Multicriteria analysis for flood risk map development: a hierarchical method applied to Brazilian cities

Area of Science:

• Environmental Science
• Geosciences
• Hydrology

Background:

• Floods cause significant global socio-economic and environmental damage, necessitating research into influencing factors.
• Understanding factors like rainfall, topography, and human activities is crucial for flood risk mapping and mitigation.
• Recurrent flood disasters in the Atlantic Forest biome highlight the need for localized risk assessment.

Purpose of the Study:

• To map and analyze flood-susceptible regions within three distinct areas of the Atlantic Forest biome.
• To identify key factors contributing to recurrent flood events in these areas.
• To provide a basis for developing effective flood damage mitigation strategies.

Main Methods:

• A multicriteria analysis was performed using the Analytical Hierarchical Process (AHP).
• A geospatial database was compiled, including layers for elevation, slope, drainage distance, soil properties, precipitation, relief, and land use/land cover.
• Flood risk maps were generated for the study areas.

Main Results:

• Intense, consecutive-day precipitation was identified as a major influencing factor.
• Specific topographical features, including low-gradient channel edges and flat areas, combined with proximity to water bodies, increased flood risk.
• Densely built-up areas near main river banks were strongly associated with flood events.

Conclusions:

• The combination of intense precipitation, specific landforms, and proximity to watercourses significantly indicates flood occurrence.
• The developed flood risk maps provide valuable insights for land-use planning and disaster management in the Atlantic Forest.
• This research contributes to a better understanding of flood dynamics and mitigation strategies in vulnerable ecosystems.