Between April and May 2024, the state of Rio Grande do Sul (RS) in Brazil experienced intense rainfall that exceeded all historical records. One of the state’s most iconic sites, the Guaíba River, rose above five meters, causing widespread flooding across urban and coastal areas. In June, a team of experts from the Inter-American Development Bank (IDB), the World Bank (WB), and the Economic Commission for Latin America and the Caribbean (ECLAC) traveled to RS to support the State Government, the Federal Government, and municipal governments in assessing the damages and losses caused by the event.
Field visits were essential for understanding the magnitude of the disaster. Experts visited devastated communities, engaging in deeply moving conversations that highlighted both the courageous actions of citizens and public officials to save lives, and the remarkable resilience of the population.
Rio Grande do Sul had already been facing major challenges before the 2024 floods. Until mid-2023, a severe drought driven by the La Niña phenomenon affected the state. Later, in September and November 2023, under the influence of El Niño, RS experienced intense rainfall that caused more than 50 deaths and strained drainage and flood protection systems. Just a few months later, rainfall far surpassed historical records, with accumulations of up to 800 mm in 15 days in some regions—eight times more than expected for April and May 2024.
In addition to the Guaíba, other rivers—such as the Taquari, Jacuí, Caí, Gravataí, and dos Sinos—also exceeded alert levels, leading to severe flooding. The northern, central, and eastern regions of the state were the hardest hit, with municipalities such as Bom Retiro do Sul, Muçum, Canoas, Roca Sales, Santa Tereza, and Porto Alegre receiving more than 500 mm of rain in ten days—over 200% above their historical average.
How the assessment was conducted
The assessment involved more than 40 specialists with extensive experience in Brazil and other Latin American and Caribbean countries. It responded to requests for support from the RS Secretariat of Finance and the National Secretariat for Civil Protection and Defense. The team applied the DaLA (Damage and Loss Assessment) methodology to estimate the impacts of the floods across all sectors and to develop recommendations for resilient reconstruction.
During the mission, the active participation of municipal, state, and federal institutions, universities, and professional associations helped gather key information to better understand the factors that exacerbated the flood impacts, estimate damages, losses, and additional costs, and formulate recommendations for resilient reconstruction.
The IDB also conducted a workshop with local experts to assess the event’s impacts and the risk conditions that contributed to the 2024 floods. The Bank applied an innovative methodology known as a “failure mode workshop” and collaborated with a special mission from the Government of the Netherlands to analyze short- and medium-term measures for the metropolitan region of Porto Alegre.
According to the DaLA results, the event caused an impact of R$ 88.9 billion (approximately $15 billion), of which 46% represented damages, 38% losses, and 15% additional costs. The private sector absorbed 78% of total costs, while the public sector covered 90% of additional emergency-related expenditures.
Recommendations for resilient reconstruction were developed in alignment with the Sendai Framework for Disaster Risk Reduction and Brazilian regulations, particularly the National Policy for Civil Protection and Defense. They also followed the IDB’s Disaster Risk Management Policy and the Environmental and Social Policy Framework, emphasizing the need to reduce vulnerability, address gaps in disaster risk management policies, and strengthen institutional capacities.
Reconstruction strategies
The DaLA report includes specific recommendations for resilient reconstruction across sectors, including measures to improve planning, ensure the continuity and safety of services and infrastructure in transportation, energy, water and sanitation, agriculture, industry, commerce, and others. The report also presents recommendations for the cultural and tourism sectors.
For housing, the report recommends identifying, in the short term, areas where risk reduction investments are feasible (mitigable-risk areas) and areas where risk cannot be reduced (non-mitigable-risk areas). This distinction is crucial for determining whether families whose homes were damaged need permanent relocation or if they can return after risk reduction measures are implemented.
Experience from past disasters shows that relocation should be the last resort, as it causes displacement and disrupts livelihoods. This aligns with the recommendation to manage housing recovery with a realistic timeline—considering the time needed to build new housing solutions, equip them with basic services, and provide temporary options for affected families, such as rental assistance preferably within their original communities.
All rehabilitation and reconstruction actions must prioritize income and job generation for the most affected families. In this regard, the significant efforts of federal, state, and municipal governments to reduce economic losses—through major injections of financial resources—have helped mitigate the disaster’s impacts on economic activity. According to DaLA projections, without government transfers and reconstruction works, RS’s GDP growth would have dropped from 6% (no-disaster scenario) to 3.6% (post-disaster). Thanks to investments made during the response and recovery phases, GDP growth is now projected at 4.9%, representing a positive impact of 1.3 percentage points.
Resilient reconstruction: a long-term project
In the short term, recommended risk reduction measures include repairing dikes, inspecting floodgates, improving alert systems for the next rainy season, and planning the studies and resources needed to guide medium-term decision-making.
However, resilient reconstruction is fundamentally a long-term endeavor. Its success requires establishing solid foundations now so that development processes—such as public investment planning and land-use planning—effectively integrate disaster risk management. Updating regulatory, institutional, and budgetary frameworks for risk governance will be essential, along with fostering active participation from decision-makers, researchers, civil society, and local communities. The IDB is supporting RS in applying the Governance and Public Policy Index for Disaster Risk Management (iGOPP), which will guide needed policy reforms.
Effective flood risk management will require a deeper understanding of RS’s complex hydraulic system, its interactions with development dynamics and population patterns, and the influence of climate change. For this knowledge to inform long-term decision-making, it is crucial that these studies be led by local universities and that permanent cooperation agreements between academia and government be established. Equally important is communicating scientific findings to society so they can enrich public dialogue.
The extreme droughts and floods in RS have had devastating effects, but they also offer opportunities to learn, reflect, and take decisive action. We invite all stakeholders to collaborate in implementing effective disaster risk management strategies to achieve resilient reconstruction. With strong coordination among federal, state, and municipal governments and active participation from civil society, we can design safer cities and territories, strengthen infrastructure and natural systems, and empower communities to protect lives, assets, livelihoods, and ecosystems.
Let’s act now for a safer and more resilient future!