Análise temporal do uso e ocupação do solo e o efeito no deflúvio nas microbacias dos córregos São Pedro, Humaitá e Carlos Chagas

Abstract

Historically, cities have been established near water bodies to facilitate water supply and transportation. However, this relationship has become problematic due to disorderly urban expansion, especially in Brazil, where urban control and monitoring of watersheds are insufficient to mitigate the impacts of extreme events. Urbanization reduces the time of concentration and increases peak flows, reducing soil infiltration and promoting silting of watercourses, increasing susceptibility to hydrological risks. Water resource management contributes to reducing these risks in urban areas. In this context, aiming to contribute to the management of the municipality of Juiz de Fora, this study aimed to analyze the contribution of urbanization to the increase in runoff from the Humaitá, Carlos Chagas and São Pedro streams. To this end, an analysis of Land Use and Occupation was carried out between 1985 and 2023 using the Qgis software, which allowed us to obtain changes in urban areas, dense vegetation, pasture and exposed soil. In addition, unit hydrographs were developed for each microbasin through hydrological modeling, with the ABC6 software, allowing us to compare the runoff before and after the urbanization process. The results of this analysis showed that the microbasins underwent significant changes in their use and occupation classes, increasing the urban area and recovering part of the vegetation cover in places that were previously pasture. Finally, from the unit hydrographs, it was found that there was a reduction in the volume infiltrated into the soil, an increase in surface runoff, an increase in peak flows, and a reduction in the concentration time of all the microbasins studied. Among them, the São Pedro stream microbasin stands out, with the highest urbanization rate (an increase of 177.66% in 38 years) and the Carlos Chagas stream microbasin with the highest percentage of impermeable area (72.1% of the total area of the microbasin). All the factors observed contribute to the increased susceptibility to hydrological events, reaffirming the need for water control and management.