Avaliação do potencial de produção de sedimentos na bacia hidrográfica do Lajeado São José

Abstract

One of the most recurrent and harmful phenomena to the soils is erosion, which can cause serious environmental, agricultural and economic problems by means of severe alterations of the water systems . One of the empirical methods of investigation as well as analysis of erosion is the USLE (Universal Soil Loss Equation). By applying this method, the erosion can be estimated under different rainfall, soil types, topography and land use conditions. The objective of this study was to evaluate the current sediment yield potential of the Lajeado São José basin, the main source of water supply for Chapecó- SC, and the influence of 30-year changes in basin soil use that are allowed by the guidelines of the Master Plan of the Municipality of Chapecó in the production of sediment through the application of USLE. The potential production of sediments for the present conditions of soil use varied in the area of the basin between 0 and 30.2 t.ha-1 .month-1 , presenting an erosive rate of 3.88 t.ha-1 .year-1 using the method of obtaining C from the NDVI, while by the method of C from literature, the production of sediments varied between 0 and 26.6 t.ha-1 .month-1 presenting a mean of 2, 41 t.ha-1 .year-1 . Considering the trend of urbanization of the basin, the forecast is that in 30 years the rate will reach 2.26 t.ha-1 .year-1 . This is due to the fact that currently the main land use of the basin is agricultural, and in the process of urbanization would be replaced by urban area.