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Summary
Flooding has become a critical and recurrent challenge for Internally Displaced Persons (IDP) camps in Dikwa Local Government Area (LGA), Borno State, Nigeria, exacerbating the vulnerability of displaced populations and highlighting the urgent need for effective flood risk mitigation measures. The devastating floods of 2022 displaced over 2.4 million people nationwide, damaging thousands of shelters and leaving vulnerable populations exposed to significant risks. Recognizing the persistent nature of these challenges, the International Organization for Migration (IOM) commissioned Deltares to conduct a Rapid Flood Hazard Assessment to evaluate the current flood risks and explore solutions to enhance the resilience of IDP camps in Dikwa.
This study aimed to assess the effectiveness of existing drainage channels, model flood hazards under various rainfall scenarios, and propose actionable interventions to mitigate flood risks. The assessment included comprehensive data collection, including rainfall records, digital elevation models, and field surveys of drainage systems and historical flood marks. Advanced hydrological and hydraulic modeling tools, such as Delft3D FM, were used to simulate flood scenarios for return periods of 2, 10, 25, and 100 years. The analysis compared conditions without drainage, with existing drainage, and with proposed drainage designs, focusing on 17 IDP camps across the study area.
The results revealed that most camps are highly vulnerable to flooding due to their location on low-lying, flood-prone land, inadequate or absent drainage infrastructure, and the use of lightweight shelters susceptible to water damage. Camps such as 1000 Camp and Agric IDP Camp exhibited significant flood exposure, with negligible mitigation provided by existing drainage systems. The modeling demonstrated that while current drainage infrastructure offered minimal improvements, the implementation of proposed improved drainage can substantially reduce flood risks, increasing the number of shelters classified as "Not Flooded" and decreasing the number of high-risk zones. For example, the proposed designs showed marked improvements in flood mitigation for extreme events, such as the 100-year return period.
Based on these findings, the study recommends that IOM and other agencies prioritize investments in improve drainage systems, including expanding coverage, ensuring adequate sizing, and maintaining channels to prevent blockages. In high-risk camps where drainage alone cannot mitigate risks, relocation to safer areas should be considered, with careful site selection to avoid transferring vulnerabilities. Integrating drainage considerations into camp layout planning is strongly recommended. Planners can utilize the interactive dashboard developed by this study, empowering them to make informed decisions and implement evidence-based interventions.
This assessment highlights the critical role of effective drainage systems in mitigating flood risks and improving living conditions in IDP camps. By addressing vulnerabilities and scaling up flood risk reduction efforts, humanitarian agencies and local authorities can enhance the safety and resilience of displaced populations in Dikwa and contribute to long-term disaster preparedness elsewhere in the region.