Hierarchization of the dwellings with geomorfological risks associated to the Arroio Cadena – Santa Maria, RS: Oliveira, Lídia and Urlândia villages

Abstract

In the city of Santa Maria, the growth of the urban area occurred with the occupation of the margins of Arroio Cadena, which was responsible for the emergence of many risky areas. Oliveira, Lídia and Urlândia villages are in the most problematic areas of the city. In this context, the main objective of this paper is to determine the surface dynamics processes that trigger the risk and to identify and hierarchize the risky dwellings of these villages. To identify the dwellings at margin erosion risk, it was considered the distance between the dwellings and the margins of the Arroio; for the dwellings at overflow risk there was considered the quota of the land where the dwellings are constructed; The dwellings that are both at margin erosion and at flood risk were hierarchized based on the frequency of accidents and on the dwellings’ constructive and structural features; the hierarchization of the dwellings at flood risk was realized based on the frequency of the accidents that occurred. In these villages there are 567 dwellings at risk, from which 107 present margin erosion risk, 260 present flood risk, 64 present both margin erosion risk and flood risk, and 136 present overflow risk. Key words: Geomorphologic risk. Margin erosion. Overflow/flood.