Analysis of soil loss by erosion in Coreaú river basin (Ceará-Brazil)

Abstract

The science of soil erosion intensity contributes to the environmental river basin planning, especially those inserted in the semiarid context of the Brazilian Northeast. This is the case of the Coreaú river basin, located in the Northwest portion of Ceará state. This study aims to analyze the soil erosion potential in the Coreaú river basin through the calibration and use of the Universal Soil Loss Equation (USLE). The rainfall erosivity factor was calibrated from the statistical analysis of historical rainfall series of the meteorological posts inserted inside the basin. The other variables of the USLE Equation were acquired through of a Geographic Information System (GIS), used for geospatial analysis of the drainage basin. In summary, the results of the analyzes obtained by the USLE, an average of 15,80 t.ha-1.year-1 of soils is lost, with 993,709 Km2 of the Coreaú river basin showing an annual soil loss of over 50 t.ha-1.an-1, which is equivalent to 9.4% of the research area. In these areas, erosion processes are much more intense and often occur directly on the exposed rock, because the soil has already been fully loaded.