Vulnerabilidade à erosão hídrica na área de drenagem da barragem do Rio Juramento, MG

Abstract

The water erosion is one of the most important problems of soil degradation in the world today, considered a phenomenon of great concern. The assessment of areas with problems of water erosion it necessary to propose conservation techniques that mitigate this phenomenon.The Geotechnology, through the several techniques of remote sensing, may help in the collection of information inherent to the erosive process. The Juramento River Dam Reservoir (ADBRJ), responsible for 67% of the water supply in the city of Montes Claros, has been subject to water restrictions in the last five years. Some technical notes emphasize the importance of an environmental diagnosis, in current time, is still non-existent. In this context, this study has as main goal, identify areas of Laminar Erosion Risk in the ADBRJ through free geotechnology tools. In a specific way, also was studied: Characterization of the Physical Environment (Morphometry, Geology and Pedology) and Climatic of the study area; analyze of the Dynamics of Land Use in the years of 1985, 1995, 2005 and 2015, as well as estimating soil loss through the Universal Soil Loss Equation (USLE) in 2015.The results showed that Pastureland, Silviculture and Bare Soil were the main classes responsible for the changes in the land use in the ADBRJ. The increase in Pastureland and Silviculture areas, in general, led to the reduction of natural areas, mainly in the Forest Formations, especially the fitofisionomy Deciduous Forests (i.e. tropical dry forests) and ‘Cerradão’, respectively.There is a tendency of growth, based on the years 2005 and 2015, of the Anthropized Areas to the detriment of the Natural Areas, being the Pastureland, the class responsible for this increase (24.10%). On the other hand, the Silviculture areas has remained unchanged in the last evaluated years. Already areas with Bare Soil decreased 35.18%. It is evident that topography is a determining factor in the erosion process of ADBRJ. Thus, the same influences the process of infiltration of water into the soil, velocity and volume of runoff. In areas of rugged topography and high erodibility, the erosion potential naturally increase. The laminar erosion risk increases significantly when conservation practices are disregarded .Almost 52% of the total area of the watershed is found with Very Low and Low Laminar Erosion Risk. However, 32.91% are with High and Very High Laminar Erosion Risk. Regarding the geotechnology tools used, it was possible to elaborate the present study, merely with tools (software, applications and images from satellites sensors) 100% free, corroborating the importance of such technologies in the geographic spatial analysis.