A presente pesquisa propôs o desenvolvimento e a aplicação de um web-GIS interativo alimentado por usuários visando ao mapeamento do risco de inundações por meio da coleta de dados de ameaça, exposição e vulnerabilidade percebidos pela população. Foi também estimado o risco de inundação a partir de uma expressão de indicadores propostos por Mendiondo (2008). As duas metodologias foram aplicadas em sub-bacias urbanas da cidade de São Carlos. Foram realizadas entrevistas com a população da cidade para coletar dados de percepção de risco, enquanto se desenvolvia o web-GIS, para o qual, uma vez terminado, foram transferidos os referidos dados online. O portal se mostrou uma ferramenta de uso simples e confiável. As estimativas de risco calculadas por meio da expressão citada levaram a concluir que as sub-bacias com maior risco de inundação são as dos córregos Tijuco Preto e Medeiros. Entretanto, o risco estimado a partir da análise de percepção evidenciou as sub-bacias Gregório e Santa Maria Madalena como as de maior risco de inundação. As duas ferramentas apresentaram-se valiosas e econômicas para estimativa de risco de inundação em ambiente urbano, podendo constituir ótimos sistemas de apoio à decisão. O webGIS, em particular, é potencialmente útil para informar aos moradores sobre quais são as áreas de risco de inundação na cidade. / This dissertation presents the development and application of an interactive web-GIS in which internet users map flood risk collaboratively by filling up a geotagged form with questions on flood hazard, exposure and vulnerability. Flood risk was also assessed through the use of a set of environmental risk indicators proposed by Mendiondo (2008). The two methodologies were applied to six urban watersheds of the city of São Carlos (State of São Paulo, Brazil). Interviews including questions asked on the web-GIS were carried out in city streets while the portal was being developed. Thus perceived risk data gathered from the interviews was later transferred online onto the web-GIS. The web-GIS proved to be an easy to use and intuitive tool. According to the results of risk calculation obtained with the indicators expression the watersheds with higher flood risk were the Tijuco Preto and Medeiros, which were also the ones with smallest area and higher population density. The results of perceived risk, which was assessed through the analysis of the interviews data, gave evidence that Gregorio and Santa Maria Madalena where the watersheds at higher risk. These watersheds are the two which experience a higher rate of occurrence on a year basis. The two approaches for assessing risk proved to be consistent and relatively inexpensive for the estimate of flood risk in urban areas, with the potential of representing valid decision support systems. The webGIS is a particularly interesting solution as a medium of information to inhabitants on the level of risk to which they are exposed.

A presente pesquisa propôs o desenvolvimento e a aplicação de um web-GIS interativo alimentado por usuários visando ao mapeamento do risco de inundações por meio da coleta de dados de ameaça, exposição e vulnerabilidade percebidos pela população. Foi também estimado o risco de inundação a partir de uma expressão de indicadores propostos por Mendiondo (2008). As duas metodologias foram aplicadas em sub-bacias urbanas da cidade de São Carlos. Foram realizadas entrevistas com a população da cidade para coletar dados de percepção de risco, enquanto se desenvolvia o web-GIS, para o qual, uma vez terminado, foram transferidos os referidos dados online. O portal se mostrou uma ferramenta de uso simples e confiável. As estimativas de risco calculadas por meio da expressão citada levaram a concluir que as sub-bacias com maior risco de inundação são as dos córregos Tijuco Preto e Medeiros. Entretanto, o risco estimado a partir da análise de percepção evidenciou as sub-bacias Gregório e Santa Maria Madalena como as de maior risco de inundação. As duas ferramentas apresentaram-se valiosas e econômicas para estimativa de risco de inundação em ambiente urbano, podendo constituir ótimos sistemas de apoio à decisão. O webGIS, em particular, é potencialmente útil para informar aos moradores sobre quais são as áreas de risco de inundação na cidade. / This dissertation presents the development and application of an interactive web-GIS in which internet users map flood risk collaboratively by filling up a geotagged form with questions on flood hazard, exposure and vulnerability. Flood risk was also assessed through the use of a set of environmental risk indicators proposed by Mendiondo (2008). The two methodologies were applied to six urban watersheds of the city of São Carlos (State of São Paulo, Brazil). Interviews including questions asked on the web-GIS were carried out in city streets while the portal was being developed. Thus perceived risk data gathered from the interviews was later transferred online onto the web-GIS. The web-GIS proved to be an easy to use and intuitive tool. According to the results of risk calculation obtained with the indicators expression the watersheds with higher flood risk were the Tijuco Preto and Medeiros, which were also the ones with smallest area and higher population density. The results of perceived risk, which was assessed through the analysis of the interviews data, gave evidence that Gregorio and Santa Maria Madalena where the watersheds at higher risk. These watersheds are the two which experience a higher rate of occurrence on a year basis. The two approaches for assessing risk proved to be consistent and relatively inexpensive for the estimate of flood risk in urban areas, with the potential of representing valid decision support systems. The webGIS is a particularly interesting solution as a medium of information to inhabitants on the level of risk to which they are exposed.

One of the most important issues in the study of Urban-Service Distribution is the choice of the unit of analysis. Because of the ready availability of various data at the level of residence units, census tracts have been the spatial units most commonly selected. In some cases, municipally defined service districts have also been selected, and they are, in fact, only the aggregates of several neighboring census tracts. The problem encountered in the current study is the fact that Census-based Neighborhoods such as census tracts and the aggregations of census tracts frequently do not correspond with commonly recognized neighborhoods experienced informally in daily life, and they do not match local residents' perceptions of their neighborhoods as social areas. The primary purpose of this study was to investigate the effects of Resident-perceived Neighborhood Boundaries (as the alternative unit of analysis to conventionally-used Census-based Neighborhood Units) on the accessibility to public parks based on equity consideration and its relationship to park utilization. The study also addressed whether the neighborhood boundaries perceived by the actual residents may exhibit more actual neighborhood construct than Census-based Neighborhood Units when the relationship between park accessibility and utilization is considered. First, the results indicate that when Resident-perceived Neighborhood Boundaries are adopted, there is no significant change, either in accessibility measures or in the equity of public park distribution among neighborhoods of different social strata. Second, there was no significant relationship between parks accessibility and utilization, which means that even though a park may be closest to a household, it is not always true that the household will choose to use that park. Third, it was confirmed that the relationship between park accessibility and utilization was significantly affected by some utilization factors. That is, travel distances to the parks were significantly affected by different types of utilization factors and, according to the classification of park type, the affecting utilization factors were different. Lastly, as the spatial unit of analysis, Resident-perceived Neighborhood Boundaries do not significantly enhance the strength of the relationship between public services accessibility and utilization compared to using Census-based Neighborhood Units.