*Assessing and Communicating Flood Risk in Peri-Urban Dakar

2. Introduction

Peri-urban areas, characterized by their transitional landscape between urban and rural environments, are particularly susceptible to flooding due to factors like:

• Rapid and often unplanned urbanization: This can lead to the construction of infrastructure and housing in flood-prone areas, as well as the degradation of natural floodplains that would otherwise mitigate flood impacts.

• Inadequate drainage systems: Peri-urban areas often lack the robust and well-maintained drainage infrastructure found in more established urban centers, increasing their vulnerability to flooding during heavy rainfall events.

• Climate change: Rising sea levels and changes in precipitation patterns are exacerbating the frequency and intensity of flooding in coastal cities like Dakar.

Addressing flood risk in peri-urban Dakar requires a paradigm shift from reactive, post-disaster responses to a proactive and integrated approach that emphasizes:

• Understanding Flood Hazard: This involves a thorough analysis of the types of flooding that affect peri-urban Dakar, the underlying hydrological and meteorological drivers, and the potential impacts of climate change on future flood risk. Sources recommend the use of flood hazard maps to better understand and communicate flood extent and characteristics like water depth and velocity.

• Accurate Risk Assessment: Collecting reliable data on historical flood events, land use patterns, and population distribution is essential for accurate flood risk assessment. This data can be used in conjunction with hydraulic models to simulate different flood scenarios and assess potential damages. According to sources, accurate flood hazard assessment is the crucial first step toward comprehensive flood risk assessment.

• Effective Communication: Translating complex scientific data into accessible and actionable information for communities is vital. This requires understanding the local context, including literacy levels, language barriers, and trusted sources of information.

• Community Engagement: Recognizing the valuable knowledge and capacity of peri-urban communities is essential. Engaging them in all stages of flood risk management, from assessment to planning and implementation, is crucial for developing sustainable and locally appropriate solutions. Sources emphasize that community engagement in flood risk management is not just a one-time activity, but an ongoing process that needs continuous support.

The last two infographics above provide a description of the phenomenon of flooding in Dakar. Understanding the specific flood hazard in Dakar is crucial for effectively designing measures and solutions to mitigate its impacts. By understanding the unique characteristics of flooding in Dakar, such as the frequency, intensity, and duration of floods, decision-makers can tailor interventions to address the specific challenges faced by the city. This knowledge allows for the implementation of targeted strategies, such as improved urban planning, early warning systems, and infrastructure upgrades, to better protect communities and reduce the impact of flooding events. Ultimately, a thorough understanding of the specific flood hazard in Dakar is essential for developing sustainable and effective solutions to minimize the risks posed by flooding in the city.

4. Data Collection and Modeling for Flood Hazard Assessment

Accurate flood hazard assessment requires robust data collection and modeling efforts. Key data sources include:

• Historical Flood Data: Records of past flood events, including their extent, depth, and impacts, are crucial for understanding flood behavior and identifying flood-prone areas. Sources recommend consulting local municipalities, regional or national data archives, and international organizations like the World Meteorological Organization (WMO) for data collection

• Topographic Data: Detailed elevation data, often obtained through Light Detection and Ranging (LiDAR) or Interferometric Synthetic Aperture Radar (SAR), is essential for understanding the flow of water across the landscape.

• Land Use/Land Cover Data: Information on soil types, vegetation cover, and the built environment helps determine how much water infiltrates the ground versus running off the surface, influencing flood risk. Sources mention the use of digital terrain models and surface models, generated through data collection and integration.

• Hydro-meteorological Data: Real-time and historical data on rainfall intensity, duration, and distribution, as well as river flow rates, are crucial for flood forecasting and warning systems. The Central Water Commission developed a website (WISDOM) to share hydrological and hydro-meteorological data with the public.

5. Communicating Flood Risk: From Science to Community Understanding

Effective communication of flood risk information is crucial for bridging the gap between scientific assessments and community action. Key considerations for communicating flood risk in peri-urban Dakar include:

• Know Your Audience: Peri-urban areas are often characterized by diverse populations with varying levels of literacy, language proficiency, and access to technology. Tailoring communication strategies to these different audiences is essential. Sources suggest that understanding dialects, accents, and people's motivations is vital to making the information accessible and acceptable.

• Use Multiple Channels: Relying solely on written reports or technical jargon will not suffice. Combining diverse communication channels, including community meetings, visual aids (maps, posters, infographics), radio broadcasts, and mobile phone messaging, can broaden reach and enhance understanding. Sources highlight the importance of clear communication, repetition of key messages, and the use of language that conveys urgency.

• Build Trust and Credibility: Establishing trust between scientists, authorities, and peri-urban communities is paramount. Community members need to feel heard, and their local knowledge and experiences should be valued and incorporated into communication efforts. Source mentions that the involvement of external partners like the charitable organization Tearfund can support the identification of key messages and the building of trust with local communities.

• Focus on Actionable Information: Providing information on what residents can do to prepare for, mitigate, and respond to flooding is essential. This could include instructions on developing household emergency plans, identifying evacuation routes, and accessing flood insurance. Sources suggest that raising awareness about risks that can be reduced and providing information on mitigation measures are crucial aspects of a wider flood risk intervention strategy.

6. Community Engagement and Capacity Building: Empowering Local Action

Empowering peri-urban communities to take ownership of flood risk management is crucial for developing sustainable and locally appropriate solutions. Key strategies for community engagement include:

• Establish a Community-Based Organization (CBO): Forming a dedicated CBO provides a platform for community members to come together, discuss flood-related issues, and coordinate action. This CBO should be representative of the diversity within the community, ensuring that marginalized voices are heard. Sources highlight that communities often have existing coping mechanisms and local institutions that can be leveraged for flood risk management.

• Conduct Participatory Risk Assessments: Involving community members in mapping flood-prone areas, identifying vulnerable households, and assessing local capacities and resources is essential. Tools like participatory mapping, transect walks, and vulnerability mapping can be valuable in this process. Sources underscore the importance of incorporating local knowledge and understanding community capacities, as they are often overlooked in traditional approaches.

• Develop a Community-Based Flood Risk Management Plan: Building on the risk assessment, the CBO can work with technical experts and authorities to develop a context-specific plan. This plan should outline a combination of structural and non-structural measures, prioritizing those that are most feasible, affordable, and acceptable to the community. Sources suggest that community-based organizations can lead the development of disaster risk assessments and disaster management plans tailored to their specific needs and priorities.

• Build Local Capacity: Providing training on flood preparedness, early warning systems, first aid, and search and rescue can equip community members with the skills and knowledge needed to respond effectively to flood events. Sources recommend conducting disaster preparedness training with community members and raising awareness about what to do before, during, and after a disaster.

• Facilitate Access to Resources: Connecting CBOs with microfinance institutions, government agencies, and NGOs can help communities access the financial and technical resources needed to implement flood mitigation measures. Source provides an example from Bangladesh where microfinance initiatives support community-led flood resilience projects.

7. Conclusion: Building a Flood-Resilient Future for Peri-Urban Dakar

Addressing flood risk in peri-urban Dakar requires a paradigm shift towards integrated and community-centered approaches. By bridging the gap between science and community action, empowering local communities, and prioritizing sustainable and locally appropriate solutions, Dakar can build a more flood-resilient future. This requires:

• Continued Investment in Data Collection and Modeling: Improving the accuracy and reliability of flood risk assessments requires ongoing investment in data collection, monitoring systems, and advanced modeling techniques.

• Strengthening Communication Channels: Exploring innovative and context-specific communication strategies is vital for ensuring that flood risk information reaches all segments of peri-urban communities.

• Supporting Community-Based Initiatives: Providing financial and technical support to CBOs and recognizing their crucial role in implementing and sustaining flood risk reduction measures is essential.

• Integrating Flood Risk Management into Urban Planning: Incorporating flood risk considerations into land use planning, building codes, and infrastructure development is essential for mitigating future flood risks.

By embracing these principles and fostering collaboration among scientists, authorities, and communities, Dakar can create a safer and more resilient future for all.