Fragilidade ambiental à erosão laminar na bacia hidrográfica do córrego São Domingos, em Ubá/MG

Abstract

Ubá is located in the southeastern portion of the State of Minas Gerais, in the middle region of the Zona da Mata. It is polo of a micro-region of 17 municipalities. Ubá is the core area of the micro-region, having diversified range of products, goods and services, which generates a significant economic and demographic concentration, and differs considerably from most towns located around it. Demographically, this situation is evident from the population data provided by the Instituto Brasileiro de Geografia e Estatística (IBGE) and made available by the Instituto de Pesquisa Econômica Aplicada (IPEA), which show a disproportionate density of micro-regional population in the city of Ubá and has important consequences on the growth of the city. The sharp increase of the urban population has resulted in the expansion of occupation to areas of hillsides, many with high steepness. This probably intensified the action of erosion due to exposure of the soil in these areas. The Bacia Hidrográfica do Córrego São Domingos (BHCSD), study area of this research, is one of the urban growth area of the city of Ubá. With the opening of allotments, areas of exposed soils within the basin will increase considerably, which could increase the occurrence of erosive processes. The methodology proposed by Ross (1990, 1994) was chosen to assess and map the fragility of the studied area in relation to soil sheet erosion. So, the objective of this research is to identify the different fragilities to erosion in BHCSD, from the most fragile areas at less fragile, based on that author methodology. It was found that the areas of the slopes are the most fragile in relation to sheet erosion, as are those with the highest slopes of the basin and surfaces exposed soils, particularly by the opening of allotments and due to intense erosive processes underway. As for the less fragile areas are the flood plains, because have the smaller slope and their surfaces are highly impermeable due to the urbanization process. However, are the areas that receive the most amount of sediment, causing clogging of the drainage system, littering the streets, obstructing the water courses, among other consequences, which are responsible for intensifying problems such as flooding.