Cadastral analysis of natural hazard in the community of Rio Cachoeira –Saco dos Limões neighborhood, Florianópolis/SC

Abstract

Relief forms are natural elements that serve as a substrate for the settlement of human structures, such as buildings, streets, bridges and others. However, the occupation of certain landforms can create areas of risk due to the local geomorphological dynamics. This is the case of the community Cachoeira River Basin, in Saco dos Limões neighborhood, Florianópolis/ SC, installed in a dissected portion of the crystalline slope of the Morro da Cruz Massif. The aim of this paper is to make an analysis of the hazards resulting from the geomorphological dynamics in study area because of episodes of rain and the anthropic changes of the relief. The study included field surveys, a cadastral map of human occupation and the elaboration of a detailed geomorphological map and a hazard map, which contains the relief features, evidence of the occurrence of morphogenetic processes and anthropic changes in landforms. Elements vulnerable to hazards found in the study area were also identified. Hazards represented by runoff, torrential flows, flooding, riverbank erosion, falls of rock blocks, rupture of retaining walls have been found in the area and affect many buildings. The scale of detail of this work shows that, despite the small spatial extent, the area presents many hazards and, even a single residence, can be subject to a series of hazards.