Spatial Analysis of Disadvantaged Population: A Case Study of Flood Exposure in the Itapocu River Basin, Brazil

Abstract

People's vulnerability to disasters depends largely on their social and physical aspects, such as economic disadvantages and mobility constraints related to age. Those characteristics will influence how individuals experience the disaster and recover. Thus, assessing the vulnerable population's location and exposure to hazards such as floods is important for designing disaster risk reduction policies. This study conducts such an analysis considering five disadvantage dimensions: age, gender, race, socioeconomic status, and housing spatially distributed in cell grids, which were compiled into a disadvantage index (DI). The DI is further overlayed with the population density (DI*pop.dens.). From the derived DI*pop.dens. map, priority areas for flood management budget allocation can be extracted. The methodology is applied to the Itapocu River Basin (IRB), in southern Brazil, as a case study and compared with the flood inundation area estimated by a hydrological simulation. The places that could be regarded as priority areas for future public policy were classified into high, medium, and low-priority areas, considering higher exposure of the disadvantaged population, higher flood depth, and higher flood frequency. In the IRB, there are priority areas near the main urban areas. Thus, flood control budgets are suggested to be allocated there to protect the vulnerable population.