Flooding is the most common climate-related disaster in Latin America and the Caribbean, accounting for nearly 60 percent of all weather-related events between 2000 and 2022. These events have affected an average of two million people annually and caused over $30 billion in economic losses. The frequency and intensity of extreme rainfall events have increased significantly, and projections indicate a 70 percent rise in urban flood risk by 2050 if no action is taken (UNDRR 2023).
Effective drainage systems are essential for protecting communities, supporting economic activity, and ensuring cities can withstand weather events. In many Latin American and Caribbean cities, rapid urbanization has outpaced infrastructure development, leading to serious challenges with drainage and flood management. In informal settlements and smaller urban centers where infrastructure is often inadequate, these risks are also particularly acute.
As part of its commitment to climate resilience, the IDB has been supporting countries across several fronts, providing financial support and technical expertise to prioritize investments in sustainable and resilient drainage solutions. The IDB’s experience in three Brazilian cities has reduced urban flooding risk for vulnerable households, while addressing other development challenges.
The DRENURBS program in Belo Horizonte (BR0397, BR-L1335) focused on enhancing drainage infrastructure while addressing environmental and housing issues. It rehabilitated urban streams, built flood control reservoirs, and relocated families from high-risk areas, reducing flood risks and increasing property values by 25 percent in vulnerable neighborhoods.
Similarly, in Manaus, the PROSAMIN and PROSAMIN II programs (BR-L1217, BR-L1553) tackled informal settlements along waterways by integrating drainage improvements with housing, sanitation, and social services. These efforts benefited over 500,000 residents, emphasizing environmental sustainability through green infrastructure and reforestation, and ensuring community participation in socially responsible resettlement.
Additionally, in Belém, the PROMABEN and PROMABEN II programs (BR-L1065, BR-L1369) targeted the flood-prone Estrada Nova watershed with stormwater drainage systems, sanitation upgrades, and improved roads and housing. They also strengthened local institutions for better infrastructure planning and management, relocating over 500 households to safer areas.
These initiatives highlight the importance of integrating drainage into broader urban development strategies as a strategic necessity, to safeguard investments from flood risks, ensure inclusive urban development, and protect economic gains.
Hydrological and hydraulic studies are vital for identifying infrastructure gaps and modeling future climate risks. The IDB, together with the private sector, developed the HydroBID Flood tool for flood mitigation, urban drainage planning, and the design of hydraulic infrastructure. Additionally, the Blue Spot Analysis tool helps cities identify flood-prone areas by combining hydrological modeling with spatial data, enabling local governments to prioritize drainage investments and integrate flood risk into urban planning (Blackman 2025).
For more information, see the project pages for BR0397, BR-L1335, BR-L1217, BR-L1553, BR-L1065 and BR-L1369, and the Project Completion Reports for BR0397 and BR-L1335, BR-L1217, and BR-L1065.
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