of data available from this project for the executive summary and this report. The full series of A3 page size maps are provided separately in Volume 5 of this report. All data (as shown on the maps) are digital and can be viewed at different scales and interrogated interactively using Geographic Information System (GIS) software. The data are also open source, freely available, and will be available for download. | Issue | 27 September 2018 Page 7 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 1 Hazard Natural hazards are “natural processes or phenomena that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage” (UNISDR, 2017). Flooding in Bo Bo is 180km directly southeast of Freetown in the Southern Province in south central Sierra Leone (Figure 2)Bo has been built amongst natural low-lying, low- relief topography, which in combination with the tropical monsoonal climate of the country, forms natural swampland. Bo is particularly susceptible to flooding in the rainy season because the lack of topographic relief results in limited conveyance of floodwaters through the natural swampland drainage network (Figure 3). The low-lying wetlands do provide conditions suitable for wetland crops including rice. The river channels and their floodplains are zones of natural, medium and high flood hazard. Bo city has experienced significant flooding in its recent history. The September 2015 floods, which were caused by widespread torrential rain over the course of 3 days in September 2015, are reported to have impacted over 3,300 people of that total population of Bo of around 175,000. Landsliding is not interpreted to be a significant problem in Bo city. This is because the topographic relief is low. The qualitative landslide hazard assessment indicated that there are localised areas within the city that have high landslide susceptibility. These areas appear to coincide with river embankments, which are likely to become more susceptible to small scale failures/slips during the wet season. Table 1 – High-hazard hotspots in Bo. High Hazard Flood Hazard Hotspot Area The natural river valleys, particularly those in the southeast of the city, including: East Ward-Batiema, East Ward-Bumpeh-Who, East Ward-Messima, East Ward-Gbondo Town, Flooding and East Ward-Manjama. Many of the highest flood-hazard areas are surrounding the main urbanised area of the city. | Issue | 27 September 2018 Page 8 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 2 – The relatively flat, low relief of Bo city and surrounding areas, southern province Sierra Leone. Grey lines and stippling indicates the extent of urban roads and the urban area, thicker brown lines are the ward boundaries, thick yellow lines the main highways and thick blue lines are main rivers. | Issue | 27 September 2018 Page 9 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 3 – Image of standing flood waters after moderate annual flooding in Bo in March 2017. Patterns of High Hazard • Surface and river water flooding: the natural broad, low-lying river channels in the city have been highlighted as high flood hazard areas. Fortunately, some of the areas that have the highest flood-water depth estimates for the 100-year flood event have been identified outside of the main urbanised area of the city e.g. Kpandobu and Sewa in the far east of the study area (MAP BO- 0009 Page 11) • Landsliding: (Map BO-0005, Page 14) | Issue | 27 September 2018 Page 10 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 11 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 12 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Hazard Zones to Inform Urban Planning Map BO-0018 (Page 14) shows the hazard zones for Bo, which are defined by the modelled extent of flood hazard. The current, i.e. present day, hazard zones are shown in dark pink, the lighter pink areas show the extent of the Combined Hazard Zones in the near future (year 2050) accounting for climate change. This map has two key functions for decision makers: • The map indicates the areas of the city at risk from natural hazards currently. These maps can help to inform decision makers where further development should be discouraged, unless appropriate planning and engineering procedures are in place. It also identifies the areas where public awareness with regard to natural hazard and risk should be focussed. • The map indicates that, in the near future (2050), a greater extent of the city will be within hazard zones due to the impact of climate change. This needs to be taken into consideration for urban planning, development and zoning for the city. It would be sensible therefore to increase the density of future urban development in areas of lower hazard and to minimise development in areas of the city where the hazard is highest. It is understood that a wider range of issues need to be taken into consideration by decision makers when planning urban development. This report only provides recommendations related to natural hazard and risk specifically for Bo related to flooding, and to a lesser extent, landsliding. | Issue | 27 September 2018 Page 13 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 14 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 2 Exposure “The situation of people, infrastructure, housing, production capacities and other tangible human assets...” (UNISDR, 2017). Bo is the second largest city in Sierra Leone with a population of around 175,000. It is the major administrative and economic centre of the Southern Province. People, buildings and infrastructure in Bo There are approximately 26,000 buildings and 40km of sealed road and 720km of unsealed road in Bo city. This project has generated a digital exposure model for Bo. The model provides a spatial inventory of population, buildings, and roads aggregated to a 30m x 30m grid (Figure 4). The grid scale of the exposure model is appropriate to assess city- wide hazard and risk. Figure 4 – Overview of the exposure gridding process: A. Buildings digitised to approximate outline in OpenStreetMap and downloaded into GIS; B. Building location, value and typology are gridded to a 30m regularly spaced grid; and C. This grid is used to facilitate hazard and risk calculations. Light to dark on grid (B. and C.) indicates increasing building density. Field of view is approximately 700m across. Map BO-0003 (Page 16) shows the built environment density of Bo modelled by this project. Darker grey areas indicate parts of the city where the building density is greater. Map BO-0003 (Page 11) shows how the urban landscape of Bo has developed over time between 2006 to 2017. | Issue | 27 September 2018 Page 15 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 16 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 17 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Patterns of exposure This study has provided, for the first time, digital, spatially accurate datasets at city-scale documenting the locations and lengths of the sealed and unsealed roads in Bo city, and the estimated number of individual buildings, 25,777. Additionally, this study has provided the estimated number of buildings in different usage categories and the estimated total value in USD$ of these buildings. The typical building type in Bo is a low-rise concrete building (e.g. Figure 5). Map BO-0029 (Page 19) shows the modelled population distribution produced by this project. This population distribution is based on the distribution of the built environment, and indicates the densest population and building density in the central part of Bo. Population and building distribution has also expanded, particularly, along the major road infrastructure routes. Figure 5 – View of a typical residential house in Bo | Issue | 27 September 2018 Page 18 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 19 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Existing Development in Hazard Zones A major problem with the rapid population growth and unplanned urban development in Bo is that people now live in areas that are subject to natural hazards, particularly flooding, and can be impacted on a regular basis. The hazard and exposure data have been overlaid and used to identify where existing development coincides with the current (dark pink) and future 2050 (lighter pink) Hazard Zones across Bo (Map BO-0019, Page 21). The Hazard Zones will be larger by 2050 due to climate change causing more flooding. Decision makers can use Map BO-0018 and Map BO-0019 in combination to inform urban zoning plans for the city. These zoning plans should take into account the location and distribution of the high-hazard zones. Lower-hazard areas can potentially be used to accommodate more of the existing population living in high-hazard areas and be used to accommodate future population growth. Around 7% of Bo’s population currently lives in high-hazard zones (Table 2). Table 2 – Existing development within flood hazard zones Map Bo-0019 (Page 21) Current 100 year return period 2050 future 100 year return flood areas period flood areas* Population ~13,500 ~22,000 Buildings ~1,500 ~2,500 *Based on current model for population and buildings. Does not consider probably population and building count increase to 2050. | Issue | 27 September 2018 Page 20 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 21 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 3 Vulnerability “The conditions determined by physical, social, economic and environmental factors or processes which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards.” (UNISDR, 2017). The fragility of buildings and vulnerability of the population have been modelled (estimated numerically). For example, fragility functions that relate the depth of flood water to the severity of building damage have been created for a selection of property types. Vulnerability functions have been developed, which then relate the fragility functions to the estimated numbers of fatalities or people affected. This project has principally modelled physical vulnerability. The factors contributing to social vulnerability have not been investigated via this systematic review of natural hazard and risk. | Issue | 27 September 2018 Page 22 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 4 Risk “The potential loss of life, injury, or destroyed or damaged assets which could occur to a system, society or a community in a specific period of time, determined probabilistically as a function of hazard, exposure, vulnerability and capacity.” (UNISDR, 2017). Risk from flooding Risk calculations have been undertaken as part of this study to determine the potential impact of flooding. The flood-risk results are presented in terms of potential for fatalities and potential number of people affected as well as numbers of buildings damaged and the direct financial losses associated with the building damage. Table 3 – Quantitative flood risk to Bo Risk Metrics Average Annual Loss Estimates Average annual number of fatalities 2 Average annual number of persons affected 607 Average annual direct loss to all buildings (USD$) $194,000 Floods occur every year in Bo city. When they occur, relatively large numbers of people are affected, and large areas of the city experience damage and disruption. However, it is relatively uncommon for people to be killed by flooding in Bo city but longer return period, extreme events, may result in fatalities. Map BO-0016 (Page 24) shows flood risk in terms of number of people affected (relative to Ward area). Risk from landslide hazard Areas of low to medium landslide hazard in Bo city are associated with the limited areas of relatively steeper, high relief terrain. The landslide hazard in the remaining part of the study area is very low with localised areas of low hazard. The risk associated with landslides in Bo city is therefore expected to be small and detailed quantitative landslide risk calculations have not been undertaken as part of this study. | Issue | 27 September 2018 Page 23 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 24 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 5 DRR/DRM in Bo “Disaster Risk Reduction (DRR) aims to reduce the damage caused by natural hazards like earthquakes, floods, droughts and cyclones, through an ethic of prevention.” (UNISDR, 2017). “Disaster risk management (DRM) is the application of disaster risk reduction policies and strategies to prevent new disaster risk, reduce existing disaster risk and manage residual risk, contributing to the strengthening of resilience and reduction of disaster losses.” (UNISDR, 2017). Catchment-scale DRR/DRM Options for Bo In line with international best practice, this study recommends that individual DRR/DRM measures are combined for practical implementation as opposed to implementing individual measures in isolation. Herein, the combinations of measures proposed in this study are referred to ‘DRR/DRM Options’. Combining measures typically reduces the risk from multiple types of hazard. For example, reforestation, hazard signage and flood-landslide communication and community engagement in combination are relatively low cost and reduce the hazard-risk from flooding and landslides. All DRR/DRM measures should be integrated across multiple sectors for developing a well-functioning and resilient city. It is recommenced that development planning moves away from the traditional single siloed master planning approach for each sector separately in favour of integrated planning of appropriate interventions across multiple sectors including all the required disaster risk reduction and management measures (considering all the risks) is an integral part for building urban resilience. In developing the DRR/DRM Options for Bo, a range of best practice DRR/DRM measures have first been provided. Several complimentary measures have then been grouped together to form two different DRR/DRM Options for Cost-Benefit Analysis (CBA)(Appendix A). Finally, a prioritised list of DRR/DRM recommendations has been proposed. Implementing nature-based DRM measures has the potential to be the most cost-effective solutions in both the long and short term and this is recommended however ‘hard’ engineering solutions are also required in to achieve optimal DRM effectiveness within a specific time-frame and within the constraints of an urban setting. International good practice for DRM measures (flood risk management in particular) is moving toward holistic, | Issue | 27 September 2018 Page 25 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment sustainable, green, urban drainage systems (Forbes et al. 2015; Woods Ballard et al. 2016). This holistic, sustainable approach is in line with the Greening Africa initiative (White et al., 2017) and clear guidance in Implementing Nature-Based Flood Protection (World Bank, 2017). This guidance emphasizes the importance of approaching planning of nature-based flood protection at a system or catchment scale perspective. Figure 6 demonstrates a selected range of DRM measures to mitigate against flooding that are recommended to be implemented in combination using a system or catchment-scale approach. Implementing a combination of measures that are applicable in the upper catchment helps to avoid implementation of more expensive and intrusive ‘hard’ engineering solutions in the lower catchment. It is essential that DRR/DRM Plans for the city of Bo are aligned with Urban Development Plans and Zoning Plans for the city. It is also essential that these plans are co-ordinated within a broader Urban Resilience Framework that takes into consideration the specific characteristics and vulnerabilities of the location, the diverse livelihoods of the citizens and social and economic requirements of the city infrastructure. | Issue | 27 September 2018 Page 26 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 6 –Schematic illustration of a typical river catchment in Bo and proposed flood hazard DRR/DRM options for Bo. Illustrations of measures adapted from the Sustainable Urban Drainage Manual (Woods-Ballard et al., 2007). | Issue | 27 September 2018 Page 27 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Selected range of best-practice DRR/DRM measures for Bo Table 4 presents the broad range of appropriate DRR/DRM measures that have been reviewed for Bo. Column 4 of Table 4 indicates the Option into which the measure has been included. Table 4 – Appropriate DRR/DRM measures for Bo Hazard DRR/DRM Measure DRR/DRM Option Flood + Hazard and risk communication and 1 Landslides engagement Flood Early warning systems 1 Flood Revegetation of the natural channels Flood + Community drainage implementation 2 Landslides Flood Instrumentation and monitoring Flood Flood water storage ponds Flood Flood hazard signage 1 Zoning (including land-use plans), land Flood + readjustment and building regulations - Landslide implementation and enforcement2 Flood Rooftop rainwater harvesting Flood Engineered green channels Flood Engineered concrete culverts 2 Flood Drainage channel clearance 2 Details of these proposed DRR/DRM recommendations for Bo are given in Section 8 of this report. The recommendations are both hazard specific and catchment specific and within each catchment DRR/DRM measures are location specific. Figure 7 gives an example of indicative location-specific flood-warning hazard signage. 2 High cost relates to implementation and enforcement, but establishing a ‘zoning regulation’ which will include a technical study and establishing a bye-law is not high cost and is advised. | Issue | 27 September 2018 Page 28 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 7 – Excerpt from MAP BO-0028, Page 111 showing the 100 year flood mapping and several of the DRR measures proposed for Bo city. | Issue | 27 September 2018 Page 29 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Prioritised DRR/DRM Recommendations Effective prioritisation of DRR/DRM needs to be informed by more than cost-benefit analysis on the basis of natural hazard and risk. Due to the scale of the study, the level of granularity of the CBA done is not sufficient to assess whether or not a specific intervention in a given area is economically justifiable. Rather it allows relative comparison of interventions at city scale and across cities. The cost-benefit analysis has indicated the potential for lives saved and losses avoided by implementing proposed DRR/DRM solutions. However, prioritization decisions cannot be based on reduction of natural hazard and risk alone. It is important that wide urban/economic development plans are taken into consideration. A holistic city wide and site specific (taking account of catchment scale), community driven DRM strategy is recommended with phased investment. Prioritised proposals based on the natural hazard and risk assessment results of this study are given below. These recommendations have been informed from a combination of international best practice and findings of project/stakeholder feedback and results of the hazard and risk analyses. The recommendations are not an all-encompassing road map to address the other many cross-cutting challenges to Bo’s urban resilience. They are recommended to be implemented for optimal long-term improvement for city resilience however viable alternatives including other structural measures e.g. flood defence bunds, exist and may deliver quicker short-term improvements to city resilience but these would require more detailed flood modelling and analysis. Priority 1 – Re-sizing of engineered culverts and clearing of waste from existing drainage This DRR option involves the construction of new engineered culverts at selected locations across Bo and the clearing of waste from existing manmade and natural drainage channels. It should be noted that the proposed culvert engineering works are at discrete locations where major roads cross natural drainage channels. Well- designed culverts at these locations will potentially have a significant impact on flood hazard reduction, offering a possible benefit of over $2.5M USD over a 33- year period. Priority 2 – City-Wide Hazard and Risk Communication Cost benefit analysis undertaken on potential city-wide DRR/DRM options indicates that, city-wide hazard and risk communication (e.g. Figure 8) would be beneficial for Bo. Establishing a hazard and risk communication program, including formation of a hazard and risk communication team, installation of hazard and risk signage, and establishment of an early warning system for Bo is beneficial in terms of the risk reduction that can be achieved. | Issue | 27 September 2018 Page 30 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 8 – Murals educating communities about Ebola, an example of effective hazard and risk communication in Freetown. Community: DRM is everybody’s business. DRR/DRM is most effective when complimentary measures are combined and there is engagement from all levels of society (Sendai Framework, Guiding Principles). Figure 9 shows some of the many roles of the community in effective DRM. This reference notes that in Japan, although both central government and local government play a leading role in mitigating against disaster, that community-based DRM activities are (and need to be) well integrated into the daily lives of people, ensuring that awareness of natural hazards is never far from their minds. The summer 2016 ‘Operation Clean Freetown’ initiative3 highlighted that citywide community involvement in Sierra Leone can result in citywide flood hazard reduction. People were incentivised to clear waste from their homes for collection, helping to significantly reduce the impacts of flooding related to blocked urban drainage during the rainy season. 3 http://apanews.net/en/news/sierra-leone-announces-operation-clean-freetown http://www.presidentsrecoverypriorities.gov.sl/single-post/2017/05/14/Youth-groups-trained-in- door-to-door-waste-management-under-Operation-Clean-Freetown-are-equipped-to-begin-work | Issue | 27 September 2018 Page 31 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 9 – Diagram extracted from the World Bank report “Learning from Mega disasters – Lessons from the Great East Japan Earthquake”. Priority 3 – Urban Planning and Zoning One of the most effective ways to save lives and reduce losses going forward is to minimise further building in the combined hazard zones. (MAP BO- 0018, Page 14). Currently ~7% of Bo’s population live in these combined higher hazard zones and this number will increase if further building in these zones is not managed. If further building is allowed to continue in an unmanaged way then the risks associated with flooding will continue to increase. It is recommended that further consideration, are undertaken for the wider range of DRR/DRM options to help prioritise and inform the implementation of a holistic and sustainable DRR and DRM plan for the city of Bo. This further work should be undertaken at the next stage when alignment can be made with urban planning. In the next stage, good urban planning should focus on the relationships between buildings, the spaces they create, the people in the communities and their | Issue | 27 September 2018 Page 32 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment livelihoods and the sustainability and resilience of the urban development. The urban planning should consider the geographic distribution of natural hazard and risk identified in this project. This will help move the city away from a reactive development approach to one that prioritizes the prevention and management of risk and encourages sustainability and resilience as an intrinsic component of the economic development. Bo should focus on ‘efficient utilization’ of existing safe land within the urban area (low hazard zones) by considering varied urban design tools for densification of safe zones, such as increasing square footage by land- readjustment, building additional floors, infill development, spot zoning etc. based on the specific site condition and land-use. This would allow the city to grow in a more sustainable and resilient way with reduced cost of service delivery for compact city, encouraging public-private partnerships for cost recovery. While establishing zoning, and building regulations for the whole city may seem overwhelming, spot zoning of low risk zones is a feasible approach to the same issue, and this can quite easily be done by demarcating zone along existing natural boundaries (road, drain etc.), and by giving it a special zoning district status for integrated multi-use redevelopment, that can help to densify safer zones for accommodating residents currently living in high-risk areas. Implementation of DRR/DRM Generally, implementation of DRR/DRM on a catchment-by-catchment basis is a good approach, since it is often necessary to manage the upper catchment before issues with the lower catchment can be resolved. However, in certain hot-spots, it may be possible and indeed sensible to implement DRR/DRM on a more localised scale as a priority. This is more likely to be the case in broad, lower-relief catchments such as near Bo than in steep catchments such as in Freetown. This report provides a summary of the priority DRR/DRM options, however does not provide the full set of necessary information to implement these options. There are numerous guides available and under development which describe the implementation process. UNISDR (2018 - https://www.unisdr.org/files/57399_drrresiliencepublicreview.pdf) describe a process which includes: 1) Defining local disaster risk reduction and resilience strategies; 2) Considering enabling factors for developing local disaster risk reduction and resilience strategies; and 3) Implementing local disaster risk reduction and resilience strategies. | Issue | 27 September 2018 Page 33 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 1) Defining local disaster risk reduction and resilience strategies The definition of a DRR strategy is an important first step in the implementation process. A strategy informs the development of DRR plans and subsequent actions. A strategy should have (from UNISDR, 2018): • A shared vision and understanding of DRR which is integrated into the city development strategy; • A designated core team leading and coordinating the process to ensure successful implementation; • Some form of clearly defined and allocated budget; and • A timeline of activities to fulfil the preparation of the strategy and its implementation through an action plan. Activities include various types of work, meetings, preparation of a baseline document, and outline of roles and responsibilities etc. Furthermore, an action plan addresses the following questions (UNISDR, 2018): • Set goals and priority areas – what do we need to do? • Responsibilities and roles – who has what role? • Indicators – how do we measure progress? • Time – when do we expect to complete activities? • Budget – how much will it cost and what are the possible funding sources? 2) Considering enabling factors for developing local disaster risk reduction and resilience strategies Certain enabling factors can help to develop and implement a successful DRR strategy. These factors include (UNISDR, 2018): • Having local government at the forefront of the process; • Engaging with local communities; • Engaging with other key actors e.g. NGOs. • Putting participatory mechanisms in place. It is important to also a shared understanding of local disaster risk and resilience. This report presents a city-scale assessment of natural hazard and risk; however, it may be necessary to develop a more localised understanding of risk prior to implementation of DRR options. This could be done by more detailed hazard and risk assessment (e.g. high-resolution elevation mapping for culvert re-design in hazard hot-spots) or through more detailed community engagement (e.g. to develop a locally led flood warning system). 3) Implementing local disaster risk reduction and resilience strategies The implementation of DRR strategies entails: | Issue | 27 September 2018 Page 34 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment • Organizing for DRR, which includes an understanding of governmental and organizational structures for DRR (e.g. the ONS) and considering other important institutional elements such as written laws, regulations and codes, building capacities and coordination; • Knowing and understanding risks (as above, this is partly addressed by this report, but may need to be further assessed prior to implementation based on the DRR strategy content); • Having the financial resources to be able to plan and act; and • Monitoring and measuring the performance of implemented DRR strategies and ensuring that lessons learned are recorded, shared and revisited during the revision of DRR strategies in the future. | Issue | 27 September 2018 Page 35 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 36 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 1 Introduction 1.1 Project background The geographical location of Sierra Leone makes it prone to intense and recurring natural hazards such as flooding and landslides. Increasing urbanisation together with the effects of climate change is compounding the problems faced by cities in Sierra Leone. The lack of available and reliable data on the frequency and impact of natural hazards on these cities is hindering DRR and DRM, urban planning and investment. To better understand and quantify natural hazard and disaster-risk in Sierra Leone, the World Bank and Global Facility for Disaster Reduction and Recovery (GFDRR) are supporting, with Africa Caribbean Pacific – European Union (ACP- EU) funding, the development of new natural hazard and risk information in Sierra Leone for three cities: Freetown, Makeni and Bo (See Table 5). The World Bank have commissioned Ove Arup and Partners International Ltd (Arup), with sub-consultants: Integrated Geo-information and Environmental Management Services (INTEGEMS, Freetown), JBA Risk Management (JBA) and the British Geological Survey (BGS) (collectively, the ‘Project Team’) to undertake this consultancy assignment. Table 5 – Natural hazard and risk assessment scope in Freetown, Makeni and Bo Freetown Makeni Bo Flooding Landslides Sea level rise Coastal erosion The results of this study will help to inform the understanding of natural hazards and risk for the three cities and build on ongoing DRR and DRM work in Sierra Leone by recommending simple but practical and effective solutions to natural hazard-risk to reduce risk and increase resilience in each of the three cities. Throughout the assignment, the Project Team has been working closely with the Office of National Security (ONS) and local stakeholders through ongoing in- country engagement, workshops and sharing of information and findings. | Issue | 27 September 2018 Page 37 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 1.2 Outline of this report This report is Volume 4 of 5 of the Final Report. Volume 4 contains: Use theses sections to • Section 0 – Summary of report; understand: • Background and Bo • Section 1 – Brief introduction to the project (; context including current resilience challenges that • Section 2 – Overview of Bo from a review of the literature effect or are affected by and from knowledge gathered at the in-country workshops, flooding, land sliding with specific reference to the vulnerabilities and resilience challenges posed to Bo from natural hazards; Use these sections to understand: • Section 3 – Review of exposure and vulnerability in Bo; • Bo exposure (people, buildings and • Section 4 – Detailed review and discussion of flood hazard infrastructure); and risk results; • Physical vulnerability of exposure to natural • Section 5 - High level review and discussion of landslide hazards; locations of flood, hazard and risk results; landslide on maps; • Location and potential • Section 6 – Identification of current development in Hazard losses (people affected and Zones; $) due to risk from natural hazards in maps and tables of losses and reported by ward; • Maps and description of highest risk urban areas. Use these sections to understand: • Section 7– General opportunities for DRR/DRM in Bo; • High-level DRR/DRM linked to Sendai • Section 8 – Specific opportunities for DRR/DRM in Bo; Framework for Bo; • Hazard specific • Section 9 – Recommendations DRR/DRM measures; • Catchment-scale location and hazard specific DRR/DRM measures; • Recommendations for DRR/DRM in Bo. Use these appendices to understand: • Appendix A – Cost benefit analysis • High level preliminary estimate of DRR/DRM • Appendix B – Natural hazard and risk maps costs and benefits; • See a full set of maps of distribution of hazard, exposure and risks. Volume 1 contains the wider Sierra Leone country profile, context, and methodology for assessing the natural hazard and risks. Volumes 2 and 3 contain city-specific information relating to Freetown and Makeni in the same format as this volume. Volume 5 contains a series of A3 maps showing the spatial distribution of natural hazard and risk in each of Freetown, Makeni and Bo. | Issue | 27 September 2018 Page 38 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 1.3 Maps and data Throughout this report, maps showing the spatial distribution of natural hazard and risk in Bo city are included as examples or when specifically referred to. These maps have been reduced in size to fit an A4 page. For the full series of A3 maps, see Volume 5. Whilst the maps provide an overview of natural hazard and risk in Bo, most value can be gained from this study by viewing and interrogating the data produced by this study using a Geographic Information System (GIS) such as ArcGIS or QGIS (QGIS is open-source and freely available). Throughout this report, example screenshots from GIS are included to demonstrate this. All data produced by this study are available from the World Bank. 1.4 Limitations to this report Limitations to this project include (but are not limited to): • This study is a city scale study and results have been reported and discussed at city scale. Data input at city scale does not allow for output at detailed resolution and would not be appropriate for design of individual engineering structures; • There are many limitations and assumptions of data input and modelling practices necessary for a city scale study in a data-poor region and there are addressed in the Methodology Report (Volume 1); • This study addresses specific natural hazards. It is recognised that Sierra Leone suffers from many other hazards including epidemics, wild fire, land degradation, household fires etc. Information has been compiled in this project which could be used to study these hazards in the future, however the focus of this project is on addressing the hazard and risk associated with flooding and landslides (and coastal erosion and sea-level rise in Freetown only). • Risk to agriculture is not included in this multi-city project given the primarily urban context. • For the cost assumptions, 2017 USD$ values are assumed. • This report is only focused on shocks and does not consider chronic stresses such as lack of clean basic services, poverty, unemployment, low coping capacity etc. that adds to the vulnerability quotient of the population at risk. • No indirect costs or benefits are included in the calculation of cost-benefit ratio of DRR/DRM options. Costs are quantified in terms of the capital and operational expenditure required to implement the proposed DRR/DRM measure (e.g. the cost to construct and maintain flood protection measures). The net costs and the net benefits are calculated over an assumed design life of 33 years (i.e. from 2018 to 2050) for all proposed DRR/DRM options. The results of this project can be used to support the planning and provision of disaster risk reduction and disaster risk management measures that will increase | Issue | 27 September 2018 Page 39 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment the resilience of the city against disasters. The results provide input information to inform and contribute to urban planning of the city. The hazard and risk results and related maps provided should be used to inform and build the Bo city council’s capacities in term of natural hazard and risk knowledge, disaster risk prevention and management, and provide recommendations to help preparedness and strengthen urban community’s resilience against disasters. | Issue | 27 September 2018 Page 40 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 41 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 2 Bo: City Profile and Context 2.1 Introduction This section of the report provides a general introduction to Bo city. It includes an overview of the geographic setting of Bo city with reference to natural hazards, and provides a summary of some of the resilience challenges faced by the city. 2.2 Geographic setting of Bo Bo is in the Southern Province in south central Sierra Leone. It is around 180km directly southeast of Freetown and around 100km directly south of Makeni city. Bo has been built amongst natural low-lying, low-relief topography, which in combination with the tropical monsoonal climate of the country, forms natural swampland. The country experiences a rainy season between May and November, which brings torrential downpours with up to 3200mm precipitation annually. The climate is tropical and humid all year, but hotter and dryer between December and March. Bo is particularly susceptible to flooding in the rainy season because the lack of topographic relief results in limited conveyance of floodwaters through the natural swampland drainage network. The low-lying wetlands do provide conditions suitable for wetland crops including rice. 2.2.1 Geology of Bo The geology of Bo is characterised by ancient geological granitic basement rock of the West Africa Craton (Figure 10). The bedrock geology has been deeply weathered over geological time. The bedrock geology is locally overlain by recent alluvium and lake deposits which infill the lower-lying natural drainage network. Small scale mining of alluvium sand lacustrine clays and silts occurs at unplanned locations across the city to provide construction materials. Bo is one of the larger diamond mining regions of Sierra Leone. Most of the diamond production is also reported to come from mining of alluvium deposits (sands and gravels) using artisanal methods (USGS, 2004). | Issue | 27 September 2018 Page 42 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Bo city Figure 10 – Simplified geological map of Sierra Leone. Bo city is outlined in black. Source, Ministry of Water Resources/ASI (2015)4. 2.2.2 Flooding in Bo Of the total number of people affected by disasters in Sierra Leone in the last 30 years, 90% of were affected by flooding (UNDP, 2012). From 1980 to 2010, over 220,000 people were affected by floods, and 145 people were killed (EMDAT, 2009). Floods occur frequently and can occur any time but are particularly common in the rainy season between May and October. Flooding in Bo is particularly concentrated within the broad river channel flood plains (Figure 11). Agriculture dominates the land use in the areas near the rivers and on the flood plains. Urban expansion onto the flood plains has resulted in buildings that have been constructed on reclaimed swampland within or adjacent to the river floodplains. As urban development continues to cover the natural swampland, the flooding hazard and risk will be further intensified and increased. Bo city has experienced significant flooding in recent years, in particular, the September 2015 floods were caused by widespread torrential rain over the course of 3 days. Around 3,300 people of a population of around 175,000 were affected by this flooding. 4 http://earthwise.bgs.ac.uk/index.php/OR/15/009_Introduction | Issue | 27 September 2018 Page 43 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 11 – Satellite imagery of eastern Bo. The natural river floodplain is covered in green vegetation predominantly in well organised plots indicating farmed land in this image. It is surrounded by buildings and roads, which are pale yellow-orange. Imagery source: Google Earth Pro, 2017. 2.2.3 Landslides in Bo The area of Bo city is relatively low-lying (90 to 100 m a.s.l.) with few areas of significant relief. Landslides are not considered to be a significant hazard in Bo city. 2.3 Urbanization in Bo Bo is the second largest city in Sierra Leone with a population of around 175,000 (Statistics Sierra Leone, 2015). It is the major administrative and economic centre of the Southern Province. The urban area of Bo has grown extensively over the last 11 years. Map BO-0002, below, shows a map which highlights built environment expansion in Bo between 2006 and 2017. | Issue | 27 September 2018 Page 44 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 45 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment In 2006, the built-up area at the city centre was approximately 19 km2, centred around a dense road network and major roads including Sewa Road and Bo- Kenema Highway. By 2012, the urbanised area expanded in all directions to approximately 33 km2. More significant extension of urbanisation took place towards the east and south, along the main roads to Borbor Kombor, New Site and Kandeh Town Extension. The most recent extent of built environment in 2017 has an area of about 51 km2, expanding mainly along main roads or highways towards Manjama, Bandajuma, Gawura, Jombohun and Matru (Table 6). Table 6 – Approximate urbanised area and built environment expansion rate in Bo. Year Approximate Urbanised Approximate Urban Approximate Annual Urban Area (km2)1 Expansion Rate Expansion Rate (%) 3 (%)2 2006 19 - 9.5 2012 33 74 9.5 2017 51 168 1 Area extent of city expansion is estimated from satellite image interpretation. 2 Urban area expansion rate is the rate of increased urbanised area compared with Year 2006. 3 Annual urban expansion rate between dates (e.g. 2006 to 2012). Figure 12 shows the southern part of Bo. The images clearly show that a significant number of buildings have been constructed between 2003 and 2017, mostly along the roads leading into and away from the city centre. Figure 12 – Satellite images in the southern part of Bo in (a) Year 2003 and (b) Year 2017 showing rapid built environment expansion. Google Earth Pro, 2017. | Issue | 27 September 2018 Page 46 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 2.4 Socio-economics in Bo Sierra Leone’s urban areas are facing rising populations, rapid urbanization (3.3%), high levels of unemployment, uncontrolled settlements, a rising number of informal businesses and severe pressure on the provision of basic services such as water supplies, sanitation and solid waste management services. The migration of citizens from rural to urban areas has further increased the demand on public services (Abarca and de Vreede, 2013). The end of the civil conflict in 2002 led to renewed arrivals by business travellers, as well as members of the diaspora visiting friends and relatives. This in turn has stimulated some investment in the existing hotel and guesthouse infrastructure in Bo and in the construction of new hotels such as Sahara Hotel, by other domestic investors. These investments indicate that general investment in the tourism sector has increased in Bo, and elsewhere in the country (World Bank, 2015). The city became an educational centre in 1906, when the Bo Government Secondary School was established. Like many other parts of the country, Bo was affected by the outbreak of Ebola in 2014, however, in general the Southern Province was less badly affected than the north and particularly the western region of the Northern Province, Freetown (National Ebola Response Centre, NERC 2015). The major economic activities of the district population are gold and diamond mining, other activities include trading, agricultural production of rice and root crops, cash crops such coffee, cacao and oil palm plantation. Trading is also a livelihood means for many residents as the district serves the important trade route and business hub for the south west of the country. Traditional farming is a common livelihood nationally but less than half (~49%) of Bo residents are engaged in farming (ReliefWeb, 2015). 2.5 Governance in Bo Bo city sits within Bo District. The city is locally governed by a directly elected city council, known as the Bo City Council (BCC), headed by a Mayor. Members of the Bo City Council are directly elected every four years in a municipal election. Bo District has its own directly elected local government, the District Council, which is where executive and legislative authority is vested at local level within Bo District. The Bo District Council is headed by a council chairman, who is an elected official and is responsible for the general management of the district. The current City and District Mayors are members of the Sierra Leone People's Party (SLPP). Sierra Leone has a National Disaster Risk Management Policy (2014). Functional disaster management committees have been formed at the chiefdom level, with community-based volunteers having been trained at both provincial and district levels. Local ONS representatives have joined the workshops for this project in Bo. | Issue | 27 September 2018 Page 47 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 2.6 Resilience challenges in Bo There are specific vulnerabilities in Bo city, including lack of urban planning, DRM capacity and solid waste disposal, that contribute to poor resilience against flooding in the city. 2.6.1 Resilience challenges for urban planning Lack of legislation from Central Government related to urban planning, land policy and building codes hinders real progress in urban planning and up until now data related to footprint of flood hazard and risk has not been available. Significant built environment expansion has multiple direct and indirect consequences increasing both the hazard and the vulnerability of the city of floods. The high population growth in Bo has forced vulnerable and low-income communities to settle in areas of the city which are both close to a source of livelihood and where land is cheap; these are often ecological corridors that serve as natural river systems for the city. This is the case in for example the flood hazard zone close to Coronation Field Road and Water Lane and many other parts of the main urbanized area that flood frequently. In addition, culverts under the roads that intersect the natural river channels may be undersized and are often blocked either with silt or with solid waste. As the communities that live in these high hazard locations are often low-income groups, the building materials used to make houses are typically more vulnerable to flooding, resulting in higher losses of life and numbers of properties damaged than might occur with more robust dwellings. 2.6.2 Resilience challenges for solid waste management Solid waste management is a problem in Bo that BCC are well aware of. Lack of reliable house-to-house collections, particularly in the low-income areas results in disposal of plastic and other waste in the natural river channels used to convey flood water, reducing the capacity of the drains and causing blockages at culvers where the channels run under roads. However, BCC is making good progress in this area. The BCC with funds from the UK Department for International Development (DFID) is closely working with a German Non-Governmental Organization Welthungerhilfe (WHH) to reduce waste in the Township. The project has also sponsored private individuals in the production of plastic tiles for pavement of compounds and roads with the aim of reducing plastic waste within the Township of Bo (Awoko, 2015). 2.6.3 Resilience challenges for disaster risk management The Rapid Damage and Loss Assessment (DaLA) Report (World Bank, 2017) carried out by the World Bank following the Regent-Lumley Disaster in August 2017 identified the recurrent observation that across sectors, complexities of institutional systems management cause weaknesses in the overall DRR/DRM system and resilience of Freetown to absorb shocks. These issues also apply to | Issue | 27 September 2018 Page 48 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Bo. Within the workshops held as part of this project, two main areas of governance were reported to particularly influence capacity issues around DRR/DRM for flooding. These were; planning regulation and the devolution of responsibility to the ministries and local city and district councils. Planning regulation is intrinsically linked to urban planning. A good urban design will focus on the relationships between buildings and on the spaces they create in and in the case of Bo, take account of high flood hazard zones. This will help move the city away from a reactive development approach to one which prioritizes the prevention of risk as recommended by the DaLA Report for Freetown (World Bank, 2017). To do this capacity building in planning regulation is required. It was reported in the project workshops (although not verified by other sources) that there is no central database of locations where ‘permits to build’ have been granted. There were anecdotal comments made by workshop participants about house plots where ‘permits to build’ were issued more than once, resulting in land disputes. It was reported that there are not enough surveyors to verify and regulate the building process i.e. that the house is built in the location where the permit was given and that it has the permitted dimensions and is structurally appropriate and safe. Many of the issues around building in high hazard zones are understood by the technical staff of planning related ministries, however, there is a lack of structure in place to enforce planning regulation. An additional step in Makeni and Bo is that sign off of ‘permits to build’ is also required by Paramount Chiefs prior to issuance of ‘permit to build’ by the authority in Freetown. This adds a further complication to the system. A draft version of the National Building Code exists from 2015, which states that planning responsibility rests at local council level, but this legislation has yet to be passed. Devolution issues exist and national-level involvement is significant in local planning processes. On reflection of these significant legislation and governance issues the DaLA Report (World Bank, 2017) has recommended that: “A preventive approach would require the development of policies and an enabling legislative framework and procedures for action by different institutions endorsed by representative stakeholders: central government, local government, private sector and civil society organizations that interface with the communities. The National Disaster Management Policy and National Disaster Preparedness and Response Plan are to be strengthened and operationalized into the development plans and operations of government entities, both central and local.” | Issue | 27 September 2018 Page 49 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 50 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 3 Exposure and Vulnerability in Bo 3.1 Introduction The Volume 1 Final Report describes the methodology used to estimate exposure in Bo, in terms of: • Population distribution • Building value and distribution; and • Road value and distribution. This Section of this Report describes the modelled distribution of these elements in Bo. The accompanying Volume 1 Report should be read in conjunction with these observations to fully understand the limitations of the datasets. Each of these exposure elements was modelled distributed to a 30m x 30m grid across Bo. 3.2 Population Map BO-0029 (Page 53) shows the modelled gridded distribution of population in Bo. Bo is the second largest city in Sierra Leone with an urban population which has been growing rapidly over the past 10 years or so. This population is centred in East Ward-Moriba Town, West Ward-Moriba Town, West Ward-Njiagboima and to some extent North Ward-Kissy Town. In each of these central urban wards, population density in places is >25 people per 30m grid unit. Areas of increased population density are aligned with settlements of buildings which have grown adjacent to road networks, particularly heading to the east from Bo through Sewa Ward along the Bo-Kenema Highway. Population density here is typically between 5 and 25 people per 30m grid unit. 3.3 Buildings Map BO-0030 (Page 54) shows the modelled gridded distribution of building value in Bo. Modelled gridded building value in Bo is typically <$100,000 per 30m grid unit, except for the very central parts of Bo near to the Bo School, where building value is estimated to be > $250,000 per 30m grid unit in places. In Bo, this increased gridded building value reflects both increased building density, and increased occurrence of formal planned buildings (e.g. shops, healthcare facilities etc.). The buildings exposure model for Bo contains 25,777 individual buildings. Table 7 shows the modelled typology of these as determined by the method detailed in the Volume 1 Report. | Issue | 27 September 2018 Page 51 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Table 7 – Modelled distribution of building typology in Bo Type Modelled component of total buildings Educational buildings 0.3% Formal residential buildings 92.0% Government buildings 0.4% Healthcare buildings 0.3% Industrial buildings < 0.1% Informal residential buildings 6.9% Utility buildings < 0.1% 3.4 Roads Map BO-0031 (Page 55) shows the modelled gridded distribution of road value in Bo. It is apparent that the exposed value of roads is largely dictated by surface type. Paved roads have a modelled average replacement value of $341,700/km, whereas unpaved roads have a modelled average replacement value of $52,800/km. Bo can be accessed by from any of seven main paved roads: two from the south; one from the west; two from the north; and two from the east. The Bo-Kenema Highway comes towards Bo from the north and heads out of Bo City centre to the east, towards Kenema. In central Bo, the paved road network joins and is transacted by numerous unpaved roads. These unpaved roads are generally of lower replacement value. There are approximately 40km of sealed roads and 720km of unsealed road in the Bo city area. 3.5 Vulnerability The fragility of buildings and vulnerability of the population have been modelled (estimated numerically). For example, fragility functions that relate the depth of flood water to the severity of building damage have been created for a selection of property types. Vulnerability functions have been developed, which then relate the fragility functions to the estimated numbers of fatalities or people affected. This project has principally modelled physical vulnerability. The factors contributing to social vulnerability have not been investigated via this systematic review of natural hazard and risk. | Issue | 27 September 2018 Page 52 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 53 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 54 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 55 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 4 Flood Hazard and Risk in Bo 4.1 Introduction This section of the report provides an overview of the qualitative and quantitative flood hazard and risk assessments undertaken for this project. This section should be read in conjunction with Volume 5, which contains maps showing the spatial distribution of flood hazard and risk across Bo. 4.2 Overview of qualitative assessment Areas of medium to high flood hazard are associated with an extensive network of inland river channels in the study area (Map BO-0004, Page 57). Major watercourses extend through the main urbanized area and also the peri- urban areas to the north, east, south and west of the city. The qualitative hazard map highlights that the potentially worst-affected flood hazard in the most built- up areas are in: North Ward-Njai Town, East Ward-Lower Samamie, East Ward- Moriba Town and East Ward –Kindia Town. The major river channels, tributaries and floodplains are zones of natural flooding. As such, areas with a medium to high risk of flooding are widespread. Where buildings have been constructed on reclaimed land within the low-lying natural swampland and within the watercourse channels and floodplains they are within the high hazard flood zones. In addition, the low-lying terrain and low relief in the Bo area means the flood hazard has the potential to encroach land relatively far from watercourses and to cover a relatively large proportion of the available land. Care is required to ensure that seasonal flood waters are not unnecessarily obstructed and can flow to the regional scale rivers via the natural drainage network. | Issue | 27 September 2018 Page 56 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 57 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 4.3 Overview of quantitative flood hazard and risk assessment Map BO-0008, BO-0009 and BO-0010 (Pages 59 – 61) show the modelled quantitative flood hazard maps for the 20, 100 and 1500 year return period flood levels respectively. The distribution of modelled 20 year return period flood levels (Map BO-0008, Page 59) suggests that the majority of central Bo city would not be significantly affected by flooding. The depth of flooding is predominantly less than 1.0m except on the outlying regions of the city urban area where flood depths could reach 3 to 5m depth. The main watercourse in the east of the city is the main flood zone and shows modelled floodwater depths of up to 1m within the channel and floodplain. The southern area of East Ward-Manjama has the potential for greater floodwater depths in the channel of up to 3m. The distribution of modelled 100 year return period flood levels (Map BO-0009, Page 11) indicates greater spatial extent and higher flood depths over areas of the Bo city as would be expected. Some of the urban areas are shown to experience higher flood levels between 1 to 3m depth and some of the outlying regions of the city area have local flood depths greater than 5m. The distribution of modelled 1500 year return period flood levels (Map BO-0010, Page 61) indicates a greater still spatial extent of flooding. The majority of the tributaries that drain central Bo city become larger flood hazard zones and more of the modelled flood depths in these zones reach floodwater depths of up to 3m. The flood hazard maps described above have been combined with information related to the distribution and value of buildings in Bo city to quantitatively determine the flood risk to buildings. Information related to the distribution of people inside and outside buildings across the Bo urban area has been used to determine the flood risk to people. | Issue | 27 September 2018 Page 58 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 59 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 60 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 61 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment The flood risk results are presented both in terms of absolute values and relative to the ward area. Map BO-0011, Page 63 shows the distribution of modelled flood risk in terms of average annual direct loss to buildings caused by flood damage. In general, the losses for the majority of wards is less than $10,000 to $50,000. Map BO-0012, Page 64 shows the modelled average annual direct loss to buildings relative to ward area. East Ward-Bumpeh-Woh and East Ward-Manjama, in the east and south of the city respectively, have the highest relative flood risk of all of the wards. Generally speaking, the wards in the main urbanized areas have higher relative flood risk than the wards surrounding the city centre as would be expected. Map BO-0013, Page 65 shows the modelled average annual number of potential fatalities are very low throughout the wards of the main urbanized area and those in the north and the south of the city centre. Only Kpandobu Ward in the northeast indicates that greater than one fatality may occur. This risk is likely related to the channel that is modelled to experience greater than 5m floodwater depth (Map BO-0008, Page 59). Such depths are not observed in many other parts of the study area. Relative to Ward area, East Ward-Babema in the east of the city has the highest modelled number of fatalities relative to the other wards (Map BO-0014, Page 66). The modelled average annual number of people affected is highest in the northwest of the study area, Samamie Ward has the greatest number (>100) of affected people. Whilst for most of the study area, between 10 and 50 people are affected. Some wards have large areas so as the losses can be higher. | Issue | 27 September 2018 Page 62 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 63 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 64 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 65 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 66 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 13 gives an example of the qualitative flood hazard data viewed in a GIS. The flood hazard levels are calculated at a resolution that is sufficient to identify individual houses and other buildings in the GIS model for Bo city. However, it is emphasised that the accuracy of the input elevation data and the precise level of individual buildings is limited and the actual flood levels at individual buildings cannot be confirmed. More detailed elevation information is required to determine the flood hazard and risk at individual building locations. Figure 13 – Example of quantitative flood hazard data viewed in a GIS (river and surface water flooding, 20 year return flood). Area shown is in East Ward - Batiema (see inset map for approximate location). Light blue indicates lower floodwater depth and dark blue indicates greater floodwater depth. Building polygons and road polylines are from the exposure dataset developed as part of this study and derived from OpenStreetMap. Field of view is approximately 1.5km across and oriented north. | Issue | 27 September 2018 Page 67 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Table 8 below provides a summary of the modelled flood risk in Bo in terms of the average annual losses of potential fatalities, number of persons impacted and the cost of damage to different types of building usage types. These results indicate that quantitative flood risk across Bo is relatively low in terms of the potential for fatalities and number of people impacted as well as the potential direct damage and economic losses. In comparison, the equivalent risk in Freetown is considerably higher as would be expected. Flood risk is similar but slightly higher in Bo city. Makeni city has the lowest risk results of the three cities assessed. Table 8 – Summary of flood risk for Bo Risk metric Average estimate Average annual number fatalities 2 Average annual number persons affected 607 Average annual direct loss to all buildings $194,000 (USD) Average annual direct loss to educational < $1,000 facilities (USD) Average annual direct loss to formal $193,000 residential buildings (USD) Average annual direct loss to government < $1,000 facilities (USD) Average annual direct loss to healthcare < $1,000 facilities (USD) Average annual direct loss to industrial < $1,000 buildings (USD) Average annual direct loss to informal $1,000 residential buildings (USD) Average annual direct loss to utility facilities < $1,000 (USD) Table 9 provides a summary of the breakdown of modelled flood losses for a range of flood return periods for Bo. Table 9 – Summary of the flood losses for different return periods for Bo Return period (years) Mean loss to all buildings (USD$) 10 $632,000 20 $1,681,000 50 $2,391,000 100 $3,348,000 250 $4,850,000 500 $6,089,000 1000 $6,364,000 | Issue | 27 September 2018 Page 68 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 14, Figure 15 and Figure 16 show loss exceedance curves for risk to the population and to buildings in Bo compared to Freetown and Mekeni. They show that the potential losses in Bo are significantly less than the potential losses calculated for Freetown. Figure 14 – Loss exceedance curve (flooding, no. people affected) for Bo (also showing Freetown and Makeni for comparison). | Issue | 27 September 2018 Page 69 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 15 – Loss exceedance curve (flooding, no. fatalities) for Bo (also showing Freetown and Makeni for comparison). Figure 16 – Loss exceedance curve (flooding, direct loss to all buildings) for Bo (also showing Freetown and Makeni for comparison). | Issue | 27 September 2018 Page 70 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 71 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 5 Landslide Hazard and Risk in Bo 5.1 Introduction This section of the report provides only a very high-level summary of the landslide hazard and risk results for Bo. Since the qualitative landslide hazard and risk assessment revealed that the level of landslide risk across the city was relatively low, a further quantitative assessment of the landslide risk was not considered necessary. 5.2 Overview of qualitative assessment MAP BO-0006, Page 72 shows the results of the qualitative landslide hazard modelling for Bo. The topographic relief in Bo is very low and therefore there are very few regions of significant landslide hazard. Most of the area of Bo City shows very low landslide hazard. There are some small localised areas of medium and higher landslide hazard. These are dominantly located to the northwest and northeast of the North Ward-Reservation, in central East Ward-Lower Samamie, and in the northwestern area of West Ward-Moriba Town. These localised relatively higher landslide hazard zones appear to be associated with regional topographic features that have slightly higher relief than the surrounding low- lying plains. Other small zones of medium landslide hazard across the study area appear to be associated with localised changes in relief related to the river embankments and other local slopes (Figure 17). The qualitative landslide risk model results indicate very limited local areas of low and medium risk scattered across the study area of Bo. Occasional higher landslide risk areas appear to be related to where people have built on or close to the localised relief associated with the river channel embankments. In general, the landslide risk is very low because relatively few people have built in the lower- lying alluvial flood plain areas and therefore the exposure of both buildings and people is very low. Figure 18 gives an example of the qualitative landslide hazard data viewed in a GIS. When viewed at higher resolution within a geographical information system, it is apparent that there are very localised areas of higher landslide hazard which appear to be related to local changes in slope potentially related to natural changes in topography but also potentially related to man-made activities such as road or house embankments. The qualitative landslide hazard and risk assessments undertaken for Bo revealed very low levels of landslide hazard city-wide (e.g. MAP BO-0006, Page 72), a quantitative assessment of this hazard was not considered necessary. | Issue | 27 September 2018 Page 72 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 17 – Excerpt of MAP BO-0006 showing the qualitative landslide hazard results. Localised areas of the city where there are hills have higher landslide susceptibility. | Issue | 27 September 2018 Page 73 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 18 – Example of qualitative landslide hazard data viewed in a GIS. Area shown is in North Ward - Reservation (see inset map for approximate location). Light pink indicates low qualitative landslide hazard and darker pink indicates high qualitative landslide hazard. Building polygons and road polylines are from the exposure dataset developed as part of this study and derived from OpenStreetMap. Field of view is approximately 1.5km across and oriented north. | Issue | 27 September 2018 Page 74 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 75 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 6 Identification of Areas at Highest Risk 6.1 Introduction This section of the report identifies the areas of highest natural hazard risk in Bo. This is done by identifying specific areas of high risk as informed by the qualitative and quantitative hazard and risk assessments undertaken in this study and by consideration of ‘hot-spots’ identified by stakeholders during in-country workshops. 6.2 Urban development in flood hazard zones Using the results of the quantitative flood hazard assessments it is possible to define the zones with highest flood hazard across Bo city and the surrounding area, however it should be noted that as this is a city-scale study the existing hazard maps are not sufficient to accurately define no build zones and that more detailed assessment would be required to do so. The flood hazard zones for Bo are defined by the spatial extent of the current 100 year return period flood levels. In addition, in order to account for the anticipated influence of climate change on flood levels, the spatial extent of the 100 year return period flood has been re-calculated for the 2050 climate change scenario. Map BO-0018, Page 77 shows the spatial extent of the flood hazard zones defined by these criteria. It is recommended that future urban development plans take into consideration the extent of these flood hazard zones with future development avoiding these higher hazard zones. In particular, critical infrastructure, such as Government buildings, hospitals, schools should not be constructed in these zones, unless special hazard and risk reduction measures are implemented. These issues are discussed further in Section 7 of this report. | Issue | 27 September 2018 Page 76 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 77 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment It is then possible to determine the number of existing buildings and the existing population that is currently located within these flood hazard areas. Map BO- 0019, Page 7979 shows the approximate spatial distribution of the urban development within flood hazard zones as determined by the location of existing buildings. Table 10 provides a summary of the estimated number of people and estimated number of buildings within these flood hazard zones. Table 10 – Urban development within flood hazard zones. Current 100 year return period 2050 future 100 year return flood areas period flood areas* Population ~13,500 ~22,000 Buildings ~1,500 ~2,500 *Based on current model for population and buildings. Does not consider probably population and building count increase to 2050. Map BO-0019, Page 79, shows the approximate spatial distribution of existing development within flood hazard zones as determined by the location of buildings. Map BO-0022, Page 80 shows the estimated distribution of buildings within flood hazard zones aggregated to wards. Map BO-0023, Page 81 shows the estimated number of buildings within the 2050 flood hazard zones aggregated to wards. | Issue | 27 September 2018 Page 78 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 79 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 80 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 81 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 82 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 7 Opportunities for DRR/DRM in Bo 7.1 Introduction This section of the report presents DRR/DRM opportunities to address the risk to the city of Bo from flood hazard. The proposed DRR/DRM measures have been framed according to the priorities of the Sendai Framework for Disaster Risk Reduction (United Nations, 2015) to capture overarching recommendations that are necessary to bring about long term and sustained improvements in reducing disaster risk. In order to build a long list of appropriate DRR/DRM measures, Section 7.2 considers flood hazard and risk within the context of the Sendai Framework for Bo. Next, Section 7.3 summarises the link between Bo’s vulnerabilities and challenges and the DRR/DRM measures proposed. A number of tangible measures/recommendations for flood hazard and risk reduction are noted in Section 7.3 and are described in detail in Section 8 onwards. 7.2 Sendai Framework The Sendai Framework provides a useful context in which to set the opportunities for disaster risk reduction. The Sendai Framework is a 15-year, voluntary, non-binding agreement which recognizes that the State has the primary role to reduce disaster risk but that responsibility should be shared with other stakeholders including local government and the private sector. Its main aim is the substantial reduction of disaster risk and losses in lives, livelihoods and health and in the economic, physical, social, cultural and environmental assets of persons, businesses, communities and countries (UNISDR, 2009). The four broad DRR priorities of the Sendai Framework are: 1) Understanding disaster risk (Priority 1); 2) Strengthening disaster risk governance to manage disaster risk (Priority 2); 3) Investing in disaster risk reduction for resilience (Priority 3); and 4) Enhancing disaster preparedness for effective response and to ‘Building Back Better’ in recover, rehabilitation and reconstruction (Priority 4). In line with the priorities of the Sendai Framework for Disaster Risk Reduction, 15 general recommendations are captured in this Section (Table 11) to begin the process of reducing urban risks and increasing building resilience against flooding in Bo. The recommendations necessarily have some overlap between each Sendai Framework Priority but ultimately all recommendations need investment and this is captured in Priority 3. The recommendations have been prioritised to address the major challenges seen in Bo from the natural hazards, and in particular flooding, that are the subject of this report. | Issue | 27 September 2018 Page 83 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment The Sendai Framework and the recommendations in Table 11 are not an all- encompassing road map to address the other many cross-cutting challenges to Bo’s urban resilience. The Sendai Framework sets out the big picture principles of DRR/DRM strategy, however the DRR/DRM strategy with prioritized actions should be prepared for each catchment based on the local context. 7.3 General DRR Approaches for Bo 7.3.1 Improved Urban Planning Urbanisation due to the increasing population in Bo has been discussed in Section 2. Urban planning has not kept pace with population growth in Bo resulting in communities (often low-income groups in vulnerable buildings) relocating in high flood hazard zones within the natural channels and floodplains of rivers and on reclaimed swampland. Map BO-0018 (Page 77) shows the hazard zones for Bo, which are defined by the modelled extent of flood hazard. The current, i.e. present day, hazard zones are shown in dark pink, the lighter pink areas show the extent of the Combined Hazard Zones in the near future (year 2050) accounting for climate change. This map has two key functions for decision makers: • The map indicates the areas of the city at risk from natural hazards currently. These maps can help to inform decision makers where further development should be discouraged, unless appropriate planning and engineering procedures are in place. It also identifies the areas where public awareness with regard to natural hazard and risk should be focussed. • The map indicates that, in the near future (2050), a greater extent of the city will be within hazard zones due to the impact of climate change. This needs to be taken into consideration for urban planning, development and zoning for the city. It would be sensible therefore to increase the density of future urban development in areas of lower hazard and to minimise development in areas of the city where the hazard is highest. Additionally: • It is specifically recommended that no new school or hospital should be constructed within these flood hazard zones and that existing schools or hospitals within these zones should be reviewed within the context of the appropriate site specific global program for safer schools/hospital studies or similar. • Urban planning capacity building is recommended to improve the understanding of the distribution of natural hazards across the city and how this information should be used to inform planning decisions. | Issue | 27 September 2018 Page 84 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 7.3.2 Stopping unplanned sand mining The product of population pressure in the city coupled with poor urban planning results in a number of environmentally damaging practices within Bo that exacerbate the flood hazard and risk already present. A major environmentally damaging practice in Bo is sand mining of the natural river channels within the city. This practice can alter the natural course of rivers and the communities mining the sand settle close to or within the channel and or floodplain. These activities obstruct the flow of floodwaters and affects the natural infiltration rate of floodwaters in the floodplain. These communities increase the population and number of buildings located in higher flood hazard zones and therefore increase the risk associated with annual flooding. It is understood that sand and other construction materials are required for urban development. It is therefore recommended that planned and managed sites for obtaining sand are established. Planned development of these natural resources would also provide an opportunity for economic development. 7.3.3 Limitation of deforestation and encouraging revegetation Deforestation related to urbanization is also an environmentally damaging problem in Bo. Removing trees and natural vegetation from natural flood areas and replacing them with buildings decreases the infiltration capacity of the ground to drain floodwaters effectively. In the first instance, the public should be encouraged to minimise deforestation. Education, financial incentives and stronger urban planning and planning regulation and enforcement are required. Reforestation and revegetation schemes could be initiated in Bo as part of a wider greening initiative. Representatives from EPA note that these revegetation schemes already exist, however greater investment in government-led re- forestation and stronger financial incentives are required to promote wider uptake and faster improvements. 7.3.4 Solid waste management A further product of population pressure in the city is the significant increase in solid waste. Under the leadership of William Alpha (now Chief Administrator in Makeni), Bo City Council has made good advances in solid waste management. Bo City Council run a waste management scheme including house to house and city centre collections for SLL 25,000 per month per house. In addition, with DFID funding, Bo City Council are clearing the old 1957 dump site from the centre of the city with the aim of creating a city park. Bo City Council also support a number of recycling initiatives. Further capacity building and funding for the Bo City Council Waste Management Department should be prioritised to ensure that these initiatives become sustainable. | Issue | 27 September 2018 Page 85 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 7.3.5 Community engagement and shared learning There are many examples of successful community engagement initiatives to promote all cycles of the urban resilience agenda from preparedness to recovery and this is crucial to the success of any DRR measures proposed in this project. Bo city is home to the Bo Teacher's College, many primary and several secondary schools, including one of the elite secondary schools in West Africa, The Bo Government Secondary School. As a hub of education, the well-educated youth of the city could be further engaged and incentivised to develop ongoing community natural hazard and risk management practices, as well as reforestation, waste clearance and recycling initiatives. | Issue | 27 September 2018 Page 86 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Table 11 – DRR/DRM for Bo within the context of the Sendai Framework. Priority 1 – Understanding Natural Disaster Risk No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale5 Improvement (lead in bold) guidance? Knowledge of Better understand and Further investigation and study Detailed flood hazard maps National Government Brief note in Short- term. flood hazard in characterize flooding at of flood hazard building on this for each ward in Bo. (for funding and National Disaster Bo. catchment scale. data. assignment of roles), Preparedness Plan. Fund courses on Civil EPA. Engineering at university level. 1 Better understand the Support existing UNDP Climate Weather and climate National Government (for UNDP funded Medium term. characteristics of the river project (CIDMEWS) to collect network. funding and assignment project network response to flooding and openly share rainfall and River gauge network. of roles), EPA. CIDMEWS). in Bo. weather data. Collect and openly share river gauge data. Knowledge of Data collection on exposure Perform detailed site surveys Detailed survey data and National Government, National Land Short to exposure and and vulnerability (site for priority assets. reports to be available in an Local Government, ONS, conference 2017? Medium term. vulnerability in assessments) for priority accessible database in Ministry of Land Country Bo. assets in Bo, including geospatial format managed Planning and Noted in Sierra hospitals, emergency by an appointed government Environment, EPA, Leone Disaster response facilities, schools agency. Technical Specialists (in- Management and critical infrastructure county and international), Policy, Draft 2006. 2 including roads and bridges. New mapping agency. Consider building on Open Street Map dataset from this project. As a secondary priority, data should also be gathered on drainage or flood defence assets in selected catchments. 5 Proposed timescales (same for each table): Short term – 1 year; Medium term – 1 to 3 years; Long term – 3 years | Issue | 27 September 2018 Page 87 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 1 – Understanding Natural Disaster Risk No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale5 Improvement (lead in bold) guidance? Gather and share post-disaster Form an in-country Field investigation reports National Government (for National Land Short to damage and loss data for organization to carry out multi- and related data. funding and assignment conference 2017? Medium term. physical assets. disciplinary post-disaster data of roles), ONS-DMD, Noted in Sierra Gather and share post-disaster collection missions. This should Technical Specialists (in- Leone Disaster site effect data (flood high- include investigation of: county and international), Management water mapping). performance of physical assets, Insurance. Policy, Draft 2006. geological and flood data, evaluation of disaster management and socio- economic effects. Communicate findings with key stakeholders including the insurance industry. Education and Increase awareness of natural Continue public awareness Radio, television National Government, Noted in Sierra Short term. communication hazards and risk. campaigns through national and broadcasts. ONS-DMD, Ministry of Leone Disaster to citizenry Inform public officials and local media. Written materials. Information and Management about flood other decision makers. Communication (MIC). Policy, Draft 2006. Wall murals and posters. hazard. Promote competency of professionals. Implementation of flood hazard Schools curriculum for Medium term. 3 disaster awareness in schools. teachers and students on flood risk. Education of government and Training materials and Medium term. municipal officials through guidance documents for training and written materials. government and municipal officials. | Issue | 27 September 2018 Page 88 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 1 – Understanding Natural Disaster Risk No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale5 Improvement (lead in bold) guidance? Education of engineers and Continued Professional National Government, No. Medium to architects. Development (CPD) Local Government, ONS- Long term. courses for engineers and DMD, Sierra Leone architects. Universities. University curriculum on natural hazards and risk, including design requirements. Education of communities in Community engagement to Local Government, ONS- Noted in Sierra Short term. flood hazard awareness. empower community DMD, Ministry of Leone Disaster Consideration should be given groups and local leaders. Information and Management for gender and age factors, Communication (MIC), Policy, Draft 2006. cultural differences as well as Communities. more vulnerable groups. | Issue | 27 September 2018 Page 89 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 2 – Strengthening disaster risk governance to manage disaster risk No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale Improvement (lead in bold) guidance? DRM To strengthen the DRM legal To update and approve DRM A finalised and adopted National Government, Sierra Leone Short term. Framework. framework and policy in Bo, policy based on Sierra Leone DRM strategy enabling ONS-DMD. Disaster including aspects which address Disaster Management Policy, climate-smart and resilient Management DRM for flood hazards. draft June 2006. decisions at city scale. Policy, draft June To establish consistent DRM Investment plans to carry 2006. 4 terminology among out DRM actions. stakeholders and in laws related Strategy for obtaining funds to DRM and DRR. to carry out DRM (from National Government, local government and NGOs). The legal Overall, to reduce the risk from Enact laws which require urban Legal framework to require National Government, National Land Short to framework for natural hazards for new and areas to have up-to-date zoning up-to-date urban plans. Local Government. conference 2017? Medium term. urban plans for existing development. plans. Bo City Specifically, to ensure the Council. regulatory framework requires the development and adoption of up-to-date zoning plans. Ensure urban plans take into Provide funding and added Hiring of additional staff in National Government, National Land 5 account up-to-date information capacity to those who carry out Local Government, Local Government, conference 2017? on flood hazard and risk. urban planning to access, Ministry of Land and other Ministry of Land understand and incorporate government agencies Country Planning and natural hazard and risk involved in producing Environment, ONS- considerations into zoning zoning planning. DMD, Technical planning documents. Training programmes for Specialists. This should involve the ability existing staff involved in to access relevant databases zoning planning in natural which contain hazard and risk hazard and risk. data (GeoNode and others). | Issue | 27 September 2018 Page 90 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 2 – Strengthening disaster risk governance to manage disaster risk No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale Improvement (lead in bold) guidance? The capacity Improve the quality of reviews Ensure the building permitting Updated regulatory Local Government, Draft National Medium term. and capability ahead of design approvals and process is simple and requirements and processes. Ministry of Land Country Building Code Draft of design. construction permits. transparent. Added capacity for officials Planning and 2015. Ensure consistent construction Introduce information involved in the regulatory Environment, Ministry of monitoring. communications technology process. Works Housing and Framework for (ICT) for building control Infrastructure. review and Ensure consistent enforcement Revised requirements for checking of of regulatory documents. procedures. obtaining engineering good practice. Increase capacity and professional licences. remuneration of officials 6 involved in design approvals and construction monitoring. Ensure fees are consistent with the cost of regulatory services. Ensure penalties are enforced for lack of compliance. Increase inspection requirements for construction, particularly residential construction. | Issue | 27 September 2018 Page 91 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 2 – Strengthening disaster risk governance to manage disaster risk No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale Improvement (lead in bold) guidance? Regional and To promote internal Create role exchanges at city Established exchange Local Government, No Medium term inter-city collaboration and exchange of level within a dedicated team of programmes with targets Universities, Technical collaboration in knowledge in the area of natural specialists. that are monitored. Specialists (in-county and the areas of hazard engineering and disaster Government scholarships to international). natural hazard risk reduction. foreign universities (which engineering and include conditions such as disaster risk returning to Sierra Leone 7 reduction. for a certain number of years after completion of degree). Hosting of international conferences related to natural hazard engineering and/or DRR. Central, quality To update and improve existing Roles and responsibilities to be Establishment of openly National Government, No Medium term reviewed, city-wide databases for natural assigned for the maintenance of accessible databases. ONS-DMD and other maintained and hazard and risk data including databases and sharing of appointed stakeholders, managed open location and characteristics of information among government Technical Specialists (in- 8 source data on physical assets and expected agencies and other stakeholders. county and international). flood hazard, damage and losses. exposure and risk. | Issue | 27 September 2018 Page 92 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 3 – Investing in Natural Disaster Risk Reduction for Improved Urban Resilience No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale Improvement (lead in bold) guidance? Invest in To reduce the risk from flood, Produce up to date zoning plans Hazard and risk maps and National Government, No, Land Policy Medium term improved urban hazards for new and existing based on the results of this data to be integrated into Local Government, ONS- Conference, 2017? planning and development in Bo. study and the ‘high hazard zone zoning planning and DMD, Ministry of Noted in Disaster zoning plans maps’. regulations. Lands, Country and Management taking into Produce guidance on Infrastructure (particularly - Environment, Ministry Policy, Draft 2006. consideration infrastructure planning and + and drainage) to be of Works Housing and hazard and risk installation. designed and installed prior Infrastructure. information and to house construction. Add capacity and capability to ‘high hazard zone local authorities and others who 9 maps’ from this carry out zoning planning so study. they can access and use hazard and risk data from this study. Educate government officials in Guidelines for site selection Local Government, No, Land Policy Short term planning and engineering for critical buildings Technical Specialists, Conference, 2017? professionals on selection of (schools, hospitals, Ministry of Lands, safer sites for critical/higher emergency response Country and importance buildings and facilities) and infrastructure. Environment. infrastructure. Invest in To train engineering Develop and deliver Continuing Training materials in CPD. National Government for No, Land Policy Long term improved professionals in climate-smart Professional Development University courses on investment planning. Conference, 2017? understanding and designs resilient to flood (CPD) courses on the current hazard resilient and climate- Universities, Local Noted in Disaster 10 among engineers, hazards. best practice for climate-smart smart designs and principles Government. World Management developers and and resilient design principles of ‘build-back-better’. Bank. Policy, Draft 2006. communities and detailing. | Issue | 27 September 2018 Page 93 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 3 – Investing in Natural Disaster Risk Reduction for Improved Urban Resilience No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale Improvement (lead in bold) guidance? about disaster risk To build understanding at Develop practical, locally Guidance notes targeting Local Council, Ministry Noted in Disaster Long term. reduction and community level about appropriate guidance for community on a range of of Information and Management mitigation. disaster risk reduction and community education on DRR-related topics Communication (MIC). Policy, Draft 2006. mitigation measures. actions that would improve including: recommended urban resilience to flooding. flood prevention construction of houses, and; recommended solid waste disposal that does not block drainage. Invest in To produce/update building Recommendations related to Revised Norms. National Government, No. Long term. improved codes codes. updates for the building code Guidance materials relating Ministry of Works and standards and To improve the provisions for include: to the Norms. Housing and guidance related disaster-resilient and climate- Updated flood, hazard and risk Infrastructure. to disaster smart design for housing and maps. resilient and infrastructure. New provisions for non- climate-smart 11 structural mitigations. house designs. Update Norms and/or guidelines on hazard assessment of buildings and infrastructure. Update Norms related to hazard retrofit of buildings and infrastructure. | Issue | 27 September 2018 Page 94 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 3 – Investing in Natural Disaster Risk Reduction for Improved Urban Resilience No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders Existing Timescale Improvement (lead in bold) guidance? Invest in To reduce the impact on the Review proposed intervention Detailed investment plans National Government for Freetown Structure Medium and intervention DRR population of Bo in terms of DRR measures from this report. for each ward including investment planning. Plan 2013-2018 & Long term. measures to loss of life and economic Review priority of intervention detailed cost for each DRR Local Government Freetown City reduce economic costs from damaging floods. measures by considering Urban intervention measures. (BCC) for Development Plan losses and loss of To improve resilience of the Planning and cost-benefit Identify funding to carry out implementation of the 2016-2018 & life from population of Bo to damaging analysis. investment plans. plans. Environmental 12 damaging floods. floods. Assessment and Implementation of risk Evaluation of reduction measures to Natural Disaster reduce flooding for each Risk and Mitigation ward including engineering in Freetown. No measures. similar plan is available for Bo. | Issue | 27 September 2018 Page 95 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 4 – Enhancing Preparedness for Natural Disasters No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders (lead Existing Timescale Improvement in bold) guidance? 13 Improved To improve emergency In general, the results of this Updated national, regional National Government, National Disaster Medium term. understanding and preparedness in different key study should be used to inform and city level emergency Local Government, Preparedness Plan implementation of sectors (education, health, emergency response and plans. Ministry of Health and & National Disaster actions for flood critical infrastructure, cultural preparedness planning at a Sanitation. Management and landslide heritage) and at different national and local level. Policy. preparedness. scales (National, regional, Cross sectoral collaboration and city-level and communities). sharing of information is essential for robust planning. For hospitals, MoHS to Sharing of emergency National Government, National Disaster Medium term. coordinate which hospitals are response plans among Local Government, Preparedness Plan more critical for emergency stakeholders. Ministry of Health and & National Disaster response and expected number Hospital emergency Sanitation. Management of causalities for flood/landslide response plans and training Policy. scenarios. materials for hospital staff. Countywide emergency preparedness planning and training for hospital staff including communication and coordination post-disaster and maintaining emergency medical supplies. Provision of mobile emergency medical facilities to allow adequately resourced emergency medical response for remote regions or where access to permanent medical facilities is not available. | Issue | 27 September 2018 Page 96 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 4 – Enhancing Preparedness for Natural Disasters No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders (lead Existing Timescale Improvement in bold) guidance? For emergency response Sharing of emergency National Government, National Disaster Medium Term. facilities (including fire response plans among Local Government, Preparedness Plan stations), MoHS to coordinate stakeholders. Ministry of Health and & National Disaster which emergency responses National, regional and local Sanitation. Management facilities are more critical for emergency response plans Policy. emergency response. and training materials for Countywide emergency first responders related to preparedness planning and natural hazard risks. training for emergency response Countrywide coverage for staff including communication emergency response plans and coordination post-disaster and resource (permanent and maintaining emergency and voluntary), including supplies. rural and remote areas. Countrywide programme for community first responders. For schools, MoE to Sharing of emergency National Government, National Disaster Medium term. coordination with response plans among Local Government, Preparedness Plan municipalities on which schools stakeholders. Ministry of Education. & National Disaster they plan to use for emergency Training materials for Management response. teachers and students. Policy. Countywide emergency preparedness training for teachers and students. 14 Improved Assess emergency response Scale-up programmes for Updated investment plan National Government, National Disaster Medium term. responsiveness capability in country or training of community first for improving capacity for Local Government, Preparedness Plan and through wider international responders in areas without emergency response Communities. & National Disaster comprehensive assistance (shelter, food, designated emergency response including capacity building Management systems for search and rescue). personnel. in communities. Policy. emergency Early warning system. Implementation of the plan. response. | Issue | 27 September 2018 Page 97 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 4 – Enhancing Preparedness for Natural Disasters No. Area for Objectives Actions Outputs/Outcomes Key Stakeholders (lead Existing Timescale Improvement in bold) guidance? Improved early warning systems for flood, storm surge and landslides. Improved and country-wide communications network for emergency response. 15 Improved To understand the funding Gather and share risk Engagement with National Government, DaLA report Long term. economic gap for potential losses from assessment loss data to international, regional and ONS- DMD, Insurance, National Disaster resources to natural disasters. understand funding gap and local insurance stakeholders Technical specialists. Preparedness Plan address post- To identify potential sources ensure fair pricing of insurance. to share loss data to inform & National Disaster disaster funding of funds that can be allocated The National Government updated catastrophe models Management and recovery. post-disaster. should consider viability of for the country and region. Policy. To strengthen government exte-ante funding arrangement, A disaster risk financing regulation of the insurance insurance pools, traditional plan for the National market to ensure financial insurance and re-insurance. Government. This could stability and growth of Train and retain more insurance include in the longer term, capitalisation and incentivize professionals in Sierra Leone. public and private insurance take up of disaster risk partnerships (countrywide Update laws and regulations insurance. and regional/global). relating to insurance. To spread insurance risk Training for insurance Standardize insurance coverage regionally/globally. professionals related to with respect to natural disasters. policies for disaster related To increase robustness and Raise public awareness about insurance. penetration in insurance the benefits of private insurance market to respond to natural coverage for natural disaster hazard losses. events. | Issue | 27 September 2018 Page 98 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 99 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8 Hazard and Catchment Specific DRR/DRM Measures 8.1 Introduction The DRR/DRM options for Bo proposed in this section have been informed by discussion with the stakeholders, field observations, expert judgment and research, and by the qualitative and quantitative flood hazard and risk maps that have been developed by this study. A broad range of DRR measures have been considered based on a high-level qualitative review of cost, practicality, and consideration of the climate, topography and nature of the flood hazard in Bo. In line with international best practice, this study recommends that individual DRR/DRM measures are combined for practical implementation as opposed to implementing individual measures in isolation. Herein, the combinations of measures proposed in this study are referred to ‘DRR/DRM Options’. Combining measures typically reduces the risk from multiple types of hazard. For example, reforestation, hazard signage and flood-landslide communication and community engagement in combination are relatively low cost and reduce the hazard-risk from flooding and landslides. All DRR/DRM measures should be integrated across multiple sectors for developing a well-functioning and resilient city. Development planning should move away from traditional single silo master planning and integrate appropriate interventions, combining multiple DRR/DRM measures. High- level cost-benefit analysis (CBA) is one tool to help establish prioritised DRR/DRM Options, however, unfavourable CBA results should not exclude potentially effective measures. 8.2 Flood Hazard Specific DRR/DRM Measures International ‘state-of-the-practice’ in flood management is moving towards natural catchment management, which focusses on revegetation of the natural river channels and reforestation of the upper catchment (e.g. Forbes et al. 2015; Woods Ballard et al. 2007). This strategy is in line with the Greening Africa initiative (White et al. 2017). Greening measures, particularly in the upper catchment are interpreted to be the best way to mitigate for the effects of severe flooding in the lower catchment urban areas. Implementing DRR measures in the upper catchment also helps to avoid unnecessary implementation of more expensive and intrusive ‘hard’ engineering solutions in the lower catchment. The terrain in and surrounding Bo city area has low relief the catchments are relatively large and contain main river channels with several tributaries with broad | Issue | 27 September 2018 Page 100 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment floodplains. The study area has five drainage catchments (C1-C5; Map BO-0028, Page 111), but of these there are two main catchments (C1 and C5) that contain almost all the wards, including the entire main urbanized area. Bo is naturally vegetated and swampy, with low topographic relief. Hence, some of the greening aspects of the natural catchment management are already in place in Bo. However, the low relief results in some other challenges for DRR, specifically related to conveyance of floodwaters efficiently through the natural drainage system. Figure 19 provides a summary of each of the proposed DRR/DRM measures at schematic catchment scale. | Issue | 27 September 2018 Page 101 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 19 – Schematic illustration of a river catchment in Bo and proposed flood hazard DRR/DRM options for Bo. Illustrations of measures adapted from the Sustainable Urban Drainage Manual (Woods-Ballard et al., 2007). | Issue | 27 September 2018 Page 102 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Table 12 – Flood hazard DRR/DRM options recommended for Bo. Measure Hazard DRR/DRM Measure DRR/DRM number Option Flood + 1 Hazard and risk communication and engagement 1 Landslides 2 Flood Early warning systems 1 3 Flood Revegetation of the natural channels Flood + 4 Community drainage implementation 2 Landslides 5 Flood Instrumentation and monitoring 6 Flood Flood water storage ponds 7 Flood Flood hazard signage 1 Zoning (including land-use plans), land readjustment Flood + 8 and building regulations - implementation and Landslide enforcement 9 Flood Rooftop rainwater harvesting 10 Flood Engineered green channels 11 Flood Engineered concrete culverts 2 12 Flood Drainage channel clearance 2 8.2.1 Flood hazard and risk communication and engagement Communication of hazard and risk information and the associated community engagement should be an essential component of the holistic and sustainable DRR/DRM strategy for Bo. It is very important that citizens be provided with access to the information related to the hazards that threaten their communities. It is recommended that the hazard and risk information be provided to communities through a range of communication mechanisms taking into consideration the broad range of stakeholders and their communication needs. Examples could include, local and national radio warnings, flood hazard sensitisation programs in schools, community WhatsApp groups for sharing information and hazard warning communication co-ordinated administrated by a council representative linked to the ONS. City and District Council website information dedicated to flood hazard and a designated flood hazard reporting phone number for the rainy season. Some of these communication methods are already in use in Bo, but they can still be more strongly supported and strengthened, in addition to new methods added to create a co-ordinated framework of communication at every level in the city, from the community to the councillors. | Issue | 27 September 2018 Page 103 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8.2.2 Early warning systems The Climate Information, Disaster Management, and Early Warning System – Sierra Leone (CIDMEWS-SL) web portal7, which is scheduled to launch early 2018, will provide early warning system capability across Sierra Leone. The system will be the first of its kind in Sierra Leone and serve as both a planning and response tool (UNDP Newsletter, November 20178). The rainfall data available from CIDMEWS-SL could be used to inform flooding early warnings based on flood triggering rainfall thresholds. Typically, these systems are defined at the regional scale, regardless of the different susceptibility of each catchment. Global good practice indicates that early warning systems require a strong technical basis calibrated to local conditions. It is important that the warning system is “people centred”, with a robust dissemination system that functions under difficult and extreme environmental conditions, with clear messaging to all recipients, and is co-ordinated with other DRM measures to effectively direct the impacted population to defined safe areas such as disaster response shelters within the city (discussed below). 8.2.3 Revegetation and reforestation of the natural catchment areas This concept capitalises on use of the natural hydrological processes, landscape features and characteristics of an area to manage flooding. It involves altering or restoring a landscape to reduce, store or transport flood waters. There are many ways in which this could be achieved. In Bo, since development in the natural channels and floodplains is limited at present, it would be important to maintain this state to stop flood hazard and risk increasing. Indicative regions for maintaining the natural state of vegetation within the flood hazard zone areas. Often, re-vegetation and reforestation measures are proposed for upper catchments to increase the rate of rainwater infiltration and to reduce the volume and rate of flow of floodwaters where there are steep mountain slopes and the rates of precipitation are typically higher. Although Bo does not have this type of upper catchment topography, it is still important to maintain the natural state of vegetation in the river channels so that rates of infiltration are maintained. 8.2.4 Community drainage implementation Most urban development, particularly away from the city centre areas, has no planned drainage infrastructure to collect rainfall run-off and transport the water to the natural drainage network in a controlled manner. It is recommended that drainage infrastructure be planned for all urban development in Bo. The World Bank funded, Management of Slope Stability in Communities (MoSSaiC) approach, established by researchers from the University of Bristol, provides a community-based and scientific approach for delivering flood (and landslide) 7 CIDMEWS-SL @ https://www.cidmews-sl.solutions/index.php/component/users/?view=remind 8 http://www.sl.undp.org/content/sierraleone/en/home/library/crisis_prevention_and_recovery/disas ter-recovery-and-risk-management-newsletter--.html | Issue | 27 September 2018 Page 104 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment hazard reduction measures (Anderson and Holcombe, 2013). A schematic illustration of the MoSSaiC system is shown in Figure 20. It is recommended that a pilot study of the MoSSaiC drainage system be undertaken within a catchment area of Bo to demonstrate the benefits that can be achieved. Following the successful implementation of a pilot study, the installation of drainage infrastructure more widely across Bo could be more accurately costed and undertaken. Whilst this type of study is more typically applied in areas of higher relief, the principles could still be applied for Bo. Figure 20 – The MoSSaiC community based drainage system to reduce flooding and landslide hazard and risk (World Bank Project Insights 78723 Issue #12). 8.2.5 Instrumentation and monitoring There are very few or no locations where rainfall and rivers flows are systematically recorded in Bo city and the surrounding area. It is therefore difficult to calibrate any quantitative analysis of rainfall distribution, run-off and the resulting flows in rivers and streams in the region. It is recommended that a network of rain gauges and stream gauges are established across the region to provide the required scientific information for related analysis. If funding were made available, it is recommended that appropriate academic institutions in the region are given the task of operating and | Issue | 27 September 2018 Page 105 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment maintaining the instrumentation and for the systematic storage and interpretation and dissemination of the resulting information. 8.2.6 Flood-water storage ponds Floodwater storage ponds can be natural low topographic areas either within the flood plain of the river system or along the river channel itself. There are two main reasons for providing temporary detention of floodwater: • Compensate for the effects of catchment urbanisation; and, • Reduce flows passed downriver and mitigate downstream flooding. Achieving either or both above objectives would help reduce the flood hazard across Bo. There are a number of different floodwater storage options that can be considered and the selection of the type and location of such measures would require more detailed engineering and hydrological investigation. Example locations for flood storage ponds are shown on MAP BO-0028, Page 111. 8.2.7 Flood hazard signage Hazard signage is a relatively low-cost, high impact risk-reduction measure that will raise awareness of flood hazards across the city. The aim of is to facilitate a general citywide education program related to flood hazards and risk. Associated plans and evacuation routes should also be developed. It is recommended that signs are located where they can receive maximum visual impact to the communities, chiefly at main road junctions, typically in urban areas, and close to high hazard areas as identified by the quantitative hazard mapping. If hazard signage is to be implemented, it is recommended that the sign locations should be decided in conjunction with the ONS. Example locations for flood hazard signs are shown on MAP BO-0028, Page 111. | Issue | 27 September 2018 Page 106 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8.2.8 Zoning regulations It is recommended that zoning planning maps are developed for Bo. Zoning maps should be used to help inform future urban development in the city and to ensure that future development takes into consideration the spatial distribution of natural hazards across the city. It is recommended that the hazard maps prepared for this study are used to inform decision makers whether land is suitable for specific building usage types including emergency response facilities, Government administrative buildings, hospitals and other medical facilities, schools and critical infrastructure. Bo should focus on ‘efficient utilization’ of existing safe land within the urban area (low hazard zones) by considering varied urban design tools for densification of safe zones, such as increasing square footage by land- readjustment (Figure 21), building additional floors, infill development, spot zoning etc. based on the specific site condition and land-use. This would allow the city to grow in a more sustainable and resilient way with reduced cost of service delivery for compact city, encouraging public-private partnerships for cost recovery. | Issue | 27 September 2018 Page 107 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Figure 21 – Land readjustment can be an alternative to high-rise construction for densification of safer areas through spot zoning (diagram from https://unhabitat.org/books/remaking-the-urban- mosaic-participatory-and-inclusive-land-readjustment/ ) | Issue | 27 September 2018 Page 108 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8.2.9 Rooftop rainwater harvesting The aim of rooftop rainwater harvesting is to store rainwater in artificial, closed containers, made from a safe, sanitary material. This flood risk-reduction option helps to reduce the volume of rainwater runoff flowing into the watercourses. The ‘harvesting’ method can capture intense rainstorm runoff and the stored (clean) water could then be used for drinking, cooking, cleaning and for agriculture and livestock. 8.2.10 Engineered green channels Engineered green channels involve re-profiling and re-vegetating natural or man altered drainage channels, helping to increase the capacity for floodwaters and slowing their flow. These engineered green channels have been proposed in the catchment locations where flow is currently restricted and where main transport routes cross existing channels with high flood hazard levels. 8.2.11 Engineered concrete culverts Undersized culverts were identified at a number of locations in Bo city. It is recommended that further civil engineering design calculations are undertaken to correctly size the culverts to ensure that design flows are not restricted. These engineered culverts are proposed in the catchment locations where flow is currently restricted and where main transport routes cross existing channels with high flood hazard levels. It is important that the resizing of culverts is undertaken in conjunction with related channel works upstream and downstream of the culverts such that flows are transferred through to large scale natural drainage system outside of Bo city. 8.2.12 Drainage channel clearance It is recommended that a systematic program of unblocking waste from the existing open drainage channels and culverts is undertaken as a priority. Clearance of the existing drainage network will promote improved conveyance of floodwaters, particularly in the denser urban areas where solid waste significantly obstructs drainage. It is recommended that community groups and the wider community could be incentivised to participate in the clearing of waste from the drainage network of the city. The summer 2016 ‘Operation Clean Freetown’ initiative9 highlighted that citywide community involvement in Sierra Leone can result in citywide flood hazard reduction. People were incentivised to clear waste from their homes for collection, helping to significantly reduce the impacts of flooding related to blocked urban drainage during the rainy season. 9 http://apanews.net/en/news/sierra-leone-announces-operation-clean-freetown http://www.presidentsrecoverypriorities.gov.sl/single-post/2017/05/14/Youth-groups-trained-in- door-to-door-waste-management-under-Operation-Clean-Freetown-are-equipped-to-begin-work | Issue | 27 September 2018 Page 109 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8.2.13 Multi-purpose disaster response shelters It is recommended that multi-purpose disaster response shelters are established at locations across the city of Bo. It is important that the shelters are located outside defined flood and other hazard zones, are evenly distributed across Bo and at secure locations accessible to the public via existing infrastructure. It is recommended that the disaster response centres are established my upgrading existing schools or other existing community facilities or by construction of new school or community facilities. It is important that the shelter is multi-purpose so that social benefits to the community are maximised and the facility is used and maintained while not required for its disaster response shelter function. Schools and community facilities are recommended because they are typically perceived as safe and secure for children, woman and vulnerable members of society including the elderly. It is recommended that the shelters include separate sections for women and their children – as it is very important that shelters are regarded as providing a “safe haven” (World Bank, 2014). One of the purposes of the centre will be to provide temporary accommodation for displaced people during and immediately after a disaster such as flooding. It is therefore important that the centre has suitable covered space such as a hall or other building for the required number of displaced people and in addition, sufficient open space where additional people could be accommodated in tents if required. It is also important that the centre has sufficient welfare facilities that could be used by an increased number of people if required. Welfare facilities would include toilets, water and bathing, and facilities cooking. In addition to welfare facilities for impacted population, it is recommended that open space is available if possible for livestock which allows improved economic recovery. | Issue | 27 September 2018 Page 110 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 111 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 8.3 Flood DRR/DRM recommendations by catchment for Bo Map BO-0028, Page 111 shows the DRR/DRM measures proposed for each catchment. Below, the hazard-risk context and the proposed flood risk-reduction measures for each catchment are described. The proposed measures have been described at potential flooding hotspots identified from satellite imagery. These flood hotspots are not verified. 8.3.1 Nguabu-Sewa1 (C1) In the west of Bo city, the spatial extent of the 100 year return period flood level intersects and flows west through a culvert under the Bo-Kenema Highway, approximately 110m north of the Forbie Street junction to the highway (MAP BO-0028, Page 111). This is the main highway into and out of the city. This Highway also links secondary roads to the greater than 10 hospitals and medical centres which serve the Bo community. The proposed DRR measures for C1 at this potential flooding hotspot include: • Flood-hazard signage to communicate the hazard and risk in the catchment; • Clearing the drainage channels and culverts of waste and sediment to increase the conveyance of flood waters through the urban areas; • Re-sizing of channels and culverts to ensure flow is not restricted; • Restoring the natural floodplain to help infiltration of flood waters into the ground; and • Investigation of low-lying rural areas close to or already part of the natural floodplain for water storage adjacent to but higher in the catchment than the flooding hotspot. 8.3.2 Nguabu-Sewa2 (C1) This potential flooding hotspot is located in the west of the city where the spatial extend of the modelled 100 year return period flood water level intersects with the Bo-Kenema Highway, 110m northwest of the Towama Road junction on the highway (MAP BO-0028, Page 111). The watercourse flows through a culvert beneath both the Towama Road and the Bo-Kenema Highway. Restriction of flow and potential flooding would affect two of the city’s main transport connections. Additionally, a hospital and a medical centre lie within the flood zone at this location. The proposed DRR measures for C1 at this potential flooding hotspot include: • Flood-hazard signage to communicate the hazard and risk in the catchment; • Clearing the drainage channels and culverts of waste and sediment to increase the conveyance of flood waters through the urban areas; • Re-sizing of channels and culverts to ensure flow is not restricted; | Issue | 27 September 2018 Page 112 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment • Restoring the natural floodplain to help infiltration of flood waters into the ground • Investigation of low-lying rural areas close to or already part of the natural floodplain for water storage adjacent to but higher in the catchment than the flooding hotspot. 8.3.2.1 Nguabu-Sewa3 (C1) In central Bo City, the spatial extent of the modelled 100 year return period flood levels affects one of the most densely built up areas of the city, and also one of the main roads facilitating transport north-south through the city. At the roundabout of Mahei Boima Road and Galu Road the watercourse flows beneath the road via culvert(s) (MAP BO-0028, Page 111). Intense flooding at this site would affect hundreds of buildings and disrupt transport on the main road. The proposed FDRR measures for C1 at this potential flooding hotspot include: • Flood-hazard signage to communicate the hazard and risk in the catchment; • Clearing the existing drainage channels and culverts of waste and sediment to increase the conveyance of flood waters through the urban areas; and • Re-sizing of channels and culverts to ensure flow is not restricted. 8.3.2.2 Samamie (C5) In the south of the city the spatial extent of the modelled 100 year return period flood waters levels intersects with the culvert below the roundabout of the Bo- Tiama Highway and Sewa Road (MAP BO-0028, Page 111). Flooding damage at this hotspot would disrupt north-south transport along the major Bo-Tiama Highway and Sewa Road and would impact community access to the hospitals and medical centres that serve the Bo community. The proposed FDRR measures for C5 at this potential flooding hotspot include: • Flood-hazard signage to communicate the hazard and risk in the catchment; • Clearing the drainage channels and culverts of waste and sediment to increase the conveyance of flood waters through the urban areas; • Re-sizing of channels and culverts to ensure flow is not restricted; • Restoring the natural floodplain to help infiltration of flood waters into the ground; and • Investigation of low-lying rural areas close to or already part of the natural floodplain for water storage adjacent to but higher in the catchment than the flooding hotspot. | Issue | 27 September 2018 Page 113 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 114 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 9 9 Recommendations 9.1 Recommendations for DRR/DRM Priorities This study has provided, for the first time, quantitative spatially accurate digital natural hazard and risk data for Bo city. This data is now freely available in printed A4 and A3 size documents and in digital GIS format. It is recommended that awareness of this information is promoted so that all members of the Government, ministries, the Bo city councils, and community are engaged and can communicate about natural hazard and risk issues in their city. The aims of the DRR/DRM recommendations described in this report are to save lives, reduce the number of people impacted, and to reduce the direct losses and economic impact caused by damage and disruption to the built environment from natural hazards. The DRR/DRM recommendations are presented in terms of a wider holistic strategy at city region scale. The holistic strategy takes into consideration the setting and terrain of the city with an emphasis placed on understanding the distribution of hazards and risks, community involvement and communication, re-establishing green and environmental solutions throughout the city to manage the risk associated with natural hazards, and providing early warning where possible and providing shelter for impacted people when disaster strikes. Priority 1 – Re-sized engineered culverts and clearing of waste from existing drainage This DRR option involves the re-sizing of the engineered culverts at selected locations across Bo and the clearing of waste from exiting manmade and natural drainage channels. Well-designed culverts (linking to designed) at these will potentially have a significant impact on flood hazard reduction, offering a possible benefit of nearly $2.5M USD over a 33-year period. Priority 2 – City-Wide Hazard and Risk Communication Cost benefit analysis undertaken on potential city-wide DRR/DRM options indicates that, city-wide hazard and risk communication would be beneficial for Bo. Establishing a hazard and risk communication program, including formation of a hazard and risk communication team, installation of hazard and risk signage, and establishment of an early warning system for Bo is beneficial in terms of the risk reduction that can be achieved. In addition to the potential avoided direct damage and financial losses associated with flooding it is estimated that the average annual potential loss of life avoided through hazard and risk communication will be approximately 1 to 2 lives saved every 2.5 to 5 years. | Issue | 27 September 2018 Page 115 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Priority 3 – Urban Planning and Zoning One of the most effective ways to save lives and reduce losses going forward is to minimise further building in the combined hazard zones. (Map BO-0018, Page 77). Currently ~7% of Bo’s population live in these higher hazard zones and this number will increase if further building in these zones is not managed. If further building is allowed to continue in an unmanaged way then the risks associated with flooding will continue to increase. It is recommended that further consideration, are undertaken for the wider range of DRR/DRM options to help prioritise and inform the implementation of a holistic and sustainable DRR and DRM plan for the city of Bo. This further work should be undertaken at the next stage when alignment can be made with urban planning. In the next stage, good urban planning should focus on the relationships between buildings, the spaces they create, the people in the communities and their livelihoods and the sustainability and resilience of the urban development. The urban planning should consider the geographic distribution of natural hazard and risk identified in this project. This will help move the city away from a reactive development approach to one that prioritizes the prevention and management of risk and encourages sustainability and resilience as an intrinsic component of the economic development. Bo should focus on ‘efficient utilization’ of existing safe land within the urban area (low hazard zones) by considering varied urban design tools for densification of safe zones, such as increasing square footage by land- readjustment, building additional floors, infill development, spot zoning etc. based on the specific site condition and land-use. This would allow the city to grow in a more sustainable and resilient way with reduced cost of service delivery for compact city, encouraging public-private partnerships for cost recovery. While establishing zoning, and building regulations for the whole city may seem overwhelming, spot zoning of low risk zones is a feasible approach to the same issue, and this can quite easily be done by demarcating zone along existing natural boundaries (road, drain etc.), and by giving it a special zoning district status for integrated multi-use redevelopment, that can help to densify safer zones for accommodating residents currently living in high-risk areas. 9.2 Recommendations from Stakeholders Throughout the course of the Project, the Project Team have held workshops and tried to engage with local stakeholders. Workshops were held in Bo on two occasions, with further stakeholder meetings and city walkovers with local stakeholders also undertaken. During these workshops, key stakeholders provided a wealth of information to support the Project. The stakeholders also highlighted | Issue | 27 September 2018 Page 116 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment numerous recommendations for future studies which were beyond the scope of this project. These recommendations included: • The Sierra Leone Multi-City Hazard Review and Risk Assessment Project was originally intended to cover six cities across Sierra Leone: Freetown, Makeni, Bo, Bonthe, Kenema and Koidu. During the inception stages of the project Bonthe, Kenema and Koidu were removed from the project scope. Numerous key project stakeholders have identified the importance of undertaking a similar natural hazard review and risk assessment in each of these additional cities to ensure each state capital has an appropriate natural hazard and risk assessment. • During most project workshops it has been identified that fire is a significant hazard in Sierra Leone. This relates to both wild-fire and man-made fire (either due to slash and burn farming practises or poor-quality electrical systems in some urban areas). Numerous key project stakeholders have called for further investigation into fire hazard and risk in the cities of Sierra Leone. • During the final project workshops, it was demonstrated that the data produced by this project is most useful when viewed and interrogated in a Geographical Information System (GIS). Doing so allows the user to overlay maps, add other data layers for context in addition to producing plans, measuring distances and performing spatial analyses. However, the capacity to use GIS in Sierra Leone is, at present, limited. It is therefore a strong recommendation from both the Project Team and key project stakeholders that GIS training be made available, particularly to those involved in the urban planning process in Bo. INTEGEMS are well placed to offer GIS training services in Sierra Leone and would welcome the opportunity to discuss the provision of training. The Project Team are extremely grateful to the stakeholders for their time and feedback received throughout the project. 9.3 Hazard and Risk Research and Development for Bo There remains uncertainty in the spatial distribution and level of flooding hazard and risk in Bo. This is because the Project analysis assessed the flood hazard and risk at city-scale. Further research and development is required to reduce the uncertainty and to provide information to allow data and evidence based decision making. It is recommended that a natural hazard and risk research and development programme is prepared for Bo and the surrounding region. Some priority research and development considerations related to natural hazards include the following: • Instrumentation and monitoring to compile important weather data, particularly rainfall data, across the region at higher resolution. • Instrumentation and monitoring to compile important river and drainage level and flow data across the region at higher resolution. This is needed to better calibrate existing and future flood modelling. | Issue | 27 September 2018 Page 117 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment • Development and calibration of early warning systems related to weather and flooding. All early warning systems require local calibration. • Development and management of databases on the built environment including all buildings and infrastructure. It is recommended that accurate cadastral survey maps showing the extent and ownership of land and location of buildings are established. It is important that this information is maintained in a geographic information system such that the same consistent digital information can be used efficiently for a range of purposes including natural hazard and risk assessment, zoning regulation planning, urban planning as well as for important local and national Government administrative issues such as the collection of taxes. 9.4 Management of Rainfall Run-off in Communities It is recommended that a trial of the Management of Slope Stability in Communities (MoSSaiC) method (Anderson and Holcombe, 2013) is undertaken in Bo. MoSSaiC has been developed for use in communities that experience heavy rainfall leading to rapid surface run-off, slope instability and flooding. The trial would comprise the implementation of several rainfall run-off and water management techniques at community scale including: • Rooftop rainwater harvesting; • Installation of drainage and soakaways; • Reforestation and revegetation of catchments and drainage channels; • Community engagement and involvement. It is recommended that a trial plan, programme and budget is developed to inform decision makers regarding the cost-benefit of undertaking this water management trial. 9.5 Call for Action It is essential to maintain the momentum and engagement developed throughout this study. This momentum and engagement can only be maintained through proactive implementation of project recommendations on the ground so that stakeholders in the communities can see progress and can see the value of their engagement. There are many related disaster risk reduction and management activities and initiatives being considered and planned across Sierra Leone by a range of Government ministries and international organisations. Co-ordination of these activities and initiatives will be difficult and can provide significant benefits for the country as a whole and for the city of Bo. | Issue | 27 September 2018 Page 118 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment | Issue | 27 September 2018 Page 119 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment 10 References [1] Abarca Verele de Vreede (2013) Waste Management in Freetown report, WASH consortium. [2] Akwoko (2015) Sierra Leone News: Integrated Waste Management rollout begins in Bo. https://awoko.org/2015/08/25/sierra-leone- news-integrated-waste-management-rollout-begins-in-bo/ [Accessed 03/03/2018]. [3] Anderson, M. G. and Holcombe E. (2013) Community-based landslide risk reduction: managing disasters in small steps. ISBN 978-0- 8213-9456-4 — ISBN 978-0-8213-9491-5 (electronic). [4] Forbes, H., Ball, K. and McLay, F. (2015) Natural Flood Management Handbook. Scottish Environment Protection Agency (SEPA). ISBN number: 978-0-85759-024-4. Available online: https://www.sepa.org.uk/media/163560/sepa-natural-flood- management-handbook1.pdf [Accessed 20/11/2017]. [5] EMDAT (2009) The OFDA/CRED International Disaster Database. Available online: http://www.emdat.be/ [Accessed 02/03/2017]. [6] Nas, T.F. (2016) Cost-Benefit Analysis – Theory and Application. Second Edition, Lexington Books. [7] NERC. (2015) Sierra Leone’s Response to the Ebola Outbreak: Management Strategies and Key Responder Experiences [8] ReliefWeb, 2015 [9] Sierra Leone (2014). National Disaster Risk Management Policy [10] Statistics Sierra Leone (2016) 2015 Population and Housing Census. Summary of results. https://www.statistics.sl/images/StatisticsSL/Documents/final- results_-2015_population_and_housing_census.pdf [11] UNDP (2012) Diagnostic analysis of climate change and disaster management in relation to the PRSP III in Sierra Leone. Available online: http://www.sl.undp.org/content/dam/sierraleone/docs/focusar eadocs/undp_sle_analysisclimatechangeDM.pdf [Accessed 02/03/2017]. [12] United Nations. (2015) ‘Sendai Framework for Disaster Risk Reduction 2015-2030’ https://www.unisdr.org/we/inform/publications/43291 [13] UNISDR. (2009) ‘2009 UNISDR Terminology on Disaster Risk Reduction’ https://www.unisdr.org/we/inform/publications/7817 | Issue | 27 September 2018 Page 120 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment [14] UNISDR (2018)- https://www.unisdr.org/files/57399_drrresiliencepublicreview.pdf) [15] UN Habitat (2016), Remaking the urban mosaic: Participatory and inclusive land readjustment, United Nations Human Settlements Programme. Available online: https://unhabitat.org/books/remaking- the-urban-mosaic-participatory-and-inclusive-land-readjustment/ [Accessed 25/09/2018] [16] USGS. (2004) The Mineral Industry of Sierra Leone by George Coakley. US Geological Survey Minerals Yearbook 2004. [17] World Bank. (2015) Bangladesh Muli-purpose Disaster Shelter Project, Report No: PAD807. [18] World Bank. (2016) The Cost of Air Pollution – Strengthening the Economic Case for Action. The World Bank and Institute for Health Metrics and Evaluation. [19] World Bank. (2017) Sierra Leone - Rapid damage and loss assessment of August 14th, 2017 landslides and floods in the western area (English). Washington, D.C.: World Bank Group. http://documents.worldbank.org/curated/en/52367151029736 4577/Sierra-Leone-Rapid-damage-and-loss-assessment-of- August-14th-2017-landslides-and-floods-in-the-western-area [20] Wei, L. W., Huang, C. M., Lee, C. T., Chi, C. C., & Chiu, C. L. (2017). Adopting I3–R24 rainfall index and landslide susceptibility on the establishment of early warning model for rainfall- induced shallow landslides. Nat. Hazards Earth Syst. Sci. Discuss., https://doi. org/10.5194/nhess-2017-428, in review. [21] White, R., Turpie, J. and Letley, G. L. (2017) Greening African Cities (No. 26730). World Bank Group. [22] Woods-Ballard, B. et al. (2007) The SUDS Manual. ISBN: 0860176975, 9780860176978. Series: CIRIA; C697. | Issue | 27 September 2018 Page 121 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX Appendix A Cost Benefit Analysis for Bo city The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment A1 Cost-Benefit Analysis of DRR/DRM Options for Bo A1.1 Introduction This section of the report provides a summary of the key findings from the cost- benefit analysis undertaken to inform the prioritization of the DRR/DRM options recommended for Bo. The cost-benefit analysis (CBA) concepts used are relatively straightforward: if the net benefits of a proposed DRR/DRM option exceeds the net costs then the proposed option is generally considered to be acceptable. Cost-benefit analysis was calculated at city-scale as this is appropriate for the aggregated and modelled data generated by this project. The burden of initial investment in infrastructure and service delivery, potential avenues for public- private partnerships should be explored. It was not possible within the scope and terms of reference of this project to collect data on indirect costs or social benefits or the many other cross-cutting factors beyond the natural hazards considered in this project. A1.2 Cost-Benefit Methodology The methodology for the cost-benefit analysis is described separately in detail in Volume 1 – Methodology and Summary of Results. The benefits of DRR/DRM options are quantified in terms of the reduction in risk (e.g. the value of the building or infrastructure damage avoided or the potential loss of life avoided). No indirect losses, (e.g. losses due to business interruption), are included. The costs of the DRR/DRM options are quantified in terms of the capital and operational expenditure required to implement the proposed measures (e.g. the cost to construct and maintain flood protection measures). The net costs and the net benefits are calculated over an assumed design life of 33 years (i.e. from 2018 to 2050) for all proposed DRR/DRM options. The order in which proposed DRR/DRM options are ranked or prioritized depends on three main decision metrics: • the Net Present Value (NPV); • the Benefit-Cost Ratio (B/C); and • the Internal Rate of Return (IRR). These cost-benefit analysis metrics are calculated over an extended time period but it is necessary to calculate the results in terms of present year cost and benefit values and to use an appropriate discount rate to adjust future costs and benefits to the current year (Nas, 2016). For the purposes of this study the present year is assumed to be 2017 (i.e. the year in which the natural hazard and risk calculations for this project were undertaken) and therefore costs and benefits are all presented in terms of USD$ values in 2017. The choice of discount rate for cost-benefit is | Issue | 27 September 2018 Page A1 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment always uncertain and has a significant impact on the cost-benefit analysis results (Nas, 2017). A discount rate of 6% is used in accordance with recommendations by The World Bank and Institute for Health Metrics and Evaluation (World Bank, 2016) for analysis in low to middle-income countries. A sensitivity analysis is presented to illustrate the sensitivity of the analysis results to the selection of the discount rate. A country-specific value of statistical life (VSL) of USD$100,000 has been used in the cost-benefit analysis to quantify the economic benefit of recommended DRR/DRM options. The assignment of VSL is an uncertain and a sensitive issue and therefore cost-benefit analyses have been undertaken with and without the analysis of the benefit of avoided potential loss of life. The methodology for determining the VSL for the cost-benefit analysis is described separately in detail in Volume 1 – Methodology and Summary of Results. A1.3 Selected DRR/DRM Options for Bo for Cost Benefit Analysis DRR/DRM measures listed in Section 8.2 have been combined into two options for cost benefit analysis to avoid a siloed approach to DRR/DRM. The DRR/DRM measures in each option were selected to be both complementary and appropriate in terms of likely cost and position within the catchment. The Scope of Work for the project requires that Cost-Benefit Analysis is undertaken for five DRR/DRM options in total. Five cost-benefit analyses have been completed as part of the reporting for Freetown. Two additional cost-benefit analyses have been undertaken for Bo city and are reported below. The following two DRR/DRM options have been selected: • Option 1 – Hazard and risk communication: including formation of a hazard and risk communication team, installation of hazard and risk signage across Bo, and establishment of an early warning system for Bo. • Option 2 – Re-sizing of engineered culverts and clearing of waste from exiting drainage channels across Bo. A1.4 Option 1 – Hazard and risk communication Option 1 – Hazard and risk communication will include formation of a hazard and risk communication team for Bo, installation of hazard and risk signage across Bo, and establishment of an early warning system for Bo. The capital and operational costs for this option are summarised in . The cost of hazard and risk communication is estimated to be approximately USD$4million including an estimated USD$10,000 to establish a hazard and risk communication team in Bo and USD$10,000 per annum to maintain the team. USD$50,000 is estimated for the establishment of an early warning system and USD$5,000 per annum for the operation and maintenance of the early warning system for Bo. USD$5,000 is budgeted for flood hazard signage across Bo and USD$1,000 per annum for maintenance of the signage. The total undiscounted | Issue | 27 September 2018 Page A2 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment capital and operational costs for Option 1 – hazard and risk communication across Bo are summarised in the tables below. Table 13 – Capital and operational costs for Option 1 – Hazard and Risk Communication Cost Item Cost Unit No. Sub-Total (USD$) (USD$) Hazard and risk team set-up 10,000 One-off 1 10,000 Hazard and risk team operations 10,000 Annual 33 330,000 Early warning system set-up 50,000 One-off 1 50,000 Early warning system operations and 5,000 Annual 33 165,000 maintenance Flood hazard signage 5,000 One-off 1 5,000 Signage maintenance 1,000 Annual 33 33,000 593,000 Note: All costs are un-discounted. The benefits of implementation of Option 1 are summarised in terms of the reduction of risk in terms of cost of building damage and in terms of reduction of potential loss of life due to flooding. Table 14 – Risk reduction benefits from Option 1 – Hazard and Risk Communication Risk metric Benefit Unit No. Sub-Total (USD$) Annual building loss – flooding - avoided 38,800 Annual 33 1,280,400 Annual fatalities loss – flooding - avoided 40,000 Annual 33 1,320,000 2,600,400 Note: All benefits are un-discounted. A series of cost-benefit analyses have been undertaken to investigate a range of factors that might inform project investment decision makers. It has been estimated that hazard and risk communication could result in a reduction of approximately 20% of the total risk from flooding. The analyses have been undertaken using a calculation period of 33 years to coincide with the 2050 timeframe used for the future climate change impact scenario analyses undertaken for this project. A discount rate of 6% is used. The cost-benefit analysis results are presented in terms of the discount rate (DR), net present value (NPV), benefit cost ratio (B/C), and internal rate of return (IRR) in below. | Issue | 27 September 2018 Page A3 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Table 15 – Cost-Benefit Results for Option 1 – Hazard and Risk Communication No. Analysis NPV B/C IRR Recommendation (USD$) (%) 1.1 Flood risk direct damage cost 264,864 1.9 73 Very beneficial. reduction Establish hazard and risk communication program and early warning system 1.2 Flood risk direct damage cost plus 834,073 3.9 >73 Very beneficial potential loss of life cost reduction These cost-benefit analysis results indicate that hazard and risk communication, including formation of a hazard and risk communication team for Bo, installation of hazard and risk signage across Bo, and establishment of an early warning system for Bo is very beneficial. In addition, it is estimated that the average annual potential loss of life avoided through hazard and risk communication will be approximately 0.2 to 0.4 lives per year or 1 to 2 lives saved every 2.5 to 5 years. Based upon these results it is strongly recommended that hazard and risk communication and early warning is established for flooding hazard and risk in Bo. A1.5 Option 2 – Re-sizing of engineered culverts and clearing of waste from existing drainage channels Option 2 is the re-sizing of engineered culverts and clearing of waste from existing drainage channels at selected locations across Bo. The capital and operational costs for this option are summarised in the table below. Table 16 – Capital and operational costs for Option 2 – Re-sizing of culverts and clearing waste from existing channels Cost Item Cost Unit No. Sub-Total (USD$) (USD$) New culverts 20,000 Culvert 10 200,000 Channel preparation works 10,000 Channel 10 100,000 Channel clearance 5,000 Channel 10 50,000 Channel clearance team 5,000 Annual 33 165,000 515,000 Note: All costs are un-discounted. | Issue | 27 September 2018 Page A4 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment The benefits of implementation of Option 2 are summarised in terms of the reduction of risk in terms of cost of building damage and in terms of reduction of potential loss of life due to flooding. Table 17 – Risk reduction benefits from Option 2 – Re-sized culverts and clearing waste from existing channels Risk metric Benefit Unit No. Sub-Total (USD$) Annual building loss – flooding - avoided 58,200 Annual 33 1,920,600 Annual fatalities loss – flooding - avoided 20,600 Annual 33 679,800 2,600,400 Note: All benefits are un-discounted. It has been estimated that re-sizing of culverts and clearance of waste from channels could result in a reduction of the total risk from flooding in Bo by approximately 30%. This estimation of risk reduction is of course very uncertain. The analyses have been undertaken using a calculation period of 33 years to coincide with the 2050 timeframe used for the future climate change impact scenario analyses undertaken for this project. A discount rate of 6% is used. The cost-benefit analysis results are presented in terms of the discount rate (DR), net present value (NPV), benefit cost ratio (B/C), and internal rate of return (IRR) in below. Table 18 – Cost-Benefit Results for Option 2 – Re-sized culverts and clearing waste from existing channels No. Analysis NPV B/C IRR Recommendation (USD$) (%) 2.1 Flood risk direct damage cost 436,204 2.1 13 Beneficial reduction 2.2 Flood risk direct damage cost plus 729,347 2.9 24 Very beneficial. potential loss of life cost reduction Re-size engineered culverts and channels and clear waste from existing natural drainage channels These cost-benefit analysis results indicate that re-sizing culverts and clearing waste from drainage channels at key locations across Bo is very beneficial. In addition, it is estimated that the average annual potential loss of life avoided through simply re-sizing culverts and clearing waste from channels will be approximately 0.3 to 0.6 lives per year or 1 to 2 lives saved every 2 to 3 years. Based upon these results it is strongly recommended that clearing of waste from | Issue | 27 September 2018 Page A5 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment drainage channels and re-sizing of culverts is undertaken to reduce flooding hazard and risk in Bo. A1.6 Summary and Recommendations of DRR/DRM Cost-Benefit Analysis Cost-benefit analyses have been undertaken for only two of the recommended DRR/DRM options for Bo. • Option 1 – Hazard and risk communication: including formation and operation of a hazard and risk communication team, installation of hazard and risk signage across Bo, and establishment of an early warning system for Bo. • Option 2 – Re-sizing of culverts and clearing of waste from urban drainage channels at selected locations across Bo. The cost-benefit analysis results for these two priority DRR/DRM options for Bo are summarised in the table below. Table 19 – Summary of Cost-Benefit Results for Bo Option Description Recommendation 1 Hazard and risk communication Establishment of early warning and provision of including formation and operation of a hazard and risk communication is beneficial hazard and risk communication team, with positive NPV and B/C ratio >1.9. installation of hazard and risk signage Budget: USD$ 600,000. across Bo, and establishment of an early warning system for Bo. 2 Re-sizing of culverts and clearing of Re-sizing of culverts and clearing of waste from waste from drainage channels drainage channels is beneficial with a positive NPV and a B/C ratio >2.1. Budget: USD$ 500,000. | Issue | 27 September 2018 Page A6 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment Appendix B Natural Hazard and Risk Maps for Bo city | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX The World Bank Sierra Leone Multi-City Hazard Review and Risk Assessment Final Report (Volume 4 of 5): Bo City Hazard and Risk Assessment B1 Map no. Map description 1 Bo | Overview 2 Bo | Approximate Extent of Urban and Peri-Urban Areas 3 Bo | Built Environment Density 4 Bo | Qualitative Flood Hazard 5 Bo | Qualitative Flood Risk 6 Bo | Qualitative Landslide Susceptibility/Hazard 7 Bo | Qualitative Landslide Risk 8 Bo | Quantitative Flood Hazard (20 Year Flood) 9 Bo | Quantitative Flood Hazard (100 Year Flood) 10 Bo | Quantitative Flood Hazard (1500 Year Flood) 11 Bo | Quantitative Flood Risk (Direct Loss to Buildings) 12 Bo | Quantitative Flood Risk (Direct Loss to Buildings relative to ward area) 13 Bo | Quantitative Flood Risk (no. Fatalities) 14 Bo | Quantitative Flood Risk (no. Fatalities relative to ward area) 15 Bo | Quantitative Flood Risk (no. People Affected) 16 Bo | Quantitative Flood Risk (no. People Affected Relative to Ward Area) 17 Bo | Overview of Catchments for DRR Recommendations 18 Bo | Recommended Hazard Zones 19 Bo | Existing Development in Hazard Zones 20 Bo | Estimated no. Buildings in Proposed Hazard Zones (by Catchment) Bo | Estimated no. Buildings in Proposed Hazard Zones (2050 target) (by 21 Catchment) 22 Bo | Estimated no. Buildings in Proposed Hazard Zones (by Ward) 23 Bo | Estimated no. Buildings in Proposed Hazard Zones (2050 target) (by Ward) 24 Bo | Estimated Population in Proposed Hazard Zones (by Catchment) Bo | Estimated Population in Proposed Hazard Zones (2050 target) (by 25 Catchment) 26 Bo | Estimated Population in Proposed Hazard Zones (by Ward) 27 Bo | Estimated Population in Proposed Hazard Zones (2050 target) (by Ward) Bo | Indicative Locations of Proposed Flood Warning Signage and Attenuation 28 Ponds 29 Bo | Gridded Modelled Population 30 Bo | Gridded Modelled Building Value 31 Bo | Gridded Modelled Road Value | Issue | 27 September 2018 G:\250000\252746-00\60_OUTPUT\1_REPORTS\6_FINAL REPORT\20180927-DOC-05A-V4OF5_BO.DOCX Bo | Overview 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title General map labels Bo | Overview Wards Main urbanized areas Main watercourses SIERRA LEONE Kilometers Primary road (yellow line) 0 0.5 1 2 Map no. LIBERIA BO-0001 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Approximate Extent of Urban and Peri-Urban Areas 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Approximate spatial General map labels Approximate spatial extent of urban and peri-urban areas Bo | Approximate Extent of has been estimated from available satellite imagery using extent of urban and Wards Google Earth Pro. Urban and Peri-Urban peri-urban areas Areas 2006 Main urbanized areas 2012 Main watercourses SIERRA LEONE Kilometers 2017 Primary road (yellow line) 0 0.5 1 2 Map no. LIBERIA BO-0002 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Built Environment Density 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Built environment General map labels Built environment density maps represent the proportion of Bo | Built Environment each 30m2 grid unit which is covered by building and/or density Wards road, where 100% means that the entirety of the area is Density < 20% covered by buildings and/or road, and 0% means that none Main urbanized areas of the area is covered by buildings and/or roads. 20 - 40% Main watercourses SIERRA LEONE > 40% Kilometers Primary road (yellow line) 0 0.5 1 2 Map no. LIBERIA BO-0003 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Qualitative Flood Hazard 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Flood hazard General map labels Each qualitative hazard assessment is a general appraisal Bo | Qualitative Flood of the likelihood of the given area to experience a particular Very low (unshaded) Wards hazard. Qualitative flood hazard was assessed based on the Hazard spatial extent of the modelled flood hazard levels and return Low Main urbanized areas periods which have been produced for the quantitative flood hazard assessment. Medium Main watercourses SIERRA LEONE Kilometers High Primary road (yellow line) 0 0.5 1 2 Very high Map no. LIBERIA BO-0004 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Qualitative Flood Risk 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Flood risk General map labels The qualitative assessment of flood hazard is combined with Bo | Qualitative Flood Risk the assessment of exposure/vulnerability (expressed as the Very low (unshaded) Wards density of the built environment) to produce qualitative estimates of risk. Low Main urbanized areas Medium Main watercourses SIERRA LEONE Kilometers High Primary road (yellow line) 0 0.5 1 2 Very high Map no. LIBERIA BO-0005 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Qualitative Landslide Susceptibility/Hazard 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Landslide General map labels Each qualitative hazard assessment is a general appraisal Bo | Qualitative Landslide of the likelihood of the given area to experience a particular susceptibility/hazard Wards hazard. Qualitative landslide hazard was assessed using a Susceptibility/Hazard Very low (unshaded) weighted scoring system, which classified and then Main urbanized areas combined slope angle and a built environment density factor with a weighting of 75:25. Low Main watercourses SIERRA LEONE This map is titled Landslide Susceptibility/Hazard because to Medium realistically represent the nature of landslides, potential Kilometers Primary road (yellow landslide flow paths need to be considered. Potential flow High line) 0 0.5 1 2 paths are considered as part of the quantitative landslide hazard assessment (Freetown only). Map no. Very high BO-0006 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Qualitative Landslide Risk 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Landslide risk General map labels The qualitative assessment of landslide hazard is combined Bo | Qualitative Landslide with the assessment of exposure/vulnerability (expressed as Very low (unshaded) Wards the density of the built environment) to produce qualitative Risk estimates of risk. Low Main urbanized areas Medium Main watercourses SIERRA LEONE Kilometers High Primary road (yellow line) 0 0.5 1 2 Very high Map no. LIBERIA BO-0007 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Hazard (20 Year Flood) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled flood water General map labels Flood hazard is expressed in terms of return period. A return Bo | Quantitative Flood period is defined as a measure of the probability of an event depth (20 year flood) Wards occurring, expressed in years. For example, an event with a Hazard (20 Year Flood) < 0.2m (unshaded) 1% likelihood of occurring each year would have a return Main urbanized areas period of 100 years. 0.2 - 1.0m Main watercourses SIERRA LEONE 1.0 - 3.0m Kilometers Primary road (yellow 3.0 - 5.0m line) 0 0.5 1 2 Map no. > 5.0m BO-0008 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Hazard (100 Year Flood) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title General map labels Flood hazard is expressed in terms of return period. A return Bo | Quantitative Flood period is defined as a measure of the probability of an event < 0.2m (unshaded) Wards occurring, expressed in years. For example, an event with a Hazard (100 Year Flood) 1% likelihood of occurring each year would have a return 0.2 - 1.0m Main urbanized areas period of 100 years. 1.0 - 3.0m Main watercourses SIERRA LEONE Kilometers 3.0 - 5.0m Primary road (yellow line) 0 0.5 1 2 > 5.0m Map no. LIBERIA BO-0009 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Hazard (1500 Year Flood) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled flood water General map labels Flood hazard is expressed in terms of return period. A return Bo | Quantitative Flood period is defined as a measure of the probability of an event depth (1500 year flood) Wards occurring, expressed in years. For example, an event with a Hazard (1500 Year Flood) < 0.2m (unshaded) 1% likelihood of occurring each year would have a return Main urbanized areas period of 100 years. 0.2 - 1.0m Main watercourses SIERRA LEONE 1.0 - 3.0m Kilometers Primary road (yellow 3.0 - 5.0m line) 0 0.5 1 2 Map no. > 5.0m BO-0010 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Risk (Direct Loss to Buildings) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled average annual General map labels This map shows natural hazard-risk as the sum of risk within Bo | Quantitative Flood each administrative unit (Wards). loss to buildings Wards Risk (Direct Loss to < $5,000 Buildings) Main urbanized areas $5,000 - $10,000 SIERRA LEONE $10,000 - $50,000 Kilometers $50,000 - $100,000 0 0.5 1 2 Map no. > $100,000 BO-0011 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Risk (Direct Loss to Buildings Relative to Ward Area) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled average annual General map labels This map shows natural hazard-risk as the sum of risk within Bo | Quantitative Flood each administrative unit (Wards) divided by Ward area, loss to buildings relative Wards giving an indication of where within the city the risk is Risk (Direct Loss to to ward area highest in terms of risk per unit area. Buildings Relative to Ward Lowest relative risk Main urbanized areas Area) SIERRA LEONE Kilometers 0 0.5 1 2 Map no. LIBERIA BO-0012 Highest relative risk Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Risk (no. Fatalities) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled average General map labels This map shows natural hazard-risk as the sum of risk within Bo | Quantitative Flood each administrative unit (Wards). annual no. fatalities Wards Risk (no. Fatalities) < 0.05 Main urbanized areas 0.05 - 0.1 SIERRA LEONE 0.1 - 0.5 Kilometers 0.5 - 1.0 0 0.5 1 2 Map no. > 1.0 BO-0013 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Risk (no. Fatalities Relative to Ward Area) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled average annual General map labels This map shows natural hazard-risk as the sum of risk within Bo | Quantitative Flood each administrative unit (Wards) divided by Ward area, no. fatalities relative to Wards giving an indication of where within the city the risk is Risk (no. Fatalities Relative ward area highest in terms of risk per unit area. to Ward Area) Lowest relative risk Main urbanized areas SIERRA LEONE Kilometers 0 0.5 1 2 Map no. LIBERIA BO-0014 Highest relative risk Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Risk (no. People Affected) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled average General map labels This map shows natural hazard-risk as the sum of risk within Bo | Quantitative Flood each administrative unit (Wards). annual no. people Wards Risk (no. People Affected) affected <5 Main urbanized areas 5 - 10 SIERRA LEONE Kilometers 10 - 50 0 0.5 1 2 50 - 100 Map no. LIBERIA BO-0015 > 100 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Quantitative Flood Risk (no. People Affected Relative to Ward Area) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Modelled average annual General map labels This map shows natural hazard-risk as the sum of risk within Bo | Quantitative Flood each administrative unit (Wards) divided by Ward area, no. people affected Wards giving an indication of where within the city the risk is Risk (no. People Affected relative to ward area highest in terms of risk per unit area. Relative to Ward Area) Main urbanized areas Lowest relative risk SIERRA LEONE Kilometers 0 0.5 1 2 Map no. LIBERIA BO-0016 Highest relative risk Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Overview of Catchments for DRR Recommendations 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 C5 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School Ngolamajie East Ward-Kindia Town C1 West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa C4 877500 C3 C2 Legend Additional information GUINEA Title General map labels Additional information and a full description of proposed Bo | Overview of DRR measures for Bo is available in the accompanying Wards report (Volume 4). Catchments for DRR Recommendations Main urbanized areas Catchments SIERRA LEONE Kilometers Main watercourses 0 0.5 1 2 Primary road (yellow Map no. line) LIBERIA BO-0017 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Combined Hazard Zones 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 C5 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School Ngolamajie East Ward-Kindia Town C1 West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa C4 877500 C3 C2 Legend Additional information GUINEA Title Combined Hazard Zones General map labels Using the results of the quantitative natural hazard Bo | Combined Hazard assessments it is possible to define hazard zones for Bo, Combined Hazard Wards which represent areas that have been spatially defined by: Zones Zones the spatial extent of a 100-year flood. Furthermore, it is Combined Hazard Main urbanized areas reasonable to extend the combined hazard zones for a year Zones (year 2050) 2050 scenario to account for the anticipated influence of Catchments climate change. The year 2050 combined hazard zones SIERRA LEONE have been defined by: the spatial extent of a 100-year flood (accounting for climate change impacts). Kilometers Main watercourses 0 0.5 1 2 Primary road (yellow Additional information and a full description of proposed line) DRR measures for Bo is available in the accompanying Map no. report (Volume 4). BO-0018 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Existing Development in Combined Hazard Zones 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 C5 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School Ngolamajie East Ward-Kindia Town C1 West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa C4 877500 C3 C2 Legend Additional information GUINEA Title Combined Hazard Zones General map labels Using the results of the quantitative natural hazard Bo | Existing Development assessments it is possible to define hazard zones for Bo, Existing development Wards which represent areas that have been spatially defined by: in Combined Hazard Zones within the Combined the spatial extent of a 100-year flood. Furthermore, it is Hazard Zones Main urbanized areas reasonable to extend the combined hazard zones for a year Existing development 2050 scenario to account for the anticipated influence of within the Combined Catchments climate change. The year 2050 combined hazard zones SIERRA LEONE Hazard Zones (year have been defined by: the spatial extent of a 100-year flood (accounting for climate change impacts). Kilometers 2050) Main watercourses 0 0.5 1 2 Primary road (yellow Additional information and a full description of proposed line) DRR measures for Bo is available in the accompanying Map no. report (Volume 4). BO-0019 LIBERIA Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated no. Buildings in Proposed Hazard Zones (by Catchment) 195000 197500 200000 202500 ° ! 885000 882500 C5 C1 880000 C4 877500 C3 C2 Legend Additional information GUINEA Title Estimated no. General map labels Additional information and a full description of proposed Bo | Estimated no. DRR measures for Bo is available in the accompanying buildings within the Boundary catchment, report (Volume 4). Buildings in Proposed proposed Hazard not included Zone Hazard Zones (by < 50 Catchments Catchment) SIERRA LEONE 50 - 100 Kilometers 100 - 500 0 0.5 1 2 Map no. 500 - 1,000 LIBERIA BO-0020 > 1,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated no. Buildings in Proposed Hazard Zones (2050 target) (by Catchment) 195000 197500 200000 202500 ° ! 885000 882500 C5 C1 880000 C4 877500 C3 C2 Legend Additional information GUINEA Title Estimated no. General map labels Additional information and a full description of proposed Bo | Estimated no. DRR measures for Bo is available in the accompanying buildings within the Boundary catchment, report (Volume 4). Buildings in Proposed proposed Hazard not included Zone (2050 target) Hazard Zones (2050 target) < 50 Catchments (by Catchment) SIERRA LEONE 50 - 100 Kilometers 100 - 500 0 0.5 1 2 Map no. 500 - 1,000 LIBERIA BO-0021 > 1,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated no. Buildings in Proposed Hazard Zones (by Ward) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Estimated no. General map labels Additional information and a full description of proposed Bo | Estimated no. DRR measures for Bo is available in the accompanying buildings within the Wards report (Volume 4). Buildings in Proposed proposed Hazard Zone Hazard Zones (by Ward) Main urbanized areas < 50 SIERRA LEONE 50 - 100 Kilometers 100 - 500 0 0.5 1 2 Map no. 500 - 1,000 LIBERIA BO-0022 > 1,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated no. Buildings in Proposed Hazard Zones (2050 target) (by Ward) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Estimated no. General map labels Additional information and a full description of proposed Bo | Estimated no. DRR measures for Bo is available in the accompanying buildings within the Wards report (Volume 4). Buildings in Proposed proposed Hazard Zone (2050 target) Hazard Zones (2050 target) Main urbanized areas < 50 (by Ward) SIERRA LEONE 50 - 100 Kilometers 100 - 500 0 0.5 1 2 Map no. 500 - 1,000 LIBERIA BO-0023 > 1,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated Population in Proposed Hazard Zones (by Catchment) 195000 197500 200000 202500 ° ! 885000 882500 C5 C1 880000 C4 877500 C3 C2 Legend Additional information GUINEA Title Estimated population General map labels Additional information and a full description of proposed Bo | Estimated Population DRR measures for Bo is available in the accompanying within the proposed Boundary catchment, report (Volume 4). in Proposed Hazard Zones Hazard Zone not included (by Catchment) < 100 Catchments 100 - 500 SIERRA LEONE Kilometers 500 - 1,000 0 0.5 1 2 1,000 - 5,000 Map no. LIBERIA BO-0024 > 5,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated Population in Proposed Hazard Zones (2050 target) (by Catchment) 195000 197500 200000 202500 ° ! 885000 882500 C5 C1 880000 C4 877500 C3 C2 Legend Additional information GUINEA Title Estimated population General map labels Additional information and a full description of proposed Bo | Estimated Population DRR measures for Bo is available in the accompanying within the proposed Boundary catchment, report (Volume 4). in Proposed Hazard Zones Hazard Zone (2050 not included target) (2050 target) (by < 100 Catchments Catchment) SIERRA LEONE 100 - 500 Kilometers 500 - 1,000 0 0.5 1 2 Map no. 1,000 - 5,000 LIBERIA BO-0025 > 5,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated Population in Proposed Hazard Zones (by Ward) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Estimated population General map labels Additional information and a full description of proposed Bo | Estimated Population DRR measures for Bo is available in the accompanying within the proposed Wards report (Volume 4). in Proposed Hazard Zones Hazard Zone (by Ward) < 100 Main urbanized areas 100 - 500 SIERRA LEONE Kilometers 500 - 1,000 0 0.5 1 2 1,000 - 5,000 Map no. LIBERIA BO-0026 > 5,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Estimated Population in Proposed Hazard Zones (2050 target) (by Ward) 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Estimated population General map labels Additional information and a full description of proposed Bo | Estimated Population DRR measures for Bo is available in the accompanying within the proposed Wards report (Volume 4). in Proposed Hazard Zones Hazard Zone (2050 target) (2050 target) (by Ward) Main urbanized areas < 100 SIERRA LEONE 100 - 500 Kilometers 500 - 1,000 0 0.5 1 2 Map no. 1,000 - 5,000 LIBERIA BO-0027 > 5,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Indicative Locations of Proposed Flood Warning Signage and Attenuation Ponds 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 C5 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School Ngolamajie East Ward-Kindia Town C1 West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa C4 877500 C3 C2 Legend Additional information GUINEA Title DRR measures General map labels Additional information and a full description of proposed Bo | Indicative Locations of DRR measures for Bo is available in the accompanying Proposed Flood Warning # * ! Indicative locations of proposed flood warning signage Wards Main urbanized areas report (Volume 4). Signage and Attenuation Ponds Indicative locations for flood attenuation Catchments SIERRA LEONE ponds Kilometers Main watercourses Additional information 0 0.5 1 2 100 year flood extent Primary road (yellow Map no. line) LIBERIA BO-0028 100 year flood extent (estimated 2050) Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Gridded Modelled Population 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Gridded modelled General map labels Population data for this project is taken from the 2015 Sierra Bo | Gridded Modelled Leone Census (Statistics Sierra Leone, 2016). This census population (people/sq. Wards information is available disaggregated to Chiefdom level Population km) only. It was necessary to statistically model the sub- < 1,000 Main urbanized areas Chiefdom level distribution of the population. This was done using the built environment density as a proxy. The 1,000 - 5,000 Main watercourses methodology for distributing population across the city is SIERRA LEONE described in the accompanying Volume 1 Report. Primary road (yellow Kilometers 5,000 - 10,000 line) 0 0.5 1 2 10,000 - 25,000 Map no. LIBERIA BO-0029 > 25,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Gridded Modelled Building Value 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Gridded modelled building General map labels Buildings location data for this project have been sourced Bo | Gridded Modelled from OpenStreetMap (OSM, www.openstreetmap.org). The value (USD/sq. km) Wards methodology for the development of the building exposure Building Value < $50,000,000 model is described in the accompanying Volume 1 Report. Main urbanized areas $50,000,000 - Information on the replacement value of buildings is $100,000,000 Main watercourses summarized in the DaLA Report (World Bank, 2017). Values SIERRA LEONE presented here are the gridded sum of building value per $100,000,000 - Primary road (yellow 30m grid square based on the average building value Kilometers $250,000,000 line) estimate. Further details are included in the accompanying 0 0.5 1 2 $250,000,000 - Volume 1 Report. Map no. $500,000,000 LIBERIA BO-0030 > $500,000,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup Bo | Gridded Modelled Road Value 195000 197500 200000 202500 ° ! 885000 Nguabu Samamie Kpandobu North Ward-Njai Town 882500 North Ward-Reservation North Ward-Bo Number 2 North Ward-Kissy Town East Ward-Lower Samamie East Ward-Batiema East Ward-Moriba Town West Ward-Nikibu - Bo School East Ward-Kindia Town Ngolamajie West Ward-Njagboima East Ward-Bumpeh-Woh 880000 East Ward-Messima West Ward-Moriba Town Sewa West Ward-Kandeh Town East Ward-Gbondo Town West Ward-Lewabu - Manjama East Ward-Manjama Seiwa 877500 Legend Additional information GUINEA Title Gridded modelled road General map labels OpenStreetMap is the primary source of information about Bo | Gridded Modelled the location and nature of roads for this study. The Global value (USD/sq. km) Wards Roads Open Access Data Set (gROADS) was also Road Value < $500,000 consulted, however was found to be less complete than the Main urbanized areas OSM roads dataset. The one freight-only railway in Sierra $500,000 - Leone is not considered by this study. $1,000,000 Main watercourses SIERRA LEONE The methodology for assigning value to roads across the $1,000,000 - Kilometers city is described in the accompanying Volume 1 Report. $2,500,000 0 0.5 1 2 $2,500,000 - Map no. $5,000,000 LIBERIA BO-0031 > $5,000,000 Client The World Bank Job Title Scale at A3 Coordinate System Sierra Leone Multi-City Hazard and 1:40,000 WGS 1984 UTM Zone 29N Risk Assessment Issue Date By Chkd Appd Job No Map Status I2 2018-09-10 PGR AM MF 252746-00 Issue © Arup