Banca de QUALIFICAÇÃO: LUANA DE HOLANDA VIANA BARROS

ANALYSIS OF THE ENVIRONMENTAL IMPACTS OF URBAN EXPANSION AND SUGARCANE ACTIVITY ON SOIL LOSSES IN THE CATU-RN RIVER HYDROGRAPHIC BASIN

Environmental impacts, watershed, USLE.

Soil erosion caused by water action is one of the main environmental problems in Brazil, and factors such as urban expansion and agricultural activities intensify this process. In this context, the Catu river basin, located in the state of Rio Grande do Norte, faces several environmental challenges such as inappropriate land use practices, as well as the suppression of riparian forests, with the removal of natural vegetation to agricultural purposes and growing and disorderly urbanization. The general objective of the research is to analyze the environmental impacts resulting from urban expansion and sugarcane activity on the potential for soil loss in BHRC-RN, using the Universal Soil Loss Equation – USLE as an analysis tool, in order to provide subsidies for the planning and sustainable management of the basin’s natural resources. Thus, the characterization of the physical-environmental aspects and land use in the basin was carried out, analysis of the evolution of urban occupation and sugarcane cultivation, and, subsequently, the proposal of mitigation measures for the problems identified. The preliminary results of the research include environmental modeling of the basin, application of the USLE equation, in which the analyzed factors presented the following results: the values of the rain erosivity factor (R factor) varied from 4,758 to 9,256 MJ.mm/ha. h.year, indicating a precipitation intensity that ranges from moderate to heavy. Meanwhile, the K factor, which represents soil erosivity, presented values between 0.0277 and 0.0722 Mg.h/MJ.mm, indicating an interpretation that varies from moderate to very high erosion intensity. The variation of the LS factor, which considers the extent and inclination of the slope, was wide, with values between 1.788 and 113.993, classified from very low to very strong. The values of the factor related to soil use, management and conservation practices (CP) varied between 0.005 and 0.40, suggesting different levels of human impact on soil erosion in the region. And factor A, which represents the area of soil exposed to erosion, varied from 439,318.19 to 22,405,228 Mg/ha.year, indicating a significant range in soil losses, ranging from very low to very high levels throughout the year. time and area analyzed. The next stages of the research involve fieldwork and characterizing the impacts of these two variables, as well as proposing mitigation measures.