Methodological proposal for mapping flood risk areas: case study of Rio Negrinho city - SC

Abstract

Floods are natural phenomena that affect the human life since antiquity.Among all the types of natural disasters, floods impact the largest number of people and making hundreds of thousands homeless every year. Despite the fact that there are many mitigation measures related to floods, flood risk mappingis distinguished byits low cost and easy application. In this context, the present study aimed to develop and implement a methodology for mapping flood risk areas.Because of its floods records, Rio Negrinho city, Santa Catarina state, was chosen as study area.The risk determination generally involves the analysis of vulnerability and hazard.Thus, having the census block as territorial unit of analysis, a Vulnerability Index was created, by whichall the census blocks were classified. After that, by observing the municipal law,the hazard area was estimated.Through the relationship between vulnerability and hazard, the risk was established.The present methodology was performed to determine which census blocks have the highest risk and should be target of public policy and mitigation measure. Moreover, with the Vulnerability Index the city can be analyzed in terms of the socioeconomic characteristics, which determines the priority areas for public investment. Thus, the present methodology can be applied in all municipalities due to its low cost characteristic and because the census is conducted over the whole Brazilian territory.