Urban scenarios can be used by decision makers on matters related to urban expansion, especially when urban areas have socio-environmental problems, such as those resulting from erosion processes. The aim is the analysis of erosion susceptibility with the construction of urban scenarios using the AHP method to assist decision making on urban expansion. Thus, the AHP (Analytical Hierarchical Process) technique was employed to analyze the data collected and a GIS for the spatialization and building of these scenarios. The methodology was developed based on a real case of a Brazilian city located in the state of São Paulo. To validate the methodology, the current scenario of the studied area was constructed and compared with the actual situation of the place. As a conclusion, the study was validated for the applied area and proved to be a tool capable of assisting local governments regarding decision-making processes for urban expansion.   Keywords: Urban Scenarios, AHP, Erosive Processes, Urban expansion, Erosion susceptibility

As consequências dos processos erosivos abrangem desde a esfera ambiental, social até a esfera econômica, trazendo prejuízos na ordem de bilhões de dólares ao ano para os países atingidos pela erosão acelerada. São Manuel, no interior do estado São Paulo, apresenta inúmeros problemas relacionados aos processos erosivos. Na área urbana, as nove feições erosivas existentes assorearam rios, destruíram infraestruturas e algumas dessas feições estão ameaçando edificações na área urbana. Para minimizar esses problemas é necessário estudar os fatores que influenciam nos processos erosivos. Alguns desses fatores estão relacionados as características geotécnicas do solo outros a parâmetros de uso e ocupação do solo e outros relacionados as condições climáticas, como a chuva. Com isso, o objetivo desse trabalho foi avaliar a interferência do fator erodibilidade, determinado a partir de ensaios propostos por Nogami e Villibor (1979), nos processos erosivos, em relação a outros fatores de influência, como a textura do solo, a permeabilidade, a erodibilidade, declividade do terreno e uso e ocupação do solo da área urbana de São Manuel. Para isso, foram coletadas amostras deformadas e indeformadas nas feições pluviais lineares da cidade e realizado ensaios de laboratório de granulometria, permeabilidade, erodibilidade. Com o auxílio de SIG, foi determinada a declividade média da área de contribuição de cada feição e o uso e ocupação do entorno das feições. As conclusões mostraram que as características geotécnicas não devem ser avaliadas isoladamente para a determinação da suscetibilidade à erosão, uma vez que todos os parâmetros influenciam concomitantemente na suscetibilidade.

There are several factors that directly or indirectly influence erosion processes. In order to properly understand the behavior of these processes, some factors need to be analyzed together. Determining them wrongly can compromise the study resulting in wrong actions. For this reason, methodologies are always sought to measure them quantitatively and qualitatively in the most accurate possible way. Land use is one of the main factors liable to inaccuracies in its determination. To use this parameter in mapping erosive processes, researchers need to delimit it, classify it, and measure it. In order to better understand the complexity of considering this parameter, the present study analyzed an erosive feature that, although stabilized, has a component in constant development. Initially, a visual analysis indicated the same classification of land use for both conditions, despite having different behaviors, leading to the need for a detailed analysis. Such analysis comprised a historical survey through aerial photos and interviews with residents and employees of the city hall about the evolution of the feature from 2008 to 2019. It also included the analysis of other influencing factors that could be responsible for this difference in behavior in the area. Two different traces of the contribution areas of the gully and branch were also considered. One considering only aerial images, and the other considering the knowledge acquired during the research about the evolution of the feature. It was concluded, then, that an analysis of the use-only occupation factor based on aerial images can accentuate the inaccuracy of the measurement of this factor.