ESTUDO DAS INUNDAÇÕES NA CIDADE DE ALEGRETE, RIO GRANDE DO SUL: PROBABILIDADE E ESPACIALIZAÇÃO DO PERIGO

Abstract

Floods are the most common natural hazard, affecting more people and causing more damage than any other type of hazard. This work presents a methodology to determine the probability and spatialization of flooded areas in Alegrete city, which is one of the city in the state with the highest amount of flood records. The analysis of the spatial dynamics of the floods was based on the projection of water levels on the digital terrain model. A relation was established between quota recorded in the river and altimetric quota in the terrain modeled, being estimated the areas reached and established as susceptible to flood. In Alegrete, the areas subject to flooding processes represent the expressive portion of 30.8% of the urban area. Considering the effectively occupied areas, they represent a little more than 3%. This number is very important because the floods with a return time of 20 years, reach 52ha of the total built area. The high area that can be affected and the significant portion already affected results in a complex management and planning of the urban occupation.