Strengthening Flood Resilience in Rapidly Growing Cities

Development Challenge

Among the most frequent natural hazards, floods pose a recurrent threat to the lives and livelihoods of over 4 billion people who reside in urban areas, including cities. Beyond the significant human impacts, flooding also threatens to undermine cities' potential as engines of growth and development. As a World Bank analysis shows, a significant share of jobs in cities - as much as 10 percent - is directly affected by floods. By 2050, yearly losses in cities are estimated to increase to a staggering $50 billion. Unplanned rapid urbanization, a changing climate and lagging infrastructure further exacerbate the flood risks. Determined to chart a more resilient future, countries and cities alike are taking steps to respond to this challenge, but have nonetheless faced many roadblocks along the way. Critically, gaps in technical, institutional, and financial capacity often make it difficult to put solutions into practice.

World Bank Group Approach

First, working closely with the Global Facility for Disaster Reduction and Recovery (GFDRR) and the City Resilience Program (CRP), the World Bank leverages its suite of financing instruments and mobilizes co-financing from both the public and private sectors to scale up financial support for urban flood resilience globally. Since 2019, the World Bank's support for urban flood resilience has reached over 58 countries, spanning 69 projects with $4.4 billion committed

Second, these projects incorporate hybrid approaches to reduce urban flood risks, combining engineering infrastructure or gray infrastructure, nature-based solutions (NBS) including green infrastructure, and non-structural measures such as urban planning, early warning systems, and policy reforms. Floods are complex hazards requiring solutions that address physical, environmental, and institutional vulnerabilities, and experience has shown that the most effective flood risk management strategies will usually combine several measures in an integrated set of interventions.

Third, the World Bank also provides client countries with analytical and technical support grounded in a standardized and scalable approach to urban flood risk assessments. A key emphasis has been to support client countries in developing clear resilience design standards while also advancing local ownership and inclusiveness. This approach enables cities to develop flood risk models and assess flood hazard and exposure, including expected annual damages. It also enables cities to clearly visualize risk in physical, social, and economic terms, guiding integrated approaches across engineering infrastructure, nature-based solutions, and non-structural measures.

Fourth, the World Bank also supports capacity building for policymakers and practitioners working on urban floods. The Urban Flood Risk Management Handbook, for example, provided step-by-step guidance for designing and implementing cost-effective interventions in urban flood resilience. The handbook was complemented by the Livable Cities Academy workshop series, which connected municipal officials with their peers, as well as resilience experts-including from the World Bank - to deepen their understanding of urban flood risk management.

Results and Outcomes

Comprehensive and integrated urban flood resilience at scale:

• In Can Tho, Viet Nam, the Can Tho Urban Development and Resilience Project (2016-2024) established a sprawling flood defense system, consisting of gray infrastructure interventions and green corridors, protecting more than 422,000 people and avoiding flood-related damages of $10.7 million per year. The project also installed 60 sensors at flooding hotspots, providing local authorities with real-time flood monitoring capabilities to anticipate and respond to flooding more effectively.
• In Abidjan, Cote d'Ivoire, the Urban Resilience and Solid Waste Management Project (2020-present) rehabilitated a vital drainage network protecting nearly 560,000 residents from flooding. With the support of CRP, the project is expected to reduce flood risk in Abidjan even further by strengthening private sector engagement in resilient urban solid waste management in collaboration with the International Finance Corporation (IFC).
• In Tunisia, the Integrated Disaster Resilience Program (2021-present) upgraded flood protection infrastructure critical to the cities of Bizerte, Monastir, and Nabeul, benefiting 64,000 people (17 percent of the population). The program also enhances the country's impact-based forecasting and early warning system, enabling better and faster responses to hydrometeorological hazards such as floods and heat waves.

Flood resilience interventions across the green-gray spectrum:

• In Buenos Aires, Argentina, the Flood Risk Management Support Project (2016-2023) enhanced flood protection infrastructure for over 3 million people. The project strengthened the city's drainage systems and supported the construction of a retention basin in the city's second largest park, Parque Indoamericano.
• In Beira, Mozambique, the Cities and Climate Change Project (2012-2020) enhanced flood protection for an estimated 50,000 people through community-based mangrove restoration and the construction of a tidal outlet to regulate the incoming and outgoing flow from the Chiveve River.
• In Sri Lanka, the Metro Colombo Urban Development Project (2012-2021) strengthened flood protection for roughly 2.5 million of the Sri Lankan capital's residents by supporting upgrades to drainage systems as well as the conservation of wetlands as a natural defense against flooding.

Accelerating risk-based planning and financing on flood resilience:

• In Romania, the World Bank supported the development of flood risk management plans, spanning 11 river basins as well as the Danube River, which drew on updated flood hazard and risk maps and a flood risk assessment. Informed by those plans, Romania has since identified priority flood risk management projects that are expected to protect 90,000 people currently at risk.
• In Burundi, a World Bank-supported assessment, which used a standardized and scalable approach, drew on risk and hazard modeling to identify the neighborhoods and populations most at risk of flooding in the capital, Bujumbura. The assessment helped mobilize financing for the Burundi Urban Resilience Emergency Project (2024-present), while also informing the design of the project. By 2029, the project is expected to enhance flood resilience for nearly a million people in Bujumbura through a mix of green and gray solutions and institutional strengthening measures.

Contribution to WBG Targets and Jobs

Flood-resilient infrastructure delivers a triple dividend: it protects jobs by avoiding disaster losses, creates employment through construction and maintenance, and spurs economic growth by reducing risk and enabling investment.

• In Tanzania, through the Msimbazi Basin Development Project (MBDP) (2023-present), the implementation of comprehensive flood protection measures, combined with the development of a 60-hectare urban green park with a flood retention function, is expected to catalyze $900 million in new investments in an economically vital area of Dar es Salaam.
• In Brazil, the restoration of a 203-hectare urban park in Fortaleza through the Fortaleza Sustainable Urban Development Project (2019-2025) not only reduced flood risk, but also revitalized the local economy by creating a vibrant hub for food vendors and community gatherings, benefiting 70,000 people.
• In Madagascar, the Integrated Urban Development and Resilience Project for Greater Antananarivo (2019-present), which has improved flood protection for over 265,000 people through improvements to roads, canals, and embankments, has generated over 126,000 person-days of temporary employment.

Lessons Learned

Combining standardized yet locally tailored analytics with partnerships and early stakeholder engagement accelerates project preparation and implementation, builds local ownership and ensures quality solutions that reflect local realities. Together, these elements can help mobilize knowledge and financing efficiently. A recent stocktaking in West Africa confirmed the impact: analytics facilitated the dialogue between the World Bank and city authorities around the prioritization of high-risk areas and development of comprehensive solutions during project preparation.

In addition, experience across countries underscores that visualizing risk in economic terms can shift political will and unlock investment. This approach has been reinforced through peer learning programs such as the Livable Cities Academy, held in Cape Town in 2024, where 18 cities worked with senior experts on resilience financing and integrated planning. The exchange helped several municipalities identify priority investments that later informed new urban resilience projects.

Next Steps

Drawing on lessons from recent operations, the World Bank will continue to deepen its support for urban flood resilience. Achieving cities' resilience ambitions, however, will require broad collaboration-mobilizing public and private financing and placing client governments firmly in the lead. A key priority for the World Bank will be to further strengthen client countries' capacity to operate and maintain flood resilience infrastructure for the long-term, drawing on best in-class expertise and technologies from the private sector. With the resilience needs of cities still outpacing the available resources, the World Bank will expand collaboration with IFC and the Multilateral Investment Guarantee Agency (MIGA), with an eye toward leveraging even more private sector financing through a strategic expansion of co-financing, lending, guarantees, and other risk management instruments. As cities' challenges and opportunities evolve in the years ahead, so too will the World Bank's response-bringing together financing, knowledge, and capacity-building to support resilient, inclusive urban development.

Additional Information

Urban Flood Risk Handbook: Assessing Risk and Identifying Interventions

E-Learning: Integrated Urban Flood Risk Management (IUFRM)

Feature: New Infrastructure Protects Viet Nam's Mekong Delta City from Chronic Floods

Video: Building a Better Beira

Global Facility for Disaster Reduction and Recovery (GFDRR): City Resilience Program

Livable Cities Workshop: Integrated Urban Flood Risk Management - Benin

Livable Cities Academy: Integrated Urban Flood Risk Management - Cape Town