O risco à erosão em cabeceira de drenagem no bairro Nova Santa Marta em Santa Maria – RS: diagnóstico, mitigação e urbanização

Abstract

In order to reduce the impacts generated by climate change and the way we live, consume and occupy the planet, organizations such as the United Nations (UN) created the Sustainable Development Goals (SDG), which in Brazil are stipulated in the 2030 Agenda. At the municipal level, Santa Maria is one of three cities in Rio Grande do Sul to participate in the Sustainable Cities Program (PCS), which is an urban sustainability agenda structured in 12 of the 17 SDGs. However, the municipality is insufficient to fulfill these objectives, mainly in guaranteeing the population's quality of life and the right to the city, especially in the poorest communities. In this context, the Nova Santa Marta neighborhood is known as the largest urban occupation in Latin America, and started with a lot of organization, where its achievements were through a lot of struggle of the population and the National Movement for the Fight for Housing. The neighborhood is located in a drainage headwater area (springs) with open water courses and therefore, there are conflicts between the fluvial and pluvial dynamics and the urbanization process that continues to expand, and due to lack of space, it is advancing in Permanent Preservation Areas, which are susceptible to erosion. Thus, the general objective of this research is to diagnose the erosion risk in a drainage headwater of the Arroio Cadena Basin located in the Nova Santa Marta neighborhood, in Santa Maria - RS, and to suggest interventions that aim to mitigate the risk and guarantee the quality of life for the residents. For this, a bibliographic study is carried out to familiarize with the theme and area. The Analytic Hierarchy Process (AHP) method is used to define areas susceptible to erosion, thus, buildings are at risk according to their location in the susceptibility zoning. Vulnerability is characterized through the situation of the building and its surroundings. And erosion risk is determined by crossing the degrees of danger and vulnerability in a matrix. Afterwards, interventions that mitigate the risk and improve the space and life of the residents are suggested. The results show that the buildings at risk are the closest to water courses and springs, which confirms the need for action by the Government to control new homes at risk and to prevent the occurrence of events in already occupied areas, building a more sustainable and resilient city.